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Biomedical subjects

K Sun

Publications and source records attributed to K Sun.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Non-invasive prenatal diagnosis of Duchenne muscular dystrophy].

OBJECTIVE: This paper was designed to investigate the feasibility of non-invasive prenatal diagnosis of Duchenne muscular dystrophy(DMD). METHODS: The nucleated red blood cells(NRBC) were separated with percoll using a discontinuous density gradient method. The cells were smeared on microscope slides using a cyto-centrifuge and then stained by Wright- Giemsa. NRBCs were detected and individually retrieved into glass capillary pipettes using a micromanipulator under microscopic observation. The whole genome of a single cell was amplified by improved primer extension preamplification(PEP). The procedures for making prenatal diagnosis of DMD and determining the origin of NRBCs proceeded at the same time using sex determination and linkage analysis of several STR loci of dystrophin. Genotypes were analyzed by amplifying the 9 STR fragments using fluorescence-PCR technique and NRBCs origin was further determined. RESULTS: A case of DMD in male fetus was diagnosed. CONCLUSION: With the use of the method reported, the non-invasive prenatal diagnosis of DMD is possible.

Female↗
PubMed2001

[An experimental study of matrix metalloproteinase inhibitor BB-94 inhibits the invasion and metastasis of the human salivary adenoid cystic carcinoma in vitro and in vivo].

OBJECTIVE: To study the inhibitory effect of matrix metalloproteinase inhibitor BB-94 on the invasion and metastasis of salivary adenoid cystic carcinoma in vitro and in vivo. METHODS: Reconstituted basement membrane invasion assay was used to evaluate invasive ability of cancer cells. Type IV collagenase was assessed by PAGE substrate zymography. In addition, the antimetastasis effect of the compound was studied in in vivo experiments using nude mice model of pulmonary metastasis with ACC-M line of human salivary adenoid cystic carcinoma. RESULTS: BB-94, at the concentrations of 10 mumol/L and 100 mumol/L, suppressed the reconstituted basement invasion of ACC-M human salivary adenoid cystic carcinoma by 32.9%, 53.2% and reduced Type IV collagenase activities in the serum-free supernatant of the same cells. The pulmonary metastasis rate of the control and treated groups was 90.0% and 20.0%, respectively (P < 0.01). The lung weight of the control and treated groups was (0.2090 +/- 0.0667) g and (0.1532 +/- 0.0378) g, respectively (P < 0.05). CONCLUSIONS: These results suggest that the matrix metalloproteinase inhibitor BB-94 has a strong inhibitory effect on invasion and metastasis of salivary adenoid cystic carcinoma.

Animals↗
PubMed2001

[Cloning and analyzing of the conserved protein gene in Streptococcus sanguinis ATCC10556].

OBJECTIVE: To clone and analyze the conserved protein gene in Streptococcus sanguinis(S.s) ATCC10556. METHODS: Southern blotting hybridization, molecular cloning techniques and dot blotting hybridization were employed to obtain the target clone which harbored the specific DNA fragment. The nucleotide sequence of the target clone was determined. The gene and its product were analyzed by Genework software and bioinformatics techniques. RESULTS: The conserved protein gene in Streptococcus sanguinis ATCC10556 was cloned for the first time and named as Streptococcus sanguinis conserved protein gene (Sscp gene). The Genbank accession number for Sscp gene is AY032739. The conserved protein gene in S.s ATCC10556 (named sscp163) was a transmembrane protein and contained two AAA domains. CONCLUSION: sscp163 protein might take part in the cell division in Streptococcus sanguinis; its function is similar to that of FtsK in E.coli.

Amino Acid Sequence↗
PubMed2001

An experimental study on drugs for improving blood circulation and removing blood stasis in treating mild chronic hepatic damage.

Large and small doses of drugs for improving blood circulation and removing blood stasis were used in model rats to treat mild chronic hepatic damage induced by carbon tetrachloride (CCl4). The results show that large dose of Dang Gui ([symbol: see text] Radix Angelicae Sinensis) and Dan Shen ([symbol: see text] Radix Salviae Miltiorrhizae) (drugs for regulating blood flow) and small dose of Yu Jin ([symbol: see text] Radix Curcumae) and Niu Xi ([symbol: see text] Radix Achyranthis Bidentatae) (drugs for activating blood flow) can significantly elevate the activity of SOD (P < 0.05) and/or lower the T/K ratio, markedly reduce the MDA content (P < 0.05 or P < 0.01) and significantly decrease the activities of ALT and AST (P < 0.05 or P < 0.01), demonstrating that these drugs are effective in combating oxygen free radicals (OFR) in chronic liver damage. On the contrary, large dose of Tu Bie Chong ([symbol: see text] Eupolyphaga seu Steleophaga) and E Zhu ([symbol: see text] Rhizoma Curcumae) (drugs for removing blood stasis) tend to increase the ALT and AST (P < 0.05) activities. The results suggest that the synergism of elevation of the SOD activity and reduction of T/K ratio contributes to the action of drugs for improving blood circulation and removing blood stasis in combating the liver damage induced by CCl4.

