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M Zeitz

Publications and source records attributed to M Zeitz.

At least 91 records · Page 5Linked to original sources
PubMed2001

Decreased CD44v6 expression in lamina propria lymphocytes of patients with inflammatory bowel disease.

Splice variants of the glycoprotein CD44 are transiently expressed on lymphocytes during T cell activation. Increased expression of CD44v6 on peripheral blood lymphocytes (PBL) of patients with inflammatory bowel disease (IBD) was described recently. The aim of this study was therefore to characterize CD44v6 expression on CD4(+) lamina propria lymphocytes (LPL) of patients with active IBD in comparison to controls. CD44v6 expression on CD4(+) LPL (n = 19) of controls and patients with active IBD (Crohn's disease n = 14, ulcerative colitis n = 15) was analyzed by flow cytometry and compared to that on autologous PBL. Thereby, in vitro regulation of CD44v6 on LPL and PBL via CD3 and CD2 and the costimulatory signal B7-1 was examined. In addition, the role of protein kinase C (PKC) in CD44v6 expression was tested. CD44v6 expression was increased in CD4(+) LPL (median, 45%) compared to PBL (median, 38%). Surprisingly, in IBD CD44v6 was downregulated on CD4(+) lamina propria T cells, irrespective of their state of inflammation (median, 28%). CD44v6 expression on LPL was not upregulated upon CD3 activation alone but following costimulation with B7-1. However, CD2-mediated T cell activation sufficiently induced upregulation of CD44v6 on LPL and PBL. In our study, downregulation of CD44v6 on LPL of patients with IBD was not due to defective PKC activation. Taken together, these data indicate that decreased CD44v6 expression on LPL in IBD might be a feature of an inappropriate costimulatory signal in T cell activation.

Adult↗
PubMed2001

Use of anti-tumour necrosis factor agents in inflammatory bowel disease. European guidelines for 2001-2003.

The introduction of novel anti-tumor necrosis factor (TNF) agents has not only led to impressive new therapeutic opportunities but also resulted in uncertainty regarding their optimal use and possible side effects. Guidelines are presented here for the use of anti-TNF agents in gastrointestinal disorders. Experts were chosen from different European countries by an algorithm to avoid bias. An expert consensus on guidelines was established using a two-stage procedure of systematic Medline and abstract search for evidence and a qualifying meeting to derive recommendations. Detailed guidelines were developed for the use and the future clinical development of anti-TNF agents in inflammatory bowel disease. Grading of available evidence and grading of recommendations were performed according to AHCPR guidelines. At present infliximab is the only registered agent for Crohn's disease. Infliximab should be always used at a dose of 5 mg/kg. The guidelines define the indications both in refractory and in fistulating disease for the readministration and before surgery. Guidelines for safety and for concomitant treatments are given. Prospects, potential clinical use, and future directions for the clinical development of other anti-TNF agents are detailed. Clinical use of anti-TNF agents will be influenced by a large number of clinical trials being concluded in 2001 and 2002. It is likely that anti-TNF therapies will become an important long-term therapy for a proportion of patients with Crohn's disease. Biological agents will be followed by smaller and more stable, orally available compounds. These guidelines will be succeeded by a formal public consensus in 2002/2003.

Crohn Disease↗
PubMed2001

Increased matrix metalloproteinase 2 concentration and transcript expression in advanced colorectal carcinomas.

Colorectal cancer is one of the most common malignant tumors and entails a relatively poor prognosis. Clinical outcome depends on the extent of local and metastatic tumor spread. Results of in vivo and in vitro studies suggest that the balance between matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases TIMPs) is altered in neoplasia, contributing to the invasive and metastatic properties of malignant tumors. We quantified tissue concentrations of MMP-2 and TIMP-2 in 65 malignant colorectal lesions and corresponding normal mucosa by enzyme-linked immunosorbent assay, western blotting, and in situ hybridization. In situ hybridization and western blot analyses demonstrated a clear increase in both stromal expression of MMP-2 transcripts and protein in primary carcinomas. The protein concentration of MMP-2 was higher in all tumor stages, except stage I tumors, than in normal mucosa and adenomas. MMP-2 concentrations were not related to tumor differentiation or to colonic versus rectal location. Surprisingly, the MMP-2 concentration was not increased in metastases. Interestingly, tissue concentrations and epithelial mRNA expression of TIMP-2 decreased significantly in primary colorectal cancer (UICC stages III and IV) but increased in metastases. Therefore an increased ratio of MMP-2 to TIMP-2 is strongly associated with advanced tumor stages, but a decreased ratio was observed in metastases. These findings suggest that the MMP-2:TIMP-2 ratio may prove useful as a marker of local invasion but not of metastasis in colorectal cancer.

