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H Merz

Publications and source records attributed to H Merz.

At least 19 recordsLinked to original sources
PubMed2006

Cytogenetic characteristics of a murine in vitro model for the human anaplastic large cell lymphoma (ALCL).

Anaplastic large cell lymphoma (ALCL) is an entity of non-Hodgkin lymphomas (NHL) that often occurs in young children and adolescents. In the majority of cases, ALCL are of T-cell origin and contain the t(2;5)(p23;q35) leading to an NPM-ALK fusion or variant ALK translocations. In addition, there is an ALK-negative subtype of ALCL. The anaplastic lymphoid cell line TS1G6 established by interleukin (IL)-9 transfection of T-helper cells represents a murine model of this subtype. Here, we describe the cytogenetic features of this cell line using spectral karyotyping (SKY) and single-color fluorescence in situ hybridization (FISH). We show that TS1G6 cells exhibit a hypotetraploid karyotype with complex structural alterations. Several unbalanced translocations involved the chromosomal region 14E5, and different translocation partners, i.e. X?A6, 3A3 and 8A1. FISH analysis using a BAC clone containing c-myc confirmed the presence of six copies, but also demonstrated that two loci were irregularly located, indicating that additional intrachromosomal rearrangements had occurred. Moreover, a duplication of the region XF2 approximately 3 was identified. Furthermore, six chromosomes 15 were found, representing a trisomy 15 in a tetraploid chromosome complement, indicating an altered gene dosage of the oncogene c-myc located in region 15D3.

Animals↗
PubMed2004

[Anaplastic large cell lymphoma and keratoacanthoma].

In CD30 positive lymphoproliferative disorders, e.g. anaplastic large cell lymphoma (ALCL) and lymphomatoid papulosis (LyP), pseudoepitheliomatous hyperplasia may occur in up to 50 percent of the cases. Epithelial tumors are rarely associated with ALCL or LyP, but the presence of single CD30 positive cells among the infiltrate accompanying epithelial tumors such as basal cell carcinomas and keratoacanthomas is well known. A 66-year-old man developed within a plaque of ALCL a rapidly growing epithelial tumor which we classified according to the clinical and histological features as keratoacanthoma. This case underlines the intimate interaction between CD30 positive lymphocytes and epithelial cells.

Aged↗
PubMed2004

[Lymphadenoma of the parotid gland without sebaceous differentiation. Immunohistochemical investigations].

An encapsulated tumor measuring 8 cm was removed from the parotid gland in a 42-year-old man. The tumor had grown for about 5 years. The histopathological and immunohistochemical evaluation revealed a lymphadenoma without sebaceous differentiation of the epithelial component. The tumor consisted of exclusively solid epithelial islands and a lymphoid stroma with rare lymph follicles and abundant predominantly IgG plasma cells. The histogenesis of lymphadenomas is discussed in consideration of the differential diagnosis from Warthin's tumor and the data in the literature.

Adenolymphoma↗
PubMed2003

A new sarcomatoid variant of multiple myeloma in a 20-year-old male.

We present a 20-year-old man with a rare variant of multiple myeloma with peculiar spindle cell morphology and sarcomatoid growth. The diagnosis of multiple myeloma was substantiated by clinical examinations. The patient was treated with several therapeutic trials including autologous stem cell support. Unfortunately, he developed a disseminated aspergillosis of the lungs and died of fatal lung bleeding. We recommended that "sarcomatous" multiple myeloma be considered in cases of "unclassifiable" sarcomatous tumors of the bone marrow.

Adult↗
PubMed2003

Cytogenetic and molecular characterization of simultaneous chronic and acute myelocytic leukemia.

