Biomedical subjects

Hua Li

Publications and source records attributed to Hua Li.

At least 109 records · Page 6Linked to original sources

PubMed2004

[Expression of adenylate kinase of Schistosoma japonicum and evaluation on the immunoreactivity of the recombinant protein].

OBJECTIVE: To express and purify the Schistosoma japonicum adenylate kinase (AK) protein of which the cDNA sequence was subcloned into the pET32a(+) soluble expression plasmid, and to evaluate its immunoreactivity. METHODS: The recombinant plasmid was transformed into E. coli BL21, and induced with IPTG for expression. The bacterial lysis was conducted by ultrasonication and the supernatant was analyzed by SDS-PAGE after boiling and centrifugation. The target protein was purified with the Ni-NTA agarose. The proteins on the gel were transferred to the PVDF film and then the immunoreactivity was tested by Western blotting using anti-6-His antibody, sera from rabbits 6 weeks after infected with cercariae or UV-attenuated cercariae. The purified protein was coated for ELISA to test the cercariae infected rabbit serum and the normal rabbit serum. RESULTS: The molecular weight of the target fusion protein was Mr 40 000 after being induced with IPTG. The fused protein showed a single band when reacted with anti-6-His antibody, the cercariae infected rabbit serum and attenuated cercariae infected rabbit serum. CONCLUSION: The AK protein is expressed as a fused protein with thioredoxin and its molecular weight is about Mr 40000. This protein has a positive immunoreactivity with sera of rabbits infected with cercariae and UV-attenuated cercariae.

Adenylate Kinase↗

PubMed2004

Solution NMR studies of the A beta(1-40) and A beta(1-42) peptides establish that the Met35 oxidation state affects the mechanism of amyloid formation.

The pathogenesis of Alzheimer's disease is characterized by the aggregation and fibrillation of the 40-residue A beta(1-40) and 42-residue A beta(1-42) peptides into amyloid plaques. The structural changes associated with the conversion of monomeric A beta peptide building blocks into multimeric fibrillar beta-strand aggregates remain unknown. Recently, we established that oxidation of the methionine-35 side chain to the sulfoxide (Met35(red) --> Met35(ox)) significantly impedes the rate of aggregation and fibrillation of the A beta peptide. To explore this effect at greater resolution, we carefully compared the (1)H, (15)N, and (13)C NMR chemical shifts of four A beta peptides that had the Met35 reduced or oxidized (A beta(1-40)Met35(red), A beta(1-40)Met35(ox), A beta(1-42)Met35(red), and A beta(1-42)Met35(ox)). With the use of a special disaggregation protocol, the highly aggregation prone A beta peptides could be studied at higher, millimolar concentrations (as required by NMR) in aqueous solution at neutral pH, remaining largely monomeric at 5 degrees C as determined by sedimentation equilibrium studies. The NOE, amide-NH temperature coefficients, and chemical shift indices of the (1)H alpha, (13)C alpha, and (13)C beta established that the four peptides are largely random, extended chain structures, with the Met35(ox) reducing the propensity for beta-strand structure at two hydrophobic regions (Leu17-Ala21 and Ile31-Val36), and turn- or bendlike structures at Asp7-Glu11 and Phe20-Ser26. Additional NMR studies monitoring changes that occur during aging at 37 degrees C established that, along with a gradual loss of signal/noise, the Met35(ox) significantly hindered upfield chemical shift movements of the 2H NMR signals for the His6, His13, and His14 side chains. Taken together, the present NMR studies demonstrate that the Met35(red) --> Met35(ox) conversion prevents aggregation by reducing both hydrophobic and electrostatic association and that the A beta(1-40)Met35(red), A beta(1-40)Met35(ox), A beta(1-42)Met35(red), and A beta(1-42)Met35(ox) peptides may associate differently, through specific, sharp changes in structure during the initial stages of aggregation.

Amino Acid Sequence↗

PubMed2004

Cardiotropic viruses in the myocardium of children with end-stage heart disease.

