[Tropheryma whipplei endocarditis]. / Tropheryma-whipplei-Endokarditis.

Whipple's disease is a rare infectious disease caused by the bacterium Tropheryma whipplei. Usually the course of the disease is characterized by fever, diarrhea, weight loss and polyarthritis. We report on a case with a 10-year course of the disease with endocarditis, myocarditis and involvement of the bone marrow but with negative histological results of the small intestine.

High-linear energy transfer (LET) alpha versus low-LET beta emitters in radioimmunotherapy of solid tumors: therapeutic efficacy and dose-limiting toxicity of 213Bi- versus 90Y-labeled CO17-1A Fab' fragments in a human colonic cancer model.

Recent studies suggest that radioimmunotherapy (RIT) with high-linear energy transfer (LET) radiation may have therapeutic advantages over conventional low-LET (e.g., beta-) emissions. Furthermore, fragments may be more effective in controlling tumor growth than complete IgG. However, to the best of our knowledge, no investigators have attempted a direct comparison of the therapeutic efficacy and toxicity of a systemic targeted therapeutic strategy, using high-LET alpha versus low-LET beta emitters in vivo. The aim of this study was, therefore, to assess the toxicity and antitumor efficacy of RIT with the alpha emitter 213Bi/213Po, as compared to the beta emitter 90Y, linked to a monovalent Fab' fragment in a human colonic cancer xenograft model in nude mice. Biodistribution studies of 213Bi- or 88Y-labeled benzyl-diethylene-triamine-pentaacetate-conjugated Fab' fragments of the murine monoclonal antibody CO17-1A were performed in nude mice bearing s.c. human colon cancer xenografts. 213Bi was readily obtained from an "in-house" 225Ac/213Bi generator. It decays by beta- and 440-keV gamma emission, with a t(1/2) of 45.6 min, as compared to the ultra-short-lived alpha emitter, 213Po (t(1/2) = 4.2 micros). For therapy, the mice were injected either with 213Bi- or 90Y-labeled CO17-1A Fab', whereas control groups were left untreated or were given a radiolabeled irrelevant control antibody. The maximum tolerated dose (MTD) of each agent was determined. The mice were treated with or without inhibition of the renal accretion of antibody fragments by D-lysine (T. M. Behr et al., Cancer Res., 55: 3825-3834, 1995), bone marrow transplantation, or combinations thereof. Myelotoxicity and potential second-organ toxicities, as well as tumor growth, were monitored at weekly intervals. Additionally, the therapeutic efficacy of both 213Bi- and 90Y-labeled CO17-1A Fab' was compared in a GW-39 model metastatic to the liver of nude mice. In accordance with kidney uptake values of as high as > or = 80% of the injected dose per gram, the kidney was the first dose-limiting organ using both 90Y- and 213Bi-labeled Fab' fragments. Application of D-lysine decreased the renal dose by >3-fold. Accordingly, myelotoxicity became dose limiting with both conjugates. By using lysine protection, the MTD of 90Y-Fab' was 250 microCi and the MTD of 213Bi-Fab' was 700 microCi, corresponding to blood doses of 5-8 Gy. Additional bone marrow transplantation allowed for an increase of the MTD of 90Y-Fab' to 400 microCi and for 213Bi-Fab' to 1100 microCi, respectively. At these very dose levels, no biochemical or histological evidence of renal damage was observed (kidney doses of <35 Gy). At equitoxic dosing, 213Bi-labeled Fab' fragments were significantly more effective than the respective 90Y-labeled conjugates. In the metastatic model, all untreated controls died from rapidly progressing hepatic metastases at 6-8 weeks after tumor inoculation, whereas a histologically confirmed cure was observed in 95% of those animals treated with 700 microCi of 213Bi-Fab' 10 days after model induction, which is in contrast to an only 20% cure rate in mice treated with 250 microCi of 90Y-Fab'. These data show that RIT with alpha emitters may be therapeutically more effective than conventional beta emitters. Surprisingly, maximum tolerated blood doses were, at 5-8 Gy, very similar between high-LET alpha and low-LET beta emitters. Due to its short physical half-life, 213Bi appears to be especially suitable for use in conjunction with fast-clearing fragments.

