Helicobacter pylori eradication and gastric ulcer healing--comparison of three pantoprazole-based triple therapies

AIM

To study the efficacy of three pantoprazole-based triple therapy regimens for the eradication of Helicobacter pylori infection and gastric ulcer healing.

METHODS

In an open, multi-centre, randomized study, 519 H. pylori-positive patients with active gastric ulcer were randomized to receive pantoprazole (40 mg) (P) and two of three antibiotics: clarithromycin (500 mg) (C), metronidazole (500 mg) (M) or amoxicillin (1000 mg) (A). Triple therapy (PAC, PCM, PAM) was administered twice daily for 7 days, followed by pantoprazole until the ulcer had healed. Antrum and corpus biopsies were taken to determine the pattern of gastritis, to assess the H. pylori status and to determine the strain susceptibility to antibiotics, and from the ulcer margins and base to exclude malignancy. Scores based on the Sydney system were used to categorize the gastritis phenotypically.

RESULTS

The H. pylori eradication rates for the per protocol (intention-to-treat) analysis were 89% (67%) for PAC, 83% (68%) for PCM and 76% (60%) for PAM, with a significant difference between PAC and PAM. Healing rates after 4 weeks were 91% for PAM, 90% for PCM and 88% for PAC (per protocol analysis). The eradication rates were lower in patients in whom strains resistant to any antibiotic used in the triple therapies were detected. Successful eradication [odds ratio, 5.2 (3.3; 8.3)] and the ulcer size (< 15 mm) were significant predictors for healing after 4 weeks. The regimens showed a comparable safety profile and compliance.

CONCLUSIONS

Pantoprazole-based triple therapies are effective in the eradication of H. pylori infection in gastric ulcer patients, as reported in previous similar sized studies in duodenal ulcer patients. Successful eradication and an ulcer size of < 15 mm are the best predictors of gastric ulcer healing after 4 weeks.

Relationship between microsatellite instability, response and survival in palliative patients with colorectal cancer undergoing first-line chemotherapy

BACKGROUND AND AIMS

The aim of this work was to investigate the relationship between microsatellite instability (MSI), treatment response and survival in palliative patients with colorectal cancer (CRC) undergoing first-line treatment with weekly 24-hour infusion (24-h inf.) of high-dose 5-fluorouracil (5-FU) and folinic acid (FA).

PATIENTS AND METHODS

Tumour material from the colorectal primary carcinomas was analysed for 43 patients. MSI analysis was carried out and immunohistochemistry was performed with hMLH1 and hMSH2.

RESULTS

Tumours of 7 patients (16%) were highly instable (MSI-H). These patients had a better response rate (72% vs. 41%; p = 0.072) and a significantly better median survival (33 months, [95% CI 20-46] vs. 19 months, [95% CI 10-28]; p = 0.021) than microsatellite stable (MSS) patients (n = 36). Furthermore, MSI status was shown to be an independent predictive marker for survival (p = 0.037).

CONCLUSION

These data provide further support for the hypothesis that MSI-H CRC might have a better response and survival than (MSS) CRC in palliative first-line treatment.

[Morphogenetic aspects of colorectal cancer]

Patterning is a spatial and temporal process by which ordered arrangements of cells and tissue structure are attained. The term is mostly applied to the morphogenesis in developmental pathology, but it can also be useful for the neomorphogenesis in tumor biology. Despite increasing data on the proliferation and differentiation of tumor cells, processes of tumor patterning are rarely studied and poorly understood. A fundamental embryonic process of patterning is the embryonic gastrulation and a basic patterning is found in the colonic adenoma-carcinoma sequence. Both processes exhibit distinct nuclear translocation and expression of beta-catenin, which is considered to be a decisive transcriptional regulator. Our recent studies demonstrated striking analogies of patterning and nuclear beta-catenin expression between the colonic adenoma-carcinoma sequence and the steps of gastrulation. The shared patterns are dissociation, reassembly, tubular reconstruction and branching of neoplastic cells in association with nuclear beta-catenin expression. These findings establish patterning as a relevant concept for tumor formation and link the neoplastic morphogenesis with embryogenesis.

