Biomedical subjects

Yan Wang

Publications and source records attributed to Yan Wang.

570 records · Page 32Linked to original sources

PubMed1998

Cloning of 3H11 mAb variable region gene and expression of 3H11 human-mouse chimeric light Chain.

AIM:To clone mouse anti-human gastric cancer mAb(3H11) variable genes and to construct 3H11 human-mouse chimeric antibody.METHODS: The entire VH and VL genes of anti-gastric cancer mAb 3H11 were cloned by RT-PCR method from 3H11 hybridoma cells, using 5' primers for leader sequences. The 3H11 VL gene was then inserted into human-mouse chimeric light chain expression vector and transfected into murine Sp2/0 myeloma cells.RESULTS: DNA sequence analysis indicated that the cloned genes included the whole leader sequences and the mature Ig variable region encoding sequences. After gene transfection, transient expression of chimeric light chain protein was detected.CONCLUSION: DNA sequences and transient expression indicated that the cloned gene was functional. This work laid basis for constructing 3H11 human mouse chimeric antibody in the future.

Journal Article↗

PubMed1998

Overexpression of P53 and its risk factors in esophageal cancer in urban areas of Xi'an.

AIM:To investigate the risk factors of esophageal cancer (EC) in urban areas of Xi'an and to determine the association between overexpression of P53 and these risk factors.METHODS: All cases (89) and controls (97) were permanent residents in urban areas of Xi'an, all cases of primary EC had been histologically confirmed, controls were inpatients with non-cancer and nonsmoking-related disease. Cancer tissues and tissues adjacent to the cancer of 65 cases and 24 available normal esophageal tissues of controls were detected for P53 overexpression by the immunohistochemical method.RESULTS: The smoking and familial history of cancer were significantly associated with EC in Xi'an inhabitants. The laboratory assay indicated that P53 positive stain in EC was 50.0%(34/65)and 6.1%(4/65) in tissues adjacent to the cancer, but no positive stain was found in normal esophageal tissues of controls. The results showed that P53 overexpression in EC was closely related to smoking and cases with familial history of cancer.CONCLUSION: Smoking and familial cancer history were important risk factors for EC,and the alteration of P53 gene may be due to smoking and inheritance factors.

Journal Article↗

PubMed1996

The Influence of Amino Acid Substitutions on the Function of Interleukin-2.

The effects of some residues in IL-2 on its activity have been studied by site-directed mutagenesis. After changing 39 Met or 43 Lys to Pro, neither the CD spectra (s) nor the biological activities of these mutants were changed, implying that the 39 Met and 43 Lys were not involved in the reported alpha-helical structure. However after changing 52 Glu, 53 Leu or 54 Lys to Pro respectively the CD spectra were markedly changed and the activities were decreased significantly, showing that these three amino acids in IL-2 were integrated in the alpha-helix structure and very important for their biological functions. The significance of the above results was discussed.

Journal Article↗

PubMedDate not supplied

Pramlintide reduces postprandial glucose excursions when added to insulin lispro in subjects with type 2 diabetes: a dose-timing study.

BACKGROUND: To assess the postprandial glucose-lowering effect of the human amylin analog pramlintide when given with insulin lispro in subjects with type 2 diabetes, with an emphasis on the optimal dose timing relative to meals. METHODS: In this randomized, single-blind, placebo-controlled, five-way crossover study, 19 subjects with type 2 diabetes using insulin lispro underwent five consecutive mixed-meal tests. In randomized order, subjects received subcutaneous injections of placebo at -15 min or 120-microg pramlintide at -15, 0, +15, or +30 min relative to the standardized breakfast after an overnight fast. Insulin lispro was injected at 0 min at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4-h postmeal period. RESULTS: When injected at 0 min, pramlintide reduced the postprandial glucose excursion by 81% compared to insulin lispro + placebo (incremental AUC(0-4 h) (mean +/- SE) 2.0 +/- 1.5 vs. 10.4 +/- 2.2 mmol/h/L, P<0.05). When pramlintide was injected at -15, +15, and +30 min, the postprandial incremental glucose AUC(0-4 h) was also significantly reduced (P<0.05), but to a lesser extent (42 to 73%). Pramlintide treatment was well tolerated and no serious adverse events were reported. CONCLUSIONS: Administration of pramlintide either at or just prior to a meal caused a greater reduction in postprandial glucose than either administration of placebo or postmeal pramlintide injections in subjects with type 2 diabetes treated with a rapid-acting insulin analog, insulin lispro.

Adult↗

PubMedDate not supplied

Differential diagnosis of hepatic cystic lesions with gray-scale and color Doppler sonography.