Deformation-induced endothelin B receptor-mediated smooth muscle cell apoptosis is matrix-dependent.

To maintain normal blood flow, pressure overload in both arteries and veins requires a structural adaptation of the vessel wall (remodelling) that involves smooth muscle cell (SMC) hypertrophy and/or hyperplasia. Due to its potent vasoconstrictor and growth-promoting effects, endothelin-1 (ET-1) is a likely candidate to initiate and/or promote remodelling in blood vessels exposed to a chronic increase in blood pressure. To test this hypothesis, isolated segments of the rabbit carotid artery and jugular vein were perfused at different levels of intraluminal pressure. In both types of segments, pressure overload (160 and 20 mmHg, respectively) resulted in an increase in endothelial prepro-ET-1 and SMC endothelin B receptor (ETB-R) expression. Moreover, in pressurised segments from the carotid artery an ETB-R antagonist-sensitive increase in SMC apoptosis in the media was observed, while in the vein medial SMC started to proliferate. Isolated SMC from these rabbit blood vessels as well as from the aorta and vena cava of the rat, when cultured on a collagen or laminin matrix, uniformly revealed an ETB-R-mediated increase in apoptosis upon exposure to mechanical deformation plus exogenous ET-1 (10 nmol/L). However, when grown on a fibronectin matrix, the cultured SMC did not respond with an increase in apoptosis under otherwise identical experimental conditions. These findings suggest that deformation-induced activation of the endothelin system in the vessel wall not only plays a crucial role in remodelling, but that the structural components of the vessel wall, in particular the cell-matrix interaction, determine how SMC respond phenotypically to these changes in gene expression.

Automated high resolution PCR fragment analysis for identification of clonally rearranged immunoglobulin heavy chain genes.

The development of rapid polymerase chain reaction (PCR) protocols for amplification of rearranged heavy chain immunoglobulin (IgH) gene sequences has facilitated the identification of clonal IgH rearrangements in non-Hodgkin's lymphomas (NHL) and leukemias of B lineage. In the present report we have explored the recently described improved strategy for assessment of clonality of rearranged immunoglobulin heavy chain (IgH) genes in more detail in a series of 101 B cell malignancies and 50 polyclonal controls. The assay is based on an IgH-PCR with an automated fluorescence-based strategy for PCR detection of IgH gene rearrangements. Third complementarity determining region (IgH-CDR3) sequences were amplified using fluorescent dye labeled consensus primers homologous to the corresponding variable (V[H]) and joining (J[H]) gene segments in combination with a thermostable proofreading DNA polymerase. PCR products were size separated on a high resolution polyacrylamide gel and analyzed for clonality by exact size determination and fluorescence quantification in an automated DNA sequencer. PCR findings obtained with the optimized IgH-CDR3-PCR assay showed an overall monoclonality detection rate of 97% (97 of 101 cases with B cell neoplasms). The specificity was 100% as determined by analysis of 50 controls, all of which gave polyclonal PCR results. We found a high rate of monoclonal IgH-CDR3-PCR results not only in the leukemias and diffuse lymphoma but also in the group of follicular lymphoma, where a high rate of false negative results is frequently reported in the literature. In summary, we identified monoclonal IgH-CDR3 junctions in 55 out of 59 cases (93%) with B cell lymphoma and in 42 of 42 (100%) cases with leukemia, immunocytoma and multiple myeloma. The results demonstrate that automated fluorescence detection of IgH-CDR3-PCR products is an ideal tool for detection of clonal and polyclonal lymphoid B cells. In combination with allele-specific primers the procedure may improve current experimental approaches to detect occult malginant B cells during initial staging and follow-up of NHL and ALL patients.