Blotting, Western↗
PubMed2001

Growth inhibition and apoptosis induced by P2Y2 receptors in human colorectal carcinoma cells: involvement of intracellular calcium and cyclic adenosine monophosphate.

Extracellular nucleotides induce apoptosis and inhibit growth of colorectal cancer cells. To understand the underlying signaling pathways, we investigated the role of nucleotide-sensitive P2 receptors and focused on the receptor-mediated signaling of intracellular Ca2+ and cyclic adenosine monophosphate (cAMP) in two colorectal carcinoma cell lines (HT29, Colo320 DM). Expression and functionality of P2 receptor subtypes evaluated by RT-PCR and [Ca2+]i imaging revealed that solely metabotropic P2 receptors of the subtype P2Y2 were expressed on a functional level in both cell lines. Short-term stimulation of P2Y2 receptors caused Ca2+ mobilization from intracellular stores and a subsequent transmembrane Ca2+ influx. The receptor-induced [Ca2+]i elevation was shown to increase basal-stimulated [cAMP]i moderately and to potentiate forskolin-stimulated [cAMP]i vigorously, since the effects were dose-dependently inhibited by preloading the cells with the [Ca2+]i chelator BAPTA. In contrast, activation of protein kinase C (PKC) did not contribute to a receptor-mediated rise in [cAMP]i, since the PKC inhibitor staurosporine completely failed to reduce P2Y2 receptor-induced increases in [cAMP]i. Prolonged application of P2Y2 receptor agonists induced a time-dependent increase in apoptosis (up to 50% above control values) in both cell lines and caused dose-dependent inhibition of cell proliferation of up to 85% (Colo320 DM) or 64% (HT29). Chelating [Ca2+]i with BAPTA almost completely abolished P2Y2 receptor-induced cell death. Rises in [cAMP]i elicited by either forskolin or cAMP derivatives inhibited growth in both cell lines, too. In line with the potentiating effect of P2Y2 receptors on forskolin-stimulated [cAMP]i increases, costimulation with forskolin and P2Y2 receptor agonists led to synergistic antiproliferative effects. Moreover, a synergistic growth inhibition was observed when coincubating the cells with the P2Y2 receptor agonist ATP and the cytostatic drug 5-fluorouracil, which forms the basis for most currently applied chemotherapeutic regimes in colorectal cancer treatment. Our results demonstrate the growth inhibitory potency of P2Y2 receptors in colorectal carcinoma cells. Receptor-induced [Ca2+]i signaling appears to play a major role in the observed antiproliferative and apoptosis-inducing effects.

Adenosine Triphosphate↗
PubMed2001

Increased acid and bile reflux in Barrett's esophagus compared to reflux esophagitis, and effect of proton pump inhibitor therapy.

OBJECTIVES: Barrett's metaplasia is an acquired condition resulting from longstanding gastroesophageal reflux disease. Approximately 10% of esophagitis patients develop Barrett's esophagus. There is increasing evidence that duodenogastroesophageal reflux plays a role in the progression of disease. We further analyzed the correlation of acid and biliary reflux with reflux esophagitis and Barrett's esophagus and tested the effects of proton pump inhibitor therapy. METHODS: Patients with either reflux esophagitis (group 1) or Barrett's esophagus (group 2) prospectively underwent simultaneous 24-h esophageal pH and bile reflux testing without any therapy affecting acid secretion or GI motility. A total of 16 patients in group 1 and 18 patients in group 2 were tested again under proton pump inhibitor therapy. RESULTS: Acid and bile exposure were significantly increased in Barrett's patients (n = 23) compared to 20 esophagitis patients (median percentage of time that pH was <4 was 24.6% vs 12.4%, p = 0.01, median percentage of time that bilirubin absorbance was >0.2 was 34.7% vs 12.8%, p < 0.05). During therapy, both acid and bile reflux decreased significantly in both groups. Median percentage of time that pH was <4 and bilirubin absorbance was >0.2 before and during therapy was 18.2%/2.3% and 29.8%/0.7% (p = 0.001 and p = 0.001) in Barrett's esophagus patients versus 14.5%/3.6% and 21.5%/0.9% (p = 0.002 and p = 0.011) in esophagitis patients. There was no significant difference between the groups. In two esophagitis patients, bile reflux increased during therapy. CONCLUSIONS: There is a good correlation of the duration of esophageal exposure to acid and bile with the severity of pathological change in the esophagus. Both acid and bile reflux is significantly suppressed by proton pump inhibitor therapy with exceptions among individual esophagitis patients. The prolonged simultaneous attack of bile and acid may play a key role in the development of Barrett's metaplasia.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

Role of T lymphocytes in rat 2,4,6-trinitrobenzene sulphonic acid (TNBS) induced colitis: increased mortality after gammadelta T cell depletion and no effect of alphabeta T cell depletion.

