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Biomedical subjects

J Franke

Publications and source records attributed to J Franke.

At least 163 records · Page 9Linked to original sources
PubMed1981

The extracellular cyclic nucleotide phosphodiesterase of Dictyostelium discoideum. Purification and characterization.

Two forms of the extracellular cyclic nucleotide phosphodiesterase (EC 3.1.4.17) of Dictyostelium discoideum have been purified. One species has a molecular weight of about 55,000 measured by gel filtration and has been purified to apparent homogeneity. This monomeric form of the enzyme can be resolved by isoelectrofocusing into 4 bands with isoelectric points between 7.5 and 9. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two bands with molecular weights of 50,000 and 48,000. The second form of the enzyme has been partially purified and has a higher molecular weight (150,000-200,000) and an isoelectric point of about 5. The high molecular weight form of the enzyme is converted to the low molecular weight monomer by isoelectrofocusing in the presence of 6 M urea. Under these conditions the isoelectric point is shifted to that of the monomeric form of the enzyme. The two species are immunologically indistinguishable after urea treatment, and react identically with the cyclic nucleotide phosphodiesterase inhibitor (see the accompanying paper: Franke, J., and Kessin, R. H. (1981) J. Biol. Chem. 256, 7628-7637). The two forms have the same Km and show equal sensitivity to a number of ions, chelators, and low molecular weight cyclic nucleotide phosphodiesterase inhibitors. Tryptic maps of the purified monomeric enzyme and the urea dissociated high molecular weight form revealed no differences.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1981

The cyclic nucleotide phosphodiesterase inhibitory protein of Dictyostelium discoideum. Purification and characterization.

We have purified the glycoprotein inhibitor of the extracellular cyclic nucleotide phosphodiesterase of Dictyostelium discoideum to apparent homogeneity. The inhibitor has a molecular weight of 47,000 measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The interaction of the inhibitor and the cyclic nucleotide phosphodiesterase occurs with 1:1 stoichiometry and with a dissociation constant of about 10(-10) M. Periodate oxidation of the inhibitor or of the enzyme destroys concanavalin A binding ability but does not affect the formation of the enzyme-inhibitor complex. Inhibitor is not produced by cells during logarithmic growth but appears in quantity during stationary phase and after transfer from growth medium to phosphate buffer.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1981

[The diagnostic value of the alveolar lamina dura in generalised bone disease (author's transl)].

Changes in the alveolar lamina dura in 134 patients have been analysed. They included 32 cases with urolithiasis in whom generalised bone disease had been excluded, 37 cases of primary hyperparathyroidism, 31 cases of secondary hyperparathyroidism and 34 with primary osteoporosis. The state of the lamina dura was related to biochemical, radiological and histological findings in the various groups. The value of the lamina dura in the diagnosis of generalised skeletal abnormalities has been defined.

Adolescent↗
PubMed1980

[Bone mineral content determination by the photon absorption technic in chronic non-occupational fluoride exposure].

Bone mineral content and bone width of radius were examined by use of bone mineral analyser in persons with long-term nonoccupational fluoride exposition. Investigations took place in 275 female and 194 male without professional fluoride influence. Comparison with normal values showed no significant differences after fluoride exposition. The meaning of these findings is discussed.

Adolescent↗
PubMed1980

[Animal experiments for intra-arterial chemotherapy with bleomycin (author's transl)].

Intra-arterial chemotherapy for treatment of head and neck carcinomas is performed on the basis of clinical reports, which postulate higher effective concentrations at the tumor for this therapeutic method than after systemic administration. This assumption, which has so far not yet been confirmed experimentally, has led to the present study. The study is concerned with different modes of application of bleomycin with the aim to achieve high cytostatic concentrations at the site of action required. In sheep the tissue concentration of 57Co-bleomycin was determined in a hypothetical tumor area, the planum buccale, and in the lymph nodes draining this area, after submucous administration (hypothetical tumor area), intra-arterial administration (A. transversa faciei, A. temporalis superficialis, A. carotis externa) and i.v. administration (V. saphena). Only submucous injection led to significantly increased 57Co-bleomycin activities in the hypothetical tumor area and in the corresponding primary draining lymph nodes. The intra-arterial administration into the A. temporalis superficialis and A. carotis externa did not show any differences compared to the i.v. injection of 57Co-bleomycin. Compared to i.v. administration, injection into the isolated A. transversa faciei led to a slightly increased concentration of radioactively labeled bleomycin, restricted to the hypothetical tumor area. The findings made by animals experiments print out that the clinical application of intra-arterial is not justified and favor intratumoral treatment of head and neck carcinomas with bleomycin.

