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Biomedical subjects

H Themann

Publications and source records attributed to H Themann.

At least 19 recordsLinked to original sources
PubMed1990

Phenotyping of macrophages with monoclonal antibodies in endomyocardial biopsies as a new approach to diagnosis of myocarditis.

Cryostat sections of endomyocardial biopsies from 53 patients (mean age 41 +/- 5 years, 38 male and 15 female) clinically indicated to suffer from myocarditis were stained using monoclonal antibodies against subpopulations of T-lymphocytes and macrophages and with polyclonal rabbit-anti-human sera marking two calcium-binding proteins expressed by monocytes and macrophages appearing in inflammatory sites only. No inflammatory infiltrate cells were found in 13 cases (25%). Mononuclear cell infiltrates were present in 40 cases (75%). Ten biopsies showed a predominance of macrophages bearing the marker 27E10, characteristic for an early acute inflammation and 18 biopsies contained 25F9 positive macrophages, characteristic for a late stage of inflammation. An intermediate type of inflammation with both macrophage types present was found in 12 patients. Patients with immunohistologically confirmed myocarditis had atrial, ventricular or combined forms of arrhythmias (78%), scars in the vectorcardiogram (100%) and radiological evidence of cardiomegaly (36%). In conclusion, typing and endomyocardial biopsies for macrophage subpopulations is a sensitive new approach to assess the diagnosis of myocarditis.

Adult↗
PubMed1989

Degenerative and regenerative processes in the peripheral nerve after disconnection and reanastomosis using the Neodym Yag laser.

The development of neuroma after peripheral nerve surgery is still an unsolved problem. Such lesions are not yet controllable by conventional methods. Reports of results achieved using various types of laser surgery appear contradictory. In this experimental study on rats, the Neodym Yag laser was found to be superior the conventional methods. After severance and reanastomosis of the sciatic nerve using this type of laser, no development of neuroma was observed in any of the animals during the first three months of observation.

Animals↗
PubMed1988

[Congenital alcoholic cardiomyopathy in 3 children].

Three cases of congenital alcoholic cardiomyopathy and cardiac defects in children are described. The mothers were heavy spirits drinkers. One child had a ventricular septal defect, two had Fallot's tetralogy, all requiring operation. At open-heart surgery left-ventricular myocardial biopsies were obtained in all three children. Histological and electronmicroscopic examination revealed primary toxic and hypotrophic changes, which differed from those seen in alcoholic cardiomyopathy of the adult. The cells, their nuclei and the myofibrils had reduced diameters. The mitochondria were damaged to differing extent. The myofibrils were arranged in parallel and some had contraction bands and ruptures. The sarcoplasmic reticulum was dilated and had vacuoles. The cell surface penetrated into the interstitial tissue. All these changes could have resulted from inhibited embryofetal cell growth and cytotoxic damage by alcohol during pregnancy. It would seem that alcoholic cardiomyopathy occurs only in extreme forms of alcohol abuse during pregnancy. The prognosis is as yet unknown.

Cardiomyopathy, Alcoholic↗
PubMed1987

Prevention of neuroma formation by Neodym Yag laser--experimental observations.

The influence of Laser radiation on neuroma formation was investigated in rat sciatic nerves. Peripheral nerve trunks were divided by focused Neodym Yag Laser and compared with those transected by microscissors. The nerves were re-exposed at different time intervals up to 240 days after initial operation. True neuroma formation could not be observed after laser transection. Sharp division resulted in widespread amputation neuromas consisting of regenerating axons and connective tissue. Neodym Yag laser radiation by its scattering effect may cause deep coagulation necrosis and thrombosis of vasa nervorum thus sealing the dome of the divided nerve trunk. The formation of amputation neuromas may be suppressed by laser application.

Amputation Stumps↗
PubMed1987

Electron microscopic investigations of the cyclophosphamide-induced lesions of the urinary bladder of the rat and their prevention by mesna.

Fully developed cyclophosphamide-induced cystitis is characterized by nearly complete detachment of the urothelium, severe submucosal edema owing to damage to the microvascular bed and focal muscle necroses. The initial response to the primary attack by the cyclophosphamide metabolites seems to be fragmentation of the luminal membrane. This damages the cellular barrier against the hypertonic urine. Subsequent breaks in the lateral cell membranes of the superficial cells and in all the plasma membranes of the intermediate and basal cells, intercellular and intracellular edema and disintegration of the desmosomes and hemidesmosomes lead to progressive degeneration and detachment of the epithelial cells with exposure and splitting of the basal membrane. The morphological changes of the endothelial cells, which become more pronounced in the later stages of the experiment, the involvement of blood vessels regardless of their diameter and the location-dependent extent of the damage indicate a direct type of damage which is preceded by a mediator-induced increase in permeability, the morphological correlate of which is the formation of gaps in the interendothelial cell connections on the venules. These changes can be effectively prevented by mesna. The only sign of a possible involvement is the increase in the number of specific granules with a presumed lysosomal function in the superficial cells.

