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Biomedical subjects

Z Song

Publications and source records attributed to Z Song.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Biological characteristics of residual leukemic cells and their drug-resistant regrowth].

OBJECTIVE: To elucidate the mechanisms of residual leukemia and its drug-resistant regrowth. METHODS: Bone marrow cells from transplantable mouse leukemia models L615 and L7811 were cultivated in long-term culture system respectively. Daunorubicin (DNR) was added to the systems to mimick in vivo chemotherapy. RESULTS: Residual leukemic cells on stromal layers escaped DNR killing. They derived from the adherent leukemic cell population, which was heterogeneous with many undifferentiated and dormant cells. They were drug-resistant and expressed bcl-2 gene. CONCLUSION: Bone marrow stromal layer was the vital microenvironment for the residual leukemic cells to survive and regrow, and might increase the drug-resistance by up-regulating bcl-2 gene expression.

Animals↗
PubMed1997

[Molfig, a software for displaying the structure and vibration of molecule].

A Molfig software has been developed for displaying the structure and vibrational mode of molecule in our lab. Various functions and a friendly interface are equipped in the software. The testing results showed that the software may enhance our understanding of the relationship between the vibrational behavior and the structure of molecules.

English Abstract↗
PubMed1997

[Curvefit, an overlapping bands resolving software for IR spectra].

A Curvefit software has been developed for resolving the overlapping band of the vibartional spectra in our lab . Various functions and a friendly interface are equipped in the software. The testing results showed that both the speed of the calculation and the reliability of the final results are satisfactory.

English Abstract↗
PubMed1997

Optical resolution of DL-alanine by using immobilized Aspergillus oryzae cells.

Mycelium pellets with diameters of 1-2 mm and containing abundant aminoacylase were obtained by the liquid fermentation of Aspergillus oryzae 3042. By the cross-linking method with reagents of gelatin and formaldehyde, the immobilized A. oryzae cells (IAC) were prepared with much higher activity and reactive properties. The effects of factors on enzymatic activity of IAC were investigated. When substrate concentration was less than 0.15 mol/L, the Michaelis-Menten mechanism was suitable for this reaction.

Alanine↗
PubMed1997

Chronic Pseudomonas aeruginosa lung infection is more severe in Th2 responding BALB/c mice compared to Th1 responding C3H/HeN mice.

The chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) is characterized by a pronounced antibody response and microcolonies surrounded by numerous polymorphonuclear neutrophils (PMN). Poor prognosis is correlated with a high antibody response to P. aeruginosa antigens. An animal model of this infection was established in two strains of mice: C3H/HeN and BALB/c, generally known as Th1 and Th2 responders, respectively, which were challenged with alginate-embedded P. aeruginosa. Mortality was significantly lower in C3H/HeN compared to BALB/c mice (p < 0.025). P. aeruginosa was cleared more efficiently in C3H/HeN mice and significantly more C3H/HeN mice showed normal lung histopathology (p < 0.02), and we found significantly fewer microabscesses in C3H/HeN mice than in BALB/c mice (p < 0.005). In supernatants from P. aeruginosa antigen and concanavalin A-stimulated spleen cells from the two strains of mice, the interferon-(IFN-) gamma levels were higher, whereas IL-4 levels were lower in C3H/HeN mice than in BALB/c mice. The implications of these findings for CF patients with chronic P. aeruginosa lung infection are discussed.

Animals↗
PubMed1996

FTIR studies of recombinant human granulocyte-macrophage colony-stimulating factor in aqueous solutions: secondary structure, disulfide reduction and thermal behavior.

Fourier transform infrared spectroscopy (FTIR) has been used to investigate the secondary structure, disulfide reduction and thermal behavior of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in aqueous solutions. The contributions of amino-acid side-chain groups to the amide I bands of rhGM-CSF in H2O and in D2O solutions were carefully scrutinized, as 40% of the total 127 amino-acid residues of rhGM-CSF is side-chain absorptive (asparagine, glutamine, etc.). The FTIR results indicated that rhGM-CSF is composed of 46% alpha-helix, 7% beta-sheet, 23% turn and 24% loop/irregular structures which are in good agreement with the X-ray diffractional data. Reduction of rhGM-CSF with dithiothreitol caused apparent unfolding of the native conformation followed by the time-dependent increase of beta-aggregation bands which arose at 1622 and 1693 cm(-1) in H2O, 1613 and 1684 cm(-1) in D2O solutions. The result also showed that tertiary structure can change independently of the secondary structure. Thermal denaturation of rhGM-CSF took place at 55 to 70 degrees C and the denatured protein adopted an irregular structure as revealed by the FTIR spectra. The thermal denaturation did not show the formation of intermolecular beta-aggregates which is typical of most thermal denatured proteins. Moreover, it is partly reversible, indicating a special thermal stability of rhGM-CSF.

Deuterium Oxide↗
PubMed1996

Polymorphic nucleotides within the human IL-4 promoter that mediate overexpression of the gene.

