Biomedical subjects

T Krenács

Publications and source records attributed to T Krenács.

35 records · Page 2Linked to original sources

PubMed1990

[Pathomechanism of the development of chronic obliterative transplantation arteriopathy in human kidney allografts].

Authors examined cells participating in intimaproliferation in transplantation arteriopathy ultrastructurally in needle and wedge biopsy material from 40 transplanted kidneys, and immunohistochemically in 10 cases. In early biopsies--even in two control kidneys--it could be observed that the smooth muscle cells of media are in direct contact with endothel cells by their small processes. Processes can fulfil a receptor function and can transmit endothel noxa to smooth muscle cells. Smooth muscle cells of media react to endothel damage caused by rejection with migration to intima and during this period they are transformed to myofibroblasts (myointimal cells). In the mean time inflammatory cells (mainly macrophages, helper and cytotoxic cells in lower number) from the lumen infiltrate the intima, and mediators, enzymes released from them can inspire smooth muscle cells to further proliferation, migration to intima and transformation to myofibroblast. To effect of mediators (gamma interferon) released from inflammatory cells, the myointimal cells during rejection will press out 2nd class transplantation antigens (HLA-DR), and as vicious circle it further aggravates immune reply to graft, causing vascular damage, intimaproliferation.

Chronic Disease↗

PubMed1990

[Gastrinoma and carcinoma-carcinoid tumor causing Zollinger-Ellison syndrome].

7 gastrinomes and 1 gastrin-producer complex carcinoma-carcinoid tumor were examined by light and electron microscopical-method and by immunohistochemical method. In six cases, the tumor was in the pancreas or in the wall of duodenum; in two cases its localisation was of extra-gastroenteropancreatic (liver, lymph node). All patients developed Zollinger-Ellison syndrome, three patients bled and one had diarrhea. One patient had other tumors, besides gastrinome, which were characteristic of MEN-I syndrome. By immunohistochemical methods all tumors proved to be gastrin and neuron-specific-enolase positive. In four cases somatostatin positivity, in some cases glucagon, pancreatic polypeptide, S-100 protein, keratin and carcinoembryonal antigen positivity were detected. Relation could not be detected between other polypeptide hormones, produced besides gastrin, and biological behaviour of tumor and clinical symptoms.

Carcinoid Tumor↗

PubMed1990

[A case of ceruminous adenocarcinoma. Ultrastructural and immunohistochemical studies].

Case of ceruminal adenocarcinoma is reported. Tumor was diagnosed in advance stage, and within a month following diagnosis it caused death. Tumor started from right auditory canal, undermined the pyramidal bone and infiltrated great part of right side of base of skull, narrowing great foramen to a certain extent. Metastasizes were only the right of dura. Besides electron microscopic studies, authors performed the immune-histochemical and lectin-histochemical examination of tumor the first time.

Adenocarcinoma↗

PubMed1989

Fibre typing using sarcoplasmic reticulum Ca2+-ATPase and myoglobin immunohistochemistry in rat gastrocnemius muscle.

Skeletal muscle fibre types were identified by using immunohistochemical detection of sarcoplasmic reticulum Ca2+-ATPase and myoglobin content in rat gastrocnemius muscle. The strong Ca2+-ATPase-reactive fibres were identical with the fast-twitch population, while the fibres with weak reactivity represented the slow-twitch type. Strong myoglobin immunoreactivity reflected the fast oxidative glycolytic (FOG) and slow oxidative (SO) types. Slight to moderate myoglobin immunostaining was found in the fast glycolytic (FG) fibres. The staining intensity of the different fibre types differed as follows: for Ca2+-ATPase FG greater than FOG greater than SO, and for myoglobin FOG greater than SO greater than FG. The immunoreactivity of Ca2+-ATPase and myoglobin were well preserved after fixation of the muscles in Bouin's solution, or in formol/acetic acid fixative, and paraffin embedding. Detection of the primary antibodies was carried out by using the avidin-biotin-peroxidase complex, and the immunogold-silver-staining methods. The latter was found to be more sensitive and suitable for postembedding ultrastructural demonstration of the Ca2+-pump enzyme on Durcupan-embedded muscles. The method, using 5 nm immunogold conjugate with silver enhancement, offered the advantages of high sensitivity and excellent visualization of the reaction product. The postembedding detection of sarcoplasmic reticulum Ca2+-ATPase also proved to be useful in the retrospective identification of the main fibre classes in human muscle biopsies.

Animals↗

PubMed1989

Application of immunogold-silver staining and immunoenzymatic methods in multiple labelling of human pancreatic Langerhans islet cells.

The use of immunogold-silver staining (IGSS) combined with immunoperoxidase and/or immunoalkaline phosphatase methods for the simultaneous demonstration of pancreatic islet cell hormones on routinely fixed paraffin-embedded human tissue sections was examined. If IGSS was applied first, the black colour of silver-enhanced colloidal gold on doubly immunostained sections contrasted with the colours of most of the chromogens used generally in the 2 immunoenzymatic methods. If IGSS was followed by immunoalkaline phosphatase and immunoperoxidase techniques in optional sequence, 3 different hormone-containing cell types could be stained simultaneously without non-specific cross-reactions. IGSS and immunoalkaline phosphatase methods, together with 2 kinds of non-cross-reacting immunoperoxidase systems, permitted the detection of 4 distinct antigens on the same tissue section. Multiple immunohistochemical labelling of the endocrine pancreas provides an opportunity for the correct and rapid analysis of the topographic and morphometric relationships between different hormone-producing cell populations under both normal and pathological conditions. IGSS is of great potential for the simultaneous immunolabelling of antigens situated within separate cells.

