Rapid and specific detection of Helicobacter pylori macrolide resistance in gastric tissue by fluorescent in situ hybridisation

BACKGROUND

The development of macrolide resistance in Helicobacter pylori is considered an essential reason for failure of antibiotic eradication therapies. The predominant mechanism of resistance to macrolides, particularly clarithromycin, is based on three defined mutations within 23S rRNA, resulting in decreased binding of the antibiotic to the bacterial ribosome.

AIM

To develop an rRNA based whole cell hybridisation method to detect Helicobacter species in situ within gastric tissue, simultaneously with its clarithromycin resistance genotype.

METHODS

A set of fluorescent labelled oligonucleotide probes was developed, binding either to H pylori 16S rRNA or 23S rRNA sequences containing specific point mutations responsible for clarithromycin resistance. After hybridisation and stringent washing procedures, labelling of intact single bacteria was monitored by fluorescence microscopy. The new approach was compared with PCR based assays, histology, and microbiological culture.

RESULTS

In comparison with the phenotypic resistance measurement by E test, the genotypic clarithromycin resistance correlated perfectly (100%) for 35 H pylori isolates analysed. In a set of gastric biopsy specimens (27) H pylori infection was confirmed by histology (17/27) and correctly detected by whole cell hybridisation. Five clarithromycin resistant strains were identified in gastric tissue specimens directly. Furthermore, non-cultivable coccoid forms of H pylori were easily detectable by whole cell hybridisation.

CONCLUSIONS

Whole cell hybridisation of rRNA holds great promise for cultivation independent, reliable, and rapid (three hours) genotypic determination of clarithromycin resistance in H pylori. Compared with PCR techniques it is independent of nucleic acid preparations, not prone to inhibition, and allows semiquantitative visualisation of the bacteria within intact tissue samples.

Cell differentiation and matrix gene expression in mesenchymal chondrosarcomas

Mesenchymal chondrosarcomas are small-cell malignancies named as chondrosarcomas due to the focal appearance of cartilage islands. In this study, the use of in situ detection techniques on a large series of mesenchymal chondrosarcoma specimens allowed the identification of tumor-cell differentiation pathways in these neoplasms. We were able to trace all steps of chondrogenesis within mesenchymal chondrosarcoma by using characteristic marker genes of chondrocytic development. Starting from undifferentiated cells, which were negative for vimentin and any other mesenchymal marker, a substantial portion of the cellular (undifferentiated) tumor areas showed a chondroprogenitor phenotype with an onset of expression of vimentin and collagen type IIA. Cells in the chondroid areas showed the full expression panel of mature chondrocytes including type X collagen indicating focal hypertrophic differentiation of the neoplastic chondrocytes. Finally, evidence was found for transdifferentiation of the neoplastic chondrocytes to osteoblast-like cells in areas of neoplastic bone formation. These results establish mesenchymal chondrosarcoma as the very neoplasm of differentiating premesenchymal chondroprogenitor cells. The potential of neoplastic bone formation in mesenchymal chondrosarcoma introduces a new concept of neoplastic (chondrocytic) osteogenesis in musculoskeletal malignant neoplasms, which qualifies the old dogma that neoplastic bone/osteoid formation automatically implies the diagnosis of osteosarcoma.

Role of antigastric autoantibodies in chronic Helicobacter pylori infection

In recent studies a significant association between H. pylori infection and antigastric autoimmunity has been reported. Antigastric autoantibodies can be found in more than 30% of infected patients. Two distinct binding patterns of these autoantibodies have been described, first at the luminal membrane of the foveolar epithelium, and second at the canaliculi membranes of the parietal cells in the body mucosa. The latter type of autoantibodies correlates with histologic and clinical parameters of gastric mucosa atrophy. The gastric H,K-ATPase, which is known to be the autoimmune target in classical autoimmune gastritis, also represents a major autoantigen in atrophic H. pylori gastritis. Molecular mimicry between H. pylori and the host does not seem to be responsible for the generation of this type of autoreactivity. The development of antigastric autoantibodies may be a relevant host factor which contributes to the final clinical outcome of chronic H. pylori gastritis.

