Biomedical subjects

Jian Sun

Publications and source records attributed to Jian Sun.

At least 109 records · Page 6Linked to original sources

PubMed2004

[Expression of p27 in renal interstital fibrosis in rats induced by unilateral ureteral obstruction].

OBJECTIVE: To explore the role of p27 in the renal tubule on the process of renal interstitial fibrosis caused by unilateral ureteral obstruction (UUO) in rats. METHODS: Rats were killed at the 7th, 14th, 21st days after UUO or sham-surgery. The protein expression of p27 in renal tubule was detected by immuohistochemistry at each time point. RESULTS: At the 7th day after the surgery, no noticeable abnormalities of p27 expression were found in renal tubular cells between UUO and the sham operated surgery. At the 14th and 21st days after UUO, the p27 expressions in renal tubular cells obviously decreased compared with those after the sham operated surgery. CONCLUSION: The p27 expression has no noticeable changes in the early UUO rats, and then it was significantly reduced with the renal interstitial fibrosis progressing.

Animals↗

PubMed2003

Superoxide anion generation by the cytochrome bc1 complex.

We have measured the rates of superoxide anion generation by cytochrome bc(1) complexes isolated from bovine heart and yeast mitochondria and by cytochrome bc(1) complexes from yeast mutants in which the midpoint potentials of the cytochrome b hemes and the Rieske iron-sulfur cluster were altered by mutations in those proteins. With all of the bc(1) complexes the rate of superoxide anion production was greatest in the absence of bc(1) inhibitor and ranged from 3% to 5% of the rate of cytochrome c reduction. Stigmatellin, an inhibitor that binds to the ubiquinol oxidation site in the bc(1) complex, eliminated superoxide anion formation, while myxothiazol, another inhibitor of ubiquinol oxidation, allowed superoxide anion formation at a low rate. Antimycin, an inhibitor that binds to the ubiquinone reduction site in the bc(1) complex, also allowed superoxide anion formation and at a slightly greater rate than myxothiazol. Changes in the midpoint potentials of the cytochrome b hemes had no significant effect on the rate of cytochrome c reduction and only a small effect on the rate of superoxide anion formation. A mutation in the Rieske iron-sulfur protein that lowers its midpoint potential from +285 to +220 mV caused the rate of superoxide anion to decline in parallel with a decline in cytochrome c reductase activity. These results indicate that superoxide anion is formed by similar mechanisms in mammalian and yeast bc(1) complexes. The results also show that changes in the midpoint potentials of the redox components that accept electrons during ubiquinol oxidation have only small effects on the formation of superoxide anion, except to the extent that they affect the activity of the enzyme.

Animals↗

PubMed2003

Enhancement of chaperone function of alpha-crystallin by methylglyoxal modification.

The molecular chaperone function of alpha-crystallin in the lens prevents the aggregation and insolubilization of lens proteins that occur during the process of aging. We found that chemical modification of alpha-crystallin by a physiological alpha-dicarbonyl compound, methylglyoxal (MG), enhances its chaperone function. Protein-modifying sugars and ascorbate have no such effect and actually reduce chaperone function. Chaperone assay after immunoprecipitation or with immunoaffinity-purified argpyrimidine-alpha-crystallin indicates that 50-60% of the increased chaperone function is due to argpyrimidine-modified protein. Incubation of alpha-crystallin with DL-glyceraldehyde and arginine-modifying agents also enhances chaperone function, and we believe that the increased chaperone activity depends on the extent of arginine modification. Far- and near-UV circular dichroism spectra indicate modest changes in secondary and tertiary structure of MG-modified alpha-crystallin. LC MS/MS analysis of MG-modified alpha-crystallin following chymotryptic digestion revealed that R21, R49, and R103 in alphaA-crystallin were converted to argpyrimidine. 1,1'-Bis(4-anilino)naphthalene-5,5'-disulfonic acid binding, an indicator of hydrophobicity of proteins, increased in alpha-crystallin modified by low concentrations of MG (2-100 microM). MG similarly enhances chaperone function of another small heat shock protein, Hsp27. Our results show that posttranslational modification by a metabolic product can enhance the chaperone function of alpha-crystallin and Hsp27 and suggest that such modification may be a protective mechanism against environmental and metabolic stresses. Augmentation of the chaperone function of alpha-crystallin might have evolved to protect the lens from deleterious protein modifications associated with aging.

