[Study on the interaction between CP and DNA]

In this paper, interaction between CP (Cis-ddp or ciplatin) and DNA (deoxyribonucleicacid) was studied using the fluorescence probe as well as the absorption spectra of DAN.

[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.

[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.

DCP-1, a Drosophila cell death protease essential for development

Apoptosis, a form of cellular suicide, involves the activation of CED-3-related cysteine proteases (caspases). The regulation of caspases by apoptotic signals and the precise mechanism by which they kill the cell remain unknown. In Drosophila, different death-inducing stimuli induce the expression of the apoptotic activator reaper. Cell killing by reaper and two genetically linked apoptotic activators, hid and grim, requires caspase activity. A Drosophila caspase, named Drosophila caspase-1 (DCP-1), was identified and found to be structurally and biochemically similar to Caenorhabditis elegans CED-3. Loss of zygotic DCP-1 function in Drosophila caused larval lethality and melanotic tumors, showing that this gene is essential for normal development.

T cell receptor (V beta) bias in the response of rheumatoid arthritis synovial fluid T cells to connective tissue antigens

T cell receptor (V beta) use in the response to type II collagen and cartilage proteoglycans was analysed in peripheral blood and synovial fluid T cells from RA patients. T cells from RA patients with an immune response to connective tissue antigens, and paired PB and SF samples were stimulated in vitro with type II collagen, high density aggrecan proteoglycans (PG), and the T cell mitogen concanavalin A. After short term culture, mRNA was extracted from cells and a reverse transcription-polymerase chain reaction was performed, using primers specific for eight TCR V beta determinants. Blood cells stimulated with ConA generated strong bands with virtually all the V beta primers tested, but the TCR (V beta) expression by SF T cells stimulated with mitogen was biased, suggesting a selection process during joint infiltration. The V beta phenotypes of cells responding to PG was restricted in individual RA patients, but the pattern of V beta use in the the RA population was not consistent. In contrast, the V beta phenotypes of SF cells responding to CII was highly biased in both individual patients and the RA population, with V beta 14, V beta 17, and V beta 8 phenotypes predominant. We conclude that the T cell response to connective tissue antigens is restricted compared with mitogen stimulation, with the highest degree of TCR bias seen in the response of SF T cells to stimulation with type II collagen.

[Comparative test on spawn culture materials of Poria cocos]

It saves much time, work and timber when Poria cocos spawn is made from cottonseed hulls and pine sawdust. Compared with the yields from pine wood chip, the difference is not significant.

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.

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.

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.

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.

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.

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.

[Chemical constituents of Clematis intricata Bunge]

Five compounds were isolated from the aerial part of Clematis intricata for the first time. On the basis of spectral data (UV, IR, MS, 1HNMR and 13CNMR), they were identified as scopoletin, caffeic acid, inositol, 1-tria-contanol and beta-sitosterol.

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.

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.

Significance of flow cytometry in the diagnosis and treatment of bladder tumors

The results of application of flow cytometry (FCM) in analysis of 139 bladder irrigations of DNA contents in tumor cells from 52 cases of bladder tumors are reported. A comparison was made between this assay and cytological examinations as well as pathological grading. The results suggested that the accuracy of cytological analysis was apparently lower than the cell DNA measurement by flow cytometry, the higher the tumor pathological grading and the deeper the infiltration, the higher the heteroploid DNA contents in the tumor cells. Treatment of high heteroploid bladder tumor required radical cystectomy while the efficiency of simple electrosection or partial cystectomy appeared inferior. When FCM and the bladder tumor pathological grading had a high degree of correlation, especially in the high grading tumor, recurrence was high even when chemical treatment with bladder instillation of BCG was adopted. However, FCM cannot substitute for cystoscopy.

Mechanochemical study of NaDNA and NaDNA-netropsin fibers in ethanol-water and trifluoroethanol-water solutions