We describe a patient initially diagnosed with a chronic myeloproliferative disorder in the accelerated phase. Cytogenetic analysis showed the presence of two independent clones. One clone contained a typical Philadelphia (Ph) chromosome due to t(9;22)(q34;q11), as the sole abnormality which was proven molecularly to result in the b2a2-BCR/ABL fusion. The other clone displayed a complex karyotype with several structural and numerical aberrations including trisomy 11 and 22 but lacking a t(9;22) or any other structural abnormalities involving chromosomes 9 and 22. Fluorescence in situ hybridization demonstrated that the t(9;22) was present only in cells with two copies of chromosomes 11 and 22. In contrast, cells with trisomies 11 and 22 lacked evidence for a BCR/ABL fusion. Based on the genetic findings, simultaneous chronic and acute myelocytic leukemias were diagnosed rather than a blastic phase of a chronic myelocytic leukemia.

Aged↗
PubMed2003

[Mycosis fungoides in childhood and adolescence with clonal T-cell receptor gamma gene rearrangement. Two cases].

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma (CTCL) characterized by its typical progress in three stages: the patch-, the plaque- and the tumour-stage. The incidence of mycosis fungoides rises with age and the average age at presentation is about 50. Children and adolescents are rarely affected and there are only few reports in the literature. We report a 12- and a 15-year-old boy showing refractory skin lesions not typical for mycosis fungoides. The histo- and immunohistological investigations and the detection of clonal T-cell receptor gamma gene rearrangements confirmed the diagnosis of early onset mycosis fungoides in both cases.

Adolescent↗
PubMed2003

Aberrant immunophenotypes of mantle cell lymphomas.

Mantle cell lymphomas (MCL) are characterized by cytomorphological criteria, a distinct immunophenotype and a characteristic chromosomal aberration (t(11;14)). In morphological variants of MCL the immunohistochemical constellation with CD5-positivity and CD23-negativity is a helpful and decisive diagnostic aid to differentiate MCL from other B-cell-lymphomas, e.g. lymphocytic lymphomas (B-CLL). In this study the morphological, immunophenotypical, and genetical features of 50 MCL were analysed. Five cases revealed an aberrant immunophenotype with lacking expression of CD5 (n = 3) and positive reactivity to CD23 (n = 2) while cyclin D1 expression could be demonstrated in all 5 cases. These constellations show that there is, besides morphological subgroups, a small group of MCL with aberrant immunophenotypes, which has to be taken into account in the differential diagnosis to lymphocytic lymphoma and other lymphomas.

Aged↗
PubMed2003

Rituximab induces remission in refractory HCV associated cryoglobulinaemic vasculitis.

OBJECTIVES: To report the successful induction of remission with the monoclonal anti-CD20 antibody rituximab in a patient with hepatitis C virus (HCV) associated cryoglobulinaemic vasculitis and a non-Hodgkin's lymphoma (NHL) resistant to previously advocated conventional treatments. CASE REPORT: The patient was a 45 year old woman with HCV associated cryoglobulinaemic vasculitis, with purpura, arthralgia, constitutional symptoms, and a polyneuropathy. A malignant NHL was found as underlying lymphoproliferative disease. At this stage the disease was refractory to interferon alpha2b and ribavirin and to subsequent immunosuppressive treatment with cyclophosphamide. Six rituximab infusions targeting the CD20 antigen on cells of the B cell lineage induced remission of the vasculitis. Bone marrow biopsy disclosed absence of the NHL. Remission has subsequently been maintained and HCV eliminated with the new pegylated interferon alpha2b and ribavirin for nearly one year. CONCLUSIONS: Transition of the underlying "benign" lymphoproliferative disease to a malignant lymphoma may result in difficult to treat HCV associated cryoglobulinaemic vasculitis. Rituximab offers a new possibility for inducing remission in refractory HCV associated cryoglobulinaemic vasculitis and the lymphoproliferative disorder. After remission, HCV may subsequently be eliminated with pegylated interferon alpha2b and ribavirin.

Antibodies, Monoclonal↗
PubMed2003

[Overexpression of NPM-ALK induces different types of malignant lymphomas in IL-9 transgenic mice].