Alcohol Dehydrogenase↗

PubMed2003

Lack of the transcriptional coactivator OBF-1 prevents the development of systemic lupus erythematosus-like phenotypes in Aiolos mutant mice.

Here we show that mice lacking the zinc finger transcription factor Aiolos develop the symptoms of human systemic lupus erythematosus (SLE), which is characterized by the production of anti-dsDNA Ab and immune complex-mediated glomerulonephritis. This finding indicates that normal Aiolos function is necessary to maintain immune homeostasis and suppress the development of systemic autoimmune disease and implicates Aiolos as a possible candidate gene for SLE. Interestingly, Aiolos-null mice can no longer mount autoimmune reactions and completely fail to develop SLE when they are deficient for the B cell-specific transcription coactivator OBF-1. The lack of OBF-1 reverses several Aiolos mutant mouse phenotypes, such as B cell hyperproliferation, high expression of activation marker on B cells, and spontaneous germinal center formation. Unexpectedly, B cell development at the immature B cell stage is severely impaired in the bone marrow of Aiolos/OBF-1 double-deficient mice, demonstrating the key role of these factors in the transition from pre-B to immature B cells. Our results indicate that B cells play a crucial role in the development of SLE in Aiolos mutant mice and might be useful for the strategy of SLE treatment.

Animals↗

PubMed2003

Quantitative analysis of HBV DNA level and HBeAg titer in hepatitis B surface antigen positive mothers and their babies: HBeAg passage through the placenta and the rate of decay in babies.

It is well documented that perinatal transmission is the major cause of chronic HBV infection in China. However, the mechanisms of HBV perinatal transmission are not defined clearly. It is not known whether hepatitis B e antigen can cross the human placenta, and the rate of HBeAg decay in babies with and without HBV breakthrough has not been studied. In this study, HBV serological markers were investigated in 95 hepatitis B surface antigen positive pregnant women. These markers were also studied in the babies at birth and at the age of 6 months and 12 months. The data show that 7.4% (7/95) children were infected with HBV during the first year after birth despite receiving passive-active immunoprophylaxis with hepatitis B immune globulin and hepatitis B vaccine. The surface gene fragment of HBV DNA was cloned and sequenced following PCR amplification in 7 cases of HBsAg positive babies and their mothers. All babies had the same sequences as their mothers, although two babies also had sequences that would produce an amino acid substitution within the "a" determinant. Furthermore, we measured HBeAg titers and HBV DNA levels by using Abbott AxSYM system and LightCycler-based real-time fluorescence quantitative PCR in 54 mother-infant pairs. Thirty-three mothers were HBeAg positive, and 21 mothers were HBeAg negative. Seventy percent (23/33) of neonates from HBeAg-positive mothers were HBeAg positive at birth compared with 0% (0/21) of neonates from HBeAg negative mothers. HBeAg was present at higher titer in the birth sera of the babies with HBV breakthrough than in babies without breakthrough. HBeAg was cleared from the serum in all 19 babies without breakthrough. In 17 of these 19 babies, the HBeAg was cleared within 6 months, and in two babies clearance took 12 months. The mean serum HBV DNA level in the mothers of the 4 infants with HBV breakthrough was significantly higher than in the mothers of babies who did not become infected. In conclusion, this data suggests that HBeAg can cross the human placenta, and disappears from serum within 6 months in most babies. HBV DNA levels in hepatitis B carrier mothers are associated with the failure of HBIG and vaccine immunization, and the additional influence of transmitted HBeAg cannot be excluded.

Amino Acid Sequence↗

PubMed2003

Energetic and structural considerations for the mechanism of protein sliding along DNA in the nonspecific BamHI-DNA complex.