[Helicobacter pylori infections and autoimmunity: the interplay in the pathogenesis of gastritis]

Recent studies suggest a significant association of Helicobacter pylori (H.p.) gastritis and antigastric autoimmunity. Sera of H.p. infected patients exhibit antigastric autoantibodies with high prevalence (over 50 percent of the cases) and with antiluminal and/or anticanalicular binding patterns on gastric mucosa. Models for the pathogenesis of this H.p. associated autoimmunity are antigenic mimicry or Th 1-induced expression of MHC class II and costimulatory molecules on gastric epithelial cells. The anticanalicular autoantibodies binding to gastric parietal cells show fine specificities for the alpha- and for the beta-subunit of the gastric H, K-ATPase, which correspond to the findings in classical autoimmune gastritis. They are significantly correlated with higher grades of corpus gastritis as well as morphologic and functional glandular atrophy of the corpus. The development of this antigastric autoimmunity apparently is a relevant pathogenic factor of the host reaction and might be crucial for the different types and outcomes of H.p. gastritis.

Eradication of H. pylori with pantoprazole, clarithromycin, and metronidazole in duodenal ulcer patients: a head-to-head comparison between two regimens of different duration

BACKGROUND

The study was conducted to compare the efficacy and tolerability of two pantoprazole-based triple therapies of different length in the eradication of H. pylori.

METHODS

In this double-blind, multicenter parallel group comparison, H. pylori-positive patients were randomly assigned to either the PCM-7 group (7 days of pantoprazole 40 mg bid, clarithromycin 500 mg bid, metronidazole 500 mg bid) or the PCM-14 m group (modified 14 day therapy of the same regimen with metronidazole only given for 10 days due to labeling reasons). H. pylori status was determined by urease test, histology, culture, and 13C-urea breath test. Treatment outcome was assessed 6 weeks after intake of the last study medication.

RESULTS

The following eradication rates were achieved: for PCM-7 in the MITT population 83% (89/107), in the PP population 84% (81/97); for PCM-14 m in MITT 87% (92/106), in PP 88% (91/104). Ulcer healing rates were: for PCM-7 in MITT population 99% (106/107), in the PP population 99% (96/97); for PCM-14 m in MITT 99% (105/106), in PP 99% (103/104). Gastrointestinal symptoms and gastritis scores decreased in both treatment groups. Equivalence of treatment regimens could be proven for all populations. In total, 64 patients reported adverse events. Five serious adverse events occurred, all unrelated to the study medication.

CONCLUSION

The two pantoprazole-based triple therapies tested in this study are equally effective in H. pylori eradication, ulcer healing and relief from ulcer pain. It is concluded that 7 days of triple therapy are generally sufficient.

Expression of nuclear beta-catenin and c-myc is correlated with tumor size but not with proliferative activity of colorectal adenomas

Most colorectal cancers have loss-of-function mutations in the adenomatosis polyposis coli (APC) tumor suppressor gene. This leads to the accumulation of nuclear beta-catenin, which, together with the DNA-binding protein TCF-4, functions as a transcriptional activator. The recently defined target genes c-myc, cyclin D1, and matrilysin are responsible for tumor proliferation or malignant progression and explain the oncogenic potential of nuclear beta-catenin. To investigate its role in early colon carcinogenesis, we analyzed the expression of beta-catenin, its target gene c-myc, and the proliferative activity in 88 colorectal adenomas of varying size and grade of dysplasia. The results revealed i) the most significant correlation of nuclear beta-catenin and c-myc expression was not with the grade of dysplasia but with the size of the colon adenoma; ii) perfect correlation of nuclear beta-catenin and c-myc expression; iii) no significant correlation of adenoma size with the proliferative activity; and iv) no significant correlation of proliferative activity and the nuclear expression of beta-catenin and c-myc. These results imply that APC mutations have additional beta-catenin-independent functions; APC mutations alone are not sufficient for nuclear overexpression of beta-catenin; and nuclear beta-catenin has additional important functions for exceeding a threshold tumor size.