BACKGROUND: Transplantation has become a lifesaving procedure for children with end-stage heart failure. The long-term outcome for children who undergo transplantation has been of considerable interest, but the causes of graft failure and death are largely unknown, and the role of pre-transplant viral infection is unclear. METHODS: Myocardial samples from 80 explanted hearts from children with end-stage heart disease caused by congenital heart disease (CHD), cardiomyopathy, or chronic rejection were analyzed using polymerase chain reaction and reverse-transcriptase polymerase chain reaction for cardiotropic viruses using virus-specific primers. We used immunohistochemical analysis of cytoskeletal proteins to evaluate myocyte architecture. RESULTS: We identified parvoviral genomes in 6 patients (3 with CHD and 3 with cardiomyopathy). We detected no other viruses. Immunohistochemistry showed normal staining for key components of the cytoskeleton/sarcolemma, sarcomere, and nuclear membrane in the 6 virus-positive samples. The clinical outcome of these children was worse (4 long-term survivors, but 2 deaths) than for individuals without the genome. CONCLUSIONS: Detecting viruses within the myocardium at the point of end-stage heart failure is not common, regardless of the primary pathology. However, the presence of viruses may result in poor outcome for the patient.

Child↗

PubMed2004

Characterization of an anti-human ovarian carcinomaxanti-human CD3 bispecific single-chain antibody with an albumin-original interlinker.

OBJECTIVE: The objective of this study was to determine the properties of a single-chain bispecific antibody (scBsAb) against human ovarian carcinoma and to develop this agent for potential use in human ovarian cancer. METHODS: ELISA and FACS were performed to determine the antigen-binding properties of the scBsAb. Its abilities to retarget the pre-activated human peripheral blood mononuclear cells (PBMCs) to human ovarian carcinoma cell line SKOV3 cells and mediate their lysis in vitro were performed by a colorimetric MTT-based assay. Nude mice bearing human SKOV3 tumor xenografts were used to study the distribution and imaging of the scBsAb. Its pharmacokinetics in vivo was also studied in naive BALB/c mice. RESULTS: The scBsAb showed nearly identical ligand binding properties at each site relative to the individual monovalent single-chain antibody prototype molecules and could bridge SKOV3 and human T cell line Jurkat, which expresses CD3 antigens on the surface of cells together. It can also retarget the pre-activated PBMCs to SKOV3 cells and mediated their lysis in vitro effectively. Imaging and distribution study demonstrated that the antibody could target the tumor. Its elimination in vivo corresponded to second-order kinetics with a terminal half-life time (t(1/2)beta) of 7.7 h. CONCLUSION: This scBsAb with easy production and reasonable blood retention time should be developed for potential use in human ovarian cancer.

Albumins↗

PubMed2004

Downregulation of wild-type p53 protein by HER-2/neu mediated PI3K pathway activation in human breast cancer cells: its effect on cell proliferation and implication for therapy.

Overexpression and activation of HER-2/neu (also known as c-erbB-2), a proto-oncogene, was found in about 30% of human breast cancers, promoting cancer growth and making cancer cells resistant to chemo- and radio-therapy. Wild-type p53 is crucial in regulating cell growth and apoptosis and is found to be mutated or deleted in 60-70% of human cancers. And some cancers with a wild-type p53 do not have normal p53 function, suggesting that it is implicated in a complex process regulated by many factors. In the present study, we showed that the overexpression of HER-2/neu could decrease the amount of wild-type p53 protein via activating PI3K pathway, as well as inducing MDM2 nuclear translocation in MCF7 human breast cancer cells. Blockage of PI3K pathway with its specific inhibitor LY294002 caused G1-S phase arrest, decreased cell growth rate and increased chemo- and radio-therapeutic sensitivity in MCF7 cells expressing wild-type p53. However, it did not increase the sensitivity to adriamycin in MDA-MB-453 breast cancer cells containing mutant p53. Our study indicates that blocking PI3K pathway activation mediated by HER-2/neu overexpression may be useful in the treatment of breast tumors with HER-2/neu overexpression and wild-type p53.