Radioimmunotherapy of small volume disease of colorectal cancer metastatic to the liver: preclinical evaluation in comparison to standard chemotherapy and initial results of a phase I clinical study.

At the time of surgery, occult metastases (micrometastases) are present in more than 50% of colorectal cancer patients, and the liver is the most frequent site of apparent metastatic disease. Frequently, adjuvant chemotherapy is unable to prevent tumor recurrence. Thus, novel therapeutic strategies are warranted. The aim of this study was to establish a model of human colon cancer metastatic to the liver of nude mice, to assess, in this setting, the therapeutic efficacy of radioimmunotherapy (RAIT) compared to standard chemotherapy and to evaluate, in a Phase I/II trial, the toxicity and therapeutic efficacy of RAIT in colorectal cancer patients with small volume disease metastatic to the liver. Multiple liver metastases of the human colon cancer cell line GW-39 were induced by intrasplenic injection of a 10% tumor cell suspension. Whereas controls were left untreated, therapy was initiated on day 10 or 20 after tumor inoculation with the 131I-labeled, low affinity anticarcinoembryonic antigen (anti-CEA) monoclonal antibody (MAb), F023C5 (Ka = 10(7) liters/mol), or the high-affinity anti-CEA MAb, MN-14 (Ka = 10(9) liters/mol), or chemotherapy (5-fluorouracil/leucovorin (folinic acid) versus irinotecan) at their respective maximum tolerated doses (MTDs). Twelve colorectal cancer patients with small volume disease metastatic to the liver (all lesions < or = 2.5 cm) were entered into a mCi/m2-based Phase I dose escalation study with 131I-labeled humanized version of MN-14, hMN-14. The patients were given single injections, starting at 50 mCi/m2 and escalating in 10-mCi/m2 increments. The MTD was defined as the dose level at which < or = 1 of 6 patients develop grade 4 myelotoxicity. In the mice, untreated controls died from rapidly progressing hepatic metastases at 6-8 weeks after tumor inoculation. The life span of mice treated with 5-fluorouracil/leucovorin was prolonged for only 1-3 weeks, whereas irinotecan led to a 5-8-week prolongation. In contrast, at their respective MTDs, the 131I-labeled low-affinity anti-CEA MAb, F023C5, led to a 20% permanent cure rate, and the high affinity MAb, MN-14, led to an 80% permanent cure rate, when therapy was initiated at 10 days after tumor inoculation. In the 20-day-old tumor stage, although it prolonged life, 131I-F023C5 was unable to achieve cures, whereas 131I-MN-14 was still successful in 20%. Histologically, no remaining viable tumor cells could be demonstrated in these animals surviving > 6 months. In patients, the MTD was reached at 60 mCi/m2 of hMN-14 (at 70 mCi/m2, two of three grade 4 myelotoxicities). Of 11 assessable patients, 2 had partial remissions (corresponding to an objective response rate of 18%), and 5 (45%) had minor/mixed responses or experienced stabilization of previously rapidly progressing disease. These data suggest that in small volume disease, RAIT may be superior to conventional chemotherapy. Antibodies of higher affinity seem to be clearly superior. The clinical response rates in patients with small volume disease are encouraging, being comparable to the response rates of conventional chemotherapeutic regimens but with fewer side effects. Ongoing studies will show whether treatment at the MTD will further improve therapeutic results.

Expression of the anaphylatoxin C5a receptor in non-myeloid cells.