Cell populations involved in pigmented villonodular synovitis of the knee

OBJECTIVE

Pigmented villonodular synovitis (PVNS) of the knee is a tumor-like process of uncertain nature. We analyzed the involved cell populations, iron deposition, and cell proliferation in PVNS to propose a pathogenetic concept of this still elusive disease entity.

METHODS

The study was performed on a series of 14 cases of localized PVNS of the knee. Histology and histochemistry were used to evaluate basic morphology and iron deposit distribution. Immunohistochemistry was performed to characterize the inflammatory cell infiltrate and to identify the proliferating cell compartments. In situ hybridization analysis using a cDNA probe against type I collagen was utilized to further characterize the mononuclear cell infiltrate.

RESULTS

In addition to the classic features (mononuclear cell infiltrate, multinuclear giant cells, iron deposits, and stromal fibrosis) we observed a chronic inflammatory cell infiltrate in all PVNS samples, in which CD8 positive T cells were conspicuous. A high portion of non-phagocytotic cells resorbed iron and became CD68 positive. A proportion of mononuclear cells expressed type I collagen, thus resembling B synoviocytes.

CONCLUSION

Our results suggest that preexisting chronic inflammation plays an important pathogenetic role in the PVNS disease process. Chronic inflammation increases the risk of articular bleeding and probably deranges the iron processing capacity of local synovial macrophages. The resulting iron overload could lead to a shift of iron storing cells from synovial macrophages to B synoviocytes and fibroblasts. A perpetuated proliferation and activation of these cells can explain why PVNS behaves like a neoplastic process.

Tumor patterning: analogies of neoplastic morphogenesis with embryogenesis

Patterning or pattern formation 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 biology, 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 gastrulation and a basic example of neoplastic patterning is the colonic adenoma-carcinoma sequence. Both processes exhibit distinct nuclear translocations and expressions of beta-catenin, which is considered to be a decisive transcriptional regulator. Our recent studies demonstrate striking analogies of patterning and nuclear beta-catenin expressions between the colonic adenoma-carcinoma sequence and the gastrulation steps. The shared patterns are dissociation, reassembly, tubular reconstruction and branching of neoplastic cells in association with nuclear beta-catenin expressions. These new findings establish patterning as a relevant concept for tumor biology and link the neoplastic morphogenesis with embryogenesis.

Lack of evidence for an involvement of Epstein-Barr virus infection of synovial membranes in the pathogenesis of rheumatoid arthritis

OBJECTIVE

To test the hypothesis that Epstein-Barr virus (EBV) infection of cells within the synovial membrane contributes to the pathogenesis of rheumatoid arthritis (RA).

METHODS

Biopsy samples of synovial membrane from 37 patients with RA and from 51 patients with other joint diseases were studied for evidence of EBV infection using in situ hybridization specific for the EBV-encoded RNAs (EBERs). Latent membrane protein 1 (LMP1) and the lytic-cycle BZLF1 protein were detected by immunohistochemistry.

RESULTS

Rare EBER-positive B lymphocytes were detected in 7 RA biopsy samples. EBV was not detectable in any other cells. Expression of the LMP1 and BZLF1 proteins of EBV was not observed in any of the samples. No EBV infection was detected in synovial membranes from patients with other joint diseases.

CONCLUSION

Our data indicate that EBV infection is not directly involved in the pathogenesis of RA. Any contribution of EBV to the pathogenic process leading to RA is likely to be indirect.