PURPOSE: This study was conducted to evaluate the effectiveness of sonography, especially color Doppler sonography, in the differential diagnosis of cystic hepatic lesions. METHODS: Ninety-two pathologically or clinically proven hepatic cystic lesions (20 cystic malignancies, 24 abscesses, and 48 simple cysts) were evaluated with gray-scale and color Doppler sonography. The sonographic features were analyzed retrospectively. The percentage, sensitivity, specificity, and positive and negative predictive values of the sonographic features of each disease category were calculated. RESULTS: On gray-scale sonography, the simple cysts were easily distinguished from cystic malignancies and abscesses. While no significant differences were found between hepatic cystic malignancies and hepatic abscesses with respect to the number, shape, margin status, and presence of thick wall of the lesion, the presence of septation and mural nodules was significantly higher in the cystic malignancies than in abscesses. The sensitivity and specificity of color Doppler sonography in differentiating cystic malignancies from abscesses and simple cysts were 85% and 96%, respectively. CONCLUSIONS: Color Doppler sonography provides information about blood flow that supplements that gained on gray-scale sonography, and the presence of color signals in the solid portion of the cystic lesions carries a high diagnostic value in differentiating hepatic cystic malignancies from abscesses and simple cysts.

Adult↗

PubMedDate not supplied

Giant cell tumor at the lateral skull base.

Giant cell tumor is a bony tumor which primarily occurs in third to fourth decade after skeletal maturation. Usually, this tumor arises in the distal end of long bone and is quite rare in the head and neck region. We had a elderly female patient with giant cell tumor at lateral skull base of the left temporal bone without classic symptoms. Team approach with neurosurgeon was used to eradicate the tumor. The detail of this case in conjunction with treatment of giant cell tumor was reported while reviewing pertinent papers.

Biopsy, Needle↗

PubMedDate not supplied

Identification of affinity ligands for protein purification from synthetic chemical combinatorial libraries.

A method to screen combinatorial libraries for the development of selective ligands for protein affinity chromatographic purification is described. The method is based on the application of parallel combinatorial libraries, and it has several potential advantages. The screening procedure is simple and straightforward, and it does not require the chemical derivatization of the target proteins or even that the target protein be pure. The experiment can also be designed to select binders that are less likely to cause protein denaturation. Feasibility of this approach is demonstrated with a model study of the chromatographic purification of bovine albumin serum (BSA) and Avidin.

Combinatorial Chemistry Techniques↗

PubMedDate not supplied

Improvement of monoclonal antibody production in hybridoma cells by dimethyl sulfoxide.

Hybridoma cultures are routinely used as a source for monoclonal antibody (mAb) production necessary for preclinical evaluation. However, these cultures typically have low volumetric and specific productivities. In this article, we examined the use and the timing of addition of dimethyl sulfoxide (DMSO) as a medium additive to improve mAb production in our hybridoma clone 19 (c19) cultures. From shake flask studies, we defined the optimal DMSO concentration and time of addition for improved productivity. This timing coordinated with high cell viability and density. Hybridoma cultures treated with DMSO up to 0.3% (v/v) possessed cell densities and viabilities comparable to untreated control. We demonstrated that 0.2% (v/v) DMSO added to shake flask cultures at their maximal viable cell densities resulted in a 2-fold increase in specific mAb production. This procedure was scaleable up to 20 L Cellbags (Wave Bioreactors) with similar titer improvement. Moreover, DMSO treatment did not affect the bioactivity or glycosylation profiles of the mAb.

Antibodies, Monoclonal↗

PubMedDate not supplied

Evaluation of L-selectin expression and assessment of protein tyrosine phosphorylation in bovine polymorphonuclear neutrophil leukocytes around parturition.

Impaired polymorphonuclear neutrophil leukocyte (PMN) function around parturition has been associated with increased clinical mastitis in dairy cows. Rolling and attachment of PMN to the endothelium is the first step in the recruitment process and is accomplished by interaction between L-selectin on PMN and its ligand on endothelial cells. Furthermore, tyrosine phosphorylation is involved in the initiation of many PMN functions. The objective of this work was to determine changes in expression of L-selectin and tyrosine phosphorylation in the perinatal period. Eight clinically healthy Holstein cows were used as PMN donors at d-21, -14, -7,0 (calving), +1, +2, +7, +14, +28. Evaluation of L-selectin expression was carried out on activated and resting PMN. Anti-bovine L-selectin monoclonal antibody (MAB) and flow cytometric analysis were used to measure the percentage of PMN fluorescing and receptor expression (log mean fluorescent channel, LMFC). Activated and resting PMN showed similar trends in % PMN fluorescence and LM FC. The percentage of PMN fluorescing tended to decrease at parturition, followed by a significant increase at d +14 and +28 (P < 0.02). For LMFC a decrease was observed on d +1 followed by an increase through d +28 (P < 0.01). Protein tyrosine phosphorylation of lysates prepared from PMN isolated throughout the study was detected by electrophoresis and western blotting using anti-phosphotyrosine MAB. Several protein bands were tyrosine phosphorylated. Two of these bands (42-44 kDa and 90 kDa) varied in intensity over time. The intensity of the 42-44 kDa band gradually increased from d -7, peaked at d +7 (P < 0.03), and steadily decreased to d +28 (P < 0.02). Antibody to activated mitogen protein kinase reacted with the 42-44 kDa band. Reduced PMN function during the periparturient period could be related to reduced L-selectin adhesion molecules on the cell surface, and to modulation in the phosphorylation of functionally important molecules.

