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Biomedical subjects

Y Cui

Publications and source records attributed to Y Cui.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Mechanical properties of weld area soldered by lasers and structural changes in hot reaction zone].

OBJECTIVE: To analyse and measure the welding depths and strengths of three kinds of welding materials under different laser welding conditions as well as the structural changes of the heat affected zone. METHODS: Under different voltages and pulse duration three kinds of measuring sticks, including Co-Cr alloy, Ni-Cr alloy and pure titanium were welded and their strengths were compared with that of control group. At the same time, the structure of the heat-affected zone was analysed by means of the gold-phase method. RESULTS: The welding depth and strength of Co-Cr alloy were in direct proportion to the setting voltage, with averages of 335MPa (250V) to 573MPa(330V). At the heat-affected zone, the crystal particle was small and the end point of welding by laser bean presented the shape of the mountain peak and the interval of finger shape. The center of measuring sticks had a black zone with the circle shape. The setting voltage was in direct proportion to the welding depth of pure titanium and in inverse proportion to the welding strength with averages of 221MPa(250V) to 154MPa (330V). The crystal particle in the heat affected zone grew large and the solid phase expanded, the interval of the crystal oxidised, and the structure showed honeycomb changes. CONCLUSION: The laser welding is favourable to the welding properties of Co-Cr and Ni-Cr alloys, but its effect on the welding properties of pure titanium needs further discussion.

Biomechanical Phenomena↗
PubMed2001

[Study on hepatitis C virus genotyping in some parts of China].

OBJECTIVE: To study the genotypes of hepatitis C virus in some parts of China. METHODS: Twenty-seven sera of plasma donors from Guan county of Hebei province, Zhoukou district of Henan province, and 36 patients with chronic hepatitis C from Beijing and Qingdao cities were tested for HCV RNA by Amplicor PCR kit. Thirty-six of 38 HCV RNA positive sera were further genotyped, using INNO-LiP A HCV II kit. RESULTS: The HCV RNA positive rates of plasma donors and patients with chronic hepatitis C were 48.15% (13/27) and 69.44% (25/36) respectively. Genotyping data from 13 plasma donors and 23 patients with chronic hepatitis C showed that 29 (80.55%) were 1b, 5 (13.89%) were genotype 2, and 2 (5.56%) remained untyped. CONCLUSION: 1b seemed to be the prevalent HCV genotype in some parts of China.

Genotype↗
PubMed2001

[Analysis of the reason that patients with chronic sinusitis having a negative CT manifestation].

OBJECTIVE: To explore the reason why the CT manifestation of the patients with chronic nasosinusitis is negative. METHOD: To analyze the clinical and CT manifestation of the patients with chronic sinusitis having a negative CT manifestation. RESULT: Pathological changes were found in all 8 patients during the course of endoscopic sinus surgery, such as pus storing in the sinus cavity, mucous swelling polypoidly, small polyps formation and so on. CONCLUSION: The reasons that the patients with chronic sinusitis having a negative CT manifestation are, 1. CT scan can only give a static one-off image, 2. partial volume effect, 3. maybe result from the location of CT scan and the resolving power of tomograph, 4. maybe attribute to the pathological classify of chronic sinusitis.

Adolescent↗
PubMed2001

[Correlation of p16 mutation and biological behavior in Chinese laryngeal cancer].

OBJECTIVE: To investigate the correlation between p16 gene mutation and laryngeal cancer biological behavior as well as its prognosis in laryngeal cancer. METHOD: 24 specimens of primary laryngeal cancer and 10 speciments with benign lesion in larynx were examined for mutations in exon2 of p16 by using PCR-SSCP silver stainning technique. RESULT: Mutations frequency of laryngeal cancer was 62.5% (15/24). Nothing was found in 10 cases with laryngeal benign lesion. CONCLUSION: There is a strong correlation between p16 gene mutation and the biological behavior of chinese laryngeal cancer, such as histologic differentiation, invasion stage, and regional lymph nodes metastasis (P < or = 0.05). PCR-SSCP silver stainning technique is one of the most sensitive and simplest measure for detecting genetic mutation. It is worth using in clinical laboratory because of its readiness, repetition and lower cost.

Genes, p16↗
PubMed2001

[DNA character of the cholesteatoma].

OBJECTIVE: To compare the DNA character with in cholesteatoma tissues with that in normal skin. METHOD: DNA content within 25 cholesteatoma tissues and 10 normal postauricular skin was measured with flow cytometry. RESULT: The content of cholesteatoma tissues and postauricular skin specimens are a normal euploid. The cell number during S phase of cholesteatoma (10.9 +/- 2.32)% was higher than that in normal skin(7.31 +/- 2.82)%. CONCLUSION: Although the cholesteatoma has a very high proliferating character, the result suggest it isn' t a malignant tumor.

Adolescent↗
PubMed2001

[Reversed-phase high performance liquid chromatography used for determination of amino acids of parasites].

