PubMed Health⌕ Search

Biomedical subjects

T Herrmann

Publications and source records attributed to T Herrmann.

At least 163 records · Page 9Linked to original sources
PubMed1986

[Computerized tomography studies in the assessment of radiogenic pneumopathy in an animal experiment].

An animal experimental study was conducted in 56 piglets exposed to radiation to establish new assessment criteria on radiogenic pneumopathy by employing computed tomography for diagnosis. The accurately measurable density changes in the lung parenchyma exposed to radiation appear invariably as soon as a dose-dependent threshold value is exceeded. Tolerance limits can be determined for 60Co and neutron irradiation in different fractions and single doses, the enhancement of lung density being correlated with the irradiation dose. It is not possible to establish a volume-dependent decrease in the tolerance dose. Likewise, there is no radiation-promoted co-reaction of adjacent pulmonary tissue not subjected to irradiation exposure. These results apply to the experimental animals used in the study.

Animals↗
PubMed1986

[Dose-time correlation in the irradiation of the lung of piglets for evaluating a model of human radiogenic pneumopathy].

Dose-time relationships with respect to a pulmonary radiogenic reaction were studied in 62 improved-breed pigs aged 3 mos. with the mass of 20-30 kg. The animals received fractionated irradiation with 60Co. Irradiation and its doses were computed in a way similar to that used in clinical practice. Clinical evidence, respiration rate, chest x-ray, histological and biochemical investigations of pulmonary tissue served as quantitative criteria of pulmonary lesion. ED50 was determined, i.e. a dose at which 50% of the experimental animals fell ill. The number of fractions produced a greater effect on an isoeffect curve than the entire period of irradiation. The pulmonary radiogenic reaction in pigs could be expressed by the calculation D approximately N0,32 T0,05. A possibility to introduce the results of the experiments on pigs into clinical practice allows practical use of the dose-time relationships obtained in the experimental studies.

Animals↗
PubMed1985

[Investigation of biliodigestive anastomosis with the help of radiopharmaceutical products].

Hepatobiliary investigation using 99mTc-diethyl-iminodiacetic acid (IDA) has permitted a new point of view about the morphological and functional investigation of the biliary-digestive anastomosis. Our clinical study concerning 31 patients (13 choledochoduodenostomies 10 hepaticojejunostomies, 6 choledochojejunostomies and 2 cholecystojejunostomies) helped to specify scintigraphic imaging (stasis in intrahepatic bile duct, reflux in stomach, strangulation phenomenon on the level of the mesocolon, incomplete or complete obstruction). The problems associated with current diagnostic procedures are discussed and we place the scintigraphic method amongst other radiologic methods (barium meal, endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography). This non-invasive diagonostic procedure plays a leading part in the investigation of the biliary digestive anastomosis, and particularly in the hepatico-jejunostomies.

Bile Ducts↗
PubMed1985

Spatial problem solving in a dual runway task by normal and septal rats.

The addition of a dual runway configuration did not disrupt the successful performance of normal animals, nor did it improve the deficit of septal rats on the Maier three-table spatial integration task. Both groups of animals displayed a preference for the outside runway configuration during exploration. During testing, however, septal animals retained this preference, whereas normal subjects attempted solution by using the inside runway configuration. This fact, in addition to the apparent lack of a habituation pattern during exploration, suggests that septal animals do not acquire a spatial representation of the test situation. It is suggested that the inability of septal rats in spatial situations is due to an inability to form rather than an inability to use spatial maps.

Animals↗
PubMed1985

Production of Listeria-specific rat T-cell clones and role of interleukin-2 receptors in regulation of Listeria-dependent T-cell clone growth in vitro.

Splenic T lymphocytes from rats immunized with the facultative intracellular bacterium Listeria monocytogenes were cloned by the limiting-dilution technique in the presence of accessory cells, heat-killed L. monocytogenes as antigen, and conditioned medium containing interleukin-2. The cloned rat T-cells were Listeria-specific cells, and their proliferation depended on class II-restricted antigen presentation by accessory cells. As demonstrated by their reactivity to the monoclonal antibody W3/25, the clones were of helper cell phenotype. Cloned-cell proliferation depended on repeated (or continuous) exposure to antigen. When antigen was omitted from the system, cell growth subsided over time, and cells finally ceased to grow. By the use of the monoclonal antibody ART-18, which recognizes the interleukin-2 receptor, it was shown that cessation of growth was accompanied by the disappearance of interleukin-2 receptors from the cell surface. The addition of antigen to the culture resulted in the reexpression of interleukin-2 receptors and concomitant resumption of proliferation.

Animals↗
PubMed1985

Inhibition of IL 2-dependent proliferation of rat T lymphoblasts by the monoclonal antibody ART62 which reacts with MHC class 1 antigens.

During the course of studies designed to obtain monoclonal antibodies (mAb) that recognize the rat interleukin 2 receptor, a mouse IgG1 mAb (ART62) was identified which inhibits the interleukin 2 (IL 2)-dependent proliferation of rat T lymphoblasts without affecting the binding of IL 2 to such cells. In order to characterize the cell surface components that react with the mAb ART62, T lymphoblasts were surface-labeled with 125I, and the radioactive molecules were immunoprecipitated by the antibody analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The mAb ART62 precipitated two major components of 48,000 m.w. and 12,000 m.w., respectively, which were different from those which react with the anti-IL 2-receptor antibody ART18, a molecule of 50,000 to 55,000 m.w. Sequential immunoprecipitation studies revealed that the mAb ART62 reacts with the MHC class 1 antigen that reacts with the classical anti-rat MHC class 1 mAb OX18, and vice versa. In contrast to the mAb ART62, OX18 that does not affect and several other mAbs known to inhibit the rat MLR failed to inhibit IL 2-dependent proliferation of rat T lymphoblasts. In contrast to the anti-IL 2 receptor antibody ART18, ART62 effectively inhibited IL 2-driven proliferation even when added to cells already committed to proliferate by IL 2-IL 2 receptor interaction. These data raise the possibility that MHC class 1 antigens could be involved in the chain of reactions mediating the signals required for cell proliferation.

Animals↗
PubMed1985

[Findings in piglets after combined application of hyperthermia and irradiation].

In a pilot study, 8 shoats of the "Edelschwein" breed were submitted to a combined treatment with hyperthermia (5 X 60 min; 42 degrees C in the thoracic region) followed by irradiation of the right lung (5 X 4 Gy). Heating was performed using an applicator of the Selectotherm equipment working at 27 MHz with a power output of 1.5 to 8.0 kW; the irradiation was done with the telecobalt machine Chisobalt. Radiologic checks of the thoracic organs and laboratory diagnostics provided useful data as to the temporal course of the radiogenic pulmonary affections and the tolerability of fractionated whole-body hyperthermia including superimposed local heating on shoats. Histologic examinations of sections of heated and irradiated (right) as compared to exclusively heated (left) lung lobes of 4 animals suggested that hyperthermia exerted a radiosensitizing effect on the right lungs. Histologically confirmed irreversible lung fibrosis occurred there after exposure to even lower total doses following hyperthermia as compared to sole irradiation.

Animals↗