Search PubMed⌕ Search

Biomedical subjects

T Herrmann

Publications and source records attributed to T Herrmann.

At least 127 records · Page 7Linked to original sources
PubMed1990

[An occurrence of a neurogenic sarcoma in an irradiated field following the combined surgical-radiologic treatment of a childhood adenosarcoma of the kidney].

Malignant neoplasias in childhood generally are an increased risk for the patient to fall ill with a second tumor. Second tumors in former irradiation field are seldom, but are acknowledged radiogenically if histology is different to that of the first tumor and a sufficiently long period is between the two tumors. A patient is represented who had been operated and irradiated because of an adenosarcoma of the kidney at the age of seven and who has fallen ill with a neurogenic sarcoma in irradiation area more than 30 years later. The same patient had to suffer from radiogenic retardation during differentiation of lumbar apparatus of attitude and locomotion and on the other hand he became father of a healthy daughter at the age of 32.

Child↗
PubMed1990

[Radiogenic effects on liver tissue].

In a review of literature the presented studies on radiogenic liver injuries are summarized. Whereas in the past the liver tissue was supposed to be radioresistant nearly completely, to newer knowledge this organ has to be classed with most radiosensitive tissues at all. The early picture of a liver injury in man is characterized by the veno-occlusive syndrome. Like in Budd-Chiari-Syndrome a congestion begins in the central veins and the centrolobular sinusoids, that has severest threatening consequences for the patients with extensive liver irradiation. The clinic picture is demonstrated. At present no suitable animal model exists for this disease yet. The presented pathological and electron microscopical findings do not allow any final estimation of the pathogenesis in this disease. The radiogenic late-effects are manifested in the liver in a centrolobular fibrosis, also starting from the Glisson's triangles, with cirrhotic reconstruction of liver architecture. The great compensatory power of the organ does not cause clinical pictures to be effected in radiotherapeutic practice with only partial liver irradiation in most cases. The dose-time-relation of the radiogenic hepatitis shows a very little alpha-/beta-value. With this the liver renders as typical late-effect tissue and should be spared effectively by choice of small single doses.

Animals↗
PubMed1990

[The functional efficiency of cardiac pacemakers as affected by ionizing radiation].

Influence of functions of cardiac pace-makers by ionizing radiation are represented, that is characterized in praxis relevant parameters as pulse duration and sensitivity in a special clear manner. For these parameters dose limits were defined in a phantom where tolerance ranges of pace-makers, guaranteed by producer, were over or underdosed. These dose values were different in dependence of installed electronic wiring diagrams. The radioresistance of pace-makers with Lewicki-wiring diagram (MCP 211 L) was higher than those with wiring diagram U 115. Measurings showed that the upper dose limits were greater than the known values with 60Co- and 9-MV-roentgen braking radiation and with that the complete programming and functional capacity of the pace-makers were conserved. The close cooperation of radiologists, physicists, cardiologists and technicians in the implantation clinic guarantees a good care for patients with pace-makers during radiotherapy without complications.

Humans↗
PubMed1990

[The determination of the RBE of neutrons based on the hydroxyproline concentration in the lung tissue of irradiated piglets].

To test the radiogenic reaction of normal lung tissue experiments were done in 99 young pigs altogether. The radiation field included the total right lobe of the lung, 5 fractions of photons or neutrons (mean energy 6.2 MeV) were applied in a total treatment of 5 or 35 days. After killing the animals and taking the lungs the examination of tissue samples and others has been done for contents of hydroxyproline (HP) that has been used to register radiogenic injuries where the relation of irradiated and non-irradiated half of the same animal was estimated as measuring value. Above a limit of 1.13 for the HP-quotient (estimated in non-irradiated controls) there was a significant correlation with dose. Between the results of HP-quotients and histopathological findings a very good correlation was found. Calculation of RBE was done from relation of the dose values of photons and neutrons on base of the same level of injuries. In the tested total dose limit (photons: 14.25-38 Gy, neutrons 3.0-8.5 Gy) RBE-values of 3.8-4.5 were reached that correlates well with other tested criteria of the study in young pigs.

