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Biomedical subjects

P Fritz

Publications and source records attributed to P Fritz.

At least 145 records · Page 8Linked to original sources
PubMed1987

Perspectives of radiotherapy.

The 5 years' survival rate of all cancer patients is 35-45%. In that survival rate radiotherapy takes part in 15%. By further development of radiological methods and techniques radiotherapy gains significance in the recent time. Optimizing radiation planning and tactics, all modern imaging techniques are applied consequently. The radiotherapist must be able to asses their immanent specifity which should remain object of the radiological training, even if separated into therapy and diagnostics. Dose distribution is calculated by computer; three-dimensional planning is done in tumors of the mediastinum, oesophagus carcinoma and paraaortic lymphomas. Critical description of radiation techniques, results, problems and prognoses are given by results in tumors of the epipharynx and gastric cancer. After-loading, done until now only in gynaecological tumors, is performed in recurrences of pharyngeal tumors by individually shaped applicators. Reducing the number of therapy failures as well as possible, the application of higher tumor doses, new kinds of rays as neutrons and combinations with physical and chemical methods is outlined. Modifications of radiation volumes are discussed, especially the irradiation of the complete abdomen in ovarian cancer, the irradiation of the complete body surface by electrons in mycosis fungoides, and the total body irradiation prior to autologue bone marrow transplantation. Modifications of fractionation are shown in short-time radiation of bone metastases and single-time radiation of brain lesions. Low penetrating electron therapy facilitates intraoperative single-time irradiation. Because of higher biological efficiency neutrons and heavy ions allow to irradiate low sensible tumors or recurrences embedded in fibrotic tissue respectively. The combination with hyperthermia yields good results in tumors of the head and neck with better local response and total remissions of 59%. There are potentials in synchronising with chemotherapeutics. Remissions of different duration were achieved in 190 patients. Because of neutrotoxicity there are still problems in applicating radiosensitizers. New methods are applied treating endocrine active tumors by labelled hormone precursers.

Brachytherapy↗
PubMed1987

Immunophotometric analysis of immunoglobulin synthesis and deposition in synovial membranes of patients with rheumatoid arthritis.

Immunophotometrical measurements of the Ig synthesis of plasma cells in joint capsules of patients with rheumatoid arthritis and osteoarthritis were compared. Patients with rheumatoid arthritis showed higher mean values in the single plasma cell than patients with osteoarthritis for all Ig isotypes except IgG. These results are indicative for a B cell activation with increased synthesis of Ig in RA.

Arthritis, Rheumatoid↗
PubMed1986

Colour development of immunogold-labelled antibodies for light microscopy.

We describe an improvement of the immunogold technique, which is based on the colour development of silver-intensified immunogold signals. This method (referred to as the coloured-SIG technique) was found to be as sensitive as the silver-intensified immunogold method and more sensitive (in two of the three tested systems) than immunoenzymatic procedures, such as the peroxidase/antiperoxidase technique or the avidin-biotin system. The coloured SIG-method results in either a magenta-red or a cyan-blue final reaction product. Therefore, this new improvement of the immunogold technique should be useful in double-staining methods, immunoblot methods and conventional immunostaining methods.

Antibodies↗
PubMed1986

Iodine-131-labeled diphosphonates for the palliative treatment of bone metastases--III. Considerations of interaction, binding and absorbed dose.

General considerations about the possible mechanisms of action of rather low dose ionizing radiation with bone metastases and stimulated nerve fibers reveal that only minute amounts of chemicals are produced by direct interaction of energetic electrons. Thus changes of the chemical milieu due to direct interaction must be ruled out in favour of a radiation-induced trigger reaction which may then initiate a cascade of cellular responses. Organ distribution studies of a series of radioiodinated benzylidenediphosphonates with H-, HO- and H2N- in the alpha- and p-position revealed best results for pHO-NH2 (BDP3). The microscopic distribution of 131I-DBP3 in bone tissue was monitored by autoradiography. Elevated uptake in normal (tibia) and neoplastic bone (experimental osteosarcoma) corresponded with the degree of vascularization and formation of new hydroxylapatite. Unlike the uptake in human osteoblastic bone metastases the experimental osteosarcoma of SD-rats accumulated 131I-BDP3 less than normal bone. This was due to the short volume doubling time, the delay of hydroxyl-apatite deposition and the formation of necroses. Theoretical replacement of 131I in iodinated BDP3 with radioisotopes emitting higher energy electrons yielded best bone metastasis/organ ratios for 32P labeled BDP3. The bone metastasis/bone marrow dose ratio by comparison with 131I labeled BDP3 is, however, almost equal. The isotopes 130I and 133I are not suited to the achievement of higher tumor/background doses although they are higher energy beta- -emitters than 131I. Because of their short physical half life and absence of different kinetics in normal and neoplastic bone no dose enhancement in bone metastases can be attained.

Animals↗
PubMed1986

In situ evaluation of immunoglobulin synthesis of synovial plasma cells in rheumatoid arthritis and osteoarthritis by plug photometry.