The molecular mechanism by which DNA-binding proteins find their specific binding sites is still unclear. To gain insights into structural and energetic elements of this mechanism, we used the crystal structure of the nonspecific BamHI-DNA complex as a template to study the dominant electrostatic interaction in the nonspecific association of protein with DNA, and the possible sliding pathways that could be sustained by such an interaction. Based on calculations using the nonlinear Poisson-Boltzmann method and Brownian dynamics, a model is proposed for the initial nonspecific binding of BamHI to B-form DNA that differs from that seen in the crystal structure of the nonspecific complex. The model is electrostatically favorable, and the salt dependence as well as other thermodynamic parameters calculated for this model are in good agreement with experimental results. Several residues in BamHI are identified for their important contribution to the energy in the nonspecific binding model, and specific mutagenesis experiments are proposed to test the model on this basis. We show that a favorable sliding pathway of the protein along DNA is helical.

Binding Sites↗

PubMed2003

Value of gallium-67 scanning in differentiation of malignant tumors from benign tumors or inflammatory disease in the oral and maxillofacial region.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of gallium-67 ((67)Ga) scanning in the differentiation of malignant tumors from benign tumors or inflammatory disease in the oral and maxillofacial region. Study design Fifty-two patients with tumors or inflammation in the oral and maxillofacial region underwent (67)Ga scanning. The results were compared with the final pathologic diagnosis. RESULTS: The gallium-67 scanning images for 20 of 21 patients who had malignant tumors were positive (95.23%); images for 3 out of 20 patients who had benign tumors also were positive (15%). There was a significant difference between malignant and benign tumors (P <.001). Images for 2 of 11 patients with chronic inflammatory lesions were positive (18.2%), but, unlike the images of malignant tumors, the image outlines of the inflammatory lesions were indistinct and larger than the actual lesions. CONCLUSION: (67)Ga scanning is a useful adjunct tool for differentiation of malignant tumors from benign tumors or inflammatory disease in the oral and maxillofacial region.

Adenolymphoma↗

PubMed2003

Adjusting distributions of the Health Utilities Index Mark 3 utility scores of health-related quality of life.

The Health Utilities Index Mark 3 (HUI3) is a multi-dimensional, preference-based measure of health status and health-related quality of life (HRQoL). HUI3 scores correlate strongly with self-ratings of health status and functional disability and vary according to age, gender and occupation. In comparative studies relating to HRQoL, it is necessary to carry out adjusted comparison of the health status of the different groups. taking into account unbalanced distribution of confounding variables. This paper describes a stratification method to adjust the distributions of HUI3 scores. This method provides a graphical representation of adjusted distribution of HUI3, which can also be used to adjust other HRQoL scores. Cross-sectional data from the 1998/1999 National Population Health Survey (NPHS) in Canada were used to verify the proposed method. Male agriculture workers and male construction workers in Canada had quite different age distributions but similar HUI3 distributions. After adjusting the age distribution of the construction group to match the distribution of agriculture group, the mean HUI3 score of the former significantly decreased.

Adult↗

PubMed2003

Protein database, human retinal pigment epithelium.

The retinal pigment epithelium (RPE) is a single cell layer adjacent to the rod and cone photoreceptors that plays key roles in retinal physiology and the biochemistry of vision. RPE cells were isolated from normal adult human donor eyes, subcellular fractions were prepared, and proteins were fractionated by electrophoresis. Following in-gel proteolysis, proteins were identified by peptide sequencing using liquid chromatography tandem electrospray mass spectrometry and/or by peptide mass mapping using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Preliminary analyses have identified 278 proteins and provide a starting point for building a database of the human RPE proteome.

Chromatography, Liquid↗

PubMed2003

Therapeutic efficacy of high-dose vitamin C on acute pancreatitis and its potential mechanisms.