Breast Neoplasms↗

PubMed2004

Infrequent cavity-forming fluctuations in HPr from Staphylococcus carnosus revealed by pressure- and temperature-dependent tyrosine ring flips.

Infrequent structural fluctuations of a globular protein is seldom detected and studied in detail. One tyrosine ring of HPr from Staphylococcus carnosus, an 88-residue phosphocarrier protein with no disulfide bonds, undergoes a very slow ring flip, the pressure and temperature dependence of which is studied in detail using the on-line cell high-pressure nuclear magnetic resonance technique in the pressure range from 3 MPa to 200 MPa and in the temperature range from 257 K to 313 K. The ring of Tyr6 is buried sandwiched between a beta-sheet and alpha-helices (the water-accessible area is less than 0.26 nm2), its hydroxyl proton being involved in an internal hydrogen bond. The ring flip rates 10(1)-10(5) s(-1) were determined from the line shape analysis of H(delta1, delta2) and H(epsilon1,epsilon2) of Tyr6, giving an activation volume DeltaV++ of 0.044 +/- 0.008 nm3 (27 mL mol(-1)), an activation enthalpy DeltaH++ of 89 +/- 10 kJ mol(-1), and an activation entropy DeltaS++ of 16 +/- 2 JK(-1) mol(-1). The DeltaV++) and DeltaH++ values for HPr found previously for Tyr and Phe ring flips of BPTI and cytochrome c fall within the range of DeltaV(double dagger) of 28 to 51 mL mol(-1) and DeltaH++ of 71 to 155 kJ mol(-1). The fairly common DeltaV++ and DeltaH++ values are considered to represent the extra space or cavity required for the ring flip and the extra energy required to create a cavity, respectively, in the core part of a globular protein. Nearly complete cold denaturation was found to take place at 200 MPa and 257 K independently from the ring reorientation process.

Bacterial Proteins↗

PubMed2004

[Minimally invasive technique of parotidectomy for benign parotid tumors].

OBJECTIVE: To evaluate a minimally invasive technique of parotidectomy in treatment of benign parotid tumors. METHODS: This retrospective review included 49 patients with benign parotid gland tumors. The modified technique included incision, flap elevation, facial nerve dissection, the great auricular nerve preservation and postoperative disposal. RESULTS: All tumors were resected completely. The operation lasted 1.5 approximately 2.5 h; the average length of incisions was from 5.5 cm to 7.5 cm, and the average postoperative hospital stay was 4 days. There were no permanent facial nerve injury, no obvious scars and no depressed deformity observed postoperatively. During the 6 months approximately 5 years following-up, no tumor recurrence was found. CONCLUSION: The minimally invasive technique of parotidectomy reduces the disadvantages of the traditional procedure, and improves the quality of operation.T.

Adenoma, Pleomorphic↗

PubMed2004

[Efficient soluble expression, purification and identification of the truncated SAG1 gene of Toxoplasma gondii in Escherichia coli].

OBJECTIVE: To express truncated SAG1 gene in Escherichia coli to obtain purified recombinant SAG1, and identify the immunoreactivity of the product. METHODS: The plasmid pET-30a(+)-trSAG1 was constructed, which was cut by Nco I and HindIII to obtain truncated SAG1 gene and inserted into pET-32a(+) cut by the same two restriction enzymes. After identification by restriction enzymes, the plasmid pET-32a(+)-trSAG1 was transformed into E.coli BL21, and the soluble product induced by 0.1 mmol/L IPTG for 4 hour before purification with Ni-NTA agarose, followed by identification of the purified recombinant protein with SDS-PAGE, Western-blotting and ELISA. RESULTS: Recombinant pET-32a(+)-trSAG1 was successfully constructed and high level of truncated SAG1 expression achieved in E.coli. SDS-PAGE showed that the expressed protein was approximately 40,000 in size and expressed in a soluble form that could be easily purified by Ni-NTA agarose. Western-blotting demonstrated that the purified product could be specifically recognized by sera from rabbits immunized with native antigen of T.gondii, and could also be recognized, as shown by ELISA, by sera from human with T.gondii infection. CONCLUSIONS: The truncated SAG1 gene was successfully expressed in E.coli in a soluble form, and the recombinant protein may be of value in the diagnosis of toxoplasmosis.