Synovial membranes of patients with osteoarthritis--a disease with unaltered immunoregulation--and rheumatoid arthritis were immunostained for the different immunoglobulin isotypes using the PAP-method and a two-layer alkaline phosphatase technique. Randomly selected plasma cells with positive immunostaining were measured by plug photometry. The average extinction of the single plasma cell is considered to be indicative of the immunoglobulin synthesis of the measured plasma cell and the isotype under study. When we compared both disease entities, patients with rheumatoid arthritis were characterized (i) by higher average extinction values for all Ig-isotypes except IgG (ii) by a higher rate of high producer plasma cells. From this data, we conclude that immunophotometry is a new in vivo method for discriminating two types of synovitis (i) one without increased Ig-synthesis at the single cell level and (ii) a second one with increased Ig-synthesis.

Antibody-Producing Cells↗
PubMed1986

[Bone marrow scintigraphy using radiocolloids in bone metastases. Sensitivity, specificity, reliability and indications].

The sensitivity and specificity of bone marrow scintigraphy in demonstrating skeletal metastases was examined in 40 patients with focal metastases. Radiology and MDP scintigraphy were used as reference methods. Sensitivity depends on the region of the skeleton. False negatives are the rule in parts of the skeleton containing little bone marrow. In relation to the entire bone marrow content, sensitivity is 0.64. The high proportion of false negatives (36%) in the presence of confirmed metastases and the incomplete demonstration of the bone marrow makes marrow scintigraphy unsuitable as a screening method. Occasionally lesions confined to the marrow can be demonstrated when radiographs and bone scintigrams are still negative. In advanced cases, marrow scintigraphy can demonstrate the extent of destruction of the bone marrow. Demonstration of displacement or of an 'empty bone' is evidence of invasion of the bone marrow in patients with tumours. In patients with reduced haematopoiesis of unknown origin or unidentified diffuse skeletal uptake, bone marrow scintigraphy may provide valuable information.

Adult↗
PubMed1986

[Nuclear magnetic resonance tomography in the diagnosis of parotid tumors. A comparison of methods].

The diagnostic value and the limitations of magnetic resonance imaging (MRI) in the management of large parotid masses were evaluated in a prospective clinical study. The results were compared with computed tomography (CT) and B-mode ultrasonography (US). MRI was performed using a Siemens 1.5 Tesla Magnetom with a RF head coil and surface RF coils. The images were evaluated by the following parameters of clinical importance: tumour detectability and marginal appearance, internal architecture, regional extension, and artifact degradation. MR imaging of parotid masses was superior to CT and US for the following reasons. The marginal appearance of the tumour was sharp and further enhanced in T2 weighted pictures. The extension of the tumour can be well seen by use of transaxial and frontal projections. This is an advantage especially when the mass extends to the retromandibular fossa or even to the pterygopalatine fossa. The position of the jaw, external ear canal, mastoid, skull base, and vessels of the neck are clearly shown without artifact degradation. Benign neoplasms can be well differentiated from malignant tumours which show local infiltration into the adjacent anatomical structures as well as irregularities of their internal structure. However, their appearance in MRI can be identical to that of an acute inflammation of the parotid gland. In summary MRI is the imaging technique of choice for extensive parotid masses, whereas US is effective for small tumours not situated in the retromandibular fossa.

Humans↗
PubMed1985

Distribution of albumin in normal and regenerating livers of mice. A light microscopic immunohistochemical and autoradiographic study.

The conditions affecting the immunohistochemical identification of albumin in livers of male NMRI-mice were investigated by light microscopy. In normal livers albumin is randomly distributed, revealing a pancytoplasmic nearly homogen reaction in groups of hepatocytes or single parenchymal cells. However, combined autoradiographic studies after pulse labelling with 3H-valine and perfusion experiments with human albumin indicate that this distribution is caused by albumin from blood plasma and does not reflect true protein synthesis. After perfusion of the livers followed by immunohistochemical amplification techniques which allowed to dilute the primary antibody up to 1:30,000, albumin could be detected nearly in all liver parenchymal cells as granular deposits decreasing in its density from periportal fields towards the terminal hepatic venules. In regenerating livers due to partial hepatectomy no remarkable differences in granular albumin deposits between G1- and S-phase of the cell cycle could be detected as was demonstrated by combined immunohistochemistry and 3H-dThd-autoradiography. However, during mitosis the content of albumin was often considerably reduced.

Albumins↗
PubMed1985

[Immunohistochemistry: theoretical potentials and practical application].

Immunhistochemical methods are increasingly used and their application in surgical pathology is obvious. Nine different immunohistochemical techniques are compared in this review article. The peroxidase anti-peroxidase method of Sternberger et al. (1970), the avidin biotin complex method of Hsu et al. (1981) and the labeled avidin biotin technique of Guesdon et al. (1979) are to be preferred. Two step methods using labeled antibodies such as alkaline phosphatase or peroxidase-labeled second antibodies are less sensitive. However, two-step methods using alkaline phosphatase-labeled antibodies offer the advantage of double staining procedures since alkaline phosphatase reacts with different azo dyes and results in a wide spectrum of colours in the final reaction product. At present, the major problems of immunohistochemistry in daily work are the selection of the fixative and of appropriate controls. Though both problems remain unresolved, immunohistochemical methods should be used for special problems in surgical pathology.