[Histopathological diagnosis of Barrett's mucosa and associated neoplasias. Results of a consensus conference of the Working Group for "Gastroenterological Pathology of the German Society for Pathology" on 22 September 2001]

There are a number of difficulties regarding the diagnosis of Barrett's mucosa and the varying grades of neoplasia that may be associated with it. It was therefore the aim of a consensus conference of the "Working Group for Gastroenterological Pathology within the German Society of Pathology" to achieve standardization regarding the following issues: definition and diagnostic criteria for Barrett's mucosa and its discrimination from intestinal metaplasia of the cardia, diagnostic criteria for intraepithelial neoplasia, number of biopsies necessary to establish the diagnosis, significance of additional immunohistochemical and/or molecular biological methods as well as importance of a second opinion in the diagnosis of intraepithelial neoplasia.

[Allergy-associated colitis. Characterization of an entity and its differential diagnoses]

There is substantial evidence that allergic reactions exist in the gastrointestinal tract (GI). However, patients with food allergy-related enteropathy pose a diagnostic challenge to physicians because the clinical features are variable, unspecific, occur in other gastrointestinal disorders, and specific diagnostic tools are missing. Several recent studies and reviews have focused on the function of eosinophilic granulocytes in GI disease. The role of eosinophils in the pathophysiology of GI hypersensitivity reactions is poorly defined. However, some findings have been reported that imply an involvement of eosinophils in allergic reactions of the gut. The presumptive histology of allergy-associated colitis in colonic and ileal biopsies is based on prominent pure eosinophilic infiltration of a normal lamina propria, submucosa and epithelium with variable degrees of degranulation. An immunoperoxidase stain for eosinophilic peroxidase is supportive in establishing the diagnosis if suspected. Neutrophils or mononuclear infiltrates are not significantly increased and damage to the intestinal tissue is not prominent. Despite characteristic histologic changes in colonic biopsy specimens, a final diagnosis depends on careful clinical examination and exclusion of several differential diagnoses.

239,240Pu and inorganic substances in aerosols from the vicinity of a waste isolation pilot plant: the importance of resuspension

Aerosol samples were collected and analyzed to characterize the spatial and temporal variations in the concentrations of plutonium and selected inorganic substances in the atmosphere around the Waste Isolation Pilot Plant (WIPP). High-volume aerosol sampling was conducted at three sites: (1) On Site, (2) Near Field, and (3) Cactus Flats. 239,240Pu was determined by alpha spectrometry following chemical separations; mass loadings were determined gravimetrically. A separate set of low-volume aerosol samples was analyzed for major ions using ion chromatography and for trace elements by inductively-coupled plasma emission spectrometry and mass spectrometry. The average 239,240Pu activity concentrations in total suspended particle (TSP) samples (12 to 16 nBq m(-3)) were consistent with those previously reported, but they varied strongly with season, with the highest values generally in spring. Further, the 239,240Pu activity concentrations were comparable among the three sites, and therefore there was no evidence for elevated 239,240Pu activities due to WIPP operations. The fraction of the 239,240Pu activity concentrations in the PM10, samples (particles less than 10 microm diameter) relative to TSP was lower than the corresponding PM10/TSP ratios of either high-volume mass or several inorganics (sulfate, aluminum or lead), indicating that 239,240Pu tends to be on large particles. Aerosol mass loadings (microg m(-3)) and 239,240Pu activity concentrations were correlated for all sets of samples, but at On Site, the TSP samples showed higher mass to 239,240Pu ratios than the other sites. Thus activities or processes occurring at or near the WIPP site evidently produced aerosols that contributed to the mass loadings but contained less 239,244Pu than ambient aerosols. About 63% of the variability in 239,240Pu activity concentrations was explained by wind travel, sampling location, length of the sampling interval, and aerosol mass. 239,240Pu activity concentrations also were correlated with aluminum (an indicator of mineral dust), further implicating the resuspension of soils as an important determinant of 239,240Pu in aerosols. The 239,240Pu/Al ratios for the aerosols were higher than in soils, and this could be explained by the preferential binding of 239,240Pu to small soil particles that have large surface area to mass ratios and also have higher aluminum contents than larger particles.