Alanine Transaminase↗
PubMed2000

Intermediates Produced in the Electron-Transfer Processes of Phenothiazine/Semiconductor Systems.

Phenothiazine radical cation PTH(+*) and phenothiazine dication PTH(2+) produced by photoinduced electron transfer in phenothiazine/semiconductor systems have been studied by using ESR, UV-visible absorption, and fluorescence spectroscopic methods. It is found that the PTH(+*) was generated by electron transfer from (1)PTH* and (3)PTH* to the conduction band of the semiconductors besides PTH(+*) resulted in the photoionization of PTH as well as PTH(2+) produced by electron transfer from PTH(+*) to the conduction band of the semiconductors successively. Very significant supplementary information provided by UV-visible absorption, ESR, and resonance Raman spectra of PTH(+*) and PTH(2+), which were obtained by oxidation of PTH with lead tetraacetate, not only confirmed the two-step mono-electron-transfer mechanism proposed for interpretation of electron-transfer processes in PTH/semiconductor systems but also demonstrated that the two successive electron-transfer steps were corresponding to the removal of a p-electron at the nitrogen atom and a p-electron at the sulfur atom in the PTH molecule, respectively. Consequently, the nonplanar configuration of the PTH molecule changed into a planar configuration of the PTH(2+). Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Genetic variation and relationships at five STR loci in five distinct ethnic groups in China.

Five short tandem repeat (STR) systems of TH01, vWA, LPL, F13B and FES/FPS were investigated in five ethnic groups living in China (Tujia, Miao, Bai, Chaoxian and Han). All five loci did not deviate from the Hardy-Weinberg equilibrium (P>0.05). At the five loci of each ethnic group, the observed heterozygosity, the mean exclusion chance (MEC), and the power of discrimination (PD) ranged from 0.42 to 0.86, from 0.20 to 0.66 and from 0.61 to 0.95, respectively. For the five ethnic groups, the combined MEC and combined PD were >0. 9360 and >0.9998, respectively, suggesting that combinations of these five systems are feasible for DNA typing in forensic investigations such as personal identification or paternity testing. Furthermore, the allelic frequencies at the five loci suggested that these five ethnic groups were distinctly different communities. Judging from the phylogenetic tree constructed based on the genetic distance among the five ethnic groups, Han, Chaoxian and Tujia were involved in an identical cluster, and Miao and Bai in another. These findings indicate that each of the five groups examined is not only a distinct community, but also has a relationship with each of the others.

Alleles↗
PubMed2000

[Effect of sepia on intracellular Ca2+ concentration, nuclear Ca2+/Mg(2+)-ATPase activities and c-jun expression in H22 cancer cells].

The effect of sepia on the intracellular Ca2+ concentration, nuclear Ca2+/Mg(2+)-ATPase activities and the expression of c-jun were studied in H22 cancer cells by using fluorescent probe and immunohistochemical method. The results showed that intracellular Ca2+ concentration decreased 69% and 79%, nuclear Ca2+/Mg(2+)-ATPase activities diminished 21% and 37%, c-jun expression decreased obviously. The results suggested that sepia probably diminished the intracellular Ca2+ concentration, affected Ca(2+)-dependent nuclear Ca2+/Mg(2+)-ATPase activities, thus reduced the amount of Ca2+ transporting into nuclei, so lessened the promoting effect of Ca2+ on c-jun expression, and therefore inhibited cellular differentiation and proliferation. This might be one of the possible anti-cancer mechanisms of sepia.

Animals↗
PubMed2000

Applications using the chlorine-selective pulsed discharge emission detector.

The use of the chlorine-selective pulsed discharge emission detector (Cl-PDED) for the GC analyses of EPA mixtures 502, 612, 624, organochlorine pesticides, and polychlorinated biphenyls has been demonstrated. The Cl-PDED is the most sensitive chlorine-selective detector with a minimum detectability of 50 fg Cl/s. A constant response/pg Cl was observed for these mixtures regardless of the number of Cl atoms/molecule and structure of the compound to which the Cl atoms are attached. The analysis of standard samples of polychlorinated biphenyls using the Cl-PDED have sensitivities comparable to those of the electron-capture detector; however, the predictable response/pg Cl from the Cl-PDED is preferred over the extremely variable response from the electron capture detector.

Chlorine↗
PubMed2000

Characterization of chlorinated compounds using a dual chlorine-selective pulsed discharge emission detector-helium-pulsed discharge photoionization detector system.