Animals↗

PubMed2004

Effects of tang mai kang capsule on angioneurotic lesions in alloxan-induced diabetic mice.

The effects of Tang Mai Kang Capsule ([symbol: see text]) on blood sugar level, gangrene of the tail-tip, pain threshold and learning and memory abilities were investigated in alloxan-induced diabetic mice. The results showed that Tang Mai Kang Capsule could significantly decrease blood sugar level and incidence rate of gangrene of the tail-tip, increase pain threshold, and strengthen learning and memory abilities, suggesting that Tang Mai Kang Capsule functions to decrease blood sugar level and improve the complicated angioneurotic lesions of diabetes.

Animals↗

PubMed2004

[Effect of estrogen and progesterone on the expression of VEGF mRNA in epithelial ovarian cancer cell line].

OBJECTIVE: To study the effect of 17beta-estradiol (17beta-E(2)) and medroxyprogesterone acetate (MPA) on the expression of VEGF mRNA in epithelial ovarian carcinoma cell line in vitro. METHODS: Human epithelial ovarian carcinoma cell line SKOV3 cells were exposed to 17beta-E(2) (10(-12) approximately 10(-8) mol/L) or MPA (10(-9) approximately 10(-5) mol/L), the expression level of VEGF mRNA was determined by RT-PCR. RESULTS: The PCR products of VEGF were mainly 606 bp and 474 bp. The expression of VEGF mRNA in the 17beta-E(2)-treated cells was significantly higher than in the untreated control (P < 0.05), the expression level of VEGF mRNA increased with the increase in 17beta-E(2) concentration. The expression of VEGF mRNA in SKOV3 cells treated with MPA (10(-9) approximately 10(-5) mol/L) was significantly lower than in the untreated control (P < 0.05), especially that of 606 bp. CONCLUSION: Estrogen can up-regulate, while progesterone can down-regulate mRNA expression of VEGF. Further studies are needed to elucidate the mechanism.

Adenocarcinoma↗

PubMed2004

[Endoscope-assisted parotidectomy for benign tumors via a short hidden auricular incision].

OBJECTIVE: To evaluate a technique of endoscope-assisted parotidectomy for benign tumor via a short hidden auricular incision. METHODS: Twenty-six volunteer patients were selected for the new approach, 16 with mixed tumor, 9 Warthin's tumor and 1 lymphoepithelial cyst. The tumor size was 1.6 approximately 3 cm (average 2.2 cm) and the incision ranged 3.5 approximately 5.5 cm(average 4.5cm) divided into two parts: 1) basic segment--started from anterio-superior crease of tragus, went downward along tragal margin and pre-earlobial fold,and stopped at earlobe root; 2) extended segment--went from earlobe root, curved down posterio-inferiorly. The length of the latter was generally not beyond 1 cm. The procedure began with raising the myo-cutaneous flap and dissecting the whole posterior portion of the gland. Thus, two working spaces needed for endoscopic manipulation could be artificially created with suitable retracting instruments. Endoscopic view was then established, and the surgeons operated continuously in the later steps. Modified techniques, such as the antegrade facial nerve dissection, retrograde great auricular nerve dissection and direct coagulate-cut method with ultrasonically activated scalpel, were employed to archive the goals of endoscopical nerve preservation and tissue resection. RESULTS: All tumors were entirely removed. No postoperative paralysis occurred, excepting 1 case who suffered from an temporary paralysis for two months. The appearance was good due to overlapping the short scar onto the irregular line of auricular contour and hiding its lowest part in the earlobe shadow. CONCLUSIONS: Parotidectomy for benign tumors could be safely done via a much-shortened incision, assisted by an endoscope. The postoperative stress of patients can be obviously reduced with the minimally invasive manipulation and the good appearance.

