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Biomedical subjects

T Kirchner

Publications and source records attributed to T Kirchner.

At least 217 records · Page 12Linked to original sources
PubMed1988

[Pemphigus vulgaris with involvement of duodenum and colon].

Pemphigus vulgaris should be numbered among the many causes of gastrointestinal hemorrhage. In our present case, the lesions of the intestinal mucosa occurred some time before those of the oral mucous membranes which finally led to the diagnosis. At the beginning of our century, the possibility of intestinal involvement in pemphigus vulgaris was well-known among dermatologists. We suggest that patients with pemphigus vulgaris should be endoscopically examined in order to confirm the clinical observations made in former times by modern scientific methods.

Adult↗
PubMed1988

Microenvironment of thymic myoid cells in myasthenia gravis.

The microenvironment of myoid cells (MyCs) was studied in myasthenia gravis (MG) thymitis with lymphoid follicular hyperplasia (LFH) (nine cases) and with diffuse B cell infiltration (one case), and compared with findings in the thymuses of non-myasthenic control subjects (ten cases). Double immunostaining was used to demonstrate MyCs labelled by anti-desmin together with other thymic components such as keratin-positive epithelial cells, Ki-M 1-positive interdigitating reticulum cells (IDCs), Ki-M 4-positive follicular dendritic reticulum cells, Ki-M 6-positive macrophages, CD22-positive B-cells, CD1-positive cells, CD3-positive T-cells or HLA-DR-positive cells. Round or elongated MyCs were confined to the thymic medulla and were surrounded by CD3-positive T-cells and CD22-positive B-cells. In MG thymitis MyCs were localized in the vicinity of, but not inside germinal centres (GCs). MyCs were always HLA-DR-negative, but were invariably embedded in a cellular micromilieu with strong HLA-DR expression. A remarkable feature of MG thymitis was that the great majority of MyCs were in intimate contact with intramedullary IDCs. Morphometric studies confirmed that such contacts were significantly less frequent in thymuses from non-myasthenic subjects. This indicates that an IDC-dependent antigen-presenting process for T-cells may actively involve MyCs in MG thymitis.

Adolescent↗
PubMed1988

Pseudoappendicitis caused by Plesiomonas shigelloides.

A 20-year-old patient was hospitalized with clinical signs of acute appendicitis. After surgery, the histological findings in the appendix and a lymphatic node suggested the diagnosis of pseudoappendicitis caused by Plesiomonas shigelloides, which was isolated in pure culture from the lymphatic node. The strain of P. shigelloides was found to elaborate a heat-stable toxin and harbored two plasmids of 280 and 4 kilobases. A large plasmid has previously been implicated as a virulence marker in P. shigelloides infections.

Adult↗
PubMed1988

Thymus in myasthenia gravis. Isolation of T-lymphocyte lines specific for the nicotinic acetylcholine receptor from thymuses of myasthenic patients.

The thymus is believed to play a central role in the pathogenesis of Myasthenia gravis (MG). According to a previous hypothesis, MG is initiated within the thymus by immunogenic presentation of locally produced nicotinic acetylcholine receptor (AChR) to potentially autoimmune T cells. Data of 10 consecutive MG patients demonstrate two critical features of MG thymuses that support the concept of intrathymic activation of autoreactive, AChR-specific lymphocytes. Morphologically, the thymuses showed lympho-follicular hyperplasia in nine cases and benign thymoma in one case. The paramount feature revealed by immunohistological double marker analyses was the intimate association of myoid cells (antigen producing) with interdigitating reticulum cells (potentially antigen presenting cells), both of which were surrounded by T3+ lymphocytes in thymus medulla. All 10 thymuses contained T lymphocytes reactive with AChR. This was in contrast to the peripheral immune compartment (blood) where in only 3 of 10 patients, significant T cell responses to AChR were observed. AChR-specific T cell lines could be established from 8 of 10 thymuses, all members of the helper/inducer subset as indicated by the expression of markers T3 and T4.

Adolescent↗
PubMed1988

Pathogenesis of myasthenia gravis. Acetylcholine receptor-related antigenic determinants in tumor-free thymuses and thymic epithelial tumors.

The authors describe an immunohistologic study of acetylcholine receptor (AChR)-related antigenic determinants in tumor-free thymuses of myasthenia gravis (MG) patients (13 cases) and nonmyasthenic controls (10 cases) and in thymic epithelial tumors of patients with MG (8 cases) and without MG (6 cases). Monoclonal antibodies (MAbs) to the cytoplasmic part and to the extracellular main immunogenic region (MIR) of the alpha subunit of AChRs were used. Their intrathymic binding sites were defined by double-immunostaining, and compared with alpha-bungarotoxin (alpha-Bgt) labeling demonstrated by fluorescence microscopy. Tumor-free thymuses of MG patients and control patients contained cytoplasmic AChR epitopes and alpha-Bgt binding sites on myoid cells and some epithelial cells. Only myoid cells also expressed extracellular MIR epitopes, suggesting that they bear complete AChRs, and are important targets for the autoimmune attack in tumor-free MG thymus. Evidence that AChR-related antigenic determinants of epithelial cells are also significant for MG is provided by our findings in thymic epithelial tumors. All eight tumors with MG but only two out of six tumors without MG showed cytoplasmic AChR epitopes and alpha-Bgt binding sites on neoplastic epithelial cells. Myoid cells and MIR epitopes did not occur in the neoplasms, but in some tumor-free thymic remnants beside thymomas. It is assumed that nonneoplastic and neoplastic thymic epithelial cells contain only incomplete AChRs or AChR-like molecules. The different expression of AChR epitopes in thymic epithelial tumors and tumor-free thymuses might explain some of the heterogeneous region specificities of anti-AChR antibodies in sera of MG patients with and without thymoma.