The Cl-selective pulsed discharge emission detector (Cl-PDED) response is dependent only upon the Cl content, irrespective of the molecular structures of the compounds. This provides a simple, fast quantitative method of analysis for chlorinated compounds. The response of the helium-pulsed discharge photoionization detector (He-PDPID) is a function of the molecular structure and the number of photoionizable electrons using the He2 band at 13.5-17.5 eV. The ratio of the responses of the two detectors is independent of concentration and can be used to characterize the Cl-containing compounds along with the retention time, or the ratio can be used as evidence for coelution. The dual Cl-PDED-He-PDPID detector system is a useful tool for peak identification. The effect of coeluting hydrocarbons on the Cl-PDED response was evaluated by spiking a gasoline sample with US Environmental Protection Agency mixture 502. All Cl-PDED responses were greater than 90% of the response in the absence of the hydrocarbons.

Chlorine↗
PubMed2000

Development and characterization of chlorine-selective pulsed discharge emission detector for gas chromatography.

A novel chlorine-selective pulsed discharge emission detector (Cl-PDED) for gas chromatography has been developed based on a reaction of krypton with chlorine and a unique design of the detector. A krypton ion produced in the krypton-doped helium pulsed discharge reacts with chlorinated compounds within the pulsed discharge to produce an excited species of KrCl* which emits at 221-222 nm. The reaction has the following advantages in respect to the detection of chlorinated compounds: (1) the reaction is an ion-molecule reaction that is 100-1000 times faster than a reaction of neutrals, which greatly enhances the sensitivity; (2) the KrCl* emission wavelength is far separated from interfering C emissions at 193. and 247.3 nm; (3) the KrCl* emission is transparent to air and can be recorded without a helium purge of the monochromator. The detector itself has been designed to have the following features: (1) the detector has a microvolume of the pulsed discharge region, ca. 0.35 microl, which increases the discharge power density to enhance the sensitivity; (2) this microvolume detector allows the use of a low flow-rate of approximately 5 ml/min, which enhances the sensitivity by the lower dilution of the column effluent; (3) the pulsed discharge is sufficiently narrow to replace the monochromator entrance slit, which gives much greater light gathering power; (4) the discharge electrodes are protected with a helium purge to prevent carbon deposition on the electrodes. This new Cl-PDED is the most sensitive chlorine-selective detector with a minimum detectability of approximately 50 fg Cl/s. The selectivity to carbon is 1000. There are no significant carbon emission lines in the KrCl* emission wavelength region, but the carbon continuum interference (stray light) limits the selectivity. The selectivity could be increased if a double monochromator were used to diminish the stray light. The detector linear range is over three orders of magnitude from 40 fg Cl to approximately 130 pg Cl, and the dynamic range is approximately 4 orders of magnitude. The relative standard deviation of the elemental response to chlorinated compounds is about 5%.

Chlorine↗
PubMed2000

Pulsed discharge emission detector: an element-selective detector for gas chromatography.

An element-specific pulsed discharge emission detector (PDED) has been coupled directly with a vacuum UV monochromator so that vacuum UV atomic emissions from Cl, Br, I and S can be observed. The observed sensitivities for the elements are in the range of mid to high pg/s, but can be lowered by direct absorption of the radiation using a vacuum UV radiation photomultiplier tube. A helium pulsed discharge photoionization detector (He-PDPID) was run simultaneously in parallel with the PDED. The chromatograms recorded with the two detectors had similar peak shapes, suggesting that there is no peak tailing in the PDED. The ratio of the detector responses PDED/He-PDPID can be used for qualitative identification of the Cl-, Br-, I- or S-containing compounds.

Chromatography, Gas↗
PubMed2000

A three-dimensional open-framework germanate containing four-, five- and six-coordinated germanium

A new three-dimensional open-framework germanate, namely ethylenediamine bis(ethylenediammonium) tetrahydroxooctadecaoxononagermanate, (C(2)H(8)N(2))(C(2)H(10)N(2))(2)[Ge(9)O(18)(OH)(4)], has been synthesized hydrothermally and its structure determined by single-crystal X-ray diffraction. The framework is built of [Ge(9)O(22)(OH)(4)] units formed by four-, five- and six-oxygen-coordinated germanium and templated by ethylenediamine. Three types of intersecting channels are formed in the framework, one by eight-membered rings running along the b axis and the other two by ten-membered rings running parallel to the a and c axes, respectively.

Journal Article↗
PubMed2000

Long-term results of functional hemispherectomy for intractable seizures.

