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Biomedical subjects

C Liu

Publications and source records attributed to C Liu.

At least 415 records · Page 23Linked to original sources
PubMed1999

[The reactions in ginseng cells induced by elicitor derived from digesting ginseng cell walls by cellulase].

After treatment of the elicitor derived from digesting ginseng cell walls by cellulase, the starch grains were degraded, and a large number of spherosomes were produced in Ginseng cells. In the mean time, the activity of amylase in the cells was increased and the activities of esterases in the cells were reduced; in addition, the content of soluble sugar and the content of lipoid were increased. These indicate that the emergency reactions and the adjustment of metabolism of lipoid were taken placed in the cells elicited. Besides, after the treatment with certain concentrations of elicitor, the content of ginseng saponin and the activity of phenylalanine ammonia lyase (PAL) were increased in ginseng cells. On the contrary, the activities of peroxidase (POD) and polyphenoloxidase (PPO) were reduced.

Amylases↗
PubMed1999

[Separation of alkylphenols in oil field water by micellar electrokinetic chromatography].

The abundance of alkylphenols in the system of water, oil and rock is of great geochemistry significance. The analysis of alkylphenols in oil field water using micellar electrokinetic chromatography with UV detection is described. The different variables that affect separation were studied and optimized. The results show that better separation was obtained with the borate concentration of 47.5 mmol/L, the SDS concentration of 70.0 mmol/L, pH 9.15, separation current of 100 microA, capillary temperature 20 degrees C. The organic additive(beta-CD) could partly improve separation. Water sample was introduced into the capillary by pressure of 5 kPa for several seconds. Detection wavelength was 200 nm and reference wavelength at 350 nm for all experiments. For the oil field water sample, the reproducibility of directly injected oil field water after filtration through a membrane filter of 0.45 micron pore size was far from good and it's concentrations of alkylphenols were too low to be detected. Therefore, a method of separation and enrichment by a column packed with tributyl phosphate(TBP) extraction resin was applied for analysis of TZ4 oil field water. Qualitative analysis show that there are phenol, o-cresol, m-cresol and p-cresol in this water sample and phenol is the main component and it's quantity is more than other alkylphenols. It's recoveries from the oil field water were 91.5%-95.3%. The results were satisfactory.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed1999

[Experimental therapy of Pagumogonimus skrjabini infection in rats with triclabendazole].

AIM: To observe the therapeutic effect of triclabendazole in rats infected with Pagumogonimus skrjabini. METHODS: Metacercariae of P. skrjabini were isolated from crabs (Sinopotamon) collected from two endemic areas (Weiyuan County of Sichuan Province and Wansheng District of Chongqing Municipality). Wistar rats were each infected intraperitoneally with metacercariae. One month and two months after infection, the infected rats were treated with triclabendazole at the total dosage of 300 mg/kg over 2 days, 450 mg/kg over 3 days and 600 mg/kg over 3 days, respectively. RESULTS: The worm reduction rates were 50%, 80% and 87% respectively one month after completion of tretment. Dead worms (about 1 mm size) recovered from the muscles, liver, abdominal cavity, chest cavity and lungs were signicantly diminished in size and weight in comparison with those of the control group. Many large (about 1 cm) black-colored distended worm cysts usually with two adult worms and many eggs were found in the lungs of the control rats. Most worm cysts in the treated groups of rats were found to be atrophied, changing into hemorrhagic-necrotic patches. CONCLUSION: Triclabendazole is highly active against P. skrjabini in rats.

Animals↗
PubMed1999

[Auditory neuropathy].

OBJECTIVE: To study the clinical feature and audiological and electrophysiological characteristics of auditory neuropathy. METHODS: The history, audiometry, stapedial reflex, electrocochleogram, auditory brainstem response, promontory stimulation tests, otoacoustic emissions (OAE) and its contralateral supression tests were studied in 17 cases of auditory neuropathy. RESULTS: The patients were predominently female teenagers with a history of gradual onset of bilateral hearing loss, pure tone auditometry revealed symmetric ascending audiograms with moderate hearing loss at frequencies below 1 kHz, but relatively normal hearing at 2 kHz and above. Speech reception thresholds were between 40 to 85 dB HL, discrimination score was from 29% to 68%. Stapedial reflex, auditory brainstem response and compound action potentials were absent or threshold elevated disproportionately to the pure tone threshold. All of the patients had normal cochlear microphonics and robust spontaneously and transiently evoked otoacoustic emissions (SOAE and TEOAE), the TEOAE showed no contralateral suppression effects as seen in normal subjects. CONCLUSION: The diagnosis of the disease depends on the discrepancies between subjective and objective hearing and pre-neural and neural responses. The crossed olivocochlear bundle function testing in terms of contralateral acoustic stimulation induced otoacoustic emission reduction is specific for differential diagnosis. There is a need for more awareness of the disease among otolaryngologists and neurologists.

