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Sturm A, Leite AZA, Danese S, Krivacic KA, West GA, Mohr S, Jacobberger JW, Fiocchi C. Divergent cell cycle kinetics underlie the distinct functional capacity of mucosal T cells in Crohn's disease and ulcerative colitis. Gut 2004; 53:1624-31. [PMID: 15479683 PMCID: PMC1774268 DOI: 10.1136/gut.2003.033613] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Different abnormalities of T cell effector function distinguish Crohn's disease (CD) from ulcerative colitis (UC). Because cell cycling determines effector function, pathogenic events in CD and UC may depend on cell cycle changes unique to each condition. METHODS Cell cycle kinetics, cycle regulatory molecule expression, apoptosis, caspase and telomerase activity, and cellular expansion were evaluated in CD2 and CD3 activated control, CD, and UC lamina propria T cells. RESULTS Compared with normal cells, CD T cells cycle faster, express increased phosphorylated Rb and decreased phosphorylated p53 levels, display less caspase activity but more telomerase activity, die less, and undergo vigorous cellular expansion. In contrast, UC T cells cycle slower, express normal levels of phosphorylated Rb and p53, display more caspase activity but have no telomerase activity, die more, and have a limited capacity to expand. CONCLUSIONS T cell cycle abnormalities in CD indicate a state of hyperreactivity compatible with loss of tolerance, but a hyporeactive state compatible with anergy in UC. Thus distinct and divergent T cell cycle characteristics underlie the pathogenesis of the two main forms of inflammatory bowel disease.
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Dignass AU, Baumgart DC, Sturm A. Review article: the aetiopathogenesis of inflammatory bowel disease--immunology and repair mechanisms. Aliment Pharmacol Ther 2004; 20 Suppl 4:9-17. [PMID: 15352888 DOI: 10.1111/j.1365-2036.2004.02047.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although the aetiopathogenesis of Crohn's disease and ulcerative colitis, remains unsolved, current evidence indicates that defective T-cell apoptosis and impairment of intestinal epithelial barrier function play important roles in the pathogenesis of both conditions. Without appropriate control of T-cell proliferation and death during an immune response, an inappropriate accumulation of T cells and subsequent intestinal inflammation may occur. Differences in T-cell responses between Crohn's disease and ulcerative colitis have been identified, with mucosal T-cell apoptosis being defective in Crohn's disease, but not in ulcerative colitis. Furthermore, cell cycling is considerably faster, with a vigorous clonal expansion, in Crohn's disease, whereas, in ulcerative colitis, T cells cycle normally, but have a remarkably reduced capacity to divide and expand. The elimination of excessive T cells therefore seems to be a reasonable approach to restore the gut to a physiological state or, at least, a controlled state of inflammation. The tumour necrosis factor-alpha blocker, infliximab, exerts its beneficial effects, at least in part, by the induction of apoptosis in lamina propria T cells and monocytes. In addition, repeated damage and injury of the intestinal surface is a hallmark of inflammatory bowel disease and may facilitate the entry of luminal antigens into the mammalian organism and the initiation and perpetuation of both nonspecific and specific immune responses. A better understanding of and enhancement of intestinal repair mechanisms may thus provide future approaches for the treatment of inflammatory bowel disease.
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Bury NR, Sturm A, Le Rouzic P, Lethimonier C, Ducouret B, Guiguen Y, Robinson-Rechavi M, Laudet V, Rafestin-Oblin ME, Prunet P. Evidence for two distinct functional glucocorticoid receptors in teleost fish. J Mol Endocrinol 2003; 31:141-56. [PMID: 12914532 DOI: 10.1677/jme.0.0310141] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Using RT-PCR with degenerated primers followed by screening of a rainbow trout (Oncorhynchus mykiss) intestinal cDNA library, we have isolated from the rainbow trout a new corticosteroid receptor which shows high sequence homology with other glucocorticoid receptors (GRs), but is clearly different from the previous trout GR (named rtGR1). Phylogenetic analysis of these two sequences and other GRs known in mammals, amphibians and fishes indicate that the GR duplication is probably common to most teleost fish. The open reading frame of this new trout GR (named rtGR2) encodes a protein of 669 amino acids and in vitro translation produces a protein of 80 kDa that appears clearly different from rtGR1 protein (88 kDa). Using rtGR2 cDNA as a probe, a 7.3 kb transcript was observed in various tIssues suggesting that this gene would lead to expression of a steroid receptor. In vitro studies were used to further characterize this new corticosteroid receptor. Binding studies with recombinant rtGR1 and rtGR2 proteins show that the two receptors have a similar affinity for dexamethasone (GR1 K(d)=5.05+/-0.45 nM; GR2 K(d)=3.04+/-0.79 nM). Co-transfection of an rtGR1 or rtGR2 expression vector into CHO-K1 or COS-7 cells, along with a reporter plasmid containing multiple consensus glucocorticoid response elements, shows that both clones are able to induce transcriptional activity in the presence of cortisol and dexamethasone. Moreover, at 10(-)(6 )M 11-deoxycortisol and corticosterone partially induced rtGR2 transactivation activity but were without effect on rtGR1. The other major teleost reproductive hormones, as well as a number of their precursors or breakdown products of these and corticosteroid hormones, were without major effects on either receptor. Interestingly, rtGR2 transactivational activity was induced at far lower concentrations of dexamethasone or cortisol (cortisol EC(50)=0.72+/-0.87 nM) compared with rtGR1 (cortisol EC(50)=46+/-12 nM). Similarly, even though RU486 inhibited transactivation activity in both rtGR1 and rtGR2, rtGR1 was more sensitive to this GR antagonist. Altogether, these results indicate that these two GR sequences encode for two functionally distinct GRs acting as ligand-inducible transcription factors in rainbow trout.