C5, a 74 amino acid peptide cleaved from the complement protein C5, represents the most potent anaphylatoxin and possesses inflammatory as well as immunomodulatory activities. In the past, expression of the receptor for the anaphylatoxin C5a (C5aR) has been thought to be restricted to cells of myeloid origin. However, recent evidence suggests that the C5aR is constitutively expressed in non-myeloid cells including epithelial, endothelial and smooth muscle cells in the human liver and lung. These findings are contrasted by results from our laboratory which demonstrated that in the normal human liver and lung C5aR expression is detectable exclusively in macrophages and macrophage-derived cells (Kupffer cells). Interestingly, we found evidence that C5aR expression may be inducible in epithelial cells as C5aR mRNA was observed in vivo in human keratinocytes of the inflamed but not of the normal skin. Herein we review the work of our laboratory and others on the expression of the C5aR in various human non-myeloid cells types. A better understanding of the expression patterns of this important anaphylatoxin receptor may provide new insights in the pathophysiological role of C5a in vivo.

Apoptosis in the small intestinal allograft of the rat.

BACKGROUND: Necrosis and apoptosis are different cell death mechanisms. Necrosis is a pathological process that occurs after destruction of the cell membrane. Apoptosis is a DNA-dependent cell death mechanism, which occurs under physiological and pathological conditions. Although necrosis is a well-defined phenomenon in an acute graft rejection, the occurrence and relevance of apoptosis during this process is largely unknown. METHODS: The enterocyte apoptosis rates in allografted (n=24) and isografted (n=24) small intestines of the rat were compared using the in situ end-labeling technique. RESULTS: In situ end-labeling showed a dramatically increased number of apoptotic enterocytes in allografted small intestines, whereas increased labeling could not be observed in isogeneic small intestinal grafts. CONCLUSIONS: We suggest that graft rejection-associated apoptosis, in addition to necrosis, plays an important role in the course of organ failure, and that the degree of apoptosis represents another reliable indicator for the diagnosis and prognosis of transplant rejection.

Thalidomide impairment of trinitrobenzene sulphonic acid-induced colitis in the rat - role of endothelial cell-leukocyte interaction.

1. Immune response-modulating drugs such as thalidomide may be of therapeutic value in the treatment of chronic inflammatory bowel diseases including Crohn's disease (CD). In the present study, we have investigated whether thalidomide exerts this effect by impairing endothelial cell-leukocyte interaction through down-regulation of the expression of pro-inflammatory gene products in these cells. 2. Transient CD-like colitis was induced in male Wistar rats by single enema with trinitrobenzene sulphonic acid (TNBS) in ethanol followed by macroscopic scoring, histology, intravital microscopy, RT - PCR and immunohistochemistry (IHC) analyses. Thalidomide or its analogue supidimide were administered in olive oil by intragastric instillation 6 h prior to the induction of colitis and then daily for one week. 3. Both thalidomide and supidimide (200 mg kg(-1) d(-1)) significantly attenuated TNBS-induced colitis as compared to vehicle-treated control animals (44 and 37% inhibition, respectively), and this effect persisted for 7 days post cessation of thalidomide treatment (46% inhibition). 4. Moreover, thalidomide significantly reduced leukocyte sticking to postcapillary venular endothelial cells in the submucosa (by 45%), improved functional capillary density and perfusion, and attenuated endothelial interleukin-8 expression, as judged by IHC analysis. According to RT - PCR analysis, both thalidomide and supidimide also significantly reduced vascular cell adhesion molecule-1 mRNA expression in the affected part of the descending colon. 5. These findings suggest that thalidomide and one of its derivatives impairs CD-like TNBS-induced colitis in the rat by down-regulating endothelial adhesion molecule and chemokine expression and, as a consequence, the interaction of these cells with circulating leukocytes.

The role of reactive oxygen species in cisplatin-induced apoptosis in human malignant testicular germ cell lines.