AIM: To observe the therapeutic efficacy of high-dose Vitamin C (Vit. C) on acute pancreatitis (AP), and to explore its potential mechanisms. METHODS: Eighty-four AP patients were divided into treatment group and control group, 40 healthy subjects were taken as a normal group. In the treatment group, Vit. C (10 g/day) was given intravenously for 5 days, whereas in the control group, Vit. C (1 g/day) was given intravenously for 5 days. Symptoms, physical signs, duration of hospitalization, complications and mortality rate were monitored. Meanwhile, serum amylase, urine amylase and leukocyte counts were also determined. The concentration of plasma vitamin C (P-VC), plasma lipid peroxide (P-LPO), plasma vitamin E (P-VE), plasma beta-carotene (P-beta-CAR), whole blood glutathione (WB-GSH) and the activity of erythrocyte surperoxide dimutase (E-SOD) and erythrocyte catalase (E-CAT) as well as T lymphocyte phenotype were measured by spectrophotometry in the normal group and before and after treatment with Vit. C in the treatment and the control group. RESULTS: Compared with the normal group, the average values of P-VC, P-VE, P-beta-CAR, WB-GSH and the activity of E-SOD and E-CAT in AP patients were significantly decreased and the average value of P-LPO was significantly increased, especially in severe acute pancreatitis (SAP) patients (P<0.05. P-VC, P=0.045; P-VE, P=0.038; P=0.041; P-beta-CAR, P=0.046; WB-GSH, P=0.039; E-SOD, P=0.019; E-CAT, P=0.020; P-LPO, P=0.038). Compared with the normal group, CD3 and CD4 positive cells in AP patients were significantly decreased. The ratio of CD4/CD8 and CD4 positive cells were decreased, especially in SAP patients (P<0.05. CD4/CD8, P=0.041; CD4, P =0.019). Fever and vomiting disappeared, and leukocyte counts and amylase in urine and blood become normal quicker in the treatment group than in the control group. Moreover, patients in treatment group also had a higher cure rate, a lower complication rate and a shorter in-ward days compared with those in he control group. After treatment, the average value of P-VC was significantly higher and the values of SIL-2R, TNF-alpha, IL-6 and IL-8 were significantly lower in the treatment group than in the control group (P<0.05 P-VC, P=0.045; SIL-2R, P=0.012; TNF-alpha, P=0.030; IL-6, P=0.015; and IL-8, P=0.043). In addition, the ratio of CD4/CD8 and CD4 positive cells in the patients of treatment group were significantly higher than that of the control group after treatment (P<0.05. CD4/CD8, P=0.039; CD4, P=0.024). CONCLUSION: High-dose vitamin C has therapeutic efficacy on acute pancreatitis. The potential mechanisms include promotion of anti-oxidizing ability of AP patients, blocking of lipid peroxidation in the plasma and improvement of cellular immune function.

Acute Disease↗

PubMed2003

[Relevant factors and management for patients with squamous carcinoma in tongue without clinical cervical lymphatic node metastasis].

OBJECTIVE: To discuss the treatment of cN(0) tongue carcinoma patients. METHODS: 185 cases of the mobile tongue carcinoma patients (male 102, female 83, aged 28 to 88) treated with surgery from 1988.5 to 1995.6 had been followed up and retrospectively analyzed. Extensive resection of the primary tumors and neck dissections were performed, and all the samples were pathological positive. RESULTS: The cervical lymphatic node metastasis rates for stage I-II, III-IV disease, grade I, II disease were 16.66%, 38.05%, 17.42% and 37.50% respectively. And the rates were 9.00%, 31.37% and 55.55% for submucous infiltration, muscle infiltration and perineural infiltration, respectively. The overall 5 year survival was 72.43%, and the 5 year specific survival rate was 44.44% and 83.96% for those having or not having cervical node metastasis. The levels of 29 patients with positive node metastasis for 148 cN(0) patients were submandibular and submental lymphatic nodes (22.64%), superior deep cervical lymphatic nodes (35.84%), middle deep cervical lymphatic nodes (26.41%), inferior deep cervical lymphatic nodes (15.09%), posterior neck lymphatic nodes (0.00%). The over all 5 year survival rates for selective neck dissection were 85.13% and 21.62% in therapeutic dissection (chi(2) = 29.73, P < 0.01). Patients performed selective neck dissection the rates were 68.96% and 89.07% respectively with or without lymphatic node metastasis. Comparably the 5-year rate was only 20.00% for the patients performed the therapeutic dissection with lymphatic node metastasis. CONCLUSIONS: (1) cN(0) patients should be observed carefully in stage I, and the selective dissection must be performed in stage II-IV. (2) Supraomohyoid ND is essential for T(2) patients, and functional ND is essential for T(3 - 4) patients. (3) There is correlation between cervical metastasis and the stage, grade or infiltration of tongue cancer (P < 0.05). The prognosis could be expected from these factors.