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Sturm A, Ziemann C, Hirsch-Ernst KI, Segner H. Expression and functional activity of P-glycoprotein in cultured hepatocytes from Oncorhynchus mykiss. Am J Physiol Regul Integr Comp Physiol 2001; 281:R1119-26. [PMID: 11557618 DOI: 10.1152/ajpregu.2001.281.4.r1119] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
P-glycoproteins encoded by multidrug resistance 1 (mdr1) genes are ATP-dependent transporters located in the plasma membrane that mediate the extrusion of hydrophobic compounds from the cell. Using cultured isolated rainbow trout hepatocytes, we characterized an mdr1-like transport mechanism of the teleost liver. Immunoblots with the monoclonal antibody C219, which recognizes a conserved epitope of P-glycoproteins, revealed the presence of immunoreactive protein(s) of 165 kDa in trout liver and cultured hepatocytes. In trout liver sections, the immunohistochemistry with C219 stained bile canalicular structures. Compounds known to interfere with mdr1-dependent transport (verapamil, vinblastine, doxorubicin, cyclosporin A, and vanadate) all increased the accumulation of rhodamine 123 by hepatocytes. Verapamil, vinblastine, and cyclosporin A decreased the efflux of rhodamine 123 from hepatocytes preloaded with rhodamine 123. By contrast, the substrate of the canalicular cation transporter tetraethylammonium and the inhibitor of the multidrug resistance-associated protein MK571 had no effect on rhodamine 123 transport. The results demonstrate the presence of an mdr1-like transport system in the teleost liver and suggest its function in biliary excretion.
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Jeena P, Thompson E, Nchabeleng M, Sturm A. Emergence of multi-drug-resistant Acinetobacter anitratus species in neonatal and paediatric intensive care units in a developing country: concern about antimicrobial policies. ANNALS OF TROPICAL PAEDIATRICS 2001; 21:245-51. [PMID: 11579864 DOI: 10.1080/02724930120077835] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Antimicrobial abuse is a serious risk factor for the emergence of multi-drug-resistant (MDR) pathogens. We report on the emergence of multi-drug-resistant Acinetobacter anitratus species over two 8-week periods in 1999 in the neonatal and paediatric intensive care units (NICU and PICU) of King Edward VII Hospital, Durban, South Africa. The source, transmission dynamics, microbiological evaluations, antibiotic utilization patterns and outcome were evaluated. MDR Acinetobacter anitratus was isolated from different body sites in 23 infants less than 2 months of age, 18 in the PICU and five in the NICU. The mortality was 56.5% and two survivors required re-admission. Ten of the 23 cases had entered the ICU with MDR Acinetobacter anitratus. Eleven of the study infants had received broad-spectrum antimicrobial agents before entering the ICU, while all infants with nosocomially acquired MDR Acinetobacter anitratus had received broad-spectrum antimicrobial agents. All the surgical cases with MDR Acinetobacter anitratus died. Microbiological data from both ICUs for 1999 indicated that gram-negative bacteria accounted for two-thirds of isolates, Acinetobacter anitratus and Klebsiella pneumoniae accounting for 33% and 27% of the isolates, respectively. Only 53% and 57% of all Acinetobacter spp isolates were susceptible to piperacillin/tazobactam and carbepenems, respectively. MDR Acinetobacter anitratus is an emerging problem to which antimicrobial abuse contributes.