Animals↗

PubMedDate not supplied

Functional analysis of recombinant bovine CD14.

Studies in mice and humans indicate that membrane CD14 (mCD14) on the surface of monocytes, macrophages and polymorphonuclear neutrophils (PMN) mediate activation of these cells by lipopolysaccharide (LPS). Soluble CD14 (sCD14), in the circulation, binds to LPS and blocks LPS binding to mCD14. The role of bovine CD14 in cellular activation by LPS is undefined. Changes in CD18 expression on PMN and steady state levels of mRNA for tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-8, sensitive markers for activation of leukocytes by LPS, were used to measure functional activity of recombinant bovine sCD14 (rbosCD14). Whole blood (n=3 cows) treated with LPS alone caused CD18 expression on PMN to increase by 12% (P<0.02), whereas pre-incubation of LPS with 10 or 100 microg/mL of rbosCD14 completely inhibited increase in CD18 expression. After treating whole blood with LPS at concentrations of 1, 100 or 10(4) ng/mL for 2 h, level of mRNA for TNF-alpha, IL-6 and IL-8 in leukocytes and concentration of TNF-alpha in plasma increased. However, pre-incubation of LPS with rbosCD14 inhibited the increase in TNF-alpha mRNA, but not the increase in IL-6 and IL-8 mRNA. Excess amount of anti-human CD14 monoclonal antibody (MAB) also inhibited LPS-induced increase in TNF-alpha mRNA. Preincubation of LPS with rbosCD14, or rbosCD14 plus MAB did not affect LPS-induced increase in TNF-alpha in plasma. Collectively, results indicate that rbosCD14 inhibit LPS-induced increase in CD18 expression and TNF-alpha mRNA. However, secretion of TNF-alpha was not inhibited by pre-incubation of LPS with rbosCD14. The TNF-alpha in plasma may partially induce transcription of IL-6 and IL-8, which contribute to the CD14-independent increase in level of mRNA for IL-6 and IL 8.

Animals↗

PubMedDate not supplied

Peroxiredoxin 6 gene-targeted mice show increased lung injury with paraquat-induced oxidative stress.

Mice with knock-out of peroxiredoxin 6 (Prdx6), a recently described antioxidant enzyme, were evaluated for susceptibility to lung injury with paraquat (PQ) administration. With high dose PQ (30 mg/kg i.p.), all Prdx6-/- mice died (LT50 54 +/- 2.05 h, mean +/- SE) by 4 days, whereas 86% of the wild-type (WT) mice (C57BL/6) survived (n = 14). At 2 days after PQ, lung wet/dry weight ratio increased significantly (p < 0.05) to 7.57 +/- 0.37 in Prdx6-/- mice vs. 5.42 +/- 0.25 in WT mice. Total protein and nucleated cells in bronchoalveolar lavage fluid and TBARS and protein carbonyls in lung homogenate also showed more marked increases in Prdx6-/- mice. At 2.5 days after PQ, light microscopy of WT lungs showed mild injury while Prdx6-/- lungs showed epithelial cell necrosis, perivascular edema, and inflammatory cells. With low dose PQ (12.5 mg/kg), mortality and lung injury were less marked but were significantly greater with Prdx6-/- compared to WT mice. These results show that Prdx6-/- mice have increased susceptibility to lung injury with PQ administration. Thus, Prdx6 protects lungs against PQ toxicity as shown previously for hyperoxia, indicating that it functions as an important lung antioxidant enzyme.

Animals↗

PubMedDate not supplied

Changes of higher order aberration with various pupil sizes in the myopic eye.

PURPOSE: To investigate the effect of pupil diameter on higher order aberration in myopic eyes. METHODS: One hundred and two eyes of 51 normal subjects were evaluated with the Nidek OPD-Scan. RESULTS: All types of aberration increased significantly with increasing pupil size (P<.001). However, optical aberrations had a less pronounced increase in C3(-1) and C3(+1) , more pronounced increase in C4(0) with pupil area increased (P<.05), 2nd coma (C5(-1) and C6(+1)) and high order astigmatism (C4(-2), C4(+2) C6(-2), C6(+2) with larger pupil diameter. Compared with the aberrations of each high order aberration at 4 mm, the average increase root mean square values were 1.54, 1.59, 1.71, and 1.87 on S3, S4, S5, and S6 respectively, with a 5-mm pupil, whereas increased root mean square values were 1.46, 1.88, 1.51, and 1.60 for a 6-mm-diameter pupil. CONCLUSION: For an equal increase of pupil size, not all Zernike polynomial coefficients induced equivalent increase of values. Coma-like aberrations increased less with pupil dilation. Spherical-like aberration showed only a small increase from 4 mm to 5 mm pupil size, but a larger increase from 5 mm to 6 mm pupil size. Other higher order aberrations (S5 and S6) increased slightly with pupil dilation. Coma-like aberration was larger than spherical aberration, and larger than other higher order aberrations for all pupil sizes.

Adolescent↗