Animals↗
PubMed1987

[Fine structure of surviving heart muscle cells in ventricular aneurysms].

Surgically-obtained tissue specimens from 41 patients with ventricular aneurysm were studied electron microscopically. The tissue from the resected aneurysms showed substantially varied morphological differences. In some, there were extensive regions of scar containing increased fibrotic material and few cells, in others there were also larger contiguous regions of myocardium with an essentially normal appearance. In the preserved myocardial regions, the cardiac cells showed moderate hypertrophy. There was an increase in contractile substance in parallel with an increase in mitochondria and enlargement of the nucleus with frequent waves and invaginations in the cell membrane. The cells at the marginal regions between fibrous tissue and preserved myocardium were frequently isolated from adjacent cells. In particular, when the isolated cells were completely surrounded by fibrous tissue, clear degeneration was apparent. These cells showed mainly a fibrillolysis with dissolution of the cross-bands and loss of the entire contractile apparatus. In compensation, occasionally there was proliferation of other cell structures, especially the free sarcoplasmatic reticulum. The hypertrophy of the still intact myocardial cells is considered compensatory for the infarct-incurred loss of tissue. The degenerative appearance is mainly attributable to fibrous tissue invasion. The diminished oxygen supply, compromised or abolished impulse conduction, loss of function and passive stretch during systole may be regarded as causes of the degeneration.

Actin Cytoskeleton↗
PubMed1986

Cardiovascular and cerebrovascular effects of isoflurane-induced hypotension in the baboon.

Mean arterial pressure (MAP) decreased by 10, 20, 40, and 50% of its baseline value in six anesthetized baboons with the administration of increasing concentrations of isoflurane. Mean arterial pressure, right atrial pressure, pulmonary artery pressures, and cardiac output were measured at each decrement in arterial pressure, and after the withdrawal of the isoflurane. At the same times, cerebral blood flow, the cerebral metabolic rate for oxygen, and the cerebral metabolic rate for glucose were determined. Cerebrovascular reactivity was assessed before, during, and after the administration of isoflurane, and morphologic evidence of ischemic cell change was sought at the end of the investigation. Isoflurane produced dose-related decreases in systemic vascular resistance and MAP; heart rate, cardiac output, and stroke volume did not change significantly. Although cerebral metabolism was depressed in a dose-related manner, the response of the cerebral blood flow (CBF) was biphasic. At low isoflurane concentrations, CBF decreased significantly and then increased to reach baseline values at the highest concentration. Cerebrovascular reactivity was intact at baseline and at the 20% decrement in MAP; it was impaired at the 50% decrease in MAP and when studied 100 min after the withdrawal of isoflurane. There was no morphologic evidence of ischemic cell damage in any animal.

Animals↗
PubMed1985

Binding and degradation of proteoglycans by cultured arterial smooth muscle cells. II. Binding sites of proteoglycans on the cell surface.

Exogenous proteoglycans stained for electron microscopy with colloidal gold and/or cuprolinic blue bind to the surface of cultured arterial smooth muscle cells at two different sites. (I) About 20% of the proteoglycans adsorbed to the cells from the culture medium interact as monomeric and multimeric proteoglycans with smooth or coated membrane areas. (II) The bulk of exogenous proteoglycans exhibits high affinity binding to cell membrane-associated 10 nm fibrils containing or being closely associated with fibronectin and to collagen. It is suggested that the self association of proteoglycans and their binding to the cell membrane and to cell surface-associated fibronectin and collagen are important for maintaining an appropriate micro-environment for the cultured cells.

Arteries↗
PubMed1983

Characterization of the cytolytic activity of a cloned antigen-specific T suppressor cell derived from a tolerant CBA/J mouse.

The antigen-specific T suppressor cell clone HF1 isolated from a CBA/J mouse made tolerant by low doses of bovine serum albumin has suppressive and cytolytic activity. The analysis of the latter gave the following results. Natural killer (NK)-sensitive YAC-1 (H-2a) and RBL-5 (H-2b) target cells are lysed whereas other NK targets, like EL4 (H-2b) or the human K562 cell line are resistant. Cytolytic activity is not antibody mediated. Its inhibition by sugar phosphate or monoclonal antibodies against LFA-1 antigens is such that HF1 can neither by typed as T killer nor as NK cells. It seems to represent a distinct T lymphocyte type.

Animals↗
PubMed1983

The correlation between tissue differentiation and production of mammary tumor virus (MTV) in transplanted murine mammary tumors. Electron microscopic observations.