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Sturm A, Cravedi JP, Segner H. Prochloraz and nonylphenol diethoxylate inhibit an mdr1-like activity in vitro, but do not alter hepatic levels of P-glycoprotein in trout exposed in vivo. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2001; 53:215-228. [PMID: 11408081 DOI: 10.1016/s0166-445x(01)00167-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
P-glycoproteins (P-gps) encoded by multidrug resistance 1 (mdr1) genes are ATP-dependent transporters located in the cytoplasmic membrane which mediate the efflux of a broad spectrum of hydrophobic compounds from the cell. The tissue distribution of P-gps suggests their role in the organismal defense against xenobiotics by effecting xenobiotic excretion and reducing xenobiotic uptake. In the present work, the interaction of P-gp(s) in the liver and in primary cultured hepatocytes of rainbow trout with two model pollutants was studied - the imidazole fungicide prochloraz and the alkylphenolic surfactant nonylphenol diethoxylate (NP2EO). Using a monoclonal antibody (mAB C219) directed against a conserved P-gp epitope, an immunoreactive protein of 160 kDa was detected in immunoblots of liver extracts from control trout. In sections of control trout livers, immunohistochemistry with the mAB C219 resulted in specific staining of bile canaliculi. In juvenile trout exposed for 7 days to sublethal concentrations of prochloraz (0.027 microM; 0.27 microM) or NP2EO (0.32 microM; 1.30 microM), no changes in levels of hepatic P-gp(s) were found in immunoblot and immunochemical investigations. The efflux of the fluorescent mdr 1 substrate rhodamine 123 (Rh123) from cultured isolated trout hepatocytes was partly inhibited by verapamil and vinblastine, compounds known to interfere with mdr 1-dependent transport. This demonstrates the presence of a mdr1-like mechanism in trout liver which is probably involved in the biliary excretion of hydrophobic xenobiotics. Non-cytotoxic concentrations of prochloraz and NP2EO were tested for effects on the efflux of Rh123 from trout hepatocytes. Prochloraz was a potent inhibitor of the mdr1-like mechanism, being effective at 0.3 microM and above. NP2EO inhibited Rh123 efflux only at the highest concentration tested (31.6 microM). The accumulation and elimination of 14C-prochloraz by cultured trout hepatocytes was not affected by mdr 1-type substrates (Rh123, vinblastine) and a mdr 1 inhibitor (verapamil). This shows that prochloraz is, despite its inhibitory potency, not a substrate of the mdr1-like mechanism in trout liver. The inhibition by prochloraz and NP2EO of the md r1-like mechanism in trout hepatocytes suggests that water pollutants can interfere with P-gp-function in fish and thus may impair the organismal defense against xenobiotics.
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Sturm A, Cravedi JP, Perdu E, Baradat M, Segner H. Effects of prochloraz and nonylphenol diethoxylate on hepatic biotransformation enzymes in trout: a comparative in vitro/in vivo-assessment using cultured hepatocytes. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2001; 53:229-245. [PMID: 11408082 DOI: 10.1016/s0166-445x(01)00168-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The suitability of cultured rainbow trout hepatocytes as a model system for the assessment of xenobiotic effects on hepatic biotransformation enzymes in fish was examined. Two model water pollutants, the imidazole fungicide prochloraz and the alkylphenolic compound nonylphenol diethoxylate (NP2EO), were investigated in a comparative in vitro/in vivo approach. Biotransformation enzymes were measured in cultured rainbow trout hepatocytes following exposure to xenobiotics in vitro, or in the liver of juvenile rainbow trout (Oncorhynchus mykiss) exposed in vivo. The patterns of biochemical responses to the model pollutants were generally similar between in vitro and in vivo investigations. Levels of cytochrome P4501A (CYP1A) protein and the catalytic activity of the CYP1A-dependent enzyme 7-ethoxyresorufin-O-deethylase (EROD) were induced in vitro after 24 h of exposure to 1.0 microM prochloraz. In vitro, higher prochloraz concentrations induced only the levels of CYP1A above control levels, but not EROD activity. In vivo exposure of juvenile trout to 0.27 microM prochloraz resulted in an induction of CYP1A and EROD after 7 and 14 days, while 0.027 microM prochloraz had no effects. In vitro, the 6beta- and 16beta-hydroxylation of testosterone was significantly decreased by 1.0-3.0 microM prochloraz, while in vivo these variables were significantly inhibited after exposure to 0.27 microM prochloraz for 7 and 14 days. NP2EO did not affect EROD activity in vitro. In vivo, EROD activity and CYP1A remained unchanged following 7 days of exposure to 0.32 or 1.30 microM NP2EO. NP2EO (15-50 microM) inhibited the 16beta-hydroxylation and glucuronidation of testosterone in vitro. In vivo, 7 days of exposure to 0.32 or 1.30 microM NP2EO resulted in a significant inhibition of the 6beta- and 16beta-hydroxylation of testosterone. The good qualitative correspondence between in vitro and in vivo results indicates that studies using trout hepatocytes allow the identification of biochemical targets of xenobiotic effects in fish liver. However, more research is needed before quantitative predictions, e.g. of effective concentrations, can be made from in vitro investigations.