Adult↗

PubMed2003

[Hepatitis B virus genotypes and the heterogeneity of its polymerase gene].

OBJECTIVE: To study the heterogeneity of polymerase gene (P gene) within hepatitis B virus (HBV) genotypes based on a systematic analysis of 202 HBV P genes, providing some useful references for further studies on the relationship among HBV genotypes, P gene mutations, replication and nucleoside analogues drug-resistance. METHODS: 202 HBV complete sequences containing P genes were obtained from GenBank and were analysed using computer softwares. RESULTS: There were some genotype-related characteristics of HBV P genes. As reverse transcriptase domain was concerned, there were more amino acid divergences in genotype C and D compared with these in genotype A. There were also amino acid substitutions in the A-F conserved regions of the reverse transcriptase domain within and between HBV genotypes. CONCLUSIONS: There are divergences of P genes and amino acids within and between HBV genotypes, which should be considered when amino acid changes are analyzed whether they are proposed to be drug-resistance mutations or the results from quasispecies-selected. Moreover, these divergences may affect the antiviral effect of nucleoside analogues on HBV with different genotypes.

Amino Acid Sequence↗

PubMed2003

[Analysis of three lamivudine-resistant HBV mutants with the method of restriction enzyme digestion and its application].

OBJECTIVE: To investigate the prevalence of three lamivudine-resistant HBV mutants in lamivudine-treated Chinese patients. METHODS: Using three pairs of of HBV polymerase gene B and C domain fragments were amplified by PCR. The PCR products were then digested by restriction enzyme Nde I and Nla III. The digested products were analyzed by electrophoresis. With this method, the prevalence of the three lamivudine-resistant mutants in lamivudine-treated Chinese patients was investigated. RESULTS: After Nde I digestion of p24 and p29 amplified product, HBV wild type could be easily separated from YMDD mutant. At the same time, YIDD could be separated from YVDD mutant after Nla III digestion of p24 and p29 amplified product. By this method, the authors found that these eleven patients were infected with lamivudine-resistant mutants. Six of them were infected with M5501 mutant; five were infected with M550V mutant (one of them had both M550V and L526M mutations). CONCLUSION: The method of the present study was demonstrated to be an easy way to detect HBV lamivudine-resistant mutants and can be applied to clinical monitoring of lamivudine resistance.

Adolescent↗

PubMed2003

[Pharmacokinetics and relative bioavailability of KC-404 sustained release tablets in healthy volunteers].

OBJECTIVE: To study the pharmacokinetics and relative bioavailability of KC-404 sustained release tablets and capsules in healthy volunteers. METHODS: The concentration of KC-404 in serum was determined by HPLC method after a single oral dose (20 mg) of tablet or capsule was administered to 19 healthy male volunteers respectively in an open randomized cross-over test. RESULTS: After being processed by 3P87 pharmacokinetics program, the experiment data showed that the pharmacokinetic parameters of the tablets and the capsules were AUC0-->infinity: 740.12 ng.h/ml and 724.04 ng.h/ml; tmax: 5.37 h and 5.11 h; Cmax: 46.98 ng/ml and 46.29 ng/ml; T1/2: 7.4 h and 7.0 h; MRT0-->infinity: 14.78 h and 14.39 h respectively. There were no significant differences in AUC, tmax, Cmax, T1/2 and MRT0-->infinity between these two preparations (P > 0.05). The relative bioavailability of KC-404 sustained release tablets was 102.6%. CONCLUSION: These two preparations are bioequivalent.

Adult↗

PubMed2003

[Effect of tongxinluo capsule on function of vascular endothelium in patients with unstable angina pectoris].