Atopy, which predisposes individuals to develop asthma, severe systemic anaphylaxis, and atopic dermatitis, is usually associated with dramatically elevated total serum IgE levels and is thought to be controlled by a major susceptibility gene and multiple minor susceptibility genes. A recent sib-pair analysis revealed a tight linkage between markers on 5q31.1 and a major susceptibility gene controlling total serum IgE levels. Due to its location within this cluster and its biologic role in Ig class switching and Th2 cell differentiation, the IL-4 gene has emerged as one major candidate for the atopy gene. In one model, polymorphisms within IL-4 regulatory elements might result in overexpression of the gene, amplifying Th2 cell differentiation and class switching to IgE. In support of this model, we report that the human IL-4 promoter exists in multiple allelic forms that exhibit distinct transcriptional activities in IL-4-positive T cells. A particular allele has an unusually high transcriptional activity. A nucleotide substitution within a recently described OAP40 element located just upstream of an NF-AT site (P sequence) appears to be largely responsible for the increased promotor strength of this particular allelic form of the IL-4 promoter. In EMSAs, this substitution results in a markedly enhanced affinity for sequence-specific complexes exhibiting an AP-1 specificity. The identification of allelic nucleotides, which results in overexpression of the IL-4 gene, provides specific targets for a comprehensive screening of atopic and nonatopic individuals and may provide a clue for genetic predisposition for atopy.

Alleles↗
PubMed1996

Biology and genetics of atopic disease.

Several immunological disorders including allergic rhinitis, bronchial asthma, atopic dermatitis, food allergies, urticaria, nonhereditary angioedema, systemic anaphylaxis, and allergic conjunctivitis are associated with a positive family history, and share a positive response in the Prausnitz-Kuster (wheal and flare) reaction. Studies have shown that 20-30% of the population has a strong genetic predisposition for this condition, termed atopy, whose hallmark is a greatly elevated serum IgE concentration. A great deal is known about the cellular interactions that mediate the sensitization, immediate and late-phase reactions that follow encounters with allergen, as well as about the cell surface and signaling events that result in mediator release from inflammatory cells. Less is known of the genes that confer genetic predisposition for atopy; however, a worldwide effort to identify atopy genes is making significant progress.

Animals↗
PubMed1996

[A brief history of studies on anti-tumor remedies in China].

This paper gives a general introduction to the studies on the formulation and invention of anti-tumor remedies from 1950s-1980s. Beginning from 50s, antitumor antibiotics were investigated. New alkylicompoun and antibiotics were found in the 60s, while more new natural compounds were found in the 70s. Researches were proceeded in the 80s based on the former achievements. Through the process of about 30 years, nearly 80 new species were produced, many anti-tumor pharmaceutical corporations established, and a contigent of high level research workers was formed. However, there still exist a rather large gap between the urgent clinical needs for clinical chemotherapeutics and the actual status. Based on some 30 years of experience in China, the following points were summarized, i.e., shifting from merely imitation to invention, developing the spirit of massive cooperation, investigating the thesaurus of TCM, developing China's plant resources, and traditional Chinese preventive idea, so that the stress point for research be laid on the invention of preventive anti-tumor remedies.

China↗
PubMed1996

[Sixty years of studies on history of Chinese pharmacy].

This paper is presented in studies on the following subtopics: 1. General history of Chinese pharmacy; 2. Study and systematization of ancient herbological works; 3. History of individual drugs; 4. History of commercial and industrial aspects of Chinese and Western drugs; 5. Unearthed historical materials of pharmacy; 6. History of pharmacy of national minority; 7. Education on pharmacy; 8. History of special subjects in pharmacy; 9. Figures of pharmacy.

China↗
PubMed1996

Effects of Chinese medicinal herbs on a rat model of chronic Pseudomonas aeruginosa lung infection.

The aim of the study was to evaluate the effects of two kinds of Chinese medicinal herbs, Isatis tinctoria L (ITL) and Daphne giraldii Nitsche (DGN), on a rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis (CF). Compared to the control group, both drugs were able to reduce the incidence of lung abscess (p < 0.05) and to decrease the severity of the macroscopic pathology in lungs (p < 0.05). In the great majority of the rats, the herbs altered the inflammatory response in the lungs from an acute type inflammation, dominated by polymorphonuclear leukocytes (PMN), to a chronic type inflammation, dominated by mononuclear leukocytes (MN). DGN also improved the clearance of P. aeruginosa from the lungs (p < 0.03) compared with the control group. There were no significant differences between the control group and the two herbal groups with regard to serum IgG and IgA anti-P. aeruginosa sonicate antibodies. However, the IgM concentration in the ITL group was significantly lower than in the control group (p < 0.03). These results suggest that the two medicinal herbs might be helpful to CF patients with chronic P. aeruginosa lung infection, DGN being the most favorable.

Agar↗
PubMed1995

Inhibition of NF-AT-dependent transcription by NF-kappa B: implications for differential gene expression in T helper cell subsets.

