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U Schmid

Publications and source records attributed to U Schmid.

At least 37 records · Page 2Linked to original sources
PubMed1996

[MALT-type low-grade B-cell lymphomas of the stomach and Helicobacter pylori].

From January 1 1994 to March 1 1995 we observed 6 patients with gastric low-grade B-cell lymphoma of MALT type in association with Helicobacter pylori infection. Endoscopically only 3 of the 6 patients presented with pathological findings. All but one patient with metastatic carcinoma received antibiotic therapy for Helicobacter pylori. Follow-up was not possible in one patient who died unexpectedly. In all 4 patients followed-up, eradication of Helicobacter pylori resulted in regression of the malignant lymphoma. During the median follow-up time of 7 months (2-13 months) no relapse of lymphoma was observed. Our results confirm that gastric low-grade B-cell lymphoma of MALT type can regress after eradication of Helicobacter pylori.

Adult↗
PubMed1996

Monocytoid/marginal zone B-cell differentiation in follicle centre cell lymphoma.

We report on two cases of low grade follicle centre cell lymphoma with a pronounced parafollicular monocytoid/ marginal zone B-cell component. One patient had a history of preceeding follicular high grade B-cell lymphoma of centroblastic type showing the same light chain restriction and identical immunoglobulin heavy chain gene rearrangement as the low grade lymphoma diagnosed 15 months later. Morphologically, in both cases the two constituents of the low grade tumours were clearly distinguishable. Immunohistochemically, the follicular component strongly expressed bcl-2 protein in contrast to a weak staining of the marginal zone B-cell component. Performing PCR, a rearrangement of the major breakpoint region of bcl-2 was not found. Identical light chain restriction of the follicular and the monocytoid B-cell/marginal zone components strongly indicates a clonal relationship between them. A monocytoid/marginal zone B-cell component in follicular lymphoma probably results from differentiation of the follicle centre cells and does not indicate a composite lymphoma.

Antigens, CD20↗
PubMed1995

Cutaneous follicular lymphoid hyperplasia with monotypic plasma cells. A clinicopathologic study of 18 patients.

Twenty cases of cutaneous follicular lymphoid hyperplasia with monotypic plasma cells are presented in a clinicopathologic study on 18 patients. The plaque-like or nodular lesions were solitary in 10 and multiple in eight patients. Immunohistochemistry showed well-defined B- and T-cell areas. Sheets of monotypic plasma cells occurred either interfollicularly or adjacent to the sclerotic stroma, with expression of IgG/kappa in 14 and IgG/lambda in six cases. In one patient with multiple lesions, one sample contained polyclonal plasma cells, whereas the other specimen showed light chain restriction. In another patient, disease recurred with a polytypic cutaneous plasma cell infiltrate. Polymerase chain reaction (PCR) revealed clonal immunoglobulin heavy chain gene rearrangements in eight of 13 cases, which was confirmed by Southern blot analysis in three samples. Clonal T-cell receptor chain gene rearrangements were not detected. Disease progression to overt malignant lymphoma did not occur within the follow-up period of up to 12 years, but recurrent disease was seen in three patients. Our data indicate that cutaneous lymphoid hyperplasia with monotypic plasma cells is a biologically distinct clinicopathological entity.

Adolescent↗
PubMed1994

Parallel assessment of glutathione-based detoxifying enzymes, O6-alkylguanine-DNA alkyltransferase and P-glycoprotein as indicators of drug resistance in tumor and normal lung of patients with lung cancer.

The levels of several potential indicators of drug resistance were measured in tumor and corresponding normal tissue of 55 untreated patients with lung cancer. The resistance parameters include glutathione (GSH) level, activities of the enzymes glutathione transferase (GST), glutathione peroxidase (GPx) and O6-alkylguanine-DNA alkyltransferase (ATase), as well as expression of P-glycoprotein (Pgp). Median values of GSH, GST and GPx were significantly higher in tumor than in normal tissue of non-small-cell lung cancer (NSCLC) or of small-cell lung cancer (SCLC), whereas ATase was elevated in tumor tissue of NSCLC only. Pgp expression as determined by Western blotting was significantly lower in tumor than in normal tissue of NSCLC. Resistance-parameter expression did not correlate with stage of disease or age of the patients. We found a negative correlation between smoking intensity and GSH level in normal tissue. Our findings indicate that the fundamental differences in chemosensitivity between SCLC and NSCLC cannot be explained by differences in the GSH-system or in the expression of Pgp. However, the level of ATase activity may be one of the factors responsible for the difference in chemosensitivity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[Primary non-Hodgkin lymphoma of the stomach. A review with special reference to the MALT concept].