Expression of deoxyuridine triphosphatase (dUTPase) in colorectal tumours

We report the generation of 2 monoclonal antibodies (MAbs), 2B12 and 3E6, suitable for the detection of human dUTPase in routinely processed paraffin sections by immunohistochemistry. Using these MAbs, we observed nuclear expression of dUTPase in the proliferation zones of normal colorectal mucosa as well as in hyperplastic polyps. Colorectal adenomas and adenocarcinomas revealed a wide spectrum of dUTPase expression, ranging from 5 to 63% (median 42%) and from 5 to 71% of tumour cells (median 42%) respectively. Non-parametric correlation of dUTPase expression with proliferation as determined by a Ki-67 antigen-specific MAb revealed a significant and moderately strong correlation between proliferation rate and dUTPase expression in adenomas, but not in adenocarcinomas. This finding was confirmed by double-labelling immunofluorescence. Unexpectedly, we found significantly lower levels of dUTPase expression in primary colorectal carcinomas without lymph-node metastases at the time of surgery (Dukes A and B stages) than in Dukes C carcinomas. While this observation requires confirmation in larger studies, it suggests that dUTPase expression may be a negative prognostic marker in colorectal carcinomas. Moreover, these reagents should prove useful in the context of attempts to develop dUTPase inhibitors for cancer chemotherapy. Since it has been demonstrated that dUTPase expression can mediate resistance to 5-fluorouracil, it is also possible that these MAbs may be helpful in identifying patients with colorectal carcinomas resistant to adjuvant chemotherapy using this and related compounds. Int. J. Cancer (Pred. Oncol.) 84:614-617, 1999.

Chondroblastoma is an osteoid-forming, but not cartilage-forming neoplasm

Chondroblastoma is defined as a 'benign tumour, characterized by highly cellular and relatively undifferentiated tissue composed of rounded or polygonal chondroblast-like cells' and the 'presence of cartilaginous intercellular matrix' (WHO). An extensive analysis of the extracellular matrix composition and gene expression pattern of a large series of chondroblastoma cases shows, however, that type II collagen, which is the main component of any cartilage matrix, is not expressed by the neoplastic cells of this tumour entity and is not deposited into the extracellular tumour matrix. Instead, osteoid and fibrous matrix is formed, with its typical biochemical composition. The multifocal expression of aggrecan proteoglycan in most chondroblastomas explains the bluish, pseudo-chondroid appearance of some of the matrix-rich areas of chondroblastomas. This study did not show chondroid matrix formation or chondroblastic cell differentiation in chondroblastomas, suggesting that chondroblastoma should be classified as a specific bone-forming, rather than cartilage-forming neoplasm.

Acute hepatitis induced by greater celandine (Chelidonium majus)

The hepatotoxic potential of conventional drugs is well known, but herbal medicines are often assumed to be harmless. In the last 2 years, we have observed 10 cases of acute hepatitis induced by preparations of greater celandine (Chelidonium majus), which are frequently prescribed to treat gastric and biliary disorders. The course of hepatitis was mild to severe. Marked cholestasis was observed in 5 patients, but liver failure did not occur. Other possible causes of liver disease (viral, autoimmune, hereditary, alcohol, and secondary biliary) were excluded by laboratory tests and imaging procedures, and liver biopsy specimens were consistent with drug-induced damage. After discontinuation of greater celandine, rapid recovery was observed in all patients and liver enzyme levels returned to normal in 2-6 months. Unintentional rechallenge led to a second flare of hepatic inflammation in 1 patient. Greater celandine has to be added to the list of herbs capable of inducing acute (cholestatic) hepatitis. A significant proportion of unexplained cases of hepatitis may be caused by greater celandine.

