Kissing stents for treatment of complex aortoiliac disease

OBJECTIVES

to determine medium term technical and clinical success of kissing stents for aortoiliac occlusive disease.

DESIGN

retrospective study.

SUBJECTS

twenty-five patients presenting with intermittent claudication (IC) or critical limb ischaemia (CLI) due to aortoiliac disease (41 complex stenoses, 8 occlusions).

METHODS

balloon- or self-expanding kissing stents, with or without predilatation depending upon the nature of the disease, were inserted via bilateral retrograde femoral artery punctures. Clinical examination, ABPI, exercise testing and duplex ultrasound were performed at 1, 3, 6, and 12 months, and then annually.

RESULTS

technical success was achieved in 86% segments. All patients with CLI improved and 6 of 7 ulcerated limbs showed complete healing. During follow-up, 7 patients died and two patients required major amputation at 7 and 8 months. The primary assisted patency rate was 94, 91 and 65% at 6, 12, and 24 months, respectively.

CONCLUSIONS

despite acceptable short-term technical and clinical success, as the medium term patency rates are clearly inferior to those of bypass surgery, the kissing stent technique should be reserved for high risk patients with a limited life expectancy.

[Experimental investigations of CO2 laser application in middle ear ossicles]

BACKGROUND

During the last few years, several laser systems have been applied for procedures in middle ear surgery. In this study, we determined the technical parameters for the dissection of the middle ear ossicles with the CO(2) laser and analyzed the histological findings.

METHODS

The malleus necks of 16 human temporal bones were dissected under standardized conditions using a CO(2) laser with a power output between 35 and 55 kW/cm(2). The specimens were fixed and histological probes of 50- micro m thickness were prepared.

RESULTS

The laser outputs led to crater diameters from 0.14 to 0.55 mm. As an analogy between laser energy and thermal tissue destruction, three zones of thermal damage were differentiated: a cinder zone, a carbonization zone, and a zone of dehydration. The metrical dimensions of these zones did not show any correlation to the applied laser energy.

CONCLUSIONS

The data of this study show that commercially available CO(2) lasers are sufficient for a safe and effective partial resection of middle ear ossicles using a power output of 35 kW/cm(2).

[Pathogenesis of MALT-type lymphoma]

Gastric marginal zone lymphoma, MALT-type (MZBCL) is thought to be derived from precursor lesions in follicular H. pylori-associated gastritis, that through accumulating genetic changes ultimately develop into an autonomously proliferating, monoclonal B-cell lymphoma. In the early phases of the disease, the proliferation is still at least partly dependent on the presence of H. pylori-induced T-cell help. Ongoing genetic alterations drive the process into an antigen independent phase. First of all, Fas mutations resulting in loss of function were found in a high frequency in MZBCL and gastric DLBCL and imply that Fas may act as a tumor suppressor gene. Therefore it is possible, that various Fas mutations may arise in mature B-cells during V(D)J recombination and other diversification processes in the course of immune responses as it was shown recently for the bcl-6 gene. Second, allelic imbalances suggest two different pathways of MZBCL development and progression. One group of tumors develops along the pathway determined by the dysregulation of the API2 and MALT1 genes brought about by the t(11;18). These tumors do not accumulate enough secondary genetic aberrations to transform into DLBCL and remain in the stage of MZBCL. Other MALT lymphomas characterized by the absence of the t(11;18) and increased accumulation of various clonal genetic aberrations, most frequently the 3q26.2-27 amplification, could be the source of tumors which eventually do transform into high-grade DLBCL.