Highly oriented calf-thymus NaDNA fibers, prepared by a wet-spinning method, were complexed with netropsin in ethanol-water and trifluoroethanol (TFE)-water solutions. The relative fiber length, L/L0, was measured at room temperature as a function of ethanol or TFE concentration to obtain information on the B-A conformational transition. The B-A transition point and transition cooperativity of the fibers were calculated. The binding of netropsin to NaDNA fibers was found to stabilize B form and to displace the B-A transition to higher ethanol concentration, as indicated by its elongational effect on the fiber bundles. An increased salt concentration was found to reduce netropsin binding. In netropsin-free ethanol solution, the dissociation of bound netropsin from the DNA fibers was observable. Pure B-NaDNA fibers were found to be more stable in TFE solution than in ethanol solution. This was interpreted as being due to a different steric factor and a larger polarity of TFE compared with ethanol, resulting in its smaller capacity to reduce the water activity and dielectric constant of the medium in the immediate vicinity of DNA fibers. Therefore, the effect of netropsin binding on the B-A transition of NaDNA fibers became less obvious in TFE solution. In another series of experiments, L/L0 was measured as a function of temperature to obtain information on the helix-coil transition, or melting, as well as the B-A transition of NaDNA and NaDNA-netropsin fibers. The melting temperature and helix-coil transition width were calculated from the melting curves. A phenomenological approach was used to describe the melting behavior of the fibers in and around the B-A transition region. The effect of netropsin on the melting of DNA fibers was attributed mainly to the stabilization of B-DNA and to a higher melting cooperativity in the B-DNA region.

Differential expression of cell surface sialoglycoconjugates on wild-type and cultured Ehrlich tumor cells as revealed by quantitative lectin-gold ultrastructural cytochemistry

Three variants of the classical Ehrlich ascites tumor (EAT) cell have been studied by quantitative, sialic acid-specific, lectin-gold ultrastructural cytochemistry. Electron microscopic examination revealed pronounced differences in the surface morphology of the three cell variants. The wild-type Ehrlich cells (EAT-wt), grown in the peritoneal cavity of mice, exhibited a smooth surface profile. A variant form selected for growth as monolayer on basement membrane (EAT-c) showed a complex surface profile with numerous microvilli. The third variant (EAT-c/m), the cultured cells reinoculated into mice and passaged 20-25 times as ascites, presented a smooth surface profile similar to the EAT-wt cells. Quantitative single as well as double lectin-gold labeling revealed significant differences in the nature of cell surface sialoglycoproteins. The most significant finding was the presence of cell surface Neu5Ac alpha 2-6Gal residues as detected with the Sambucus nigra lectin on EAT-c and EAT-c/m cells, whereas EAT-wt cells contained little or none of such carbohydrate sequences. On the contrary, labeling by Maackia amurensis lectin, which recognizes the Neu5Ac alpha 2-3Gal beta 1-4GlcNAc sequence, was intense on all three Ehrlich cell variants; it was 20-60 times greater than alpha-2,6-linked sialic acid-containing glycoconjugates. Specific cell surface lectin binding combined with morphologic study appears to have identified a small subpopulation of cells within the ascites tumor that are capable of attaching to and growing on a basement membrane.

A novel cysteine-rich sequence-specific DNA-binding protein interacts with the conserved X-box motif of the human major histocompatibility complex class II genes via a repeated Cys-His domain and functions as a transcriptional repressor

The class II major histocompatibility complex (MHC) molecules function in the presentation of processed peptides to helper T cells. As most mammalian cells can endocytose and process foreign antigen, the critical determinant of an antigen-presenting cell is its ability to express class II MHC molecules. Expression of these molecules is usually restricted to cells of the immune system and dysregulated expression is hypothesized to contribute to the pathogenesis of a severe combined immunodeficiency syndrome and certain autoimmune diseases. Human complementary DNA clones encoding a newly identified, cysteine-rich transcription factor, NF-X1, which binds to the conserved X-box motif of class II MHC genes, were obtained, and the primary amino acid sequence deduced. The major open reading frame encodes a polypeptide of 1,104 amino acids with a symmetrical organization. A central cysteine-rich portion encodes the DNA-binding domain, and is subdivided into seven repeated motifs. This motif is similar to but distinct from the LIM domain and the RING finger family, and is reminiscent of known metal-binding regions. The unique arrangement of cysteines indicates that the consensus sequence CX3CXL-XCGX1-5HXCX3CHXGXC represents a novel cysteine-rich motif. Two lines of evidence indicate that the polypeptide encodes a potent and biologically relevant repressor of HLA-DRA transcription: (a) overexpression of NF-X1 from a retroviral construct strongly decreases transcription from the HLA-DRA promoter; and (b) the NF-X1 transcript is markedly induced late after induction with interferon gamma (IFN-gamma), coinciding with postinduction attenuation of HLA-DRA transcription. The NF-X1 protein may therefore play an important role in regulating the duration of an inflammatory response by limiting the period in which class II MHC molecules are induced by IFN-gamma.