Ultrastructural localization of type VI collagen in normal adult and osteoarthritic human articular cartilage

OBJECTIVE

Type VI collagen is a major component of the pericellular matrix compartment in articular cartilage and shows severe alterations in osteoarthritic cartilage degeneration. In this study, we analysed the exact localization of type VI collagen in its relationship to the chondrocyte and the (inter)territorial cartilage matrix. Additionally, we were interested in its ultrastructural appearance in normal and osteoarthritic cartilage.

DESIGN

Distribution and molecular appearance was investigated by conventional immunostaining, by multilabeling confocal scanning microscopy, conventional transmission, and immunoelectron microscopy.

RESULTS

Our analysis confirmed the pericellular concentration of type VI collagen in normal and degenerated cartilage. Type VI collagen formed an interface in between the cell surface and the type II collagen network. The type VI collagen and the type II collagen networks appeared to have a slight physical overlap in both normal and diseased cartilage. Additionally, some epitope staining was observed in the cell-associated interterritorial cartilage matrix, which did not appear to have an immediate relation to the type II collagen fibrillar network as evaluated by immunoelectron microscopy. In osteoarthritic cartilage, significant differences were found compared with normal articular cartilage: the overall dimension of the lacunar volume increased, and a significantly increased type VI collagen epitope staining was observed in the interterritorial cartilage matrix. Also, the banded isoform of type VI collagen was found around many chondrocytes.

CONCLUSIONS

Our study confirms the close association of type VI collagen with both, the chondrocyte cell surface and the territorial cartilage matrix. They show severe alterations in type VI collagen distribution and appearance in osteoarthritic cartilage. Our immunohistochemical and ultrastructural data are compatible with two ways of degradation of type VI collagen in osteoarthritic cartilage: (1) the pathologically increased physiological molecular degradation leading to the complete loss of type VI collagen filaments from the pericellular chondrocyte matrix and (2) the transformation of the fine filaments to the band-like form of type VI collagen. Both might implicate a significant loss of function of the pericellular microenvironment in osteoarthritic cartilage.

[Characterisation and differentiation of chondroblastomas and chondromyxoidfibromas - presence and expression of collagen types I and II]

AIM

Chondroblastomas and chondromyxoidfiibromas are rare benign skeletal neoplasms with reported overlapping histology. Aim of this study was to analyse the biochemical composition of the matrix of these tumour entities in order to further characterise the cellular phenotypes of these neoplasms using typical cell biological marker genes.

METHODS

The matrix compositions of chondroblastomas and chondromyxoidfibromas were analyzed by HE-histology, histochemistry, and immunolocalization techniques. Cellular gene expression patterns were detected by mRNA in situ hybridization.

RESULTS

Chondroblastomas are rich in collagen type I and show foci of an osteoid-like matrix, whereas collagen type II as a typical marker of chondrocytic differentiation was not detected in any of the specimens. Chondromyxoidfiibromas had foci of chondroid appearance with chondroblastic cellular differentiation characterised by collagen type II expression.

CONCLUSION

These results characterise chondroblastomas and chondromyxoidfiibromas as skeletal neoplasms that have a different biology and which can be distinguished by matrix protein expression products: collagen type II, the typical marker of chondroblast differentiation, could only be detected in chondromyxoidfibromas, but not in chondroblastomas. Thus, both neoplasms are clearly different on the cell biological level.

7-Deaza-2'-deoxyguanosine allows PCR and sequencing reactions from CpG islands

CpG islands are GC rich sequences that are found in the promoters of many genes in higher eukaryotes. They contain a high frequency of CG dinucleotides, which are substrates for DNA methylases. Methylation leads to transcriptional silencing of promoters. Owing to their high GC content CpG islands exhibit strong base-base interactions, which lead to superstructures and consequently to regions with higher melting temperatures. Therefore, Taq polymerases (especially sequenases) fall off their templates, causing premature termination of the polymerase chain reaction (PCR) or sequencing reactions. The results from such reactions are thus insufficient for further analysis. Therefore, we have evaluated the use of 7-deaza-2'-deoxyguanosine for PCR amplification of the human p16(INK4A) promoter and sequencing of HUMARA exon 1 PCR products. Our results show that the addition of 7-deaza-2'-deoxyguanosine significantly improves results, particularly when small amounts of poor quality DNA are available as starting material.

