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H Knecht

Publications and source records attributed to H Knecht.

101 records · Page 6Linked to original sources
PubMed1982

Ultrastructural findings in Hashimoto's thyroiditis and focal lymphocytic thyroiditis with reference to giant cell formation.

Ultrastructural findings in two cases of Hashimoto's disease and two cases of focal lymphocytic thyroiditis are reported. Stimulated thyrocytes, oncocytes and degenerating thyrocytes were observed in all cases. Multinucleated thyrocytes and epithelial pseudogiant cells were identified in Hashimoto's disease only. Infiltrating lymphocytes, plasma cells, monocytes and macrophages were present in all cases. The ultrastructure of germinal centres was similar to that seen in lymphatic organs. Giant cells of both intra- and extrafollicular localization were seen in Hashimoto's disease. Most of the giant cells were macrophage-derived. Two different ways of giant cell formation were identified: besides the familiar dissolution of plasma membranes of adjacent macrophages, another mechanism of fusion was observed. At sites of contact, peculiar membrane structures were developed and disintegration of plasma membranes occurred in parts adjacent to these structures. These are not identical to desmosomes and are different from Langerhans' granules. They probably represent special organelles for the initiation of cellular fusion.

Adult↗
PubMed1981

[History and clinical picture of lymphogranulomatosis X (including (angio)immunoblastic lymphadenopathy].

The term lymphogranulomatosis X (LgX) designates a clinicopathological entity of unknown etiology ("X"), which was first described by Forster and Moeschlin in 1954. LgX includes the "immunoblastic lymphadenopathy" of Lukes and to a large extent the "angioimmunoblastic lymphadenopathy" of Rappaport (except for the cases with active germinal centers), but in LgX there is another morphologic variant not mentioned either by Lukes or by Rappaport. To establish the morphologic diagnosis of LgX three typical changes of the affected lymph nodes are needed: effacement of the nodal architecture, absence of active germinal centers, and markedly increased proliferation of epithelioid venules. Cases with only partial effacement of nodal architecture, and especially with active germinal centers, were considered hyperimmune reactions (HR). This "hyperimmune reaction" may be an early stage of LgX: 4 of 39 cases showed later transformation into LgX. Based on cytologic aspects, five different variants of LgX are distinguished: immunoblastic predominance, plasma cell predominance, mixed cell type, epithelioid cell predominance and lymphocytic predominance. Case history and clinical picture of the five variants of LgX (172 patients) are reported and compared with HR (37 patients). In LgX the age peak is in the 7th decade; the youngest patient was 16 years old. HR are seen in children as well as in elderly people, the mean age being 49 years. In LgX males predominate and in HR females. In LgX the disorder is usually more generalized than in HR (80% versus 46% with generalized lymph node enlargement, 69% versus 24% with hepatomegaly and 62% versus 27% with splenomegaly). Skin involvement and high sedimentation rate are less frequent in HR. In LgX a Coombs-positive anemia is occasionally found; its origin is "aplastic" rather than hemolytic. Based on the data presented, some reflections relative to the etiology and pathogenesis of LgX are presented. Rubella virus should be considered a possible etiologic agent. In most cases with drug hypersensitivity, allergic reactions to drugs appear only in the course of the illness; in these cases drugs are ruled out as an etiologic factor. Occasionally, an augmented number of azurophil granulated lymphocytes (suppressor T-cells?) is observed in the blood, a fact that could be a pointer to the pathogenesis of LgX and possibly explain the high incidence of infections seen in this disorder.

Adolescent↗
PubMed1978

[Late results after extra-anatomical shunt surgery in vascular surgery].

Alternative procedures were applied in high-risk patients or, in cases in which it was necessary, to bypass infected vascular beds. Some of our 113 procedures, especially the carotid-subclavian and the femoro-femoral grafts, showed excellent long-term results and wider application of these operations thus appears justified. Infected areas in the groin may be bypassed by the lateral iliaco-femoral graft as an alternative to the obturator bypass.

Arteriovenous Shunt, Surgical↗
PubMed1976

[Tubular structure and germ cell distribution of cryptorchid or normal testes in early childhood (author's transl)].

INTRODUCTION: Many recent publications have demonstrated that the cryptorchid testicle (and, to a lesser extent, the descended partner) are progressively injured from the second year of life onwards. Do these injuries occur in an organ which has been healthy up to this time or are they superimposed on a structurally abnormal testicle? In order to answer this, parts of cryptorchid testicles, of the descended partners, and of normal testicles were compared by histological examination of serial sections. MATERIAL AND METHODS: Parts of four testes from children aged 4-7 months (2 specimens obtained by biopsy and 2 from autoptic material) and parts of four testes from children 1 1/2 years old (2 obtained by biopsy and 2 from autoptic material) were examined. The biopsies were fixed in Stieve's fixative. Tissue samples from clinically healthy children who had died suddenly were fixed in 4% formalin. The tissue was embedded in paraffin and sectioned serially; 6 mum sections were stained with HE. The spermatogonia in each cross-section and in each oblique section of a same tubule were counted and the counts of the latter were adjusted to a cross-section 50-60 mum in diameter. This counting technique did not alter the density of spermatogonia. The graphs present data on the density of spermatogonia through the lengths of the tubules examined and demonstrate tubular branching and blind ends. In the first year of life the cryptorchid testis and its descended partner showed repeated long sections lacking spermatogonia in the same tubule, whereas in normal testes the spermatogonia were more evenly distributed. The cryptorchid testis showed increased tubule branching in the areas examined. In the second year of life the tubules of the cryptorchid testis and its descended partner manifest areas free of germ cells, increased branching, and blind ends. The cryptorchid testis also had a tubule completely free of spermatogonia. The germ cell-free parts were always associated with a smaller tubule diameter than normal. The normal testes did not disclose increased branching or spermatogonium-free areas within similar lengths of tubules and showed an even distribution of spermatogonia. DISCUSSION: The different distribution of spermatogonia within the tubules and the increased branching of the tubules in cryptorchid testes indicate a previous disturbance of testis development.

Age Factors↗