[Digital ischemia as paraneoplastic marker of metastatic endometrial carcinoma]

Digital ischemia with gangrene of one or several fingertips has been described as a paraneoplastic syndrome associated with various malignant tumors, especially adenocarcinomas. Most often this paraneoplastic syndrome represents the first symptom of an occult neoplasia in an advanced stage. We present the case of an 83 year-old patient with digital ischemia and gangrenous fingertips in association with a latent adenocarcinoma of the uterus and metastatic involvement of the paraaortal lymph nodes. Acute occurrence of digital ischemia and gangrene without pathological laboratory findings and negative past medical history concerning cardiovascular-induced emboli, arteriosclerotic occlusion, or rheumatologic and autoimmune diseases should suggest this paraneoplastic syndrome and lead to thorough search for an underlying tumor.

beta-catenin regulates the expression of the matrix metalloproteinase-7 in human colorectal cancer

Most colorectal cancers have loss of function mutations in the adenomatosis polyposis coli (APC) tumor suppressor gene. This leads to accumulation of beta-catenin, which together with the DNA binding protein TCF-4 functions as a transcriptional activator. Recently defined target genes are c-myc and cyclin D1, linking the APC gene defect to the capacity for autonomous proliferation of colon tumors. Here we report the identification of the matrix metalloproteinase MMP-7 as another target gene of beta-catenin/TCF-4. MMP-7 is overexpressed in 80% of human colorectal cancers and known to be an important factor for early tumor growth, with a potential function also for later progression steps, like invasion and metastasis. Our results explain the high percentage of MMP-7 overexpression in colon tumors. Moreover they indicate that defects in the APC tumor suppressor gene may also have an influence on later steps of colon tumor progression.

Negative regulation of CD4 expression in T cells by the transcriptional repressor ZEB

ZEB, an E-box binding transcriptional repressor, is an important regulator of T cell and muscle development. Targeted disruption of ZEB in mice resulted in a strong reduction of thymocytes and the few T cells that reached the mature stage were predominantly CD4(+). CD4 expression during the various stages of T cell differentiation is controlled at the transcriptional level by a complex array of regulatory elements in the CD4 gene locus, consisting of at least three enhancers, one promoter and one silencer. Here we present evidence that CD4 gene expression is negatively regulated by ZEB. We show that ZEB binds to the 5'E-box in the CD4-3 element of the proximal CD4 enhancer in competition with the transcriptional activators E12 and HEB, thereby reducing CD4 expression on CD4 single-positive but not CD4/CD8 double-positive T cells. The conversion of the CD4 proximal enhancer into a potential silencer element by the transcriptional repressor ZEB offers an additional concept of CD4 gene regulation in T cells.

Pleomorphic adenomas of the parotid express different mesenchymal phenotypes: demonstration of matrix gene expression products characteristic of the fibroblastic and chondrocytic cell lineages

AIMS

Pleomorphic adenomas of the salivary glands are characterized by their high tissue diversity. Many studies have explored the derivation and differentiation of the neoplastic cells. We investigated the composition of the collagenous extracellular tumour matrix and could show a specific biochemical composition pattern in the different tumour areas.

METHODS AND RESULTS

In epithelially differentiated acinar and ductal areas there was positive staining for basement membrane collagen type IV and no, or only scarce, staining for collagen types I, II, III, or VI. Solid areas mostly lacked any extracellular matrix. In areas with fibrous tissue-like appearance, the fibroblast-typical interstitial collagen types I, III and VI were seen. Chondroid areas showed abundantly the characteristic cartilage components, collagen type II and, pericellularly, type VI collagen.

CONCLUSIONS

Our data show the presence of fibroblastic and chondrocytic cell differentiation in pleomorphic adenomas. Thus, they confirm that these neoplasms display, besides epithelial cell types, also real mesenchymal cell and tissue types. Differences in the abundance and the biochemical composition of the extracellular tumour matrix account largely for the morphological heterogeneity of pleomorphic adenomas of the salivary glands.

