Search results for "inducer"
showing 10 items of 178 documents
Immunological and biological identification of tumour necrosis-like factor in sponges: Endotoxin that mediates necrosis formation in xenografts
1992
Xenografts of the sponge Geodia cydonium in its closely related species G. rovinjensis resulted in a rapid rejection of the graft within a period of 5 days. We identified an immunoreactive tumour necrosis factor (TNF)-like activity in the xenograft (Mr of 30,000) two days after grafting. In-vivo injection of 5 micrograms human recombinant TNF-alpha induced cytotoxicity in sponge cells in the same pattern and time course as during natural xenograft rejection. Anti-TNF-alpha polyclonals were found to react with xenograft extracts, by Western blot analysis, as from day 2 after grafting. Using ELISA we detected the TNF-like activity from day 2 after grafting with peak levels at days 4 and 5, wh…
The behaviour of OKT3-, OKT4- and OKT8-positive cells during phases of elevated spontaneous chemiluminescence activity (CL-A) in multiple sclerosis p…
1987
The chemiluminescence activity (CL-A; synonym = burst activity, BA) and the percentage of OKT3-, OKT4- and OKT8-positive peripheral blood cells were serially examined in four control persons and in eight patients with multiple sclerosis. When the OKT values obtained in phases of increased CL-A (clinical remission) were compared with those of the control group, the percentage of OKT3-positive cells was reduced (P = 0.014), and that of OKT4-positive cells increased (P = 0.014); there were no significant changes in the percentage of OKT8-positive cells (P = 0.171). After the CL-A had returned to normal values, the OKT4-positive cells remained elevated (P = 0.029), whereas the OKT3- (P = 0.342)…
INDUCTION OF CYTOCHROME P-448 BY 3-METHYLCHOLANTHRENE IN THE RAT DURING INHIBITION OF PROTEIN SYNTHESIS IN VIVO
1977
Administration of cycloheximide in vivo during induction of rats with 3-methylcholanthrene prevents the increase in total cytochrome P-450 content usually seen under the influence of the inducer. The population of cytochromes P-450 in the livers of these animals is, however, similar to that in the completely induced animals. Microsomal aryl hydrocarbon hydroxylase activity and biphenyl-2-hydroxylation are enhanced severalfold and biphenyl-4-hydroxylation is enhanced twofold. Monooxygenase activity shows the same pattern of preferential inhibition as in microsomes from animals which had received the inducer only. The affinity of the reduced cytochromes for the ligand metyrapone is considerab…
Comparison of enzyme phenotypes in human bladder tumours and experimentally induced hyperplastic and neoplastic lesions of the rat urinary bladder. A…
1988
The expression of a number of enzymes involved in drug metabolism, membrane function etc. was compared in hyperplastic and neoplastic lesions of the rat bladder and in human bladder tumours. Transitional cell carcinomas (TCC) in both rat and Man were characterized by decreased alkaline phosphatase (ALP) and increased gamma-glutamyl transpeptidase (GGT), beta-glucuronidase (beta-G1), succinate dehydrogenase (SD) and glucose-6-phosphate dehydrogenase (G6PD) activities. In addition, binding for antibodies specific for different cytochrome P-450 species (UT50, PB3a, MC1, MC2) and microsomal epoxide hydrolase (mEHb) was elevated in both murine and human tumours. Comparison of the enzyme phenotyp…
Differentiation driven by granulocyte-macrophage colony-stimulating factor endows microglia with interferon-γ-independent antigen presentation functi…
1993
The antigen presentation function of microglial cells was analyzed after differentiation in neonatal mouse brain cell cultures supplemented either with macrophage (M) or granulocyte/macrophage (GM) colony-stimulating factor (CSF). The cells separated from concomitant astrocytes in both culture systems turned out to exhibit cytological characteristics of macrophages and bore MAC-1 and F4/80 markers in a similar way. When comparatively tested for accessory cell function, only microglia developed with GM-CSF were able to efficiently induce antigen-directed proliferation of a series of helper T cell lines representing both the TH1 and TH2 subtype. Antigenic T cell activation by this microglia p…
Dominant role of paraoxonases in inactivation of the Pseudomonas aeruginosa quorum-sensing signal N-(3-oxododecanoyl)-L-homoserine lactone.
2008
Pseudomonas aeruginosa is an opportunistic bacterium which causes serious infections in immunocompromised and cystic fibrosis patients (10). As with many gram-negative bacteria, P. aeruginosa produces acyl-homoserine lactone (AHL) quorum-sensing (QS) signaling molecules termed autoinducers which allow the single-celled organisms to coordinate their actions (36). N-(3-Oxododecanoyl)-l-homoserine lactone (3OC12-HSL) is a key autoinducer synthesized by P. aeruginosa which regulates the expression of extracellular virulence factors and biofilm formation (5, 36). Rats and mice experimentally infected with P. aeruginosa mutants deficient in the ability to produce or respond to 3OC12-HSL exhibited…
Requirements for the growth of TH1 lymphocyte clones.
1990
Besides the signal generated in a T lymphocyte after triggering the T cell receptor (TcR), most lymphocytes need a "second signal" to become fully activated. The necessity and nature of the "second signal" differs between different types of T cells. At the level of CD4-positive T helper lymphocytes interleukin 1 (IL 1) serves as "second signal" for those of the TH2 subtype (IL4, 5, 6 producer) but not for those of the TH1 subtype (IL 2, IFN-gamma producer). This correlates with the absence of the IL 1 receptor at the surface of TH1 clones. We report herein the further purification of T cell stimulating factor (TSF), a soluble mediator involved in the proliferation of TH1 lymphocytes. A prep…
IL28B polymorphisms influence stage of fibrosis and spontaneous or interferon-induced viral clearance in thalassemia patients with hepatitis C virus …
2012
Background. Polymorphisms in the interleukin-28B are important determinants in the spontaneous and drug-induced control of hepatitis C virus infection. Design and Methods. We assessed the association of rs8099917 and rs12979860 polymorphisms with spontaneous viral clearance, severity of liver fibrosis, and response to interferon-monotherapy in 245 Thalassemia Major patients with Hepatitis C Virus infection. Results. Ninety-eight patients (40%) had a spontaneous viral clearance, while 147 patients (60%) developed a chronic infection. Spontaneous viral clearance was more frequent among patients with the T/T genotype of rs8099917 polymorphism (OR 2.130; p=0.008) or C/C genotype of rs12979860 p…
Free Radicals Mediate Systemic Acquired Resistance
2014
Summary: Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azel…
Quantitative and functional analysis of core-specific T-helper cell and CTL activities in acute and chronic hepatitis B
2008
Aims/background CD4+ T-helper cell (Th) responses to hepatitis B virus (HBV) core antigen (HBc) are increased during exacerbations in acute and chronic hepatitis B (AHB, CHB) and might influence the induction of CD8+ cytotoxic T lymphocytes (CTL) that are important for viral clearance. Methods HBc-specific proliferative responses and cytokine release of blood mononuclear cells (PBMC) were studied in patients with AHB or CHB, as well as responders and non-responders to interferon-alpha treatment (IFN-R, IFN-NR), by [3H]-thymidine-uptake, enzyme-linked immunosorbent assay (ELISA) and Elispot assay and were compared to peptide HBc18 27-specific CTL precursor frequencies among CD8+ T cells deri…