Adolescent↗
PubMed1988

Soybean agglutinin for detection of macrophages in Whipple's disease: a possible aid in diagnosis.

The lectin binding pattern of PAS-positive macrophages in Whipple's disease was examined with SBA, LPA, UEA I, PNA and WGA. All PAS-positive macrophages of Whipple's disease were SBA positive. Other macrophages and epitheloid cells, so far tested, did not react with SBA. This finding may be helpful in the diagnosis of Whipple's disease especially in lymph node biopsies, where the amount of PAS-positive macrophages usually is much lower than in intestinal biopsies.

Histocytochemistry↗
PubMed1987

Gastric endocrine cell hyperplasia and carcinoid tumors in atrophic gastritis type A.

Immunohistochemical, histochemical, and morphometrical studies of six gastric carcinoid tumors and their possible precursor lesions in gastric mucosa are reported. All tumors, presenting successively at our institute, occurred in the corpus mucosa of 45- to 78-year-old patients. Two neoplasms had already metastasized. Three tumors contained gastrin- and/or serotonin-positive cells. Two groups of carcinoids, one with atrophic gastritis type A [AGA (four cases)], and one without AGA (two cases) were discerned. Only cases with AGA showed antral G cell hyperplasia consistently as well as fundic endocrine cell proliferation and sometimes multifocal tumors. This confirms previous reports that hypergastrinemia might be a predisposing condition for the development of gastric carcinoids in AGA. Fundic endocrine cell increase, verified by quantitative methods, was either diffuse or nodular. Diffuse endocrine cell hyperplasia comprised G, EC, and ECl cells. The observation that endocrine cell nodules comprised a similar mixture of endocrine cells, sometimes communicating with glands of pseudopyloric metaplasia and proving to be reversible in one case, provides evidence that these nodules are hyperplastic, but finally may lead to gastric carcinoid tumors in AGA. Size less than 150 micron, basal location, and mixed hormone content may be helpful criteria for the distinction of hyperplastic endocrine cell nodules from small carcinoid tumors.

Aged↗
PubMed1986

Immunohistological patterns of non-neoplastic changes in the thymus in Myasthenia gravis.

Non-neoplastic thymuses from 20 patients with myasthenia gravis (MG) have been studied by routine stains on paraffin sections and by immunohistological methods on frozen sections using a panel of monoclonal antibodies against thymic epithelial cells, macrophages/reticulum cells, lymphoid cells and myoid cells. Three types of thymic histology in MG were distinguished: (1) thymitis with lymphoid follicular hyperplasia (11 cases), (2) thymitis with diffuse B-cell infiltration (5 cases) and (3) thymic atrophy (4 cases). Thymitis was more common in younger females and thymic atrophy in older patients. Both types of thymitis were associated with conspicuous structural disturbance of the thymic perivascular space (PVS) and medulla, characterized by a distinct enlargement of the PVS and disruption of the epithelium and reticulin fibre network at the medullary boundary, leading to fusion of the two compartments. The PVS and medulla contained a striking B-cell infiltration. Large well-developed germinal centers (GCs), showing the same cellular organization as in the peripheral lymphatic system, occurred in thymitis with lymphoid follicular hyperplasia, whereas thymitis with diffuse B-cell infiltration merely exhibited a few tiny lymphoid follicles, which could be demonstrated only by immunostaining of dendritic reticulum cells. In thymic atrophy a diffuse B-cell infiltration of the PVS and the medulla was also observed, but only minor alterations of the epithelial framework were seen. There was an increased number of interdigitating reticulum cells with variable expression of the T-6 antigen in all the thymuses examined, indicating an immune stimulation of the intrathymic T-cells. Myoid cells, the supposed target of the intrathymic immune reaction in MG, were found to be less frequent in thymic atrophy than in thymitis. This variable number of myoid cells may explain the different grades of immune stimulation and different types of histology seen in the thymus in MG.

Adolescent↗
PubMed1985

Immunohistological evidences of cortical and medullary differentiation in thymoma.

The phenotypical characteristics of human epithelial and lymphoid cells have been studied with immunohistochemical methods on frozen sections of 12 thymomas. On the basis of the cytohistological characteristics of thymoma epithelial cells (EC) the thymomas were divided in cortical, medullary and mixed types, according to recently developed light microscopical criteria. When tested with a series of monoclonal antibodies, thymoma EC were all stained by the antibody Ki-M3 (as in the thymus), but reacted with anti-HLA-DR, anti-HLA-A,B,C and with a new monoclonal antibody to cortical EC, 21A6, to a lesser extent and with weaker, variable intensity in comparison with the normal thymus. Cortical type thymomas were most reactive and the medullary type almost negative. Thymomas, like normal thymus showed different immunoreactivity patterns with antibodies to prekeratins of different specificities. Cortical type thymomas and areas in mixed thymoma showed an EC staining with the antibody to non-squamous type keratin (35 beta H11) whereas medullary type thymomas and areas showed staining with antibodies to squamous-type keratin (34 beta E12-IV/82) in addition. Lymphoid cells with cortical (OKT6+, Leu 1 weakly+, Leu 2a+, Leu 3a+) or mature medullary (OKT6-, Leu 1 strongly+, Leu 2a or Leu 3a+) phenotype were found to colonize tumours with different EC types. These immunohistochemical findings largely confirm our earlier cytological distinction of thymoma EC. In addition important differences have been observed in neoplastic cortical EC concerning the HLA-DR and 21A6 immunoreactivity that may be intimately related to the neoplastic process and paraneoplastic immune phenomena.

Antibodies, Monoclonal↗