Impact of ELISA and immunoblot as diagnostic tools one year after eradication of Helicobacter pylori in a multicentre treatment study

The performance of serological tests for Helicobacter pylori infections is hampered by the persistence of antibodies after eradication therapy or spontaneous healing. Detection of different antigens or immunoglobulin classes might have an impact on the validity of serodiagnosis. The aim of this study was to assess the decrease in IgA and IgG antibody levels after eradication of H. pylori. Serum samples of 242 patients with active duodenal ulcer were tested with the ELISA and the immunoblot (IB) techniques for H. pylori-specific IgA and IgG antibodies before therapy and 1 year after successful eradication. From a total of 81 patients paired sera were available. At the end of the follow-up period ELISA antibody titres from the IgA class had decreased from a mean value of 6.69 to 4.26 units (P = 0.0001), and IgG class antibody titres from a mean value of 21.9 to 12.1 units (P = 0.0001). Regarding seroreversion, from 34 initially IgA positive sera 16 (47%), and from 74 IgG positive sera 18 (24%), had definitively reverted to 'negative'. One year after eradication, when tested with the immunoblot, the antibody responses against specific antigens of 37% IgA-positive sera (23/62) and 8% IgG-positive sera (6/78) reverted to 'negative', compared to a seroreversion rate of 27% of the anti-CagA IgA-positive sera (18/67) and of 9% of the anti-CagA IgG-positive sera (7/79). In conclusion, despite an overall significant decrease of H. pylori antibodies, both tests cannot be recommended for monitoring treatment success.

Decrease of antigastric autoantibodies in Helicobacter pylori gastritis after cure of infection

H. pylori infection leads to the formation of autoantibodies against canalicular structures with human parietal cells in about 30% of all patients. This type of autoreactivity is associated with gastric mucosa atrophy. This study aimed to analyse the effect of cure of infection on anticanalicular autoantibodies. H. pylori infection was cured in 34 patients. Sera of these patients were screened for anticanalicular autoantibodies using an immunohistochemical method before, 10 weeks after and one year after cure of infection. Prevalence of anticanalicular autoantibodies significantly decreased from 26% before treatment to 9% after one year. The data presented in this study add new information to the possible reversibility of gastric mucosa atrophy.

[EHBMP-2. Initial BMP analog with osteoinductive properties]

For the first time a non natural BMP-variant (EHBMP-2) with osteoinductive properties was produced by expression in E. coli through specific mutation of the amino acid sequence. The substitution of 12 N-terminal amino acids by a nonsense sequence results in a neglectible affinity of EHBMP-2 to the extracellular matrix. In vitro EHBMP-2 induces dose-dependent cartilage formation in neonatal muscle tissue. Single intramuscular implantation in mice results in the formation of an ossicle with functional active bone marrow. The size of the ossicle depends on the amount of implanted EHBMP-2 and can significantly be increased by the combination with a collagen carrier. The largest bone formation is observed after injection of EHBMP-2 containing collagen suspensions. In rats a stronger osteoinductive activity can be achieved by coupling of EHBMP-2 to collagen discs than by coupling natural BMP-2 to the same collagen carrier. Critical size defects in rats' mandibular angels can be restored by the combination of granular collagenous bone matrix (ICBM) with EHBMP-2. Further investigations have to show whether the altered pharmacokinetics of EHBMP-2 has advantages regarding its therapeutical use and tissue-engineering.

Helicobacter pylori induces apoptosis in gastric mucosa through an upregulation of Bax expression in humans

BACKGROUND

Maintenance of gastric mucosal integrity depends on the balance between cell loss due to apoptosis and cell proliferation. Helicobacter pylori induces apoptosis in gastric epithelial cells, but the regulation of this process has been little studied. The Bcl-2 proteins are the best-studied family of proteins involved in the mechanism of apoptotic death. Some members of this family, such as Bcl-2, inhibit apoptosis, whereas others, such as Bax, induce it. The present study was performed to determine the apoptosis rate and mRNA and protein expression for Bax and Bcl-2 in the gastric mucosa of duodenal ulcer (DU) patients with H. pylori infection before and after H. pylori eradication. We recruited 8 H. pylori-negative control subjects and 20 DU patients (H. pylori-positive) given a 1-week triple therapy to eradicate H. pylori. The apoptosis was analyzed by means of terminal deoxyribonucleotide transferase-mediated digoxigenin-11-deoxyuridine triphosphate biotin nick-end labeling (TUNEL) staining, and the expression of mRNA for Bax and Bcl-2 by reverse transcription polymerase chain reaction (RT-PCR) and Southern blot. In all patients gastritis was assessed histologically on the basis of the Sydney classification, the presence of H. pylori, and analysis of cagA status.