The compositions and contents of amino acids of parasites in different areas of China have been determined by precolumn derivatization, reversed-phase high performance liquid chromatography (HPLC) separation and ultra-violet absorption quantitation in order to prevent diseases caused from parasites. The results show that there were some differences in contents of amino acids in B. malayi from seven different areas in China. The contents of amino acids gradually increased from the southern to the northern areas in China. The method is simple and accurate, and the results have important values to investigate the life activities of parasites.

Amino Acids↗
PubMed2001

[High level expression of human recombinant albumin gene in the yeast Pichia pastoris].

The yeast Pichia pastoris was transformed by the multi-copy Pichia expression vector that can express secreted human albumin. The high level expression of cell line was selected after screening. The expression of human recombinant albumin in Pichia pastoris induced by different methods were compared. The ratio of secreted human albumin is 80% in total secreted proteins and the expression level reaches as high as is 10 g/L.

Albumins↗
PubMed2001

[Studies on detecting Brugia malayi larva in mosquitoes by polymerase chain reaction].

OBJECTIVE: To establish a specific, sensitive and simple assay for the detection of Brugia malayi larva in Anopheles sinensis. METHODS: Using a new DNA purification technique (Microcon 100) and two pairs of oligonucleotide primers (p1, p2 and p3, p4) suitable for detecting B. malayi in seven areas in our country, the mosquito vectors infected by B. malayi were detected by polymerase chain reaction(PCR). RESULTS: This PCR method could amplify separately a 322-basepair(bp) and a 155 bp DNA fragment and detect as few as 1/64 of one L1 in 1 mosquito, the detectable limit was nearly 4 pg DNA of filarial larvae, and it could also detect 1 infected mosquito with one L3 of B. malayi in pools of up to 200 mosquitoes. In contrast, no such specific 322 bp or 155 bp DNA band was detected in Dilofilaria immitis and normal mosquito. CONCLUSION: This PCR technique established for supervision of mosquito vector in B. malayi endemic areas is specific, sensitive, and simple.

Animals↗
PubMed2001

[The protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression].

OBJECTIVE: To investigate the protein expression of B-cell lymphoma/leukemia-2(Bcl-2) and B-cell lymphoma/leukemia-x long(Bcl-x1) in eosinophils in nasal polyps and the influence of beclomethasone dipropionate on the expression. METHODS: Using May-Grünwald-Giemsa (MGG) method and immunohistochemical method, the protein expression of Bcl-x1 and Bcl-2 in eosinophils in nasal polyps from patients treated with beclomethasone dipropionate treatment and patients without any treatment was compared. RESULTS: (1) Nasal polyp tissues from patients without treatment had more eosinophils than those from patients with treatment(P < 0.01). (2) No protein expression of Bcl-2 was observed in all 52 patients. (3) 20.0% patients with treatment had the expression of Bcl-x1, whereas 48.1% patients without treatment had the expression. The difference between these two groups was significant(P < 0.05). CONCLUSION: These data suggest that Bcl-x1 may act as an anti-apoptotic molecule in eosinophils and corticosteroids induce eosinophil apoptosis through suppressing the expression of Bcl-x1.

Adolescent↗
PubMed2001

[Spectrophotometric study on the interaction of protein with acid dye].

Spectrophotometric characters of protein interaction with chromazurol S(CAS), bromocresol green (BCG), bromopyrogallol red (BPR) and methylthymol blue (MTB) have been studied in acid and alkaline medium respectively. Protein can combine the above mentioned dye to reduce absorptivity of dye solution of CAS and BCG at pH 3.8 and pH 4.0, to add absorptivity of dye solution of BPR and MTB at pH 3.8 and pH 10.8 for the bathochromic shift of wave length of maximal absorption of them to add 10 nm and 20 nm respectively. The linear relationship holds between the reduced or added absorptivity of dye and the optimum concentration range of protein. The interaction mechanism of protein and dye has been discussed tentatively.

Acids↗
PubMed2001

[In situ IR study of the reaction behavior of transition metal oxides-propionic acid system, Fe2Cr(mu 3-O) (mu-O2CC2H5)6(H2O)3Cl.xH2O and Cr3 (mu 3-O) (mu-O2CC2H5)6(H2O)3NO3.xH2O].

The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the propionic acid to convert to acetaldehyde and pentanone in different temperature. The sequence of the ketonization reaction activity for metal oxides Fe3O4 > MnO2 > Cr2O3 > Co2O3 > Ni2O3 has analogy to that for metal clusters [Fe2MnOPH] > [Fe3OPH] > [Fe2CrOPH] > [Fe2CoOPH] > [Fe2NiOPH] > [Cr3OPH][OPH = (mu 3-O)(mu-O2CC2H5)6(H2O)3]. For the ketonization reactions, the reaction temperatures of transition-metal oxides were much higher than that of corresponding metal clusters [Fe2MOPH]. It has been verified that the active component of metal cluster [Fe2MOPH] is not the corresponding transition-metal oxides. The difference between Fe3O4 and Fe2O3 which catalyze the conversion of propionic acid to acetaldehyde and pentanone respectively were demonstrated.

English Abstract↗
PubMed2000

Hepatic uptake of bilirubin and its conjugates by the human organic anion transporter SLC21A6.