BACKGROUND AND AIM: Indirect evidence suggests that CD4+ T cells have a pathogenic while gammadelta T cells have a protective role in the initiation and perpetuation of inflammatory bowel disease. To define the role of T cell subsets in a rat colitis model (2,4,6-trinitrobenzene sulphonic acid (TNBS)) we analysed colitis severity after effective depletion of T helper cells, alphabeta T cells, or gammadelta T cells. METHODS: T helper cells, alphabeta T cells, or gammadelta T cells were depleted using previously described monoclonal antibodies directed at the CD4 molecule (OX38), the CD2 molecule (OX34, both depleting CD4+ T cells), the alphabeta T cell receptor (R73), and the gammadelta T cell receptor (V65). Depletion was verified by flow cytometry and/or immunohistology. Colitis was induced using intracolonic application of TNBS. RESULTS: Surprisingly, depletion of T helper cells or alphabeta T cells had no influence on survival, macroscopic or microscopic scores, or myeloperoxidase activity following colitis induction. In contrast, depletion of gammadelta T cells resulted in significantly increased mortality (V65: 73%, n=15) compared with controls (30%, n=13; p<0.03). In addition, colitis was histologically more severe in the gammadelta T cell depleted group compared with controls (p<0.05). CONCLUSIONS: T helper cells or alphabeta T cells did not influence the initiation or perpetuation of rat TNBS colitis. In contrast, gammadelta T cells had a protective role in rat TNBS colitis as depletion caused increased mortality.

Animals↗
PubMed2001

JMM, past and present. Cysticerci cellulosae of the brain. 1864.

While striving to serve the needs of the international biomedical community of today, we would also like to remember JMM's long past as a venue for medical research. JMM is the successor to the Berlin Clinical Weekly (Berliner Klinische Wochenschrift), established in 1864. Below are excerpts from the Berlin Clinical Weekly's May issue from a hundred and thirty-five years ago, giving hints about the challenges and solutions being addressed by medical research of the time. Following the excerpt is a commentary by Martin Zeitz and Thomas Schneider, experts in gastroenterology at the University Clinic Benjamin Franklin in Berlin, Germany.

Animals↗
PubMed2000

Antigen-induced mucosal T cell activation is followed by Th1 T cell suppression in continuously fed ovalbumin TCR-transgenic mice.

We investigated kinetics and dose-dependent features of mucosal and peripheral immune responses following oral antigen application in a TCR-transgenic mouse model. Ovalbumin (OVA) TCR-transgenic mice were fed OVA at different doses (5-250 mg) and various frequencies (one to seven times, or continuous feeding). Low- and medium-dose (10, 100 mg) OVA feeding resulted in priming of immune responses, i.e. increased antigen-specific proliferation as well as IL-2, IL-4 and IFN-gamma secretion upon in vitro restimulation in Peyer's patches and spleen. Immune responses were suppressed with doses of one or three times 250 mg OVA feeding in the spleen. However, only the highest OVA feeding doses (7x250 mg OVA) or continuous feeding (5 mg daily in the drinking water over a 12-week period) actively suppressed immune responses and were associated with production of TGF-beta and IL-10 in the spleen and Peyer's patches. Thus, the cell population generated by continuous antigen feeding was characterized by production of suppressive cytokines and seems to be based on a counter-regulation with Th1 cytokines. These data further define the regulation of suppressive immune functions following antigen feeding in the periphery and the mucosal immune system.

Animals↗
PubMed2000

Identical T-cell expansions in the colon mucosa and the synovium of a patient with enterogenic spondyloarthropathy.

Intestinal T lymphocytes activated by antigen are suspected to play a key role in enterogenic spondyloarthropathies (SpA). Therefore, we aimed to identify and functionally characterize T-cell clones that are coexpanded in the intestinal mucosa and the synovium. Colon, peripheral blood, and synovium of a patient with enterogenic SpA were screened for clonal T-cell expansions by TCRB-CDR3 length analysis and sequencing. T-cell clones expanded in vivo were isolated from archived synovial cells by targeted T-cell cloning and characterized for phenotype, cytokine production, and antigen specificity. The synovial TCRBV18(+) T-cell repertoire of the patient was dominated by 2 CD8(+) T-cell clones using related CDR3. Both clones were expanded throughout the colon and were present in the peripheral blood. Upon in vitro stimulation with PDB/ionomycin, they showed predominantly interferon gamma and interleukin (IL)-4 but also tumor necrosis factor alpha and IL-10 production and did not specifically lyse autologous T-cell blasts, B-cell lines, or other autologous or allogeneic target or CD1d-transfected cells. These findings strongly suggest that T lymphocytes activated by antigen in the intestinal mucosa contribute to joint inflammation in enterogenic SpA by recognition of antigens specific for the inflamed synovium.