Testicular germ cell tumours (TGCT) are the most common solid tumour among young males. Whereas in 1970s, only 5% of patients with a metastatic testicular tumours survived their disease, these days 80% of patients treated by modern cisdiamminedichloroplatinum (cisplatin, CDDP)-based chemotherapy are cured. Although data are accumulating on the effect of the mitogen-activated protein kinase (MAPK) family on the CDDP-induced apoptosis in tumour cells, the mechanisms by which CDDP initiates apoptosis in TGCT are not completely understood. Applying Western blot and phosphorylated kinase-specific ELISA analyses, flow cytometry, blocking experiments, and morphological methods we sought here to define the MAPK pathway(s) involved in the CDDP-induced apoptosis in the human TGCT cell line NCCIT. Our experiments showed that within hours of CDDP application only the extracellular signal-regulated kinase (ERK) was dually phosphorylated and caspase-3 became active. Functional assays using chemical inhibitors demonstrated that the phosphorylation of ERK was mediated by reactive oxygen species in an Raf-1-independent manner and required the activation of caspase-3. Thus, our data suggest that CDDP mediates its apoptosis-inducing effect on the human malignant testicular germ cells, at least partially, through activation of the MEK-ERK signaling pathway in a ROS-dependent, Raf-1-independent manner.

Specific autologous anti-melanoma T cell response in vitro using monocyte-derived dendritic cells.

Dendritic cells (DC) are antigen-presenting cells initiating primary and secondary immune responses. Since malignant tumors are able to escape immunologic control, DC might be prime candidates to activate the immune system against tumor cells. In an autologous system, a dynamic interaction among monocyte-derived DC (MoDC), T lymphocytes, and tumor cells obtained from melanoma patients could be noted. MoDC were generated from blood monocytes in the presence of GM-CSF, IL-4, and IFN-gamma. T cells were isolated either from peripheral blood or from lymph nodes. Melanoma cells were harvested from surgically removed tumor metastases. They were then gamma-irradiated and co-cultured with autologous MoDC and T lymphocytes. After 5 days, the lymphocytes showed a high proliferative activity and the majority of them were CD8-positive. In five cases tested, they revealed a high cytotoxic activity resulting in apoptosis of tumor cells. These findings suggest that MoDC are capable of initiating an effective specific anti-tumor response in a strictly autologous mixed lymphocyte tumor culture (MLTC), even though tumor-specific antigens had not been individually defined. Therefore (I) whole melanoma cells can serve as a source of antigen, (II) monocyte-derived dendritic cells may process and present melanoma-specific antigens resulting in a strong lymphocyte proliferation, (III) the majority of responding T lymphocytes are CD8-positive, and (IV) an acquired cytotoxic response eventually leads to apoptosis of the melanoma cells. The reaction demonstrated here permits to in vitro and quantitatively monitoring the effect of T cell directed immunotherapies such as the adoptive immunotherapy of tumors.

Continuous recruitment, co-expression of tumour necrosis factor-alpha and matrix metalloproteinases, and apoptosis of macrophages in gout tophi.

Gout tophi are characterised by foreign body granulomas consisting of mono- and multinucleated macrophages surrounding deposits of monosodium urate microcrystals. After primary formation, granulomas grow associated with degradation of the extracellular matrix. Based on this background, we have sought (1) to investigate whether during granuloma's growth new macrophages are recruited into the tophi, (2) to find in situ evidence for macrophages' active role in matrix degradation and (3) to examine whether shrunk cells seen within gout tophi are apoptotic. Immunohistochemistry showed that perivascular localised mononuclear cells are CD68+, S100A8+, S100A9+, 25F9-, representing freshly migrated monocytes/macrophages. In contrast, almost all CD68+ mono- and multinucleated cells arranged within granulomas were S100A8-, S100A9-, 25F9+, representing mature (non-migrating) macrophages. Serial sections revealed that macrophages co-express tumour necrosis factor (TNF)-alpha and matrix metalloproteinases (MMPs) 2 and 9. In situ end-labelling of fragmented DNA demonstrated that CD68+ macrophages undergo apoptosis within gout tophi. Our data show that macrophages are continuously recruited into the gout tophi. These macrophages co-produce the proinflammatory cytokine TNF-alpha and two TNF-alpha inducible lytic enzymes, MMP-2 and MMP-9, suggesting that TNF-alpha may induce MMP production followed by matrix degradation within foreign body granulomas. In parallel, macrophages undergo apoptosis, a phenomenon that may restrict the destructive potential of inflammatory macrophages.