Bilirubin, the end product of heme catabolism, is taken up from the blood circulation into the liver. This work identifies a high-affinity transport protein mediating the uptake of bilirubin and its conjugates into human hepatocytes. Human embryonic kidney cells (HEK293) permanently expressing the recombinant organic anion-transporting polypeptide 2 (human OATP2, also known as LST-1 or OATP-C; symbol SLC21A6) showed uptake of [(3)H]monoglucuronosyl bilirubin, [(3)H]bisglucuronosyl bilirubin, and [(3)H]sulfobromophthalein with K(m) values of 0.10, 0.28, and 0.14 microm, respectively. High-affinity uptake of unconjugated [(3)H]bilirubin by OATP2 occurred in the presence of albumin and was not mediated by another basolateral hepatic uptake transporter, human OATP8 (symbol SLC21A8). OATP2 and OATP8 differed by their capacity to extract substrates from albumin before transport. In comparison to the high-affinity transport by OATP2, OATP8 transported [(3)H]sulfobromophthalein and [(3)H]monoglucuronosyl bilirubin with lower affinity, with K(m) values of 3.3 and 0.5 microm, respectively. The organic anion indocyanine green potently inhibited transport mediated by OATP2, with a K(i) value of 112 nm, but did not inhibit transport mediated by OATP8. Human OATP2 may play a key role in the prevention of hyperbilirubinemia by facilitating the selective entry of unconjugated bilirubin and its glucuronate conjugates into human hepatocytes.

Albumins↗
PubMed2000

Multiple-sequence information provides protection against mis-specified potential energy functions in the lattice model of proteins

The neutral nets in the lattice models of proteins are composed of a group of similar sequences that encode for the same native structure. The maximal neutral nets in an HP and an AB lattice model are investigated by exhaustive enumeration in the conformation space. The result demonstrates that the performance of mis-specified potential functions can be improved significantly by averaging over sequences in the neutral nets.

Journal Article↗
PubMed2000

Localization and genomic organization of a new hepatocellular organic anion transporting polypeptide.

Based on sequence homology to the human organic anion transporting polypeptide 2 (OATP2; SLC21A6), we cloned a new member of the SLC21A superfamily of solute carriers, termed OATP8 (SLC21A8). The protein of 702 amino acids showed an amino acid identity of 80% with human OATP2. Based on Northern blotting, the expression of OATP8 was restricted to human liver. Cosmid clones containing the genes encoding human OATP1 (SLC21A3), OATP2 (SLC21A6), and OATP8 (SLC21A8) served to establish their genomic organization. All three genes contained 14 exons with 13 identical splice sites when transferred to the amino acid sequence. An antibody raised against the carboxyl terminus localized OATP8 to the basolateral membrane of human hepatocytes and the recombinant glycoprotein, expressed in MDCKII cells, to the lateral membrane. Transport properties of OATP8 were studied in stably transfected MDCKII and HEK293 cells. Organic anions transported by human OATP8 included sulfobromophthalein, with a K(m) of 3.3 microm, and 17beta-glucuronosyl estradiol, with a K(m) of 5.4 microm. Several bile salts were not substrates. Thus, human OATP8 is a new uptake transporter in the basolateral hepatocyte membrane with an overlapping but distinct substrate specificity as compared with OATP2, which is localized to the same membrane domain.

Amino Acid Sequence↗
PubMed2000

Neovascularization with blood-brain barrier breakdown in delayed neuronal death.

Various kinds of acute pathological events in the central nervous system, such as ischemia, hemorrhage, and trauma, often cause brain edema. The edema may advance for days or weeks while inducing extensive damage in neural function, regardless of the extent of the original damage, and often results in death. Delayed edema is thought to be vasogenic; however, the mechanism underlying edema induction remains unknown. We found delayed vascular cell proliferation with a blood-brain barrier breakdown in and around the gerbil CA1 hippocampus, a region known to be involved in delayed apoptotic neuronal death 2-6 days after transient ischemia. Vascular cell proliferation, assessed by (3)H-thymidine incorporation, was most prominent 4-6 days after ischemia, and extravasation of exogenously applied dye or endogenous serum albumin from blood vessels was observed concomitantly. We propose neovascularization in delayed neuronal death as a cause of brain edema advancing days after neurological events.

Animals↗
PubMed2000

GLUT8 is a glucose transporter responsible for insulin-stimulated glucose uptake in the blastocyst.

Mammalian preimplantation blastocysts exhibit insulin-stimulated glucose uptake despite the absence of the only known insulin-regulated transporter, GLUT4. We describe a previously unidentified member of the mammalian facilitative GLUT superfamily that exhibits approximately 20-25% identity with other murine facilitative GLUTs. Insulin induces a change in the intracellular localization of this protein, which translates into increased glucose uptake into the blastocyst, a process that is inhibited by antisense oligoprobes. Presence of this transporter may be necessary for successful blastocyst development, fuel metabolism, and subsequent implantation. Moreover, the existence of an alternative transporter may explain examples in other tissues of insulin-regulated glucose transport in the absence of GLUT4.

Amino Acid Sequence↗