12-Monatsergebnisse nach lokoregionaler rt-PALysetherapie bei tiefer Beinvenenthrombose

Ziel: Klärung, ob Patienten mit frischer Beinvenenthrombose von einer lokoregionalen rt-PA-Lysetherapie mittelfristig profitieren, und ob nach 12 Monaten beginnende Klappenschäden im Vena-poplitea-Segment sowie Symptome eines postthrombotischen Syndroms nachweisbar sind. Material und Methoden: Wegen einer frischen Beinvenenthrombose erhielten 45 Patienten (27 Männer, 18 Frauen) innerhalb eines 4-Jahreszeitraums eine lokoregionale rt-PA-Lysetherapie, gefolgt von einer Antikoagulations- und Kompressions-therapie über mindestens drei Monate. Vor Entlassung erfolgte eine phlebographische Kontrolle. Bei 36 Patienten (80%) konnte ein primärer Lyseerfolg erzielt werden, in 7 Fällen (15%) war kein Lyseerfolg feststellbar bzw. <50%. 12 Monate nach Entlassung wurde die Venenklappenfunktion farbdopplersonographisch beurteilt, bei 20 Patienten wurde zusätzlich eine Venenverschlussplethysmografie (VVP) angefertigt. Ergebnisse: Von 45 Patienten konnten 37 (82%) kontrolliert werden. 28 (76%) waren klinisch und farbdopplersonographisch unauffällig. Bei 10 Patienten (27%) bestand eine Schwellneigung in der Knöchelregion, bei 8 (22%) wurde farbdopplersonographisch ein thrombosebedingter Klappenschaden verifiziert. Die VVP ergab eine Abnahme der venösen Kapazität und Drainage. Schlussfolgerung: Die lokoregionale Lysetherapie mit rt-PA ist effizient in der Behandlung von tiefen Beinvenenthrombosen auch im Hinblick auf die Entwicklung eines postthrombotischen Syndroms.

A sebaceous tumor in a patient with acquired immunodeficiency syndrome

The prevalence of cutaneous malignancies is higher in immunosuppressed patients. Here, we describe a case with a rapid growing and unusually large sebaceous tumor in a patient with acquired immunodeficiency syndrome. Sebaceous adenomas are commonly rare, benign tumors of sebaceous glands. An association of AIDS and a solitary, large sebaceous adenoma has not been described yet. This emphasizes the role of an intact immune system in the suppression of benign and malignant tumors. tubular adenoma; tumor; AIDS

Loss of Fas (CD95/APO-1) regulatory function is an important step in early MALT-type lymphoma development

Fas (CD95, APO-1) mutations were found in autoimmune diseases and some lymphomas, suggesting impairment of Fas-mediated cell death signaling that may cause tumor development. Because mucosa-associated lymphoid tissue (MALT)-type lymphoma B cells recognize autoantigens and proliferate in response to antigen and T cell-mediated signals, it is suggestive that autoreactive B cell lymphoma precursor cells may have escaped the Fas-mediated checkpoint that normally operates in healthy individuals. Using different biochemical, molecular, and functional approaches, we analyzed the Fas signaling in malignant B cells from seven MALT-type lymphomas that were additionally characterized for the t(11;18)(q21;q21) and four gastric diffuse large B cell lymphomas (DLBL). All DLBLs and three of seven MALT-type lymphomas were resistant to Fas-mediated apoptosis in vitro. Moreover, four of five MALT-type lymphomas analyzed and one of three DLBLs analyzed showed mutations in Fas mRNA transcripts but no loss of heterozygosity in the Fas promotor region. Alternative mechanisms of resistance to apoptosis, such as decreased expression of Fas or production of soluble Fas were not operative. Therefore, it is suggestive that a subgroup of MALT-type lymphoma B cells, irrespective of t(11;18)(q21;q21), escape the censoring Fas pathway by mutating and inactivating Fas. This identifies a key regulatory step in early MALT-type lymphomagenesis.

Complete remission of primary high-grade B-cell gastric lymphoma after cure of Helicobacter pylori infection

PURPOSE

Treatment of low-grade gastric mucosa-associated lymphoid tissue lymphoma by eradication of Helicobacter pylori is reported to result in complete lymphoma remission in approximately 75% of cases. The effect that cure of the infection has on the course of a primary high-grade gastric lymphoma is largely uncertain. The aim of this study was to report the effect of cure of H pylori infection exerted in patients with high-grade B-cell gastric lymphoma.

PATIENTS AND METHODS

Eight patients (4 males and 4 females; age range, 26 to 85 years) with H pylori infection and high-grade lymphoma received eradication therapy before planned treatment. The effect of H pylori eradication on the course of high-grade lymphoma was assessed by analysis of surgical specimens (n = 2) or endoscopic biopsies (n = 6).