Allogeneic hepatocyte transplantation using FK 506.

Hepatocyte transplantation is an intriguing alternative to orthotopic liver transplantation. While engraftment of syngeneic hepatocytes can be achieved with relative ease, engraftment of allogeneic hepatocytes has been far more complicated. We used FK 506 (Tacrolimus), a novel and highly efficient immunosuppressant, which has been reported to augment liver regeneration in rats. Recipients of isolated syngeneic (LEW) and allogeneic (Wistar F.) rat hepatocytes (major histocompatibility barrier) recieved different immunosuppressive regiments with FK 506 or Cyclosporine A (CsA). Mature syngeneic hepatocytes could be retrieved up to post op day 300 with the lowest number of hepatocytes on post op day 20. Following allogeneic transplantation, no mature hepatocytes could be identified after post op day 10, though ductular like structures within the spleen were found in FK 506 but not CsA-treated animals. The epithelial cells of ductular like structures exhibit cytological features of CK-19 positive cells. Our results suggest that under CsA or FK 506 immunosuppression long-term survival of mature allogeneic hepatocytes within the spleen cannot be achieved across a major histocompatibility barrier though FK 506 allows engraftment of allogeneic donor type ductular cells.

Expression of IFNgamma, coexpression of TNFalpha and matrix metalloproteinases and apoptosis of T lymphocytes and macrophages in granuloma annulare.

Granuloma annulare, a prototype noninfectious granulomatous dermatitis, is morphologically characterized by a necrobiotic core surrounded by a cellular infiltrate. Because of many morphological similarities to tuberculosis, granuloma annulare has been suggested to represent a delayed-type hypersensitivity (Th1) reaction in the course of which inflammatory cells elicit matrix degradation. In the present study we (1) investigated the expression of interferon-gamma as the most important Th1-associated cytokine, (2) sought in situ evidence for the coexpression of the proinflammatory cytokine tumor necrosis factor-alpha and cytokine-regulated matrix metalloproteinases 2 (gelatinase A) and 9 (gelatinase B), and (3) sought to determine whether shrunken cells seen within necrobiotic areas of granuloma annulare are apoptotic cells. In situ hybridization combined with immunofluorescence showed that large numbers of infiltrating CD3+ lymphocytes express interferon-gamma. Application of catalyzed signal amplification in immunodetection revealed that the vast majority of CD3+ lymphocytes and CD68+ macrophages contained tumor necrosis factor-alpha. Immunohistochemistry demonstrated that macrophages producing tumor necrosis factor-alpha coexpress matrix metalloproteinases 2 and 9. In situ end-labeling combined with immunofluorescence detected few apoptotic T cells in perivascular regions and numerous apoptotic macrophages within necrobiotic areas. These results suggest that in granuloma annulare interferon-gamma+ Th-1 lymphocytes may cause a delayed-type hypersensitivity reaction whereby macrophages are differentiated to aggressive effector cells expressing tumor necrosis factor-alpha and matrix metalloproteinases. In parallel, activation-induced apoptosis in lymphocytes and macrophages may serve to restrict the destructive potential of the inflammatory cells.

T lymphocytes and altered keratinocytes express interferon-gamma and interleukin 6 in lichen planus.