Anaplastic large cell lymphoma (ALCL) comprises approximately 25 % of all non-Hodgkin lymphomas in children and young adults. 40% of these tumours have a translocation t(2;5)(p23;q35), which fuses the nucleophosmin gene (NPM) to the anaplastic lymphoma kinase gene (ALK) resulting in a hybrid protein which contributes to the pathogenensis of ALCL. To further analyse the transforming activity in an animal model, a cDNA encoding the protein product, NPM-ALK, was incorporated into a retrovirus construct and introduced into mouse bone marrow progenitors by infection. In a bone marrow gene transfer and transplantation protocol the hematopoietic compartments of lethally irradiated IL-9 transgenic mice were reconstituted with npm-alk infected progenitor cells. IL-9 transgenic mice were chosen, because IL-9, a pleiotropic T helper 2 cytokine, is expressed in most cases of human ALCL and was shown to have an oncogenic potential at least on T cells. Reconstituted mice developed NPM-ALK positive lymphomas including lymphoblastic lymphomas of T-cell type (T-LB), mature and immature plasmacytoma (PZ) and plasmoblastic/anaplastic diffuse large B-cell lymphoma after 10-30 weeks. The combined overexpression of NPM-ALK and IL-9 exerts cooperative oncogenic activity in the transformation of murine lymphoid cells leading to accelerated and enhanced development of T-LB. Many animals developed plasmacytic/plasmoblastic neoplasms, of which the most aggressive tumours share many features with human anaplastic/plasmoblastic diffuse large B-cell lymphoma.

Animals↗
PubMed2002

Remission of a cutaneous Mycosis fungoides after topical 5-ALA sensitisation and photodynamic therapy in a patient with advanced HIV-infection.

BACKGROUND: Treatment of Mycosis fungoides (MF) in HIV-infected patients is controversially discoursed. Photodynamic therapy (PDT) after topical sensitization with 5-aminolevulinic acid (5-ALA) is a new and effective modality for treatment of skin malignancies. OBJECTIVE: In this report we describe, what is, to our knowledge, the first case of a patient with MF through advanced HIV-infection, successfully experiencing topical 5-ALA sensitization and PDT. METHODS: 5-ALA ointment was applied to plaques and held in occlusion for 4 hours. PDT was applied using the PDT 1200 irradiation source (Waldmann Medizintechnik System) with 180 J/cm superset 2. RESULTS: Complete remission of MF was achieved, after two completed cycles of photodynamic therapy. CONCLUSION: MF lesions in the presended case showed a high response to 5-ALA sensitization and PDT. This modality appeared to be very effective in treatment of MF in a HIV-infected patient and could be a valuable treatment option for cutaneous T-cell lymphoma in HIV-infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[Large nodular lymphomatoid papulosis associated with parakeratosis variegata].

A 63 year old man suffering from lymphomatoid papulosis in association with parakeratosis variegata over a period of 20 years is presented. This case is unusual in respect to long-standing history, the rare combination of the two entities, and the extraordinary size of the nodules of lymphomatoid papulosis. Extracorporal photopheresis has induced partial remission lasting up to nine months so far.

Humans↗
PubMed2000

T-cell/natural killer cell lymphoblastic lymphoma with an unusual coexpression of B-cell antigens.

Lymphoblastic lymphomas are usually B- or T-cell neoplasms. There exists a small group of T-cell lymphomas additionally coexpressing cytotoxic or natural killer (NK)-cell markers, supporting the hypothesis of a common T/NK-cell precursor and respective neoplasms. Clinically, lymphatic neoplasms of T/NK-cell phenotype are either extranodal lymphomas or acute leukemias. The clinical course of these T/NK neoplasms cannot be predicted by morphology and/or phenotype alone. However, the expression of a heterogeneous (T + NK or myeloid) marker profile or of "early" antigens (such as TdT, CD10, RAG1, RAG2) render them more likely to be in the acute leukemia group. We present a case of a 63-year-old woman with a bone marrow infiltrate, enlarged lymph nodes, and B-symptoms. A cervical lymph node biopsy showed a monomorphic blastic infiltrate with a T-cell phenotype, coexpressing NK markers (CD56, CD57, NK1) and B-cell antigens (CD20, CD79). To the best of our knowledge, this is a newly recognized phenotype that has not been reported before. T/NK-cell lymphomas, including blastic NK-cell leukemia/lymphoma and T-lymphoblastic lymphomas, have to be included in the differential diagnosis. Both groups have a different clinical behavior and prognosis. In particular, T/NK-cell lymphomas associated with an Epstein Barr virus infection are clinically very aggressive neoplasms.