Acoustic Impedance Tests↗
PubMed1999

Over-expression of the RAB5 gene in human lung adenocarcinoma cells with high metastatic potential.

The objective of this study is to better understand the molecular mechanism of tumor invasion and metastasis, and isolating tumor metastasis-related genes. Two human lung adenocarcinoma cell lines AGZY-83a and Anip973 were studied. Anip973 was derived from AGZY-83a, but it manifested a very much higher metastatic potential than the parent line. Differential cDNA fragments were isolated by using the techniques of mRNA differential display, and analyzed by means of molecular cloning and sequencing. The expression of RAB5A gene in clinical samples of non-small cell lung cancer was determined by RT-PCR. There were significant differences between AGZY-83a and Anip973 in gene expression. Part of the differential cDNA fragments were cloned and sequenced. We found that there was over-expression of RAB5A gene in the Anip973 cell line. And there was over-expression of RAB5A gene in those samples of clinical lung cancer showing metastasis. In conclusion, the expression or over-expression of RAB5A gene was associated with the metastatic phenotype of Anip973. Probably, over-expression of RAB5A gene in non-small lung cancer may serve as a diagnostic marker for metastasis.

Adenocarcinoma↗
PubMed1999

[The substituent structures and characteristic infrared spectra of alpha-furan esters].

The characteristic infrared bands of the alpha-furoic esters, alpha-furancarbinol esters and alpha-furanacrylic esters were assigned, and the changing rules of the IR absorption frequency of the alpha-furan esters with alpha-substituent structure were discussed. The results indicated there are three characteristic bands in alpha-furan ring. The strong absorption at 1641 cm(-1) is assigned to the C=C double bond stretching mode in the alpha-furanacrylic esters, while the absorption at 973 cm(-1) is the out-of-plane =C-H bending mode for a trans di-substituted alkene, the strong absorption at about 1713 cm(-1) is assigned to a C=O stretch, and the three strong absorptions near 1305, 1260 and 1165 cm(-1) are due to the symmetric and assymmetric stretching vibrations of C-O-C bond in the ester groups.

Esters↗
PubMed1999

[Fluorimetric study of Tb-EDTA-quercetin and determination of quercetin].

Tb-EDTA-Quercetin complexes were formed under basic conditions. Intramolecular energy transfer occurs in the Tb-EDTA complex with quercetin (QCT) and the terbium (III) ion fluorescence can be sensitized by QCT. Accordingly a fluorimetric method was used for the determination of QCT in urine, serum and mixed substance of rutin-quercetin. The method is simple, sensitive and fast. The linear range is 5.0 x (-7)-1.0 x10(-5) mol x L(-1) and the detection limit is 5.0 x 10(-8) mol x L(-1). This method can be applied to the determination of QCT in non-pretreated urine and serum successfully. The recoveries are in the range of 103%-96%.

Edetic Acid↗
PubMed1999

[Research into simultaneous determination of five components by ridge regression spectrophotometry].

Ridge regression spectrophotometry (LHG) is one of the computational spectrophotometry developed recently. It is used in this paper to the analysis of five component s--acetaminophen, p -aminophenol. p -nitrophenol. p -acetaminophenol acetic acid ester and p -nitrophenol acetic acid ester. The choose of medium and the determination of the amount of mixed standard solution were described in detail. The experimental results show that in the medium of 0.1 mol x L(-1) HCI, the recovery ratio of each component ranges from 95.5% to 106.1% and the RSD ranges from 0.8% to 9.8%. This approach is simple and suitable for the computer-aid analysis. The approach has been used to the analysis of the sample in the course of synthetic acetaminophen.

English Abstract↗
PubMed1999

[Research into determination of tricomponent sample by ridge regression spectrophotometry].

In this paper ridge regression spectrophotometry was used to analyze three components--Acetaminophen, P-Ni-trophenol and P-Aminophenol with absolute ethanol as the solvent. The basic principle and analytical steps of the method were described in detail. The experimental results show that the recovery of each component ranges from 99.24% to 101.31% with the medium of absolute ethanol. As compared with conventional methods, this method is simple, rapid and suitable for computer-aid analysis.

Acetaminophen↗
PubMed1999

[Study of the fluorescence of terbium-pipemidic acid system and the determination of pipemidic acid in urine and serum].

Intramolecular energy transfer occurs in the terbium complex with pipemidic acid (PPA) and the terbium(III) ion fluorescence can be sensitized by PPA. The fluorescence intensity of the Tb3+-PPA system is proportional to the amount of PPA. Accordingly, a fluorimetric method for the determination of PPA is proposed. The characteristics of the method include low background noise, high selectivity and long fluorescence lifetime. The method can be applied to the determination of PPA in urine and serum. The recovery is in the range of 94.6%-102%. Its detection limit and linear range for PPA are 3.6 ng/mL and 5.0 x 10(-8)-4.0 x 10(-6) mol/L, respectively.