Animals↗
PubMed1980

Reduction of acute pulmonary hypertension by prostacyclin.

Acute pulmonary hypertension was produced in anaesthetized dogs by inflating a balloon in a major branch of the pulmonary artery. Intravenous infusion of prostacyclin lead to a dose-related decrease in pulmonary arterial pressure. Heart rate and cardiac output did not change significantly. There was a concomitant, but more variable decrease in the systemic arterial pressure. Respiratory rate increased significantly. It is concluded that prostacyclin may offer a therapeutic potential in diseases accompanied by pulmonary hypertension, when it is not associated with significant arterial hypotension.

Animals↗
PubMed1980

[Operative treatment of lateral hyperpressure syndrome of the patella].

The lateral hyperpressure syndrome of the patella according to Ficat is characterized as a main cause of chondropathia patellae. Symptoms and course as well as roentgenology of this syndrome are illustrated. The logical method of treatment of this syndrome is the lateral release-operation according to Viernstein and Weigert. With this operation we gained good and very good results in 77 per cent of the 30 operated knee-joints.

Adolescent↗
PubMed1980

[Evaluation of the mineral content of peripheral bones (radius) by photon-absorption technique in normals as well as in patients with various types of bone diseases (author's transl)].

The evaluation of the mineral content of peripheral bones by measuring the photon absorption of the radius has proven to be a valuable method for routine clinical work: for diagnosis, follow-up and control of therapy. While there was a significant difference in the findings of normal persons compared with those of patients suffering from osteoporosis, renal osteodystrophy, osteogenesis imperfecta and skeletal fluorosis, there was no difference between normals and these patients suffering from Bechterew, Scheuermann, coxarthrosis, spondylosis, skoliosis and rheumatoid arthritis. Normal values for the mineral content and width or the radius at the junction of the middle and lower third--based on 8000 examinations--are mentioned.

Adolescent↗
PubMed1979

[Bone changes in hemoblastoses and malignant lymphomas].

In haematological systemic diseases such as acute and chronic leukoses, malignant lymphomas, lymphogranulomatoses, osteomyelofibroses, polycythaemias and aplastic anaemias with a different proportion changes of the bones in form of osteoporoses, osteolytic processes and deformations of the vertebral bodies are to be found. The proof may be performed radiologically and histologically. In 461 patients with different haematological diseases absorption measurings of monoenergetic rays of a J-125-source were performed at the distal third of radius and ulna. It was shown that the bone mineral content of patients with proved bone destructions did not significantly differ from the normal group. The too peripherally located place of the measuring and also the late inclusion of the compacta into the changes is regarded as cause for the negative result.

Bone Diseases↗
PubMed1979

Binding of inhibitor alters kinetic and physical properties of extracellular cyclic AMP phosphodiesterase from Dictyostelium discoideum.

The extracellular adenosine 3',5'-cyclic monophosphate phosphodiesterase (3',5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17) produced by Dictyostelium discoideum has two kinetic forms. The free enzyme has a Km of approximately 10 microM. The second form is the result of a complex formed with a heat-stable inhibitor and has a Km in the millimolar range. Treating the enzyme-inhibitor complex with dithiothreitol stimulated enzyme activity 20- to 100-fold and changed in Km from millimolar to micromolar. Dithiothreitol inactivated the inhibitor. Reconstituting purified enzyme with excess inhibitor returned the Km to the millimolar range. Under conditions known to inhibit the production of extracellular inhibitor or in mutants that lack it, extracellular phosphodiesterase activity was already high and could not be increased by dithiothreitol. The phosphodiesterase and inhibitor sedimented at 6 S and 3 S, respectively; the enzyme-inhibitor complex sedimented at 6.7 S.

3',5'-Cyclic-AMP Phosphodiesterases↗