RESULTS

H pylori eradication was successful in all patients and led to complete remission of the lymphoma in seven patients. One patient has experienced partial remission. Two patients were referred to surgery, one of whom (stage II(1E)) had lymph node involvement, and the histologic work-up of the resected stomach revealed residual infiltrates of a low-grade lymphoma, which prompted consolidation chemotherapy. In one patient (initially stage I(1E)), abdominal lymphoma developed 6 months after eradication therapy, which regressed completely after chemotherapy. In four patients, no further treatment was given. Six patients continue in complete remission (range, 6 to 66 months).

CONCLUSION

Primary high-grade B-cell gastric lymphoma in stages I(E) through II(E1) associated with H pylori may regress completely after successful cure of the infection. Prospective trials are needed to investigate this treatment in larger numbers of patients.

[Impaired CD95-(Fas,APO-1-)apoptosis regulation is a progression factor in early MALT-type lymphoma genesis]

BACKGROUND

MALT-type lymphomas are B cell tumors arising for so far unknown reasons on the background of chronic inflammation, e.g. Helicobacter pylori-associated gastritis. T cells are supposed to have a positive impact on tumor growth, but fail in their control function. We therefore examined the interaction of T cells with malignant B cells in vitro and focused on T cell control which normally operates by CD95L/CD95-mediated apoptosis.

PATIENTS AND METHODS

Malignant B cells were isolated from tumor tissues of 7 patients with low-grade MALT-type lymphoma and 4 patients with DLBL and cocultured in vitro with activated T cells. Normal memory B cells were used as control. We developed a T/B coculture assay for investigation of CD95L/CD95-mediated apoptosis. The influence of T cells on CD95 expression and survival of B cells was measured by FACS analysis.

RESULTS

Activated T cells induced CD95 expression and thus enhanced sensitivity to CD95L-mediated apoptosis in normal memory B cells. However, malignant B cells from 3 out of 7 low-grade MALT-type lymphomas and all 4 gastric DLBLs resisted apoptosis, although the cells showed enhanced CD95 expression.

CONCLUSION

Resistance to CD95L/CD95-mediated apoptosis allows malignant B cells from MALT-type lymphoma to escape T cell control and leads to prolonged survival. This phenomenon acts as a progression factor in early lymphomagenesis.

Primary gastric B-cell lymphoma: results of a prospective multicenter study. The German-Austrian Gastrointestinal Lymphoma Study Group

BACKGROUND & AIMS

Appropriate management of primary gastric lymphoma is controversial. This prospective, multicenter study aimed to evaluate the accuracy of endoscopic biopsy diagnosis and clinical staging procedures and assess a treatment strategy based on Helicobacter pylori status and tumor stage and grade.

METHODS

Of 266 patients with primary gastric B-cell lymphoma, 236 with stages EI (n = 151) or EII (n = 85) were included in an intention-to-treat analysis. Patients with H. pylori-positive stage EI low-grade lymphoma underwent eradication therapy. Nonresponders and patients with stage EII low-grade lymphoma underwent gastric surgery. Depending on the residual tumor status and predefined risk factors, patients received either radiotherapy or no further treatment. Patients with high-grade lymphoma underwent surgery and chemotherapy at stages EI/EII, complemented by radiation in case of incomplete resection.

RESULTS

Endoscopic-bioptic typing and grading and clinical staging were accurate to 73% and 70%, respectively, based on the histopathology of resected specimens. The overall 2-year survival rates for low-grade lymphoma did not differ in the risk-adjusted treatment groups, ranging from 89% to 96%. In high-grade lymphoma, patients with complete resection or microscopic tumor residuals had significantly better survival rates (88% for EI and 83% for EII) than those with macroscopic tumor residues (53%; P < 0.001).

CONCLUSIONS

There is a considerable need for improvement in clinical diagnostic and staging procedures, especially with a view toward nonsurgical treatment. With the exception of eradication therapy in H. pylori-positive low-grade lymphoma of stage EI and the subgroup of locally advanced high-grade lymphoma, resection remains the treatment of choice. However, because there is an increasing trend toward stomach-conserving therapy, a randomized trial comparing cure of disease and quality of life with surgical and conservative treatment is needed.