Animals↗
PubMed1990

Spatial behaviour of normal and septal rats on alternate route maze problems.

The behaviour of normal rats and rats with lesions of the septum was compared on a variety of alternate route variations of the three-table problems. In all variations of the task, septal rats were impaired on test trial performance when they displayed stereotypic body turn responses and demonstrated a strong preference for the most direct route between tables both during exploration and testing in all conditions. Normal rats displayed a similar route choice tendency in the simplest situations but shifted route choice behaviour in the most complex configuration, when they chose the inner, but longer, path. The use of the inner path may have allowed delayed-choice, single-point reference orientation, or reduction in the number of available alternatives. It is concluded that normal rats form a cognitive representation that allows them to identify environmental factors likely to facilitate solution, whereas septal rats rely on "taxon"-type strategies that can combine guidances and orientational responses.

Animals↗
PubMed1990

Application of a semi-phenomenological model to experimental data of radiation induced pneumopathy in pigs.

A semi-phenomenological model has been derived, which describes the inactivation effect on individual cells by survival curves. This model is applied to experimental data of pneumopathy in pigs. The corresponding survival curves as well as the relations between cell survival and complication probability are calculated and discussed. Furthermore, dose-response curves for single dose irradiation and different fractionation schemes are derived. The comparison between the response curve for single dose irradiation and similar curves from the literature shows a good agreement.

Animals↗
PubMed1989

The intermediate-affinity interleukin (IL)2 receptor expressed on Theileria annulata-infected cells comprises a single IL 2-binding protein. Partial characterization of bovine IL2 receptors.

Bovine high-, intermediate- and low-affinity interleukin 2 receptors (IL2R) were studied by ligand binding and affinity labeling using 125I-labeled IL2 and homobifunctional chemical cross-linking reagents. High- (Kd = 17 pM) and low-affinity (Kd greater than 6 nM) IL 2R were detected on concanavalin A-activated peripheral blood lymphocytes (PBL). Theileria annulata (TA)-infected autonomously growing PBL (TA-PBL) express predominantly intermediate-affinity IL2R (Kd = 1 nM). Affinity-labeling studies revealed that the high-affinity IL2R comprises a 55-kDa (L chain) and an additional 90-kDa IL 2-binding protein (H chain). TA-PBL express predominantly the H chain. In contrast to the human chain, the bovine form was not separable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/urea into the two distinct bands H1 and H2 and ran in parallel to the human H2 band. These results suggest (a) that the bovine intermediate-affinity IL2R comprises a single H chain and (b) that the single H chain and the L chain are sufficient to form the functional high-affinity bovine IL2R.

Affinity Labels↗
PubMed1989

Different staphylococcal enterotoxins bind preferentially to distinct major histocompatibility complex class II isotypes.

The stimulation of T cells by staphylococcal enterotoxins (SE) is strictly dependent on major histocompatibility complex (MHC) class II-bearing cells. The interaction between SE and MHC class II molecules was studied on the human B cell lymphoma Raji and its MHC class II-negative variant RJ 2.2.5. Affinity purification with SEA and SEB matrix allowed the isolation of HLA-DR-like molecules from detergent lysates of 125I surface-labeled Raji cells, but not from RJ 2.2.5 cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis also revealed preferences in the binding of other SE such as SED, SEE and toxic shock syndrome toxin 1 to DR-like molecules, SEC2 to HLA-DQ-like molecules and SEC3 to DR- and DQ-like molecules. Preadsorption of the different MHC class II MHC isotypes confirmed the preferential binding of SEA to DR and of SEC2 to DQ. The implications of these findings for the understanding of SE-induced T cell activation and the potency of SE as a tool in the study of MHC class II antigens are discussed.

Chromatography, Affinity↗
PubMed1989

[Radiation sequelae of the pancreas].