OBJECTIVE: To evaluate the effect of Tongxinluo (TXL) Capsule on function of vascular endothelium in patients with unstable angina pectoris (UAP). METHODS: Forty-six UAP patients were randomly divided into two group, the 28 patients in the treated group treated by conventional therapy plus TXL and the 18 patients in the control group treated by conventional therapy alone. Changes of blood levels of endothelin (ET), nitric oxide (NO), Von Willebrand factor (vWF), soluble vascular cell adhesive molecule-1 (sVCAM-1) and soluble intracellular adhesive molecule-1 (sICAM-1) from before treatment to after two months of treatment were observed, and the flow-mediated dilatation (FMD) in brachial artery was detected at the same time using ultrasonography. RESULTS: After treatment, the blood level of vWF and ET obviously decreased (P < 0.01), levels of NO and FMD increased (P < 0.05 or P < 0.01) in both groups. Levels of sVCAM-1 and sICAM-1 significantly decreased in the treated group (P < 0.01), while in the control group, no marked change was found in sVCAM-1 and sICAM-1 (P > 0.05). Compared with the control group after treatment, the levels of vWF, ET, sVCAM-1 and sICAM-1 in the treated group were lower (P < 0.01), and levels of NO and FMD were higher (P < 0.01). CONCLUSION: TXL might protect vascular endothelium, improve clinical therapeutic effect by path of decreasing blood levels of ET, vWF and partial cellular adhesive factor, and increasing the level of NO.

Aged↗

PubMed2003

Biological effect of ectopic expression of angiopoietin-1 and -2 in hepatocellular carcinoma cell line.

OBJECTIVES: To observe the biological effect of ectopic expression of angiopoietin-1 and -2 cDNA on SMMC7721 hepatocellular carcinoma cell line and study the possible role of the angiopoietin gene in the growth or metastasis of implantation carcinoma. METHODS: Angiopoietin-1 and -2 cDNA were subcloned into the pcDNA3 vector and subsequently transfected into a human SMMC7721 hepatocellular carcinoma (HCC) cell line without detectable angiopoietin gene expression before transfection. Then HCC cells were injected subcutaneously into 30 nude mice and the tumor growth speed and amount of newborn vasculature in the HE stained tissue were observed every 2 days till 3 weeks or the death of animals. RESULTS: The tumor grew faster with angiopoietin-2 expression; much more blood vessels were seen in the tumor tissue than that without angiopoietin-2 expression. Angiopoietin-1 gene expression seems to have no obvious effect on the increase of vasculature and tumor growth. CONCLUSIONS: The angiopoietin gene may play a role in the growth and progression of HCC and angiopoietin-2 seems to promote the angiogenesis of the tumor.

Angiopoietin-1↗

PubMed2003

[The analysis of masticatory efficiency after maxillofacial prosthetic treatment for unilateral maxillary defect].

OBJECTIVE: To evaluate the clinic results of maxillofacial prosthetic treatment for unilateral maxillary defect. METHODS: Masticatory efficiency was tested before and after maxillofacial prosthetic treatment for unilateral maxillary defect. RESULTS: There was significant difference between one week, one month, three months after treatment and before treatment(F = 0.635, P = 0.002). Masticatory efficiency was increased by 59.98% after one month. CONCLUSION: Maxillofacial prosthetic treatment can significantly increase the masticatory efficiency of unilateral maxillary defect. It remains stable one month later.

Adult↗

PubMed2003

[Effect of Astragalus membranaceus on baroreflex sensitivity in spontaneously hypertensive rats].

OBJECTIVE: To observe the chronicity decompression effect of Astragalus Membranaceus(AM) and evaluate the effect on baroreflex sensitivity (BRS). METHOD: Nineteen spontaneously hypertensive rats(SHR) were randomly divided into four groups. The AM groups were intraperitoneally administered with AM parenteral solution 0.9 mL, 1.2 mL and 1.8 mL respectively and the control group was not given AM for eight weeks. Then the change of blood pressure was observed successivly. After eight weeks, BRS were also determined. At last, the difference of blood pressure and BRS among the groups were compared. RESULT: Blood pressure in the control group became higher and higher frome the third week to the eighth week, but the other SHR admistered with AM showed no changein blood pressure level. We also found that the BRS in AM group was higher than that in the control group(P < 0.01). CONCLUSION: AM can promote the BRS in SHR.

Animals↗