Lichen planus is assumed to represent a delayed hypersensitivity reaction, in the course of which cytokines control the proliferation and differentiation of cytotoxic T lymphocytes which attack the epidermis and cause apoptosis of undifferentiated keratinocytes. Since interferon-gamma and interleukin 6 are known to be markedly generated in lichen planus, we investigated the cellular localization of these cytokines in affected skin/oral mucosa biopsy specimens using in situ hybridization for interferon-gamma and in situ reverse transcription-polymerase chain reaction for interleukin 6 mRNA. In the upper subepithelial connective tissue interferon-gamma mRNA was noted within proliferating CD3+ T lymphocytes. In this tissue compartment interleukin 6 mRNA was detected in infiltrating CD4+ and CD8+ T lymphocytes. In the epithelium, expression of interferon-gamma mRNA and interleukin 6 mRNA was observed in the basal and suprabasal keratinocytes of altered skin/oral mucosa. In contrast, normal skin did not reveal any interferon-gamma or interleukin 6 expression, although a few CD4+ and CD8+ T lymphocytes were noted in the dermis as well as the epidermis. These findings indicate that in lichen planus the proinflammatory cytokines interferon-gamma and interleukin 6 are produced not only by activated T lymphocytes but also by altered keratinocytes, and suggest that stimulated keratinocytes may amplify the course of lichen planus.

Tumor-associated neoexpression of the pS2 peptide and MUC5AC mucin in primary adenocarcinomas and signet ring cell carcinomas of the urinary bladder.

To gain more detailed insight into the histogenesis of primary nonurachal adenocarcinomas and signet ring cell carcinomas of the urinary bladder, we analyzed by immunohistochemistry the expression of a broad panel of proteins, associated with cell differentiation (pS2 peptide, MUC5AC, MUC6, spasmolytic polypeptide, cyclooxygenases-1 and -2, caveolin-1), and of various novel known or candidate tumor suppressors (14-3-3 sigma, SYK, PTEN, maspin). Included were 12 adenocarcinomas admixed to urothelial carcinomas, 10 pure adenocarcinomas and 5 signet ring cell carcinomas. As the most important finding, the majority of signet ring cell carcinomas and three quarters of the adenocarcinomas (72.7%) expressed the pS2 peptide, and nearly half of the adenocarcinomas (45.5%) as well as most of the signet ring cell carcinomas were observed to secrete the MUC5AC apomucin. Since expression of both proteins was absent in the normal nonneoplastic urothelium, their tumor-associated appearance is regarded as a neoexpression or reexpression, respectively, of normally cryptic antigenic determinants, and is assumed to be involved in the phenotypical formation of vesical adenocarcinomas, including signet ring cell carcinomas. The expression of both pS2 and MUC5AC in variants of urothelial carcinomas with a glandular differentiation and an extracellular mucus production support the concept that adenocarcinomas may histogenetically develop from preexistent TCC. Adenocarcinomas which secrete the pS2 peptide and the MUC5AC glycoprotein are proposed to be subclassified as adenocarcinomas of the intestinal type, as distinguished from those of the common type lacking an expression. The tumor suppressor genes showed a loss of protein expression in adenocarcinomas, ranging from 54.5% (14-3-3 sigma), to 31.8 (PTEN), 27.3% (SYK) and 18.2% (maspin). Similar expression profiles in the coexistent urothelial carcinomas argue against a specific involvement of these genes during the morphogenesis of adenocarcinomas.

Expression and function of protein phosphatase PP2A in malignant testicular germ cell tumours.

Testicular germ cell tumours (TGCT) represent the most common malignancy in young males. We reported previously that two prototype members of the mitogen-activated protein kinase (MAPK) family, the MAPK ERK kinase (MEK) and extracellular signal-regulated kinase (ERK), are inactive in malignant testicular germ cells and become active after drug stimulation, leading to apoptosis of tumour cells. In this study, we asked whether the protein phosphatase PP2A, a known inhibitor of the MEK-ERK pathway, participates in the proliferation and/or apoptosis of primary TGCT (n = 48) as well as two TGCT cell lines (NTERA and NCCIT). Quantitative RT-PCR, immunohistochemistry, western blot analyses and phosphatase assay indicate that primary TGCT as well as TGCT cell lines express PP2A and that PP2A is active in TGCT cell lines. The inhibition of PP2A by application of two PP2A inhibitors, cantharidic acid (CA) and okadaic acid (OA), results in a significant increase in caspase-3-mediated apoptosis of TGCT cell lines. Thereby, PP2A inhibition was accompanied by phosphorylation and activation of MEK and ERK. Functional assays using the MEK inhibitor PD98059 demonstrated that the phosphorylation of MEK and ERK was required for the induction of caspase-3-mediated apoptosis of malignant germ cells. Thus, our data suggest that inhibition of PP2A mediates its apoptosis-inducing effect on TGCT through activation of the MEK-ERK signalling pathway that leads to caspase-3-mediated apoptosis of tumour cells. In addition our results support previous observations that PP2A exerts an anti-apoptotic effect on malignant tumour cells.