Fluorescence↗
PubMed1998

[Molecular cloning and characterization of novel protein kinase gene DYRK3].

OBJECTIVE: To isolate full length cDNA of a novel protein kinase and to deduce the protein kinase's classification position and functions. METHODS: cDNA libraries gDNA library was screened with a partial cDNA clone which is homologous to human protein kinase DYRK2 as probe. FISH mapping was performed. RESULTS: Two full length cDNAs of a novel protein kinase from human muscle cDNA library and human testis cDNA library were isolated. The full length cDNA from muscle has an open reading frame which is predicted to encode a protein of 588 amino acid residues and the cDNA from testis to encode a protein of 568 amino acid residues. CONCLUSION: Because the sequence from the 27th codon to the 3' end of the cDNA from muscle is identical to that from the 7th codon to the 3' end of the cDNA from testis, they should be different transcripts of the same gene. As the gene is highly homologous to human protein kinase DYRK2, the present authors termed the gene DYRK3. DYRK3 is homologous to many serine/threonine protein kinases such as yeast Yak1, human Clk1, human Mnb, drosophila melanogaster Mnb and Cdk2. DYRK3 should belong to the Clk family in CMGC group of serine/threonine protein kinase. DYRK3 has been mapped to chromosome 1q32 by FISH.

Amino Acid Sequence↗
PubMed1998

Periplasmic chaperone recognition motif of subunits mediates quaternary interactions in the pilus.

The class of proteins collectively known as periplasmic immunoglobulin-like chaperones play an essential role in the assembly of a diverse set of adhesive organelles used by pathogenic strains of Gram-negative bacteria. Herein, we present a combination of genetic and structural data that sheds new light on chaperone-subunit and subunit-subunit interactions in the prototypical P pilus system, and provides new insights into how PapD controls pilus biogenesis. New crystallographic data of PapD with the C-terminal fragment of a subunit suggest a mechanism for how periplasmic chaperones mediate the extraction of pilus subunits from the inner membrane, a prerequisite step for subunit folding. In addition, the conserved N- and C-terminal regions of pilus subunits are shown to participate in the quaternary interactions of the mature pilus following their uncapping by the chaperone. By coupling the folding of subunit proteins to the capping of their nascent assembly surfaces, periplasmic chaperones are thereby able to protect pilus subunits from premature oligomerization until their delivery to the outer membrane assembly site.

Adhesins, Bacterial↗
PubMed1998

Long-term expression, systemic delivery, and macrophage uptake of recombinant human glucocerebrosidase in mice transplanted with genetically modified primary myoblasts.

A critical requirement for treatment of Gaucher disease via systemic delivery of recombinant GC is that secreted enzyme be in a form available for specific takeup by macrophages in vivo. In this article we investigated if transplanted primary myoblasts can sustain expression of human GC in vivo and if the secreted transgene product is taken up by macrophages. Transduced primary murine myoblasts were implanted into syngeneic C3H/HeJ mice. The results demonstrated that transplanted mice sustained long-term expression of transferred human GC gene in vivo. Furthermore, human GC is secreted into the circulation of mice transplanted with syngeneic primary myoblasts retrovirally transduced with human GC cDNA. The transplanted primary myoblasts differentiate and fuse with adjacent mature myofibers, and express the transgene product for up to 300 days. Human GC in the circulation reaches levels of 20-280 units/ml of plasma. Immunohistochemical studies of the target organs revealed that the secreted human GC is taken up by macrophages in liver and bone marrow. Immunochemical identification of reisolated myoblasts from transplanted mice showed that MFG-GC-transduced cells also survived as muscle stem cells in the implanted muscle. These results present in encouraging prospect for the treatment of Gaucher disease.

Animals↗
PubMed1998

Probing RegA/RNA interactions using electrospray ionization-fourier transform ion cyclotron resonance-mass spectrometry.

The interactions of bacteriophage T4 regA protein, a unique translational regulator, with RNAs of various size and sequence were studied using electrospray ionization-Fourier transform ion cyclotron resonance-mass spectrometry. Using very gentle interface conditions, regA/RNA complexes with a 1:1 binding stoichiometry were observed for all four target RNAs studied, consistent with solution binding studies. Competitive binding of target RNAs and their degradation products with regA demonstrated that the loss of a single nucleotide resulted in a dramatic change in binding affinity in some cases. Competitive binding of regA with four target RNAs revealed similar relative binding affinity order to that suggested by previous in vitro repression experiments. The use of sustained off-resonance irradiation for collisionally induced dissociation of a regA/RNA complex suggested the potential for directly obtaining information regarding the regA binding domain.

Bacterial Proteins↗