Antigens↗
PubMed2000

Transgenic rat hearts expressing a human cardiac troponin T deletion reveal diastolic dysfunction and ventricular arrhythmias.

OBJECTIVE: Familial hypertrophic cardiomyopathy (FHC) due to mutations of cardiac troponin T (cTnT) is associated with a high frequency of sudden death even in the absence of cardiac hypertrophy. To investigate the causal relationship of cTnT mutations and this particular phenotype, we sought to establish a transgenic rat model for the disease. METHODS: Transgenic rats were generated expressing human wild-type cTnT or two truncated cTnT molecules (del ex16, del ex15/16), resulting from an intron 15 splice donor site mutation previously observed in FHC patients. Transgenic rat hearts were characterized by histology, immunohistochemistry and in the 'working heart'. RESULTS: Human wild-type and del ex16 cTnT were stably expressed and incorporated into the sarcomere of transgenic cardiomyocytes. Del ex16 transgenic rats revealed a lower level of expression (4-5%) than human wt cTnT animals (25-40%). In the 'working heart' model del ex16 hearts exhibited significant systolic and diastolic dysfunction without cardiac hypertrophy. In contrast, human wt cTnT hearts showed improved contractile performance and moderate myocardial hypertrophy. After 6 months of daily physical exercise one del ex16 rat died suddenly and three out of five del ex16 hearts revealed ventricular tachycardia/fibrillation. No arrhythmia was observed in human wt cTnT expressors. Myofibrillar disarray was present in del ex16 hearts after training but not in human wild-type cTnT rats or non-transgenic controls. CONCLUSION: A human cTnT deletion overexpressed in transgenic rats exerts a dominant-negative effect and mimics the phenotype of FHC with diastolic dysfunction and arrhythmias. By contrast, human cTnT wild-type animals reveal a gain of function and cardiac hypertrophy without arrhythmias.

Animals↗
PubMed2000

An animal model for anaplastic large cell lymphoma in the immunocompetent syngeneic C57Bl/6 mouse.

We report on the analysis of a murine anaplastic lymphoid cell line TS1G6, established recently by interleukin (IL)-9 transfection. TS1G6 revealed a highly characteristic pattern of large anaplastic cells with mononuclear, binuclear, or multinuclear cells resembling Hodgkin (H) or Sternberg-Reed (SR) cells. This cell line is tumorigenous after injection of as few as 10(4) lymphoma cells into nude or immunocompetent C57Bl/6 mice and leads to death from progressive disease of all treated animals within a few weeks. The histological analysis of these tumors revealed a diffuse large cell malignant lymphoma that is morphologically almost identical to human anaplastic large cell lymphoma (ALCL). The lymphoma cells did not show overexpression of the anaplastic lymphoma kinase (ALK) gene, which is found in about 50% of the cases of human ALCL. Thus, this model may be an animal model for an important subset of human ALCL. The cytokine profile, which is of the T helper 2 type, showed strong parallels to the human lymphoma counterpart. Mice suffering from such lymphomas could not be cured with a regimen using high dose cyclophosphamide similar to many ALCL patients. Such an animal model for ALCL has not yet been recognized, but may provide the basis for investigating new antitumor immunotherapies in a fully immunocompetent host.

Anaplastic Lymphoma Kinase↗