RESULTS

All 20 DU patients were H. pylori-positive, and 18 (90%) were CagA-positive. The apoptotic cells were infrequently identified in gastric surface epithelium by TUNEL histochemistry in H. pylori-negative controls. In DU patients infected with H. pylori, apoptotic cells were more numerous and seen deep in the gastric glands. The infection was associated with significantly upregulated expression of mRNA and protein for Bax and suppressed mRNA and protein expression for Bcl-2, as determined using RT-PCR and Western blot analysis. The Bax overexpression was significantly stronger in the antrum than in the corpus of H. pylori-infected patients. Four weeks after the eradication a marked decrease of neutrophil infiltration, an improvement of the grade of gastritis (mononuclear infiltration), and significant reduction in apoptosis rate were observed. After eradication the Bax mRNA expression was still at an increased level, whereas the Bcl-2 mRNA expression remained suppressed.

CONCLUSIONS

1) H. pylori induces apoptosis in the gastric epithelium, at least in part, due to an upregulation of proapoptotic Bax and downregulation of antiapoptotic Bcl-2, and 2) Bax mRNA and protein expression was higher in the antrum than in the corpus, and this was probably due to greater inflammatory changes observed in the antrum than in the corpus.

[Iron deposits, cell populations and proliferative activity in pigmented villonodular synovitis of the knee joint]

Pigmented villonodular synovitis (PVNS) of the knee is a tumor-like process of uncertain nature. A chronic inflammation as well as a neoplastic process have been proposed in the literature. The aim of our study was to characterise the prevalent inflammatory cells, the proliferating cell populations, and the iron deposit distribution in PVNS in order to get insights into pathogenetically relevant processes of this condition. Thirteen cases of PVNS of the knee as well as 8 normal controls were analysed histochemically for iron deposits and immunohistochemically for the distribution of vascular structures and inflammatory cell populations. Collagen type I expressing fibroblastic cells were identified by in situ hybridization. The proliferative cell compartment was characterized using MIB-1 staining. Our analysis showed no correlation between intra- or extracellular iron deposits and proliferation, giant cell formation, vascularity, number of CD 68-positive cells, and foam cell formation. Instead, iron deposits were associated with collagen matrix formation. All PVNS specimens showed a significant increase of chronic inflammatory infiltrates compared to all normal synovial membrane specimens investigated. The identification of the proliferative cell compartments showed that besides fibroblastic cells many of the mononuclear, partly CD 68 positive cells were Ki-67 positive. Foam cells, iron-loaded cells, and giant cells were, however, negative for the Ki-67 antigen. PVNS appears to originate from the interplay of proliferating, partly CD 68 positive mononuclear cells and fibroblasts, both activated by an excessive iron load. Giant cells probably develop by fusion of CD 68-positive histiocytic cells. Foam cells are most likely secondary to fatty tissue destruction.

[Matrix gene expression pattern as indicators of the biology of cartilage-forming tumors]