Adenolymphoma↗

PubMed2004

[Optimization of microemulsion containing vinpocetine and its physicochemical properties].

AIM: To prepare the microemulsion of vinpocetine in order to increase solubility and its in vitro transdermal delivery by using appropriate proportion of oil, surfactant (S), cosurfactant (CoS) and water. The formulation of proportion was optimized. The physicochemical properties and the skin irritation of the microemulsion was studied. METHODS: Pseudo-tertiary phase diagrams were prepared to obtain the concentration ratio of components of the microemulsion. Using simplex lattice method, the formulation of microemulsion was optimized and the physicochemical properties including pH, viscosity, refractive index, conductivity and particle size distribution were examined. The MTT method was applied to test the skin irritation of the microemulsion on the Hacat cell. RESULTS: The diagrams showed that the areas of O/W microemulsion increased with the increasing ratio of surfactant to cosurfactant (S/CoS). The predicted values from simplex lattice system were close to that of the experiment. The property of optimized microemulsion showed to be stable behavior and not irritant to Hacat cell. CONCLUSION: The drug solubility and in vitro perscutaneous permeation flux of the optimized microemulsion was improved significantly and the irritation study showed that optimized microemulsion was safe as an ideal transdermal delivery system.

Administration, Cutaneous↗

PubMed2004

[The value of endoscopic technique in maxillofacial and neck regions].

OBJECTIVE: To discuss the value of endoscopic technique in maxillofacial and neck regions. METHODS: This retrospective review included 102 clinical patients with superficial masses in maxillofacial and neck regions. The indications, incisions, endoscopic space preparation and the key points of operative process were analysed. RESULT: All of the results were satisfying. CONCLUSION: The endoscopic technique in treating superficial masses in maxillofacial and neck regions had the advantage of wide indications, multiple incision choices, easy control of operative layers and less complications. And the recent and remote effects were excellent.

Endoscopy↗

PubMed2004

[Insulin secretion and insulin sensitivity in 1193 inpatients with essential hypertension].

OBJECTIVE: To evaluate the metabolic profiles of insulin secretion and insulin sensitivity in different categories of nondiabetic patients with essential hypertension, we made a retrospecting study in our hospital. METHODS: According to the criteria of WHO and ADA, we calculated the distribution of plasma glucose levels during a 75 g oral glucose tolerance test (OGTT). Nondiabetic subjects with hypertension were classified into the following four groups: (1) normal glucose tolerance (NGT) with fasting plasma glucose (FPG) < 6.1 mmol/L and 2h-plasma glucose (2hPG) < 7.8 mmol/L, (2) Isolate impaired fasting glucose (IFG) with FPG 6.1-7 mmol/L and 2hPG < 7.8 mmol/L, (3) Isolate impaired glucose tolerance (IGT) with FPG < 6.1 mmol/L and 2hBG 7.8-11.1 mmol/L, (4) impaired fasting glucose and impaired glucose tolerance (IFG/IGT) with FPG 6.1-7 mmol/L and 2hBG 7.8-11.1 mmol/L. Then we divided the groups of NGT and IGT based on the normal 30 or 60 minute plasma glucose level during OGTT respectively. 30 minute plasma glucose level < 11.1 mmol/L and 60 minute plasma glucose level < 10.5 mmol/L were considered to be normal. HOMA-IR (insulin resistance) and composite ISI (insulin sensitivity index) were used to estimate insulin resistance and HOMA-beta and DeltaI/DeltaG index to estimate insulin secretion. RESULTS: 11.1% of the 1193 subjects were newly diagnosed diabetic patients, in whom 57.9% had isolated postchallenge hyperglycemia only. In the IGT and IFG/IGT groups, HOMA-IR were significantly higher than that in the NGT group, whereas composite ISI and DeltaI/DeltaG were significantly lower than that in the NGT group. Whether 30 or 60 minute plasma glucose level was high or not, composite ISI in IGT group was significantly lower than that in the NGT group. In the NGT group, DeltaI/DeltaG in subjects with high 30 or and 60 minute plasma glucose level was significantly lower than that in subjects with normal 30 and 60 minute plasma glucose level. CONCLUSIONS: Subjects with IGT or IFG/IGT have both impaired insulin sensitivity and insulin secretion. In the NGT group, subjects with high 30 or/and 60 minute plasma glucose level have impaired beta-cell function.