Expression of the invasion factor laminin gamma2 in colorectal carcinomas is regulated by beta-catenin

The migration-inducing gamma2 chain of laminin-5, one of the best known invasion markers, is strongly overexpressed in disseminating and infiltrating tumor cells at the invasive front of colorectal carcinomas. The same tumor cells show nuclear accumulation of the oncoprotein beta-catenin, which together with T-cell factor-DNA-binding proteins, functions as transcriptional activator of genes involved in tumor progression. Here we show that beta-catenin activates the human laminin-5 gamma2 gene through two T-cell factor-binding elements in a synergistic manner together with hepatocyte growth factor and conclude that laminin-5 gamma2 is another important target gene of nuclear beta-catenin during tumor progression.

The invasion front of human colorectal adenocarcinomas shows co-localization of nuclear beta-catenin, cyclin D1, and p16INK4A and is a region of low proliferation

At the invasion front of well-differentiated colorectal adenocarcinomas, the oncogene beta-catenin is found in the nuclear compartment of tumor cells. Under these conditions, beta-catenin can function as a transcription factor and thus activate target genes. One of these target genes, cyclin D1, is known to induce proliferation. However, invasion front of well-differentiated colorectal adenocarcinomas are known to be zones of low proliferation and express the cell cycle inhibitor p16INK4A. Therefore, we investigated the expression profiles of nuclear beta-catenin, cyclin D1, p16INK4A, and the Ki-67 antigen, a marker for proliferation, in serial sections of well-differentiated colorectal adenocarcinomas. Invasion fronts with nuclear beta-catenin were compared with areas from central parts of the tumors without nuclear beta-catenin, for the expression of cyclin D1, p16INK4A, and Ki-67. It was observed that expression of nuclear beta-catenin, cyclin D1, and p16INK4A at the invasion front are significantly correlated. Such areas exhibit low Ki-67 expression indicating a low rate of proliferation. Thus, in colorectal carcinogenesis the function of beta-catenin and its target gene cyclin D1 does not appear to be the induction of tumor cell proliferation. In particular, the function of cyclin D1 should be reconsidered in view of these observations.

Metaplasia, intraepithelial neoplasia and early cancer of the stomach are related to dedifferentiated epithelial cells defined by cytokeratin-7 expression in gastritis

Cancer presumably arises from stem cells, preserved in an undifferentiated status since fetal development, or from a dedifferentiation of mature cells that return into a fetal phenotype with the potential for proliferation and renewal. Dedifferentiation in this context could represent a transient phase, passed through by cells, before they switch to redifferentiation, metaplasia or neoplasia. Cytokeratin-7 (CK7) is present in fetal, largely absent in normal adult, and transiently neoexpressed in metaplastic and neoplastic epithelial cells of the stomach according to previous observations. CK7 neoexpression in the stomach could, hence, define a fetal-like, dedifferentiated, cellular phenotype during the development of metaplasia and neoplasia. To test this hypothesis, we investigated CK7 expressions in fetal stomachs, non-neoplastic control stomachs, and neoplastic stomachs exhibiting metaplasia, intraepithelial neoplasia, and early cancer. Proliferation and beta-catenin expression of CK7-positive cells were also evaluated. The chronology of CK7 expression was studied during the experimental gastritis-cancer sequence in Mongolian gerbils. Our results show that metaplastic and neoplastic changes in the gastritis-cancer sequence are related to dedifferentiated epithelial cells which are defined by CK7 expression and can phenotypically be linked to fetal cells at the start of gastric pit development. The dedifferentiated cells exhibit a low proliferation and beta-catenin accumulation, similar to stem cells. Thus, the "stem cell" and "dedifferentiation" hypotheses for cancer origin could complement one another, and dedifferentiation-redifferentiation processes might be decisive for carcinogenesis in the stomach.