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Smith RW, Blaney SC, Dowling K, Sturm A, Jönsson M, Houlihan DF. Protein synthesis costs could account for the tissue-specific effects of sub-lethal copper on protein synthesis in rainbow trout (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2001; 53:265-277. [PMID: 11408084 DOI: 10.1016/s0166-445x(01)00171-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study investigates protein synthesis, following exposure to sub-lethal Cu, in rainbow trout in vivo and in vitro. The investigation has two aims: to determine if perturbations in protein synthesis, compared with other physiological changes, are a biomarker of Cu pollution and to evaluate the most productive role of cellular models in ecotoxicology. Protein synthesis rates were measured by labelling with 3H-phenylalanine. In vivo this was applied by a single (i.p.) injection and in vitro by bathing the cells in 3H-phenylalanine labelled culture media. The effects in vivo were tissue specific. After 3 weeks' exposure to 0.7 microM Cu only skin protein synthesis was reduced. Gills and liver from the same fish were unaffected. This reduction in skin protein synthesis appears to be more sensitive than some other biomarkers reported in the literature. However, Cu concentrations greater by orders of magnitude were required to reproduce this reduction in protein synthesis in skin cell explants (200 and 400 microM). Hepatocyte protein synthesis was unaffected by 10, 20 and 40 microM Cu and a separate investigation has also shown that 25 and 75 microM Cu does not effect protein synthesis in cultured gill cells. Oxygen consumption rates were also measured in vitro by monitoring the decline in O2 partial pressure. The Cu concentrations given above resulted in a decline in O2 consumption rates in the respective cell types. By measuring protein synthesis and O2 consumption after treatment with a protein synthesis inhibitor (cycloheximide), the costs of protein synthesis were also determined. Synthesis costs in hepatocytes are close to the theoretical minimum and are only marginally affected by Cu. Gill cell synthesis costs are also minimal and are unaffected. In skin explants, the reduction in protein synthesis was accompanied by greatly increased synthesis costs. This in vitro result offers a hypothesis as to the tissue-specific effects in vivo; i.e. the energetic demand of protein synthesis may determine tissue sensitivity or susceptibility. Cell or tissue types with high protein synthesis rates are able to avoid detrimental increases in the synthesis cost when exposed to Cu. In tissues with a low protein synthesis rate any further reduction is more likely to incur a potentially damaging increase in protein synthesis costs. Thus, whilst in vitro models may have little practical use in environmental monitoring, they may be best used as a mechanistic tool in understanding susceptibility or tolerance to sub-lethal Cu.
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Abstract
A continuously increasing number of regulatory peptides has been demonstrated to be expressed in the intestine and to modulate several functional properties of various intestinal cell populations, including the intestinal epithelium and lamina propria cell populations. These regulatory peptides include members of the epidermal growth factor (EGF) family, the transforming growth factor beta (TGF-beta) family, the insulin-like growth factor (IGF) family, the fibroblast growth factor (FGF) family, the trefoil factor (TFF) family, the colony-stimulating factor (CSF) family, and a few other seemingly unrelated regulatory peptides, such as hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), and various interleukins, interferons and tumour necrosis factor-related proteins. In addition to the well-known effects on cell proliferation, these regulatory peptide factors regulate several other functional properties of epithelial and other cell populations, such as differentiation, migration, and extracellular matrix deposition and degradation. This review is designed not to discuss all the identified factors in detail but to highlight some of the basic principles of growth factor action in the intestine. It focuses mainly on classical growth factors rather than interleukins and interferons.