Activation and apoptosis of macrophages in cat scratch disease.

Cat scratch disease is an infectious disease usually caused by Bartonella henselae. Within 1-3 weeks after inoculation, patients typically develop regional self-limited lymphadenopathy. Lymph nodes reveal granulomas consisting of central necrosis, an inner rim of palisading macrophages, and an outer rim of lymphocytes and non-palisading macrophages. In animals, cat-scratch disease leads to an interferon-gamma (IFNgamma)-mediated T-helper 1 immune response, resulting in macrophage recruitment, stimulation, and thereby granuloma formation. The present study has sought to find in situ evidence for macrophage migration, activation, and cell death in human cat scratch disease. By non-radioactive in situ hybridization and immunohistochemistry on serial sections, it was demonstrated that IFNgamma+ T lymphocytes and S100A8+, S100A9+ macrophages embrace granulomas, which consisted of S100A8-, S100A9-, HLA-DR+, CD40+, TNFalpha+ macrophages. Combination of in situ end-labelling and immunofluorescence revealed large numbers of DNA-fragmented CD68+ cells with intact plasma membranes corresponding to apoptotic macrophages. On the basis of these data, it was hypothesized that in human cat scratch disease, S100A8+, S100A9+ macrophages continuously migrate to the granulomas. During this process, they may be activated by IFNgamma T-helper 1 lymphocytes and be differentiated to S100A8-, S100A9-sessile, HLA-DR+, CD40+ antigen-presenting, TNFalpha+ pro-inflammatory macrophages forming granulomas. In parallel, macrophages undergo apoptosis in the centre of granulomata, a phenomenon that may restrict the destructive potential of macrophages and contribute to self-limitation of cat scratch disease.

Hepatic expression of inducible nitric oxide synthase transcripts in chronic hepatitis C virus infection: relation to hepatic viral load and liver injury.

Hepatitis C virus (HCV) causes acute and often also chronic liver disease. Hepatocellular injury might result from both a host response directed to inhibit viral spread and from processes initiated by the virus itself. To study mechanisms involved in hepatocellular injury, liver tissue from chronically HCV-infected patients was analyzed for the expression of the inducible isoform of nitric oxide synthase (iNOS) and for interferon gamma (IFN-gamma) by a quantitative, competitive reverse-transcription-polymerase chain reaction (RT-PCR) technique. Moreover, hepatic viral load was determined by two independent techniques, and liver tissue was evaluated histopathologically in detail. Liver tissue from HCV-infected patients was shown to express elevated levels of iNOS transcripts compared with non-HCV-infected patients. Increased iNOS transcript expression, however, was not accompanied by significantly elevated serum nitrite plus nitrate (NOx) concentration, although some of the chronic HCV-infected patients reached markedly higher serum NOx levels than the control group or healthy individuals, respectively. Hepatic iNOS expression was found to be positively correlated to hepatic HCV-RNA content on the one hand, and weakly to hepatic IFN-gamma expression, previously shown to be solely associated with hepatic necro-inflammatory activity among the histopathological parameters studied, on the other hand. In contrast to IFN-gamma transcript expression, neither hepatic iNOS expression nor hepatic HCV-RNA content were related to hepatic inflammatory activity. The presented data are compatible with the assumption that HCV might be able to stimulate iNOS expression both directly and indirectly via its capacity to induce IFN-gamma.