Transcription of cytokeratins 8, 18, and 19 in bone marrow and limited expression of cytokeratins 7 and 20 by carcinoma cells: inherent limitations for RT-PCR in the detection of isolated tumor cells

The suitability of "real-time" quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of isolated carcinoma cells in bone marrow was investigated by evaluating the expression of cytokeratin (CK)7, CK8, CK18, CK19, and CK20 in 17 gastrointestinal cancer cell lines, 64 control bone marrow specimens from noncancer patients, and 30 bone marrow specimens from patients with gastric or colorectal cancer. RT-PCR products for CK8 and CK18 were detected in all cancer cell lines, but only 16, 5, and 11 cell lines provided evidence for CK19, CK7, and CK20 transcription. Variable numbers of bone marrow specimens from noncancer patients demonstrated background transcription of CK8 (78.1%), CK18 (95.3%), CK19 (35.9%), CK20 (29.6%), and CK7 (16.7%). Maximal background transcription for CK8, CK18, and CK19 ranged from 52.2 to 56.1 copies/10(3) copies glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the corresponding values of 0.06 and 0.76 copies for CK7 and CK20 being distinctly lower. When maximal background values were used as a threshold value to define positivity in tumor cell dilution experiments, sensitivity levels of one tumor cell in 10(4) bone marrow cells were determined for CK7 and CK20 RT-PCR assays. Maximal background expression values of the different CKs as obtained in the control series were exceeded once (CK20), twice (CK18 and CK19), and 18 times (CK7) in bone marrow specimens from cancer patients, with none of these specimens exceeding the maximal background expression value of CK8. We conclude that RT-PCR for CK8, CK18, and CK19 cannot be recommended for the detection of isolated tumor cells in bone marrow of cancer patients. On the other side, the limited number of gastric and colorectal cancer cell lines expressing CK7 and CK20 indicates that assay sensitivity for these CKs might be limited because of their selective expression by carcinoma cells.

Ki-67 expression and residual tumour (R) classification are associated with disease-free survival in desmoid tumour patients

BACKGROUND

In order to evaluate prognostic factors in the long-term survival of desmoid tumour patients, analysis of clinicopathological, immunohistochemical and follow-up data was performed.

PATIENTS AND METHODS

Between 1969 and 1998, 54 patients underwent resection of aggressive fibromatosis (desmoid) and 33 of them (10 patients with FAP and 23 sporadic) were followed-up with a median time of 130 months (range 10-355 months). Additionally, immunohistochemical analysis of the desmoid tumours using Ki-67 was performed.

RESULTS

In univariate analysis, curative resection (R0) (p<0.001) and low proliferation of Ki-67 (p=0.002) were of significant positive prognostic value concerning disease-free survivaL R0 and absence of Ki-67 staining were significantly associated with each other (p=0.004).

CONCLUSION

Ki-67 seems to serve as a predictive marker concerning disease-free survival of desmoid tumour patients. In patients presenting with Ki-67 positive desmoids, which are unlikely to be resected in a curative manner, alternative treatment (e.g. sulindac) may be preferable.

Variable beta-catenin expression in colorectal cancers indicates tumor progression driven by the tumor environment

Invasion and dissemination of well-differentiated carcinomas are often associated with loss of epithelial differentiation and gain of mesenchyme-like capabilities of the tumor cells at the invasive front. However, when comparing central areas of primary colorectal carcinomas and corresponding metastases, we again found the same differentiated epithelial growth patterns. These characteristic phenotypic changes were associated with distinct expression patterns of beta-catenin, the main oncogenic protein in colorectal carcinomas, and E-cadherin. Nuclear beta-catenin was found in dedifferentiated mesenchyme-like tumor cells at the invasive front, but strikingly, as in central areas of the primary tumors, was localized to the membrane and cytoplasm in polarized epithelial tumor cells in the metastases. This expression pattern was accompanied by changes in E-cadherin expression and proliferative activity. On the basis of these data, we postulate that an important driving force for progression of well-differentiated colorectal carcinomas is the specific environment, initiating two transient phenotypic transition processes by modulating intracellular beta-catenin distribution in tumor cells.