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Wogram J, Sturm A, Segner H, Liess M. Effects of parathion on acetylcholinesterase, butyrylcholinesterase, and carboxylesterase in three-spined stickleback (Gasterosteus aculeatus) following short-term exposure. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2001; 20:1528-1531. [PMID: 11434294 DOI: 10.1897/1551-5028(2001)020<1528:eopoab>2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The sensitivity of butyrylcholinesterase (BChE) toward the inhibition by the organophosphorus insecticide (OP) parathion-ethyl was compared with that of other esterases in the fish three-spined stickleback. Earlier field and in vitro results had suggested the higher sensitivity to OPs of stickleback BChE when compared with acetylcholinesterase (AChE). In the present study, stickleback were exposed in vivo under environmentally realistic conditions using a short duration of exposure (1 h) and parathion concentrations of 0.01, 0.1, and 1.0 microgram/L. Seventy and 80% of nominal concentrations, respectively, were measured in the 0.01 and 0.1 microgram/L treatments. Following exposure, stickleback were maintained in clean water for 48 h (recovery), allowing the metabolic activation of parathion. After recovery, the activities of BChE (axial muscle, gills, liver), AChE (brain, axial muscle, gills), and carboxylesterase (CaE, liver) were determined. Following exposure to 1 microgram/L parathion, the BChE activity was significantly decreased in liver (approximately 60%) and axial muscle (approximately 30%), while its decrease in gills (approximately 30%) was not significant. No effects on BChE activity were observed with 0.1 and 0.01 microgram/L parathion. The AChE and CaE activities remained unaffected with all parathion concentrations used. The results are discussed with respect to the potential application of stickleback BChE as a biomarker of OP exposure.
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Sturm A, Noppeney R, Reimer J, Ross B, Baumgart D, Sundermann T, Sadony V, Gerken G. [AIDS and non-Hodgkin's lymphoma: initial cardiac manifestations of highly malignant B-cell lymphoma 18 years after HIV infection]. Dtsch Med Wochenschr 2001; 126:364-6. [PMID: 11332231 DOI: 10.1055/s-2001-12430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
HISTORY AND FINDINGS A 35-year-old man who, as a result of intravenous drug abuse, had become infected with HIV 18 years previously, was admitted with signs of right-heart failure. Three months earlier a systolic murmur had first been heard in the 5th intercostal space parasternally. INVESTIGATIONS Transesophageal echocardiography (TEE) demonstrated a 3 x 2 cm right atrial tumour, moderate to severe tricuspid regurgitation and pulmonary hypertension. Blood cultures grew Streptococcus. DIAGNOSIS, TREATMENT AND COURSE Endocarditis with atrial thrombi and recurrent pulmonary emboli was diagnosed and treated with antibiotics and anticoagulants. Three weeks later the TEE showed an increase in the atrial tumour. Computed tomography of skull, thorax and abdomen did not demonstrate any significantly enlarged lymph nodes. Exploratory thoracotomy revealed an infiltrating highly malignant centroblastic non-Hodgkin's lymphoma (NHL) of almost the entire free wall of the right atrium. After two courses of chemotherapy (CHOP protocol) the size of the tumour had significantly decreased. CONCLUSION The differential diagnosis of a right atrial tumour can be difficult in patients with HIV or AIDS. Even if the site is atypical and there is no lymphadenopathy, a lymphoma should be considered. In case of doubt a histological diagnosis via an exploratory thoracotomy should be performed.
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Senner V, Sturm A, Hoess N, Wassmann H, Paulus W. In vivo glioma model enabling regulated gene expression. Acta Neuropathol 2000; 99:603-8. [PMID: 10867792 DOI: 10.1007/s004010051169] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Experimental investigation of glioma biology and therapy requires a representative model and a convenient technique for regulating gene expression. We have established an in vivo model in which genetically modified rat C6 glioma cells (C6TL cells) are transplanted into nude mice brain, followed by specific transcriptional control of a transgene. Histologically, the tumors exhibit an astrocytic phenotype and closely resemble human malignant gliomas including diffuse brain invasion. Due to a stably integrated lacZ gene, individual tumor cells can be unequivocally identified in tissue sections by histochemistry for beta-galactosidase. Since C6TL cells carry the tet transactivator (tTA) gene, any additional gene under control of a tetracycline/tTA-responsive promoter can be transcriptionally regulated by the concentration of tetracycline. C6TL cells stably transfected with a tetracycline/tTA-responsive luciferase reporter gene showed 23-fold regulation of luciferase activity in vitro. After intracerebral transplantation a regulation of 4.5- to 8.3-fold was obtained, dependent on the concentration and the type of tetracycline in the drinking water. This model should be useful for studying the functional role of candidate genes in tumor biology as well as for experimental gene therapy studies.