Blood Glucose↗

PubMed2004

[Detection and typing for swine leukocyte antigen].

Traditionally the cluster of swine leukocyte antigen (SLA) was typed by serological, cytological and biochemical methods. Many special molecular typing methods have been developed with the progress of molecular biological technology, such as PCR-RFLP, PCR-SSCP , MS and DNA sequencing. Here we discussed the advantages and disadvantages of each method based on the polymorphic and conservative (from the functional aspect, such as supertype and supermotif) characteristics of SLA, and illustrated the development of typing for SLA in the future. In addition, we pointed out the editorial mistakes about the serological haplotype of SLA in reference book and emphasized that the accurate polymorphism of SLA-DQB gene must be based on the cloning sequencing.

Animals↗

PubMed2004

[Changes in level of organic acids in fructus crataegi after processing].

OBJECTIVE: To compare and analyze the organic acids level in fruit of Crataegus pinnatifida var. major before and after processing. METHOD: The amount of total organic acids and individual citric acid, malate acid, ursolic acid and oleanolic acid in fruit of C. pinnatifida var. major before and after processing were determined by pH titration and HPLC analysis. RESULT: Good linear relationship between peakarea and amount was noted for 0.28-9.02 microg of malate acid, with a correlation coefficient of 0.9998. Regression equation was Y = 2344.7 + 49309.6 X. Good linear relationships between the logarithm of peak area and amount were noted for 0.348-1.74 microg of usolic acid and 0.498-2.48 microg of oleanolic acid, with a correlation coefficient of 0.9998 in each case. Regression equations were Y = 1.3628 X + 5.9508 and Y = 1.4447 X + 5.8236, respectively. CONCLUSION: The lipid-soluble organic acids mostly remain whereas only about 70% of the water-soluble acids remain after processing in fruit of C. pinnatifida var. major.

Citric Acid↗

PubMed2004

[Studies on processing of Fructus Crataegi].

Not only the evolution of the processing of Fructus Crataegi, but also the difference of chemical consitituents, pharmacological effects and clinical application before and after the processing are reviewed, based on 26 references of literature. A way to further study the processing of Fructus Crataegi is provided.

Antidiarrheals↗

PubMed2004

[Correlation study of expression levels of prostate-specific membrane antigen and prostate-specific antigen with Gleason score of prostate carcinoma].

OBJECTIVE: To study the correlation of prostate-specific membrane antigen (PSMA) and prostate-specific antigen (PSA) expression with Gleason score of prostate carcinoma. METHODS: Monoclonal antibodies against epitopes of PSMA extracellular domain were prepared, with which the expression of PSMA of prostate carcinoma (PC) was determined by immunohistochemical staining. Correlation of its expression with Gleason score of PC was statistically analyzed, and compared with that of PSA. RESULTS: Eight hybridoma cell lines secreting monoclonal antibodies specific for PSMA were prepared. PSMA expression level was positively correlated with Gleason score. In poorly differentiated prostate carcinoma, the expression intensity of PSMA was higher than that of medium-and well-differentiated prostate carcinoma (P < 0.01). However, there was no correlation between level of PSA expression and Gleason score (P > 0.05). CONCLUSION: PSMA expression level may be used as a useful surrogate marker in Gleason grading of prostate carcinoma. It may be a more suitable target than PSA in antibody mediated immunotherapy against poorly differentiated prostate carcinoma which is usually not sensitive to hormonal therapy.

Antigens, Surface↗