Cell biology and matrix biochemistry of chondromyxoid fibroma

We studied matrix composition and gene expression pattern in chondromyxoid fibromas on the protein and the messenger RNA levels. We could clearly identify focal chondrocytic differentiation within chondromyxoid fibroma by the expression and deposition of type II collagen, which is a marker of chondrocytic cell differentiation. We also were able to show expression of collagen types I, III, and VI in the neoplasm. The major tumor portion was, however, characterized by the presence of hydrated proteoglycans and only minor amounts of collagens, a matrix composition responsible for the myxoid matrix appearance of most parts of these neoplasms. By analyzing cytoprotein expression, we found S-100 protein restricted to cells of the chondroid areas, suggesting S-100 protein staining to be of little help as a positive diagnostic marker for chondromyxoid fibroma. Our data show a specific matrix composition of chondromyxoid fibroma, not previously found in other mesenchymal neoplasms, including chondroblastoma, osteochondroma, enchondroma, and chondrosarcoma. This justifies chondromyxoid fibroma as a specific neoplastic entity, both clinically and biologically.

Right-sided shift found in metachronous colorectal adenomas

BACKGROUND AND STUDY AIMS

Patients who have had a colorectal adenoma are likely to develop a metachronous adenoma, and therefore need to be kept under surveillance. The question is whether metachronous adenomas will be found at the same anatomical site as the preceding adenomas, thus prompting us to focus surveillance examinations on this region, using flexible sigmoidoscopy or total colonoscopy.

PATIENTS AND METHODS

Between 1978 and 1996 a long-term follow up of 1091 patients was prospectively documented at the Erlangen Registry of Colorectal Polyps. The anatomical sites--distal (rectosigmoid) and proximal colon--of two subsequent generations of metachronous adenomas were analysed using logistic regression analysis.

RESULTS

In 556 (51%) patients metachronous adenomas were found during follow up. In 211 (37.9%) of these patients a right-sided shift in the first generation of metachronous adenomas in comparison with initial lesions (P<0.0001) was found. Some 305 patients underwent further follow up, and 51 (27.1%) out of 188 patients with metachronous lesions demonstrated a right-sided shift in their second generation (vs. first generation) of metachronous adenomas. Proximally located first generation metachronous adenomas would be missed by flexible sigmoidoscopy in 50.8% of patients with only distal adenomas at baseline colonoscopy, and in 58.7% of patients with second-generation lesions. Multivariate analysis revealed that multiplicity (odds ratio 2.64, 95% CI 1.49-4.66) and size of initial adenomas (>5 mm) (odds ratio 3.60, 95% CI 1.96-6.66) were significantly associated with a right-sided shift in metachronous adenomas, while female gender was associated with a significantly lower tendency to manifest a right-sided shift (odds ratio of 0.64. 95% CI 0.43-0.94).

CONCLUSIONS

Metachronous adenomas are found significantly more often in the right colon than would be expected assuming clustering at the same anatomical site as the preceding lesions. Total colonoscopy is thus needed for surveillance, regardless of the initial adenoma site.

Apoptotic cell death is not a widespread phenomenon in normal aging and osteoarthritis human articular knee cartilage: a study of proliferation, programmed cell death (apoptosis), and viability of chondrocytes in normal and osteoarthritic human knee cartilage

OBJECTIVE

Chondrocytes are crucial for adequate matrix balance and function. Cell proliferation and, recently, extensive apoptotic cell death have been reported in osteoarthritic (OA) cartilage. Apoptotic cell death would be an obvious central factor in the initiation and progression of OA, since there is no potential for replacing articular chondrocytes in the adult. Therefore, we studied the occurrence of apoptotic cell disintegration and cell proliferation in OA and normal articular cartilage obtained from the knees of adult donors of all ages.

METHODS

Following immunostaining for cellular proteins as well as staining for nuclear DNA, we performed triple-channel confocal laser scanning microscopy on thick cartilage slices to evaluate lacunar emptying and cell viability. Cell proliferation and apoptotic cell death were evaluated morphologically, by immunodetection of the proliferation-associated Ki-67 antigen, and by the TUNEL reaction.

RESULTS

With the exception of the calcified layer, we were not able to detect any major (apoptotic or nonapoptotic) cell disintegration in normal young or aged articular knee cartilage. Single apoptotic cells were detected in OA articular knee cartilage. A significant increase in lacunar emptying was observed in late-stage specimens with higher Mankin scores compared with age-matched normal control cartilage specimens, but not in low-grade lesions. A significant (but lesser) increase in empty lacunae was also observed with age in normal cartilage. Cell proliferation was rarely detected in OA cartilage samples and was not detected at all in normal cartilage samples.