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Cario E, Jung S, Harder D'Heureuse J, Schulte C, Sturm A, Wiedenmann B, Goebell H, Dignass AU. Effects of exogenous zinc supplementation on intestinal epithelial repair in vitro. Eur J Clin Invest 2000; 30:419-28. [PMID: 10809902 DOI: 10.1046/j.1365-2362.2000.00618.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Substitution of zinc modulates antioxidant capabilities within the intestinal mucosa and improves intestinal wound healing in zinc-deficient patients with inflammatory bowel diseases. The aim of this study was to characterize the modulating effects of zinc on intestinal epithelial cell function in vitro. MATERIALS AND METHODS The effects of zinc on intestinal epithelial cell morphology were assessed by phase contrast and transmission electron microscopy using the non-transformed small intestinal epithelial cell line IEC-6. Zinc-induced apoptosis was assessed by DNA fragmentation analysis, lactate dehydrogluase (LDH) release and flow cytometry with propidium iodine staining. Furthermore, the effects of zinc on IEC-6 cell proliferation were assessed using a colorimetric thiazolyl blue (MTT) assay and on IEC-6 cell restitution using an in vitro wounding model. RESULTS Physiological concentrations of zinc (25 microM) did not significantly alter the morphological appearance of IEC-6 cells. However, a 10-fold higher dose of zinc (250 microM) induced epithelial cell rounding, loss of adherence and apoptotic characteristics. While physiological zinc concentrations (< 100 microM) did not induce apoptosis, supraphysiological zinc concentrations (> 100 microM) caused apoptosis. Physiological concentrations of zinc (6.25-50 microM) had no significant effect on intestinal epithelial cell proliferation. In contrast, physiological concentrations of zinc (12.5-50 microM) significantly enhanced epithelial cell restitution through a transforming growth factor-beta (TGFbeta)-independent mechanism. Simultaneous addition of TGFbeta and zinc resulted in an additive stimulation of IEC-6 cell restitution. CONCLUSION Zinc may promote intestinal epithelial wound healing by enhancement of epithelial cell restitution, the initial step of epithelial wound healing. Zinc supplementation may improve epithelial repair; however, excessive amounts of zinc may cause tissue injury and impair epithelial wound healing.
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Sturm A, Schulte C, Schatton R, Becker A, Cario E, Goebell H, Dignass AU. Transforming growth factor-beta and hepatocyte growth factor plasma levels in patients with inflammatory bowel disease. Eur J Gastroenterol Hepatol 2000; 12:445-50. [PMID: 10783999 DOI: 10.1097/00042737-200012040-00013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE An increased mucosal expression of transforming growth factor-beta (TGF-beta) and hepatocyte growth factor (HGF) has been reported in patients with active inflammatory bowel diseases (IBD) and in proximity to injured gastric and intestinal mucosal surfaces. The aim of this study was to measure systemic concentrations of TGF-beta and HGF and to assess their potential value to predict disease activity or severity of inflammation in patients with inflammatory bowel diseases. DESIGN AND METHODS Plasma HGF and TGF-beta1 peptide levels were determined in 29 patients with ulcerative colitis, 45 patients with Crohn's disease and 28 healthy controls using commercial ELISA assays. Peptide levels were correlated with disease activity indices and various laboratory parameters. RESULTS HGF and TGF-beta1 plasma levels were detected in all control and IBD subjects. Although a tendency towards increased HGF and TGF-beta1 peptide levels in IBD patients was observed, differences between groups were not significant In ulcerative colitis patients HGF plasma levels positively correlated with white blood cell counts and negatively correlated with serum albumin concentrations and haematocrit. In Crohn's disease patients, a positive correlation between TGF-beta and platelet count was observed. CONCLUSIONS HGF and TGF-beta1 plasma concentrations are not significantly different in IBD and healthy control subjects. Stratification of IBD patients according to disease activity did not reveal any substantial differences, suggesting that HGF and TGF-beta plasma levels have no value in the assessment of disease activity or severity of inflammation in patients with IBD.