ATP-Binding Cassette Transporters↗
PubMed2000

Higher concentration of matrix-metalloproteinase 1 (interstitial collagenase) in H. pylori-compared to NSAID-induced gastric ulcers.

BACKGROUND/OBJECTIVE: Matrix metalloproteinases (MMPs) are implicated in the tissue destruction associated with inflammatory diseases. We postulated a causal involvement of MMP-1 in ulcerogenesis and quantified therefore the MMP-1 concentrations in biopsies of human gastric ulcers and the surrounding mucosa. Further, we correlated them with the individual ulcer etiology. METHODS: During upper endoscopy biopsy specimens of the ulcer and surrounding normal mucosa were taken from 45 patients with gastric ulcers of different etiology (Helicobacter pylori, NSAID-intake, both or none of these). MMP-1 concentration was measured using a MMP-1 ELISA in 35 patients, western blot was performed in the remaining 10 patients. RESULTS: In general, median expression of MMP-1 in the ulcer tissue was significantly increased compared to the surrounding mucosa (16.8 [4.7-33.4] vs. 10.9 [2.8-17.8] ng/mg protein) (p < 0.001). Western blot analysis revealed increased concentration of the active forms of MMP-1 in ulcer tissue. Interestingly, the MMP-1 concentration was significantly higher in 15 H.p.-induced ulcers compared to 19 NSAID-induced ones: 19.3 (8.3-33.2) vs. 11.4 (4.7-33.4) ng/mg protein, p = 0.0354). CONCLUSION: MMP-1-expression in the ulcer tissue depends on the ulcer etiology. However, MMP-1 does not seem to be causally involved in ulcerogenesis. In NSAID-induced ulcers the MMP-1-synthesis may be suppressed by NSAID-induced decrease of mucosal prostaglandin concentration.

Adult↗
PubMed2000

Modulation of gastrointestinal inflammation by chimeric proteins in experimental models.

Conventional drug therapy in patients with chronic gastrointestinal inflammation is clinically effective in the majority of patients. However, in a relevant group of patients with highly active disease refractory to conventional drugs and for patients with severe side effects new therapeutic strategies are necessary. An advanced understanding of the immune mechanisms underlying chronic diseases resulted in the possibility to use chimeric proteins, in which the variable domains of an immunoglobulin are replaced by extracellular domains of cell surface molecules or cytokines for specific immunomodulation. The immunomodulating effects of chimeric proteins such as CTLA-4-IgG, interleukin-10-IgG, IL-2-IgG or tumour necrosis factor (TNF)-receptor IgG have been proven beneficial in a variety of in vitro and in vivo models of chronic gastrointestinal inflammation and autoimmune diseases. It thus seems likely that genetically engineered fusion proteins targeting specific elements of the immune response may become an essential element in new clinical treatment protocols.

Animals↗
PubMed2000

The double duct sign in patients with malignant and benign pancreatic lesions.

BACKGROUND: The double duct sign, a simultaneous stenosis of the common bile duct and the pancreatic duct by endoscopic retrograde cholangiopancreatography (ERCP), has been reported to predict the presence of pancreatic cancer with a high degree of certainty. METHODS: To test the specificity of the double duct sign for pancreatic cancer in patients with malignant and benign pancreatic lesions, we have reviewed all ERCP films obtained during a 24-month period (n = 1209) and corresponding clinical follow-up data obtained during a period of 4 years. RESULTS: Forty-three patients were identified as having a double duct stenosis on ERCP, 15% of whom did not have pancreatic carcinoma. In 4 patients chronic pancreatitis was confirmed by serial histologic sections of the surgical specimen. Data on the lengths of the stenotic segment in either the pancreatic duct or the bile duct did not contribute to a better discrimination between benign and malignant disease. CONCLUSION: The specificity of the double duct sign in predicting the presence of pancreatic cancer appears to be lower than previously reported. Better discrimination between malignant and benign disease of the pancreas will be difficult to achieve with existing imaging techniques.

Aged↗