CONCLUSION

Our results confirm the findings of previous studies showing that cell proliferation occurs in OA cartilage. They also show that, contrary to previous suggestions, apoptotic cell death is not a widespread phenomenon in aging or OA cartilage.

Tenascin: a sensitive and specific diagnostic marker of minimal collagenous colitis

Collagenous colitis is a rare cause of chronic watery diarrhea. In this condition, endoscopic findings are usually normal. Currently, the diagnosis relies on the histological presence of thick subepithelial bands of collagen deposits and an inflammatory infiltrate within the mucosa. However, these subepithelial bands may be developed only focally and may be too subtle to allow a definitive diagnosis upon routine hematoxylin and eosin (HE) and van Gieson's stainings. Recently, we and others were able to show a prominent staining of tenascin and type-VI collagen in the subepithelial band-like structures. In this study, we tested the diagnostic value of tenascin staining and type-VI collagen immunolocalization for the identification of collagenous colitis and compared it with conventional histology and histochemical detection of collagens. The analysis was based on 434 biopsy specimens of collagenous colitis, other forms of colitis, and normal mucosa. We were able to show that the immunohistochemical detection of increased amounts of tenascin, selectively in the subepithelial zone, is a specific test for collagenous colitis, with a sensitivity superior to conventional histological and histochemical detection, especially in minimal collagenous colitis (P<0.001). Of note, tenascin staining also allows the diagnosis of collagenous colitis in biopsies obtained only from the rectum and sigmoid colon, thus avoiding the need for colonoscopic investigations. Tenascin immunostaining is a simple and safe tool to complement conventional histological diagnostics in clinically and histopathologically unclear cases of diarrhea.

Isolation of RNA from small human articular cartilage specimens allows quantification of mRNA expression levels in local articular cartilage defects

Human adult cartilage is an inherently difficult tissue from which to isolate RNA. The RNA isolation techniques described so far have generally only been successfully applied to the isolation of RNA from larger amounts of cartilage. However, it is important to be able to analyse focal cartilage lesions in order to understand the local processes in the cartilage degeneration process. Therefore, we have developed a protocol for isolating RNA directly from as little as 10 mg wet weight of cartilage followed by quantitative PCR analysis. We were able to analyse the expression levels of several genes in parallel including aggrecan and type II collagen.

Matrix gene expression analysis and cellular phenotyping in chordoma reveals focal differentiation pattern of neoplastic cells mimicking nucleus pulposus development

Chordoma is the fourth most common malignant primary neoplasm of the skeleton and almost the only one showing a real epithelial phenotype. Besides classic chordoma, so-called chondroid chordoma was described as a specific entity showing cartilage-like tissue within chordomatoid structures. However, since its first description, strongly conflicting results have been reported about the existence of chondroid chordoma and several studies suggested chondroid chordomas being in fact low-grade conventional chondrosarcomas. In the present study, we used cytoprotein expression profiling and molecular in situ localization techniques of marker gene products indicative of developmental phenotypes of chondrocytes to elucidate origin and biology of chondroid chordoma. We were able to demonstrate the chondrogenic potential of chordomas irrespectively of the appearance of overt cartilage formation by identifying the multifocal expression of type II collagen, the main marker of chondrocytic differentiation. Additionally, the cartilage-typical large aggregating proteoglycan aggrecan was present throughout all chordomas and, thus, a very characteristic gene product and marker of these neoplasms. Biochemical matrix composition and cell differentiation pattern analysis showed a high resemblance of classic chordomas and in chordoid areas of chondroid chordomas to the fetal chorda dorsalis, whereas chondroid areas of chondroid chordomas showed features similar to adult nucleus pulposus. This demonstrates on the cell function level the chondrocytic differentiation potential of neoplastic chordoid cells as a characteristic facet of chordomas, mimicking fetal vertebral development, ie, the transition of the chorda dorsalis to the nucleus pulposus. Our study firmly establishes a focal real chondrocytic phenotype of neoplastic cells in chordomas. Chondroid chordoma is neither a low-grade chondrosarcoma nor a misnomer as discussed previously.