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Sturm A, Dignass AU. [Clinical relevance of phospholipids in the gastrointestinal tract]. Dtsch Med Wochenschr 2000; 125:192-8. [PMID: 10719395 DOI: 10.1055/s-2007-1024019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sturm A, Sanner B. [Sleep medicine. A new cross-sectional subject of internal medicine]. Dtsch Med Wochenschr 1999; 124:1573-6. [PMID: 10664660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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Cario E, Becker A, Sturm A, Goebell H, Dignass AU. Peripheral blood mononuclear cells promote intestinal epithelial restitution in vitro through an interleukin-2/interferon-gamma-dependent pathway. Scand J Gastroenterol 1999; 34:1132-8. [PMID: 10582765 DOI: 10.1080/003655299750024940] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Acute intestinal mucosal inflammation is associated with recruitment of peripheral blood mononuclear cells (PBMN) into the mucosa and migration across the epithelium. It has recently been shown that several PBMN-derived cytokines, including transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), and interferon-gamma (IFN-gamma) may modify intestinal epithelial cell function, resulting in rapid improvement of wound repair. Our aim was to characterize the modulating effects of PBMN on intestinal epithelial restitution, the initial step of wound healing. METHODS PBMN were separated from whole blood, obtained from healthy volunteers, by using a density gradient. The effect of PBMN on intestinal epithelial restitution was assessed by using an in vitro coculture wounding model with non-transformed small-intestinal epithelial IEC-6 cells. RESULTS Coculture of PBMN caused a significant enhancement of epithelial cell restitution in vitro. The modulatory effects of PBMN could be significantly blocked by adding immunoneutralizing anti-IL-2 or anti-IFN-gamma to the culture media, suggesting that PBMN may modulate intestinal epithelial migration through an IL-2- and IFN-gamma-dependent pathway. In contrast, PBMN-induced stimulation of intestinal epithelial restitution was not influenced by addition of anti-TGF-beta or anti-TNF-alpha, suggesting that these cytokines are not critical for the modulation of restitution by PBMN. CONCLUSIONS These findings suggest that PBMN may promote intestinal epithelial wound repair by enhancing restitution through secretion of various cytokines, among them IL-2 and IFN-gamma, which are abundantly expressed in the course of several inflammatory diseases of the gut.
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Tang GQ, Sturm A. Antisense repression of sucrose synthase in carrot (Daucus carota L.) affects growth rather than sucrose partitioning. PLANT MOLECULAR BIOLOGY 1999; 41:465-79. [PMID: 10608657 DOI: 10.1023/a:1006327606696] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
To unravel the roles of sucrose synthase in carrot, we reduced its activity in transgenic carrot plants by an antisense approach. For this purpose, the cDNA for the main form of carrot sucrose synthase was expressed in antisense orientation behind the 35S promoter of cauliflower mosaic virus. In independent antisense plant lines grown in soil, sucrose synthase activity was reduced in tap roots but not in leaves. In the sink organs, sucrose utilization was markedly decreased and higher levels of sucrose but lower levels of UDP-glucose, glucose, fructose, starch and cellulose were found. The phenotype of the antisense plants clearly differed from that of control plants. Both leaves and roots were markedly smaller, and the antisense line with the lowest sucrose synthase activity also developed the smallest plants. In most of the plant lines, the leaf-to-root dry weight ratios were not changed, suggesting that sucrose synthase in carrot is a major determinant of plant growth rather than of sucrose partitioning. In contrast to the acid invertases, which are critical for partitioning of assimilated carbon between source leaves and tap roots (Tang et al., Plant Cell 11: 177-189 (1999)), sucrose synthase appears to be the main sucrose-cleaving activity, feeding sucrose into metabolism.
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Sturm A, Tang GQ. The sucrose-cleaving enzymes of plants are crucial for development, growth and carbon partitioning. TRENDS IN PLANT SCIENCE 1999; 4:401-407. [PMID: 10498964 DOI: 10.1016/s1360-1385(99)01470-3] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Sink organs of most plant species are supplied with carbon and energy in the form of sucrose. The channeling of sucrose into sink metabolism requires its cleavage by several isoforms of invertase and sucrose synthase, which are localized in different subcellular compartments. These activities regulate the entry of sucrose into distinct biochemical pathways, such as respiration or biosynthesis of cell wall polysaccharides and storage reserves. Other vital roles for the sucrose-cleaving enzymes include invertase activity at the site of phloem unloading and vacuolar invertase and sucrose synthase in sink organs, which drives the long-distance transport of sucrose. In addition, invertases have been implicated in the defense response and in turgor-driven cell expansion, and sucrose synthase expression is associated with low temperature and anaerobiosis responses. Finally, because sugars also regulate gene expression, the sucrose-cleaving enzymes play a fundamental role in controlling cell differentiation and development.
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Abstract
BACKGROUND The relative potency of prokinetics in patients with gastroparesis has not been systematically studied. This study, therefore, aimed to assess the available data and to compare the effects of different prokinetics on symptoms and gastric emptying rates in patients with gastroparesis. METHODS A systematic search of the literature was performed, covering the period 1980 to March 1998. All identified studies were reviewed and the following data elements assessed: characteristics of study populations; sample sizes; treatment regimes; drug doses; study design; main outcome variables, and the validity of measurements. RESULTS In 36 studies, 514 patients were treated with prokinetics p.o. Most studies had methodological limitations (i.e. nonvalidated measurement of symptoms or unblinded treatment). The mean improvement in gastric emptying and the reduction in the symptom score was higher in the open trial group than in patients treated double-blind. Overall, erythromycin seems to have had the strongest effect on gastric emptying as compared to domperidone, cisapride or metoclopramide. Concerning gastrointestinal symptoms, the symptom scores appeared to improve more during treatment with erythromycin than with domperidone, metoclopramide or cisapride. CONCLUSIONS Most of the available trials have methodological limitations; this limits the conclusions. However, the data suggest that the motilin-agonist erythromycin is superior with regard to the acceleration of gastric emptying, while both erythromycin and domperidone appear to be the most effective with regard to improvements in the symptom score. Additionally, there is a lack of association between changes in gastric emptying times and improvements in symptoms.