Primary extranodal malignant lymphomas are most often localized in the stomach. In contrast to gastric carcinomas, primary gastric non-Hodgkin's lymphomas show an increasing incidence. According to their grade of malignancy they are divided into low-grade and high-grade non-Hodgkin's lymphomas and according to their immunophenotype into B-cell and T-cell non-Hodgkin's lymphomas. In most cases they show a B-cell phenotype while high-grade tumors are more frequent than those of low-grade malignancy. However, primary gastric Hodgkin's disease is still a rarity. A new entity, the so-called low-grade B-cell non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue (MALT) type, is characterized by a diffuse infiltrate of centrocyte-like cells intermingled with immunoblasts of the same clone, plasma cell differentiation of the tumor cells, lymphoepithelial lesions, and reactive intratumoral lymphoid follicles. It may secondarily transform into a high-grade B-cell lymphoma but remains limited to the stomach for a considerable period of time with a favourable prognosis. The most important prognostic factors of primary gastric lymphomas are stage at initial diagnosis, classification and grading according to the histopathological concept of the MALT, and depth of infiltration. Although a considerable number of early stage gastric lymphomas achieve complete remission after surgical therapy only, primary treatment of gastric lymphoma is still controverted, thus underlining the urgency of a multicenter prospective study. Chronic Helicobacter pylori infection may play a major role in the pathogenesis of low-grade B-cell lymphoma of MALT type. Complete remission of some cases of low-grade B-cell lymphoma of MALT type with concomitant Helicobacter pylori gastritis after Helicobacter pylori eradication may lead to a new pathogenetic, therapeutic, and prognostic concept.

Helicobacter Infections↗
PubMed1994

[Simultaneous occurrence of breast carcinoma and malignant lymphoma. Case observations and literature review].

Based on the observation of 5 patients with simultaneous breast cancer and malignant lymphoma, we discuss the phenomenon of synchronicity of two different tumors in the same individual. Synchronicity of malignancy is rare and could point to a genetic predisposition (family history) or common environmental influence in generating cancer. In elderly patients, the appearance of multiple tumors may coincide by chance. In the case of synchronous or metachronous tumors it is essential to examine the new tumor manifestation by biopsy. In view of the therapeutic and prognostic implications, the second tumor should not be confused with a progression of the known primary malignancy.

Adult↗
PubMed1994

Coexpression of cytokeratin and vimentin intermediate filaments in benign and malignant sweat gland tumors.

The coexpression of cytokeratin and vimentin intermediate filaments has been immunohistochemically evaluated in 124 benign and malignant sweat gland tumors of various types in comparison to normal sweat glands. In addition, all neoplasms have been stained by an antibody to alpha-smooth muscle actin. Epithelial cells reacted with the pan-cytokeratin antibody lu-5. In normal sweat glands, vimentin immunoreactivity was restricted to myoepithelial cells and to some cells of the coiled duct. In benign sweat gland tumors (n = 88), coexpression of vimentin and alpha-smooth muscle actin was frequently found in basal cells of neoplasms considered to differentiate towards the secretory coil of the eccrine or apocrine gland. These included eccrine spiradenoma, apocrine cystadenoma, hidradenoma papilliferum, syringocystadenoma papilliferum, and cylindroma. Thus, in these tumors, vimentin-reactive cells corresponded to myoepithelial cells. Vimentin-positive cells were also found in 14 of 36 sweat gland carcinomas, including 1 case of sclerosing sweat duct carcinoma, 1 case of porocarcinoma, 4 cases of eccrine adenocarcinoma, 1 case of mucinous eccrine carcinoma, and 5 cases of apocrine adenocarcinoma. Co-expression of vimentin and alpha-smooth muscle actin was observed in some cells of eccrine and apocrine adenocarcinomas. Therefore, in these neoplasms, some vimentin-positive cells appear to represent myoepithelial cells. In contrast, vimentin-positive cells in all other malignant tumors did not express alpha-smooth muscle actin. Our results indicate that coexpression of cytokeratin and vimentin may be frequently found in a variety of benign and malignant sweat gland tumors. In the majority of these neoplasms, vimentin-positive cells correspond to myoepithelial cells. Because vimentin is not specific for myoepithelial cells, additional stains for alpha-smooth muscle actin should be performed to prove the myoepithelial nature of vimentin-positive cells.

Humans↗
PubMed1994

Skin involvement in myelogenous leukemia: morphologic and immunophenotypic heterogeneity of skin infiltrates.