Heterogeneity of the API2-MALT1 gene rearrangement in MALT-type lymphoma

The translocation t(11;18)(q21;q21), which is the most frequent chromosomal aberration in extranodal marginal zone B cell lymphomas of MALT-type, was characterised in a series of 34 biopsies, including 18 gastric non-Hodgkin's lymphomas (NHL) of MALT-type, six MALT-type NHL of extragastral origin and 10 extranodal large B cell lymphomas (LBL). Based on fluorescence in situ hybridisation, STS-PCR analysis and screening of genomic PAC libraries, a physical map of contiguous DNA probes on chromosome 11 was constructed containing the anti-apoptotic genes API2 and API1 adjacent to the translocation breakpoint. RACE-PCR experiments revealed MALT1 the chromosome 18-derived fusion partner of API2, which has also been reported recently by other groups. RT-PCR analysis and DNA sequencing demonstrated the expression of an API2-MALT1 fusion transcript in 18/24 gastral and extragastral MALT-type lymphomas. In none of 10 LBLs was a translocation specific RT-PCR product detected. Five variants of the fusion transcript were identified and in all instances the open reading frame of the fused portion of the MALT1 gene was maintained. The molecular analysis of these variants allowed the design of optimised assays for the diagnosis of the API2-MALT1 gene rearrangement.

Characterization of Wue-1, a novel monoclonal antibody that stimulates the growth of plasmacytoma cell lines

A new monoclonal antibody, Wue-1, which specifically recognizes normal and malignant plasma cells, is characterized. Biochemical studies showed that monoclonal antibodies (mAbs) recognize a protein of 94 kDa. Using triple-staining flow cytometry and double-labeling immunohistochemical techniques, two populations of plasma cells, i.e. lymphoplasmocytoid plasma cells located in the germinal center of lymphoid organs and reticular plasma cells at the paracortex or medullary cords of secondary lymphoid tissues, were distinguished. Wue-1 is expressed when B-cell markers become lost and secretory activity with plasma cell morphology appears. Cell surface markers were identified on normal plasma cells and compared with their malignant counterpart in vivo. Terminal plasma-cellular differentiation of malignant low- and high-grade B-cell lymphoma and anaplastic plasmacytoma, otherwise difficult to identify with conventional B-cell markers on tissue sections or fluorescence-activated cell sorter analyses, were detectable by Wue-1. In cell culture, Wue-1 enhanced the proliferation of myeloma cell lines but not normal plasma cells in a dose-dependent manner. Since Wue-1-induced proliferation was increased by interleukin (IL)-6, Wue-1 recognizes a so far unidentified antigen with functional properties. Therefore, Wue-1 represents a useful new tool for therapy and for the in vivo and in vitro studying of B-cell lymphomas and the mechanisms of B-cell differentiation.

The role of microsatellite instability in gastric low- and high-grade lymphoma development

DNA mismatch repair genes and their dysfunction as evidenced by microsatellite instability (MSI) play an important role in the pathogenesis of a variety of tumors, most prominently hereditary nonpolyposis colorectal cancer (HNPCC). However, their role in development of extranodal lymphomas has not been established yet. We therefore evaluated for MSI 25 gastric low-grade marginal-zone B-cell lymphomas of mucosa-associated lymphoid tissue type and 31 gastric high-grade diffuse large B-cell lymphomas (DLBCLs) with 29 and 118 microsatellites, respectively. Compared with HNPCC, the overall level of MSI was much lower with a mean of 2.6% MSI-positive repeats in the DLBCLs; the frequency of MSI showed a tendency to increase with age (P = 0.01), as did MSI variability (P = 0.02). Low-grade mucosa-associated lymphoid tissue lymphomas displayed even less MSI (sevenfold) than DLBCLs (P = 0.009). MSI frequency thus increases with the transition from low- to high-grade disease and with age; it does not seem to initiate lymphomagenesis. Other microsatellites than those typically mutated in HNPCC frequently revealed MSI in these lymphomas, especially dinucleotide repeats on chromosomes 3, 5, and 18. To facilitate rapid screening of lymphomas for MSI and to establish a tool for future MSI frequency comparisons, we recommend to use repeats D3S1261, D3S1530, D5S346, D17S250, D18S474, and DCC.