Alkaline Phosphatase↗
PubMed1985

[Contact therapy in the pharynx and oral cavity areas: after-loading technic, irradiation planning and results].

The contact irradiation in the region of pharynx and mouth with an afterloading unit is presented. Twelve patients with recurrent carcinomas of the squamous cell epithelium have been treated. A stable and reproducible positioning of the source probes in the tumor region is made possible by special applicator prostheses which are adapted to the post-operative situation. The irradiation scheme is based on the transformation of the source co-ordinates from the stereoradiographic localization system into the co-ordinate system of the computed tomogram. At least three fixed metal points which are inserted in the applicator prostheses and visualized by stereoradiography as well as by computed tomography serve as mutual reference points for both co-ordinate systems. The source positioning in the tumor region is optimized by CT irradiation planning. Three cases are presented in order to describe the principles of the method. Preliminary results are discussed.

Brachytherapy↗
PubMed1984

Effect of ASTA Z 7557 (INN mafosfamide) a precursor of 4-hydroxy-cyclophosphamide on human T-lymphocytes' Fc-receptors and immunoregulatory functions.

The precursor ASTA Z 7557 of the in vivo active metabolite 4-hydroxy-cyclophosphamide (4OH-Cy) of cyclophosphamide (Cy) was tested for selective effects on human T-lymphocytes' Fc gamma-receptor expression and certain immunoregulatory functions. It has been found that ASTA Z 7557 does not alter the expression of Fc gamma-F- or Fc gamma-I-receptors on the T-cell membrane nor does it exhibit differential toxicity for either T-cell subpopulation. PWM-induced B-cell proliferation is inhibited by ASTA Z 7557, whereas B-cells' Ig-synthesis as well as ConA-driven T-cell proliferation is only blocked with higher doses of the reagent. Final concentrations above 1 microgram/ml may therefore abrogate ConA-induction of suppressor T-lymphocytes. Already ConA-activated suppressor cells of PWM-driven B-cell cultures, however, are not inhibited even with high doses of ASTA Z 7557.

B-Lymphocytes↗
PubMed1984

Analysis of mast cells in rheumatoid arthritis and osteoarthritis by an avidin-peroxidase staining.

As demonstrated by labeling with peroxidase, avidin was found to bind selectively and distinctly to mast cell granules. Inhibition studies suggested that avidin is bound by heparin. Based on this new mast cell staining procedure, mast cell distribution in the inflamed synovium of rheumatoid arthritis (RA) and osteoarthritis (OA) has been investigated. In the subsynovial layer, a significant decrease in mast cell numbers was observed in RA-synovium when compared with OA-synovium. This decrease correlated with the presence of lining cell ulcers and granulation tissue and can be interpreted as the result of mast cell degranuation induced by complement-mediated or immune complex-triggered mechanisms.

Arthritis, Rheumatoid↗
PubMed1984

Investigations concerning the correlation between liver cell proliferation, production of alpha-fetoprotein, and DNA-synthesis of lymphocytes in the spleen of NMRI-mice. An autoradiographic and immunohistochemical study.

To obtain more information concerning the correlation between liver cell proliferation, production of alpha-Fetoprotein (AFP) and DNA-synthesis of lymphocytes in the central and peripheral parts of periarteriolar lymphatic sheaths ( PALS ) of the spleen, these parameters were monitored in intervals of 12h after CCl4-poisoning of NMRI-mice using autoradiographic and immunohistochemical methods. The results indicate that synthesis of AFP is not linked closely to proliferation of hepatocytes because in contrast to DNA-synthesis the production of AFP was only detectable in a very small subpopulation of liver parenchymal cells reaching a peak before the majority of hepatocytes was found to enter the S-phase of the cell cycle. Beyond this, in vivo no general suppressive effect of AFP on proliferation of lymphocytes in preferably T-dependent areas of the spleen could be detected since the 3H-TdR-labeling index in these compartments increased, reaching a peak 48h after the maximum of hepatocytes producing AFP had occurred.

Animals↗
PubMed1984

[Multiple Cancers].

According to the criteria of Warren and Gates the course of disease of 11972 patients--8099 of them carcinomas under treatment in the Universitäts-Strahlenklinik--were examined in respect to multiple malignomas. In 232 cases such multiple malignomas were diagnosed, corresponding to 2.86%. We found more women (3.49%) than men (2.13%). In 165 cases (67.2%) multiple malignomas appeared metachronically, i.e. after an interval of more than 2 years, 76 (32.8%) of those patients were synchronic multiple malignoma--carriers. In women we found with 3.49% significantly more often metachronic manifestations than in men (2.13%). According to synchronic multiple malignomas we stated that they are to be found in males and females in an equal amount. On the average the second malignoma appeared in males and females 10 years after diagnosis of the primary tumor. Localizations of the multiple malignomas as well as combinations of certain tumors are shown and discussed.

Adult↗