Chronic Disease↗

PubMed1989

Studies into gastrinomas and combined carcinomatous carcinoid tumors. Optical light- and electron microscopy and immunohistochemistry.

The clinical, microscopic, immunohistochemical and ultrastructural features of 7 gastrinomas and 1 combined carcinoma-carcinoid tumor were evaluated. The tumors were located in the pancreas or duodenal wall in 6 cases, and on extragastro-enteropancreatic sites in 2 (liver or peripancreatic lymph node). All patients had the Zollinger-Ellison syndrome, 3 of them with additional bleeding and 1 with diarrhea. One patient with gastrinoma had additional tumors characteristic of the MEN-I syndrome. Immunohistochemistry showed gastrin and neuron-specific enolase-positivity in all of the tumors. Somatostatin was found in 4 cases, and single cell glucagon, pancreatic polypeptide. S-100 protein, keratin as well as carcino-embryonic antigen positivity in another few. Additional hormone production did not appear to be connected with biological behaviour of the tumors or with the clinical symptoms.

Adolescent↗

PubMed1989

S-100 protein immunoreactivity in human islets of Langerhans.

S-100 protein-containing cells were demonstrated by immunogold silver staining in human islets of Langerhans from patients with chronic pancreatitis (CP) with (n = 6) (Group I) or without (n = 6) (Group II) diabetes mellitus, (DM) and from nondiabetic, non-pancreatic controls (n = 6) (Group III). In all three groups S-100 protein containing cells were observed in all islets of Langerhans throughout the pancreas. Quantitative analysis of cell composition of islets did not reveal significant differences in S-100 protein cell content between the three groups. When double immunohistochemical staining was used to demonstrate different endocrine cell types (insulin, glucagon and pancreatic polypeptide) and S-100 protein immunoreactive cells, the latter proved to be a distinct cell type. Somatostatin-producing cells and S-100 protein-containing cells were usually also present as two distinct cell populations, but positive staining for both S-100 protein and somatostatin was occasionally observed within the same cells.

Chronic Disease↗

PubMed1989

[Characterization of striated muscle fiber types by Ca2+-ATPase and myoglobin immunohistochemistry of the sarcoplasmic reticulum].

By the immunohistochemical demonstration of SR calcium ATPase and myoglobin a fibre classification method was developed. Fast fibres showed intense, while slow fibres weak SR calcium ATPase reactivity. Immunohistochemical reaction of myoglobin characterized the oxidative metabolic state of fibres similar to the succinate dehydrogenase (SDH) reaction. By means of SR calcium ATPase and myoglobin immunohistochemistry fibres were classified as slow oxidative (SO), fast oxidative glycolytic (FOG) and fast glycolytic (Fg) groups. The SR calcium ATPase activity of the different fibres varied in the FG greater than FOG greater than SO order, while myoglobin immunoreactivity in the FOG greater than SO greater than FG order. Both proteins studied preserved their antigenicities in Bouin's fixative or in formol-acetate and paraffin embedding. The light microscopic immunogold-silver method was found suitable also for electron microscopy. The silver intensification of small particle-size (5 nm) gold conjugate results in a reaction with the joint advantages of high sensitivity and optimal visibility. The described immunohistochemical method proved to be suitable for the retrospective differentiation of human biopsy materials.

Calcium-Transporting ATPases↗

PubMed1989

[Significance of plasma cells in the rejection of kidney grafts].

Authors studied with immunohistochemical methods the immunoglobulin content of plasma cells during the rejection of renal grafts, in different rejections, in Cyclosporin-A nephro-toxicity and in chronic interstitial nephritis, as a comparison. By far the most plasma cells occurred in chronic rejection, containing more than 80% IgG. Whereas great majority of plasma cells were IgG positive in chronic interstitial nephritis. Probably, in chronic rejection a special, secondary type humoral immune reaction has a significant role in addition to cellular immune mechanisms.

Graft Rejection↗

PubMed1989

[Immunohistochemical, immunocytochemical and electron microscope studies in experimental E. coli pyelonephritis].

Authors have studied in apostematous pyelonephritis induced by the ligation of the ureter and the intravenous injection of E coli bacteria the localization and elimination with time of the pathogen. The pathogen was demonstrated by light and electron microscopy, its parietel antigen was localized with the light microscopic peroxidase antiperoxidase and post-embedding electron microscopic immunogold techniques. Two days after inoculation the suppurative inflammation of tubulo-interstitial foci was observed; in the capillaries, interstitium, and tubuli, free and phagocyted bacteria were encountered. In the interstitium, in the proximal tubuli and in the capillary space of some glomeruli bacterial groups were observed. Intracapillary bacteria were attached by their outer wall to the surface of endothelial cells. In the tubuli this adherence occurred with pili or with the outer layer of bacterial wall. From the seventh day after inoculation macrophages containing PAS-positive globuli appeared in the interstitium. Under the electron microscope these globuli proved to be features composed of myelin figures of phagolysosomal origin. Globuli and the myelin figures possessed an E. coli antigenicity. Thirteen weeks after inoculation E. coli antigen positivity was found in the cytoplasm of inflammatory cells in the tubular walls and in the suppurative cylinders, The organism was apparently unable to eliminate the materials derived from the pathogenic microorganisms.

Animals↗

PubMed1988