A systematic morphological analysis of cutaneous infiltrates in acute myelogenous leukemia and myelodysplastic syndrome revealed that in many cases the infiltrating cells have a different phenotype from those in the bone marrow. This study sought to answer two questions: (a) How wide is the range of cytological features and immunoreactivity of the cutaneous infiltrates and what danger is there of misinterpretation? (b) What are the possible causes of the wide spectrum of differentiation of the cells infiltrating the skin? Skin biopsy specimens from 16 patients with myelogenous leukemia or myelodysplastic syndrome were investigated. The diagnosis was acute myelomonocytic leukemia (M4, according to the French-American-British/FAB system of classification of acute leukemias) in eight cases, acute monocytic leukemia (M5) in four cases, aleukemic leukemia cutis as a recurrence of M2 leukemia after treatment in one case, and myelodysplastic syndrome in three cases, including one case of myelodysplasia with an excess of bone marrow blasts (RAEB-T) and two cases of chronic myelomonocytic leukemia, one of which presented as aleukemic leukemia cutis. Reactivity with the macrophage-associated antibodies anti-CD68, Ki-M1p, and anti-lysozyme was the most consistent. However, the naphthol AS-D chloroacetate esterase reaction and staining with DAKO-M1, Ki-My2p, anti-neutrophil elastase, and anti-CD34 were found to be of little value for identifying the cutaneous infiltrate as myelogenous. Some antibodies (e.g., anti-S100 protein and MB2) even produced staining in a few cases that could have led to a mistaken diagnosis of histiocytic neoplasm or malignant lymphoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Presenting Cells↗
PubMed1993

Monoclonal antibody accumulation in experimental and spontaneous lung metastases of human malignant melanoma in rodents.

Monoclonal antibody (mAb) uptake in metastatic lung lesions was depicted and evaluated by digital autoradiography. The models examined were experimental metastases of a human melanoma in nude mice and spontaneous metastases of human melanoma in immunocompromised young rats. By comparing uptake patterns in local (s.c.) tumours and in lung processes of various sizes it was found that patterns were essentially similar in both types of malignant tissue. From the point of view of visualization, however, the high blood content of lung tissue resulted in high background and low contrast. This could be overcome by the use of rapidly cleared antibody fragments.

Animals↗
PubMed1993

[Osteoinduction with the dog tibial defect model].

The objectives of this study were to investigate the osteoinductive effect of demineralized bone matrix powder and of cancellous bone in a comparative experiment in a standardized dog defect model. 16 adult shepard dogs were divided into two test subgroups. One group underwent application of demineralized bone matrix (DBM) into the defect. The second group had their defects treated with autogenous cancellous bone (ACG) only. The progress of bone formation was observed for twelve weeks. The excised tibiae were examined by correlating serial X-rays with histologic sections stained with Giemsa and fluorescent labels. In this experiment no osteoinductive effect of demineralized bone powder could be demonstrated. The amount and localisation of bone regeneration in the matrix group seemed to be spontaneous, corresponding to the radiological and histological parameters. In the group of cancellous bone grafts, the defect (length 30 mm) was bridged by incorporation of the graft and graft mediated bone formation within twelve weeks. Disturbing factors such as instability, infection, insufficient vascularity, and cellular immune response to the graft were excluded in this model. The failure of the osteoinductive implants in our experiment compared with the good results obtained in rodents limits their value also in clinical situations. As long as there is no explanation for this failure, this technique should not be used in a clinical situation.

Animals↗
PubMed1993

Preferential antibody targeting to small lymphoma metastases in the absence of the primary tumour.

Targeting of spontaneous liver metastases of the ESb.MP murine lymphoma was achieved with anti-CD2 monoclonal antibody (MAb) 12-15A, which does not react with normal liver tissue. Using quantitative autoradiography on whole body sections of animals that had received a standard dose of 1.1 MBq of 125I-labelled monoclonal antibody, metastases accumulated up to > 90% of the injected dose per gram (id/g). The average uptake of primary tumour lesions was at a low level of 24 Bq/mg (corresponding to 2.2% id/g) because of highly non-uniform accumulation, while metastatic lesions were all above 50 Bq/mg. Uptake was particularly pronounced in animals tested after resection of the primary tumour: 85% of metastases showed levels above 300 Bq/mg, which was the upper limit of uptake in metastases of non-resected animals. These findings demonstrate the potential of the antibody approach with regard to attacking residual metastatic lesions after debulking.

Animals↗
PubMed1992

Metastatic signet-ring cell melanoma in a patient with an unknown primary tumor. Histologic, immunohistochemical, and ultrastructural findings.

Signet-ring cell melanoma is a rare morphologic variant of malignant melanoma. We describe a 27-year-old man with widespread cutaneous and internal metastases of an unknown primary tumor. One skin biopsy specimen and a fine-needle aspirate showed polygonal tumor cells consistent with the diagnosis of metastatic melanoma, but a second skin biopsy specimen revealed neoplastic cells with a signet-ring cell appearance. Both specimens, however, yielded identical immunohistochemical findings. Tumor cells were positive for vimentin and S-100 protein and reacted with the melanoma markers HMB-45 and NKI-C3. Ultrastructural studies revealed abundant intermediate filaments in the cytoplasm of the signet-ring cells. Based on these findings, a diagnosis of metastatic melanoma was made. In this report we describe the fourth case of metastatic signet-ring cell melanoma, and discuss how malignant melanoma may lead to metastases that have divergent morphologic appearances in the same patient.

Adult↗