OBJECTIVE: From May 1989 to April 1997, functional hemispherectomy was performed in 8 cases of intractable seizures. We retrospectively analyzed our experience to evaluate the seizure control and complications of this surgical technique. METHODS: Following Dr. Rasmussen's model of functional hemispherectomy or performing a modification of this operation, we removed the sensorimotor cortex and temporal lobe associated with disconnection of the remaining portions of the frontal lobe and parieto-occipital lobe. RESULTS: All the patients were followed up for 3-11 years (mean 6.7 years). Satisfactory seizure control was obtained in all the cases. Life quality improved and patients worked or studied well after the operations. No cases of superficial cerebral hemosiderosis were found. CONCLUSION: Modified functional hemispherectomy may allow the patients to lead more independent lives by leading to a cessation or reduced frequency of seizures.

Adolescent↗
PubMed2000

Assessment of aortic atherosclerosis and carotid atherosclerosis in coronary artery disease.

The present study investigated the relationship between aortic atherosclerosis and carotid atherosclerosis, and studied the effects of coronary risk factors for these arteries. The subjects consisted of 78 patients with coronary artery disease (CAD) and 69 patients without CAD. All subjects underwent enhanced computed tomography and B-mode ultrasonography within a short time period to determine the extent of aorta and carotid atherosclerosis. Significant correlations between maximal aortic wall thickness (MAWT) and aortic wall volume (AWV) with carotid intima-media thickness (IMT) were demonstrated. MAWT, AWV and IMT were significantly higher in patients with CAD compared with controls (p=0.009, p=0.024, p=0.001, respectively). Furthermore, there were significant differences in MAWT, AWV and IMT among groups classified by the number of coronary artery stenoses, and no significant differences among groups classified by risk factors, but it was shown that MAWT, AWV and IMT increased gradually as the risk factors increased in number. MAWT, AWV and IMT had positive correlations with age, systolic blood pressure and triglyceride, and a negative correlation with high density lipoprotein-cholesterol. This study demonstrated that both aortic atherosclerosis and carotid atherosclerosis are closely correlated with coronary atherosclerosis, and that the atherosclerosis indices are independently associated with age and hyperlipidemia.

Aortic Diseases↗
PubMed2000

[Detection of epidermal growth factor receptor gene amplification in human laryngeal carcinomas by means of fluorescence in situ hybridization].

OBJECTIVE: To detect epidermal growth factor receptor(EGFR) gene amplification in human laryngeal carcinoma Hep-2 cell line and laryngeal carcinoma tissues. METHODS: The technique of fluorescence in situ hybridization(FISH). RESULTS: The EGFR gene amplification of a laryngeal carcinoma Hep-2 cell line and 5 laryngeal carcinoma tissues were detected by FISH. In the metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues, distinct cluster and multiple dot signals were found. In the interphase nuclei of the other 3 laryngeal carcinoma tissues, no increase in the number or extent of the hybrid signals was found. CONCLUSION: Compared with normal diploid cell, the EGFR gene amplification was observed at different levels ranging from 2 to 8 folds in metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues while no amplification was observed in the other 3 laryngeal carcinoma tissues. The results demonstrate that quantitative detection of amplified gene by FISH in the metaphase chromosome and interphase nuclei is useful for detection of laryngeal carcinoma tissues.

ErbB Receptors↗
PubMed2000

HER2 promoter controlled specific expression of the reporter gene in ovarian cancer cell line.

OBJECTIVE: Construct a retrovirus vector that expresses the downstream gene specifically in ovarian cancer cells so as to increase the specificity of gene therapy. METHODS: HER2 promoter obtained by PCR was cloned into P(LXSN); mutant GFP cDNA was inserted just downstream of this promoter. Transfect SK-OV3 and MCF-7 cell lines with the new vector, P(LHGSN). RESULTS: Three days after transfection with P(LHGSN), green fluorescence was observed in SK-OV3 cells while not in MCF-7 cells. CONCLUSION: HER2 promoter can control tumor specific expression of the reporter gene in ovarian cancer cell lines. With proper modification, the vector is expected to be useful in tumor specific gene therapy of ovarian cancers.

Female↗
PubMed2000

[Ligand of platelet and T cell activation antigen 1 (PTA1) expressed on Colo205 cell surface].

OBJECTIVE: To confirm the existence of PTA1 ligand (PTA1L). METHODS: PTA1/Ig fusion protein was prepared by gene recombination and expression in COS-7 cells by DEAE-dextran transfection. The fusion protein was used as a probe in the investigation of PTA1L by immunohistochemical staining. Existence of PTA1L was further identified by adhesion experiment. RESULTS: Colo205 cells could be stained by PTA1/Ig fusion protein specifically but not by hIg, and the adhesion of activated Jurkat cells with Colo205 could be blocked by PTA1/Ig and PTA1 mAb. CONCLUSION: PTA1 ligand is present on the surface of Colo205 cells. These results provide a solid basis for further investigation of the role of PTA1-PTA1L interaction in the pathogenesis of neoplasm.

Animals↗