Activation of individual CD4+ T cells results in differential lymphokine expression: interleukin 2 (IL-2) is preferentially produced by T helper type 1 (TH1) cells, which are involved in cell-mediated immune responses, whereas IL-4 is synthesized by TH2 cells, which are essential for humoral immunity. The Ca(2+)-dependent factor NF-ATp plays a key role in the inducible transcription of both these lymphokine genes. However, while IL2 expression requires the contribution of Ca(2+)- and protein kinase C-dependent signals, we report that activation of human IL4 transcription through the Ca(2+)-dependent pathway is diminished by protein kinase C stimulation in Jurkat T cells. This phenomenon is due to mutually exclusive binding of NF-ATp and NF-kappa B to the P sequence, an element located 69 bp upstream of the IL4 transcription initiation site. Human IL4 promoter-mediated transcription is downregulated in Jurkat cells stimulated with the NF-kappa B-activating cytokine tumor necrosis factor alpha and suppressed in RelA-overexpressing cells. In contrast, protein kinase C stimulation or RelA overexpression does not affect the activity of a human IL4 promoter containing a mouse P sequence, which is a higher-affinity site for NF-ATp and a lower-affinity site for RelA. Thus, competition between two general transcriptional activators, RelA and NF-ATp, mediates the inhibitory effect of protein kinase C stimulation on IL4 expression and may contribute to differential gene expression in TH cells.

Animals↗
PubMed1995

Mapping of the interaction site of the defective transcription factor in the class II major histocompatibility complex mutant cell line clone-13 to the divergent X2-box.

We have previously described a mutant B lymphoblastoid cell line, Clone-13, that expresses HLA-DQ in the absence of HLA-DR and -DP. Several criteria indicated that the defect in this cell line influences the activity of an isotype-specific transcription factor. Indeed, transient transfection of HLA-DRA and DQB reporter constructs indicated that the affected factor operates via cis-elements located between -141 base pairs and the transcription initiation site. A series of hybrid DRA/DQB reporter constructs was generated to further map the relevant cis-elements in this system. Insertion of oligonucleotides spanning the DQB X-box (but not the DQB-W region or the DQB Y-box) upstream of -141 in a DRA reporter plasmid rescued expression to nearly wild-type levels. Substitution promoters were then generated where the entire X-box, or only the X1- or X2-boxes of HLA-DRA were replaced with the analogous regions of HLA-DQB. The DQB X2-box was able to restore expression to the silent DRA reporter construct. Moreover, replacement of the DQB X2-box with the DRA X2-box markedly diminished the activity of the DQB promoter in the mutant cell. None of the hybrid reporter constructs were defective when transfected into the wild-type, HLA-DR/-DQ positive parental cell line, Jijoye. These studies suggest that the divergent X2-box of the class II major histocompatibility complex promoters plays an important role in influencing differential expression of the human class II isotypes.

B-Lymphocytes↗
PubMed1995

Expression and function of beta 1 integrins on adherent and nonadherent Ehrlich ascites tumor cells.

Differences in integrin-mediated cell-matrix adhesion between two types of Ehrlich ascites tumor (EAT) cells, adherent and nonadherent EAT cells, have been studied. The adherent EAT (a-EAT) cells adhere to and spread on laminin- or fibronectin-coated plates, whereas the nonadherent EAT (na-EAT) cells do not. The adhesion of a-EAT cells to laminin or fibronectin requires the presence of both Ca2+ and Mg2+. Anti-human fibronectin receptor (alpha 5 beta 1 integrin) antiserum blocks a-EAT cells from adhering to both laminin- and fibronectin-coated plates. An RGD-containing peptide (GRGDSP) inhibits the adhesion of a-EAT cells to fibronectin-coated but not to laminin-coated plates. Taken together, these data suggest that a-EAT cells interact with laminin and fibronectin via different beta 1 integrins. As determined by immunofluorescence flow cytometry assay, both a-EAT and na-EAT cells express similar amounts of surface antigen(s) recognized by the same anti-alpha 5 beta 1 integrin polyclonal antibody that blocks a-EAT cells from adhering to laminin and fibronectin. The alpha 5 and beta 1 subunits expressed on both types of EAT cells appear to have the same molecular weight when analyzed by immunoblotting. The same amount of 125I-labeled membrane protein was isolated from both types of EAT cells on immobilized laminin and fibronectin affinity columns. These data indicate that na-EAT cells express similar amounts of cell surface integrins, and these integrins, when isolated, react with laminin and fibronectin in the same manner as the integrins of a-EAT cells, even though na-EAT cells are unable to adhere to laminin and fibronectin. Previous work has shown that both types of EAT cells express Neu5Ac alpha 2,3 Gal-beta 1, 4 GlcNAc residues on their cell surface and that they both react with Maackia amurensis lectin which specifically recognizes this carbohydrate structure. Here we show that both types of EAT cells attach to M. amurensis lectin-coated surfaces, but only a-EAT cells spread; this suggests that the differences between these two types of cells in responding to extra cellular matrix molecules may reside in some differences within the cell.

Animals↗