The spontaneous mammary tumors of the NMRI mouse are well developed microcystic adenocarcinomas. Serial isologous transplantation of the tumors results in nearly complete dedifferentiation to a solid tumor, in which only electron-microscopically rudimentary acinus-like microlumina can be observed. The adenocarcinomas produce A and B particles in abundance, with the A particles appearing intracellularly in the adluminal cytoplasmic regions of the epithelial cells in association with typical cellular structures and the B particles being restricted to closed extracellular compartments such as vacuoles or acini alone. The loss of alveolar organization in the solid tumors is followed by an almost complete reduction in mature B particles, while A particles are still regularly observed and appear to be less reduced in number. This suggests that the production of extracellular B particles is dependent upon the secretory activity of the tumor cells and that in nonsecreting cells it is predominantly a late step in virus release that is inhibited, not the synthesis of intracellular precursors.

Adenocarcinoma↗
PubMed1983

Kidney tubule cell injury of male rats after estrogen treatment.

Ultrastructural changes in the tubular epithelium of the rat kidney following a large dose of estrogen (300 micrograms per week for 20 weeks) were studied by means of electron microscopy. The ultrastructural changes in estrogen-treated rats were confined to the proximal tubule. The changes consisted of intracytoplasmic vacuoles and dilatation of the intracellular space between adjacent tubule cells. The cisternae of the endoplasmic reticulum exhibited some degree of vesiculation characterized by club-like formations. In addition, large masses of collagen could be observed within the peritubular capillaries. In contrast to the controls the tubular cells of estrogen-treated rats exhibited large areas or granules with dense inclusions and membranous, filamentous material in a process of being transformed into an autolysosome and residual body. The results are discussed in the light of those of other authors.

Animals↗
PubMed1982

Alterations of tight and gap junctions in mouse hepatocytes following administration of colchicine.

Following the administration of colchicine at a dosage (1 mg/mouse) known to cause an antimicrotubular effect, membranes as well as tight and gap junctions of hepatocytes were studied using the thin-sectioning and freeze-fracturing technique. As early as 1 h after administration of colchicine the intercellular spaces were dilated and vacuoles were visible within the cytoplasm. The bile canaliculi became enlarged, and after lanthanum perfusion the tracer was found in the canalicular lumen, i.e., the tight junctions became permeable to the tracer. These findings correlated with a disorganized arrangement of the tight junctional strands of the zonula occludens. In some regions the strands showed interruptions and frequently ended freely in a diffuse pattern on the plasma membrane. Proliferation of tight junctions could be observed at various locations on the plasma membrane. The gap junctions also exhibited alterations. They showed an irregular outline with outpouchings, in addition to an enlargement in their total area from approximately 0.5 microns 2 in controls up to approximately 2 microns 2 in treated mice. The surface area occupied by these junctions increased from 4% (controls) to 20% (treated) of the hepatic plasma membrane. In the cytoplasm of hepatocytes from colchicine-treated mice gap-junctional vesicles were frequently observed. In view of the antimicrotubular effect of colchicine it is tentatively suggested that the intact microtubular system of the cell may play a decisive role in the regular formation of gap and tight junctions, either directly or indirectly via microfilaments.

Animals↗
PubMed1982

Long-term study of liver damage following subcutaneous injection of airborne particle extracts and polycyclic aromatic hydrocarbon fractions.

Female NMRI mice aged 9-12 weeks were each given a single subcutaneous injection of 0.5 ml of a suspension containing either the total extracts or the polycyclic aromatic hydrocarbon (PAH) fraction of airborne particles. Both the total extracts and PAH fractions contain 3 microgram benzopyrene. After about 15 months the livers were removed from the animals, which had by that time developed tumors at the injection site, and were subjected to electron-microscopical study. The essential alterations were observed in the nucleoli and the cell nuclei, which had greatly proliferated and exhibited irregular nuclear membranes. Advanced fibrosis was observed in central liver specimens of all groups. Marked alterations were also observed in the mitochondria and the mitochondrial cristae as well as in the bile canaliculi, Intracytoplasmic glycogen usually occurred densely clustered along the periphery of the cell. It may be concluded from the observations that both the total extract of atmospheric suspended particulate matter and the PAH fraction cause hematogenic damage to the liver following subcutaneous injection, a finding which cannot be interpreted as metastatic carcinoma.

Air Pollutants↗
PubMed1982

Tissue connections in a transplantable virus-producing sebaceous adenoma of the mouse. II. A freeze-fracture study in conjunction with filipin.

The distribution, size, and configuration of intercellular junctions in the sebaceous tumor of mice were examined using the freeze-fracture technique. Three types of junctions were observed: desmosomes, gap, and tight junctions. Tight junctions in general consisted of short linear unbranched fibrils, and macular or complex tight junctional patterns were present only occasionally. Gap junctions ranged from small sports of 0.9 x 10(-3) micrometer2 to areas of approximately 0.46 micrometers2. Desmosomes were the most frequent junctional specializations, and it is concluded that they are at least partially responsible for this tumor not being metastatic. Filipin in conjunction with freeze-fracture showed filipin-sterol complexes on the plasma membrane, the nuclear envelope, and the membranes of the endoplasmic reticulum and mitochondria. The intercellular junctions were devoid of these complexes indicating that these regions are low in cholesterol.

Adenoma↗