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Sturm A. Invertases. Primary structures, functions, and roles in plant development and sucrose partitioning. PLANT PHYSIOLOGY 1999; 121:1-8. [PMID: 10482654 PMCID: PMC1539224 DOI: 10.1104/pp.121.1.1] [Citation(s) in RCA: 374] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
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Sturm A, Sudermann T, Schulte KM, Goebell H, Dignass AU. Modulation of intestinal epithelial wound healing in vitro and in vivo by lysophosphatidic acid. Gastroenterology 1999; 117:368-77. [PMID: 10419918 DOI: 10.1053/gast.1999.0029900368] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND & AIMS Lysophosphatidic acid (LPA) is assumed to play an important role in the modulation of injury and tissue repair in nonepithelial tissues. The effects of LPA on intestinal epithelial wound repair in vitro and in vivo were characterized. METHODS Effects of LPA on intestinal epithelial restitution and proliferation were assessed by using an in vitro wounding model with confluent intestinal epithelial cell line 6 (IEC-6) monolayers and colorimetric thiazolyl blue (MTT) assays. In addition, LPA signaling pathways were characterized. Effects of LPA on intestinal wound healing in vivo were studied by using the trinitrobenzene model of colitis in rats. RESULTS LPA significantly enhanced migration and inhibited cell proliferation of IEC-6 cells in vitro. The effects on intestinal epithelial cell migration and proliferation were mediated through transforming growth factor beta (TGF-beta)-independent pathways and binding to a G-protein receptor. In addition, LPA significantly ameliorated intestinal epithelial injury in the trinitrobenzene model of colitis in rats. CONCLUSIONS These findings suggest that LPA enhances intestinal epithelial wound healing by modulation of intestinal epithelial cell migration and proliferation through TGF-beta-independent pathways. Thus, exogenous administration of LPA may provide a new approach for modulating intestinal injury in vivo.
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Sturm A, Betz U, Scipione G, Hahna H. Grain growth and phase stability in a nanocrystalline ZrO2 - 15w% Al2O3 ceramic. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s0965-9773(99)00353-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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100
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Kimura Y, Hess D, Sturm A. The N-glycans of jack bean alpha-mannosidase. Structure, topology and function. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:168-75. [PMID: 10447685 DOI: 10.1046/j.1432-1327.1999.00598.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The acid hydrolase alpha-mannosidase, which accumulates in plant vacuoles and probably is involved in the catabolism and turnover of N-linked glycoproteins, is itself a glycoprotein with at least one high-mannose-type and one complex-type N-glycan. The puzzling finding that alpha-mannosidase stably carries its own substrate suggests that the N-glycans have unique topologies, and important functions in protein folding, oligomerization or enzyme activity. As a first step towards the elucidation of this enigma, we purified the N-glycans of jack bean alpha-mannosidase and determined their structures by sugar composition analysis, mass spectrometry and 1H-NMR. The structures of two N-glycans were identified in an approximate ratio of one-to-one: a glucose-containing high-mannose-type glycan (Glc1Man9GlcNAc2) and a small xylose- and fucose-containing complex-type glycan (Xyl1Man1Fuc1GlcNAc2). Isolation and sequencing of glycopeptides strongly suggests that one high-mannose-type and one complex-type glycan are linked to specific glycosylation sites of the large alpha-mannosidase subunit. The high-mannose-type glycan, which is a good substrate of the endoglycosidase (endo-H), can only be removed from the enzyme after denaturation and cleavage of disulfide bonds by a reducing agent, suggesting that this glycan is buried within the folded polypeptide and, thus, protected from its hydrolytic activity. Denaturation and reduction of the native enzyme led to a marked decrease in alpha-mannosidase activity. However, the activity could largely be recovered by renaturation in an appropriate renaturation buffer. In contrast, recovery of alpha-mannosidase activity failed when the high-mannose-type glycan was removed by endo-H prior to renaturation, indicating that this glycan appears to be important for enzyme activity.
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