The pancreas has been considered a radioresistant organ for a long time. This classification originates in absence of clinical symptoms or in the vague position of the organ within the symptom-complex of radiogenic malabsorption after pancreas irradiation. Experiments with animals show considerable alterations after irradiation yet, especially in ultrastructural sphere. These disorders appear to be altered qualitatively after fractionated radioexposure: whereas in high single doses the parenchymatous part is affected more, in severe small single doses in area of small vessels with relatively early fibrotic alteration more severe alterations are described by different investigators. Alterations in parenchymatous structures of pancreas are capable of regression. Nevertheless it is not explained till now, why lasting pancreas-enzyme reduction can develop after a longer period. The great compensatory ability of pancreas results in merely non-essential enzyme alterations in serum as a rule in small-fractionated irradiation of upper abdomen. Unanimously all investigators find a small or no impairment of island cell apparatus after irradiation. Continuation of studies on radiogenic impairment of pancreas seems to be required earnestly, in particular in investigations of different fractionation rhythm too. However it renders more difficult by the problem to mark off clear endpoint-criteria.

Animals↗
PubMed1989

Demonstration of two distinct forms of released low affinity-type rat IL-2 receptors.

The release of IL-2 binding proteins, derived from the 55,000 MW low affinity IL-2R (L chain), has been observed for virtually all L chain-bearing cells in either humans, the mouse or the rat. Based on the characterization of the released human L chain as a molecule 10,000 MW smaller than the cell surface receptor, either proteolytic cleavage or differential splicing of the L chain encoding mRNA have been suggested as mechanisms underlying the receptor release. Combining affinity labelling of the L chain with [125I]IL-2 and immunoprecipitation with L chain-specific monoclonal antibody (mAb) applied for the detection of soluble rat IL-2R revealed the existence of two classes of soluble receptors, one being of the same size as cell surface-expressed L chain, the other of 40,000 apparent molecular mass. These findings raise the possibility of other mechanisms of receptor release than those discussed for human L chain.

Affinity Labels↗
PubMed1988

Determination of picogram amounts of lipoxin A4 and lipoxin B4 by high-performance liquid chromatography with electrochemical detection.

A new method for the determination of lipoxins with electrochemical detection after high-performance liquid chromatography is described. The half-wave potentials of lipoxin A4 and lipoxin B4 at a glassy carbon electrode and a mobile phase of methanol-water (65:35 v/v) and 1 mM trifluoroacetic acid was found to be +1.14 V versus an Ag/AgCl reference electrode. The use of trifluoroacetic acid instead of sulphuric acid and lithium perchlorate led to a background current of 6-8 nA at +1.20 V. The detection limits for both lipoxins, based on a signal-to-noise ratio of 3:1 were found to be 5-10 pg (15-30 fmol). The new method was applied to an extract of human polymorphonuclear granulocytes, preincubated with 15-hydroxyeicosatetraenoic acid and stimulated with Ca2+ ionophore A23187.

Chemical Phenomena↗
PubMed1988

[Primary extranodular non-Hodgkin's lymphomas--observations on etiopathogenesis, histology and prognosis].

The total non-Hodgkin's lymphoma-population treated between 1978 and 1986 by means of radiotherapy or combined chemo/radiotherapy was analysed as to primary extranodular manifestation. 39 cases, 16 women and 23 men, were observed (stage IE 12, stage IIE 22 and stage IIIE 5). Immunoblastic (10), lymphoblastic (9) and centroblastic (6) lymphomas are the most frequent with respect to histology. Gastroenteron (16) and otorhinolaryngological region (13) are in the lead with regard to localisation. 5-year-survival-rates are determined in dependence on clinical stage: IE 65.8%, IIE 39.2% (low, connected with the proportion of high-malignant histology) and IIIE 25.0%. The 5-year-survival-rate of primary gastrointestinal manifestation amounted to 51.5%. With respect to aetiopathogenesis of primary extranodular lymphomas gut-, mucosa- and bronchial-associated lymphoid tissue, aberrant lymph-nodes and the influence of viral- and immunologic factors seem to be important.

Adult↗