[beta-Catenin induces invasive growth by activating matrix metalloproteinases in colorectal carcinoma]

beta-catenin was shown to be a major oncoprotein in colon cancer development. Its oncogenic function as a transcriptional activator is upregulated by mutations in the APC tumor suppressor gene, leading to a constitutive activation of the proliferation-associated genes c-myc and cyclin D. The aim of this study was to demonstrate a role of APC-mutations and dysregulated beta-catenin also for the progression of colorectal cancer, by identifying new target genes of beta-catenin associated with tumor invasion and metastasis. Potential invasion genes regulated by beta-catenin and its DNA binding partner TCF4 were identified by a computer search for the consensus DNA binding sequence in relevant promoter regions. Specific DNA binding was confirmed by gel shift assays. Functional importance of beta-catenin for the activation of identified genes was determined by luciferase reporter assays. The significance was demonstrated by coexpression of nuclear beta-catenin and the identified target genes by immunohistochemistry. Among other invasion genes, we identified the matrix metallo proteinases MMP-7 and MMP-1 activated by beta-catenin in the tumor cells. MMP-7 is an important factor for invasion and metastasis and overexpressed in 75% of colon carcinomas. The significance for human colon cancer development was demonstrated by a correlated overexpression of beta-catenin and the MMPs, beginning in large, severely dysplastic adenomas. Our results explain the high percentage of MMP-7 overexpression in colorectal tumors and the resulting activation of invasive growth. Moreover by identifying dysregulated beta-catenin as a transcriptional activator of MMPs and other invasion factors, we demonstrated an important role of mutated APC not only for early steps but also for the progression of colorectal carcinogenesis.

Tip60 is a cell-type-specific transcriptional regulator

Tip60 was originally identified as cellular HIV-Tat interacting protein and has been shown to augment Tat-dependent transcription. It has also been shown to interact with various cellular transcription factors and to belong to the nuclear histone acetyltransferase (HAT) family. To further elucidate the function of Tip60 and its HAT domain in transcription regulation, we compared Tip60 activity in HeLa and Jurkat T lymphoma cells. Here we show that Tip60 augments the HIV-1 Tat activity at the HIV-LTR promoter in HeLa but inhibits it in Jurkat cells. Moreover, we isolated two new variants of the Tip60 protein (Tip60Delta1, Tip60Delta2) from Jurkat cells. The Tip60Delta2 variant lacks the entire HAT domain but modulates HIV-1 Tat activity like full-length Tip60. In addition, Tip60 and the transcriptional repressor ZEB (zinc finger E box binding protein) interact specifically in the yeast two-hybrid system and additively inhibit the CD4 enhancer/promoter activity in Jurkat cells. Thus, Tip60 may function as corepressor of the ZEB protein. In summary, these data show that Tip60 functions as a cell-type-specific transcriptional regulator and that the HAT domain is not required for either transcriptional activation or inhibition. This indicates that Tip60 may function by recruiting additional cell-type-specific cofactors.

Lack of gastritis and of an adaptive immune response in interferon regulatory factor-1-deficient mice infected with Helicobacter pylori

To study the role of T cell responses in Helicobacter pylori gastritis, C57BL/6 wild-type and interferon regulatory factor-1-deficient (IRF-1(-/-)) mice were infected with the mouse-adapted H. pylori Sydney strain. Mice lacking the transcription factor IRF-1 are defective in Th1 development and are therefore biased to mount a Th2-type response. After 4 months of infection, C57BL/6 mice developed severe gastritis and atrophy and mounted a Th1-type response towards H. pylori. The Th1 response was abrogated in IRF-1(-/-) mice. This defective Th1 response was associated with the total lack of gastritis and atrophy in IRF-1(-/-) mice despite severe colonization with H. pylori. In addition, IRF-1(-/-) mice did also not develop a Th2 reaction, since they failed to generate H. pylori-specific antibodies and to produce IL-4 in response to H. pylori antigens in vitro. Thus, the transcription factor IRF-1 is necessary for the development of gastritis and atrophy in H. pylori-infected wild-type mice, suggesting a role of Th1 cells in the pathogenesis of H. pylori-associated diseases.