Marginal zone B-cell lymphomas (MZBL) arising at different sites represent different biological entities

Most entities of B-cell malignant non-Hodgkin's lymphomas (NHL) are characterized by typical primary chromosomal changes such as the t(14;18) in follicular lymphoma or the t(11;14) in mantle cell lymphoma. In contrast, marginal zone B-cell lymphomas (MZBL), arising at different nodal and extranodal sites, are poorly characterized on the genetic level. We performed cytogenetic investigations in 20 splenic and in 10 nodal MZBL and analyzed 52 MZBL (including 12 MALT-type lymphomas) for deletions of TP53, D13S25, and RB1 loci by fluorescence in situ hybridization. A new nonrandom chromosomal aberration, del(10)(q22q24), was found as a clonal anomaly in 3 out of 20 cases of splenic MZBL. Further recurring abnormalities such as del(7q) or trisomy 3 were found to be characteristic chromosomal changes in a subset of splenic MZBL. TP53 was deleted in 5/25 cases of splenic MZBL. Deletions involving band 13q14 were only rarely encountered, challenging a previous report that stated a dissociated D13S25-RB1 status as characteristic in splenic MZBL. There are fundamental differences between the different subtypes of marginal zone lymphomas as defined with current classification schemes. Splenic MZBL, in contrast to most other entities of B-cell NHL, seems to constitute a heterogeneous disease especially with regard to genetic alterations. del(10)(q22q24) could be of importance at least in a subset of this lymphoma entity.

Helicobacter pylori in gastric mucosa-associated lymphoid tissue type lymphoma

Infection with Helicobacter pylori triggers the acquisition of gastric mucosa-associated lymphoid tissue (MALT) and provides the background for MALT-type lymphoma development. This concept has been supported by a high association of H. pylori infection and MALT-type lymphoma and by the regression of most lymphomas after eradication therapy. In almost all patients with MALT-type lymphoma, serum antibodies to H. pylori were detectable. However, H. pylori was found only in 78% of the patients on histological examination. In addition to other effects, changes in the gastric micro-milieu caused by tumor infiltration of the gastric mucosa may be responsible for the loss of the bacterium. The discrepancy of high seroprevalence and lower histological yield has been already described in other gastric diseases, e.g. atrophic gastritis or gastric carcinoma with extensive destruction of the gastric mucosa. H. pylori strains expressing the CagA protein have been associated with duodenal ulceration and gastric carcinoma. A very high percentage of patients with MALT-type lymphoma is also infected by CagA+ strains of H. pylori as tested by immunoblotting. Antibodies directed to CagA were detectable in the serum as well as in micro-cultured gastric mucosa. Infection with H. pylori may be a precondition for the development of gastric MALT-type lymphoma. In particular, CagA+ strains of H. pylori may, together with additional up to now unknown factors, play a role in the development of gastric MALT-type lymphoma.

Tumor biology of mucosa-associated lymphoid tissue lymphomas

Extranodal lymphomas arising at mucosal sites exhibit clinicopathological features that suggest a closer relationship of these tumors to the structure and function of mucosa-associated lymphoid tissue (MALT) than to lymph nodes. The factors that induce MALT in these tissues are operative in early MALT lymphoma development and the progressive independence on T-cell help defines late stages of MALT lymphoma genesis.