Mesenchymal cells can be characterized by the expression of specific sets of extracellular matrix (ECM) proteins. The aim of our study was to identify such expression pattern in cartilage-forming tumours in order to elucidate the biology of these neoplasms. In situ hybridisation and immunohistochemistry for various ECM components were performed on enchondromas, conventional chondrosarcomas of various grades and dedifferentiated chondrosarcomas. Chondroid areas of all investigated neoplasms showed strong expression of cartilage collagen types II and IX and aggrecan core and link protein. Focally, also the expression of other collagen subtypes such as collagen type X and collagen types I and III was observed. Non-chondroid areas of dedifferentiated chondrosarcomas lacked any expression of the cartilage-typical gene products and were instead positive for interstitial collagen types I, III, and VI. The hallmark of all investigated cartilaginous neoplasms was the expression of the chondrocyte-typical genes. Neoplastic chondrocytes showed the differentiation facettes similar to their physiological counterparts resulting in the high heterogeneity, which is characteristic for chondrogenic neoplasms. A different biology is suggested for dedifferentiated chondrosarcomas, in which the "dedifferentiated" portion is proposed to have a separate (e.g. fibroblastic) mesenchymal origin.

Eradication of Helicobacter pylori with lansoprazole, roxithromycin and metronidazole--an open pilot study

BACKGROUND

The most extensively studied Helicobacter pylori eradication regimen comprises omeprazole, clarithromycin and metronidazole. Macrolide antibiotics other than clarithromycin should achieve similar efficacy, but they have not yet been thoroughly tested.

AIM

To determine the efficacy and safety of a triple therapy regimen using lansoprazole, roxithromycin, and metronidazole on the basis of multicentre outpatient care in an open pilot study.

METHODS

163 patients with duodenal ulcer and proven H. pylori infection received lansoprazole 30 mg b.d., roxithromycin 300 mg b.d. and metronidazole 500 mg b.d. for 7 days followed by another 7 days of lansoprazole 30 mg once daily. H. pylori status was determined by urease quick test, histology, microbiology and 13C-urea breath test before starting and at least 4 weeks after completing treatment.

RESULTS

150 patients were available for evaluation; H. pylori was successfully eradicated in 84.7% (127/ 150) as determined by urease quick test, 78.0% (117/150) by histology, 81.3% (109/134) by 13C-urea breath test; and in 75.3% (113/150), at least two tests were negative. Side-effects were reported in 34 patients (most commonly diarrhoea and changes in liver function tests), in two cases the study medication was interrupted. Prior to treatment, 23% of the H. pylori isolates were resistant against metronidazole and 3.4% against roxithromycin. After unsuccessful treatment, 84% of the isolates were resistant against metronidazole and 21% against roxithromycin. Primary resistance to metronidazole increased the chance of treatment failure approximately sevenfold (7% vs. 53%).

CONCLUSIONS

For H. pylori eradication, the combination of lansoprazole, roxithromycin and metronidazole proved to be as safe as other current triple therapy regimens, while a comparison of efficacy rates yet remains to be assessed in prospective controlled trials. The metronidazole-resistant H. pylori is not rare in Germany and, in the present study, has strongly influenced treatment success.

Nuclear overexpression of the oncoprotein beta-catenin in colorectal cancer is localized predominantly at the invasion front

Sixty to eighty percent of all colorectal cancers are characterized by mutations in the APC tumor suppressor gene. Recently, it was shown that these mutations lead to a nuclear overexpression of beta-Catenin by disruption of the wingless/WNT signal pathway. Since nuclear beta-Catenin functions as a transcriptional activator of hitherto unknown tumor genes, this form of beta-Catenin is now considered a major oncoprotein in colorectal cancer. Using immunohistochemistry, we investigated the distribution of overexpressed beta-Catenin within individual colorectal carcinomas. In the majority of the tumors, we found no homogeneous staining, but a strong nuclear expression of beta-Catenin predominantly localized at the invasion front with strongest nuclear staining of isolated, scattered tumor cells. In contrast, cells in the tumor center often showed no nuclear staining, but retained a membranous expression of beta-Catenin, comparable to normal colon epithelium. It is, therefore, likely that in addition to the overexpression of beta-Catenin caused by defects in the APC locus, regulatory events in the tumor itself lead to a different distribution of this oncoprotein. Possibly, surrounding tissue at the invasion front can give signals to the tumor cells, leading to a nuclear translocation of beta-Catenin, where it may play a direct role in tumor invasion processes.