[MALT-type non-Hodgkin's lymphoma: advances in biopsy diagnosis and pathogenesis]

Malignant Non-Hodgkin's lymphomas of the mucosa-associated lymphoid tissue display unique morphological and biological features. Unlike the situation in nodal lymphomas, they almost invariably arise from defined and recognisable precursor lesions, such as chronic infections or autoimmune diseases. From the diagnostic point of view, efforts have been undertaken to define (1) the minimal requirements for the unequivocal diagnosis of MALT-type lymphoma, (2) the regression stages after Helicobacter pylori eradication, and (3) to establish a grading system for the respective lesions. Of importance, it must be emphasized that in most cases the biopsy received in first-line is not enough in establishing a correct diagnosis with regard to biological and therapeutic implications. In particular, the accurate estimation of the biological aggressiveness of the tumour will in most cases require extensive rebiopsies. As in nodal tumours, the genetic constitution of low grade MALT-type lymphomas is more and more revealed. While data on the importance of numerical aberrations are conflicting, certain structural aberrations, such as the t(1;14) and the t(11;18), have been unequivocally linked to MALT-type lymphomas. Preliminary data suggest that these aberrations may target the apoptotic pathway. Their recognition may herald the evolution of new tumour features, such as independence from outer regulatory influences, obviously in early stages determined by the microenvironment and might be closely related to the site of tumour development and hence be a feature of the primary inflammatory disorder.

[MALT-type B-cell lymphomas escape fas-mediated apoptosis]

Important prognostic factors in primary MALT-lymphomas are stage and grading since the localized low-grade lymphoma may be cured with antibiotic treatment that may result in lymphoma regression as exemplified in Helicobacter eradication (H.p.) in gastric low-grade MALT-lymphomas. For obscure reasons, around 20% of low-grade MALT-lymphomas do not respond to eradication therapy or contain in 25-33% high-grade components as a possible consequence of tumor cell transformation. Given that MALT-lymphoma B-cells are autoimmune in nature and proliferate in response to antigen and T-cell-mediated signals, it is suggestive that autoreactive B-cell lymphoma precursors generated during chronic inflammation escaped the tolerance checkpoint. This mechanism normally operates in healthy individuals through CD40-L/FAS-L expressing activated T-cells and is fundamental in the deletion of harmful B-cells. Analyzing the role of FAS/FAS-L mediated apoptosis in lymphomagenesis, we purified B- and T-cells from low- and high-grade MALT B-cell tumors and tonsillar memory B-cells as control. T-cells were stimulated in vitro to express CD40-L and FAS-L using anti-CD3 antibodies and were subsequently cocultivated with B-cells. Apoptosis was 3 times increased in normal memory B-cells and, to a lesser extent, in a subgroup of low-grade MALT-lymphomas as compared with the spontaneous apoptosis without T-cell coculture. In striking contrast, all primary high-grade MALT-type lymphomas showed increased survival but were resistant to FAS-mediated apoptosis. Furthermore, 40% of low-grade MALT-type lymphomas were resistant to apoptosis and showed mutations in the FAS-gene. The conclusion that self-tolerant high-grade but also a subgroup of low-grade MALT-lymphoma B-cells escaped censoring by the FAS pathway may therefore identify a novel regulatory step in early MALT-lymphomagenesis.

Genetic imbalances in primary gastric diffuse large B-cell lymphomas: comparison of comparative genomic hybridization, microsatellite, and cytogenetic analysis

Extranodal malignant non-Hodgkin's lymphomas account for about 40% of lymphoid neoplasms, but few data are available concerning the genetic background of primary gastric diffuse large B-cell lymphoma (DLBCL). A study was performed of 27 primary gastric DLBCLs and 5 gastric DLBCLs with a concomitant low grade component of mucosa-associated lymphoid tissue-type lymphoma using comparative genomic hybridization (CGH), microsatellite studies, classic cytogenetics, and fluorescence in situ hybridization (FISH) to search for specific genetic aberrations. The most frequent aberrations were losses of material on chromosome 6q and gains of parts of chromosome 3. In three cases, a total of six high level DNA amplifications were detected, with five of them involving chromosomal regions not having been reported before in gastric DLBCL. A high overall concordance of 91.4% between microsatellite analysis and CGH was observed using DNA extracted from the same tissue block. The concordance achieved using DNA from different tissue blocks of the same patient was 85%. Microsatellite studies, CGH, FISH, and classic cytogenetics represent complementary techniques that facilitate a comprehensive view of genetic alterations in malignancies such as primary gastric DLBCL.