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Biomedical subjects

H Fischer

Publications and source records attributed to H Fischer.

At least 433 records · Page 24Linked to original sources
PubMed1981

[Vitamin B12-level in serum of diabetics receiving long-term buformin therapy].

Disturbances of the vitamin B12 resorption by the therapy with biguanides above all metformin are known from literature. In 59 patients with Buformin retard-monotherapy we determined in 18.7% slight reductions of the vitamin B12 level in the serum, in one patient the serum concentration was lower than 50 pg/ml. That means that also under therapy with Buformin can be reckoned with easy disturbances of resorption for vitamin B12. Occasional controls of Hb and anamnestic establishment of neurological symptoms are to be recommended during a therapy with Buformin, in order not to overlook the clinical signs of a vitamin B12 hypovitaminosis.

Biguanides↗
PubMed1981

Measurement of chemiluminescence in freshly drawn human blood. I. Role of granulocytes, platelets, and plasma factors in zymosan-induced chemiluminescence.

The present investigations were undertaken to find out whether chemiluminescence measurements of stimulated granulocytes can be carried out in freshly drawn blood and -- because of the ease of the method -- be introduced into routine diagnostics. Blood was drawn from the cubital vein of healthy volunteers at various times and under various conditions. Subsequently the zymosan induced and luminol amplified chemiluminescence was recorded and analyzed. It could be demonstrated that variations existed between individuals which can, however, be minimized when photon counts obtained under standard conditions were related to the number of granulocytes present in the blood samples. It could be further demonstrated that also platelets are activated by zymosan as well an that they, contribute to the total chemiluminescence by a share of about 5%. Platelet chemiluminescence can effectively be suppressed by aspirin. Opsonising factors in plasma (presumably antibodies and/or complement) play a decisive role in the intensity and kinetics of blood chemiluminescence. Measurements of zymosan induced chemiluminescence in freshly drawn unfractionated and fractionated blood seem to be especially suited to monitor and analyze deviations and defects of the cellular and humoral defence mechanisms.

Aspirin↗
PubMed1981

Activation of bone marrow-derived macrophages by repeated zymosan phagocytosis leads to enhanced prostaglandin synthesis.

Bone marrow-derived macrophages were stimulated by the addition of zymosan. Phagocytic activity and prostaglandin release were taken as a measure of the activation state of the macrophages. Repeated stimulation with zymosan of macrophages which had been freed from extracellular zymosan led to further phagocytosis and prostaglandin formation. Very low amounts of prostaglandins were synthesized after the second phagocytic stimulus if the time interval between the first and second stimulation was one or two hours. In contrast, however, if the second phagocytic stimulation occurred 9 hours after the first stimulation there was a doubling of the number of phagocytosed zymosan particles and a fifteen fold increase in prostaglandin synthesis. These findings are explained as the consequences of internalized membrane material which provides additional substrates for the generation of prostaglandins.

Animals↗
PubMed1981

Episomal simian virus 40 genomes in human brain tumors.

Eight out of 35 human intracranial tumors were shown by restriction enzyme analysis to contain unintegrated simian virus 40 (SV40) DNA molecules. The relative amount of viral DNA was estimated to be the equivalent of one viral genome within every 10th to 20th cell. No infectious virus was detected in tissue cultures established from the tumors. From only one tumor was it possible to rescue, by cell fusion, infectious SV40 displaying wild-type properties. In those cases that permitted a more detailed analysis, the restriction enzyme cleavage patterns appeared to correspond to the wild-type patterns with one exception, in which the SV40 episomes displayed a deletion of approximately 70 base pairs close to the origin of DNA replication. From one tumor, the SV40 genomes were transferred into permissive CV-1 monkey cells by transfection with the total tumor DNA. Despite their persistence as episomes no infectious virus was produced. Furthermore, no viral antigens were detectable, although the SV40 messengers for the small and the large tumor antigens were present. These cells had, however, acquired the ability to form colonies in low concentrations of serum. Thus this report provides, by restriction enzyme analysis, direct evidence for the presence of SV40 DNA in human tumors.

Base Sequence↗
PubMed1981

Autologous antibodies to meningioma cell surface antigens.

Sera of 32 patients with meningioma were tested for reactivity to cell surface antigens of autologous meningioma cells with protein-A assay (PA), immune adherence assay (IA), and anti-C 3-mixed hemadsorption assay (C3-MHA). Antibodies against autologous meningioma could be detected in 6/32 patients by PA, in about half the patients by IA and in almost all patients by C3-MHA with titers ranging from 1:2 to 1:28. Only the serum reactivity detected by C3-MHA was high enough for analysis of the specificity of the reaction by absorption tests. By absorption with a panel of autologous, allogeneic and heterologous cells we were unable to demonstrate a meningioma-specific antigen. Most autologous sera detected oncofetal antigens. Serum reactivity to autologous meningioma showed no correlation to antibodies to SV-40.

Antibodies, Neoplasm↗
PubMed1981

[Semiquantitative determination of destruction dynamics at the joints of hands and feet in rheumatoid arthritis-two roentgenological methods controlling the course of the disease as part of treatment studies (author's transl)].

The article discusses briefly the problem of classifying the degree of severity in rheumatoid arthritis. The selection of the X-ray film criteria which are best representative of the destruction dynamics, is explained. Two measurement methods are described which can be used to visualise and to measure the dynamics of the destructive processes. The destruction dynamics can be visualised graphically in a co-ordinate system or as a quotient series via calculatory or planimetric evaluation - at a later stage, this can be done photometrically. It is stated that both methods, namely, the one using the standardised evaluation foil and the one utilising the special transparent foil, can yield information on the extent and progress of joint destructions.

Arthritis, Rheumatoid↗
PubMed1981

Circadian fluctuations in the activity of phagocytic cells in blood, spleen, and peritoneal cavity of mice as measured by zymosan-induced chemiluminescence.

Circadian variations in the phagocytic activity of mouse whole blood, spleen, and peritoneal cells were studied using the zymosan-induced chemiluminescence assay as a measure of phagocytosis. On a regimen providing for light from 7:00 to 19:00 alternating with darkness, the phagocytic activity of mouse blood, spleen, and peritoneal cells was high around 10:00 and low around 22:00, the integrated counts of chemiluminescence being 82.33 x 10(5) and 52.76 x 10(5) for peritoneal cells, 83.3 x 10(5) and 32.2 x 10(5) for spleen cells, and 12.33 x 10(5) and 3.99 x 10(5) for blood cells. Variations of a similar tendency were also found in blood leukocyte and granulocyte counts, the counts being again higher at 10:00 compared with the blood samples withdrawn at 22:00. In contrast to the differences in the intensity of the zymosan-induced chemiluminescence, the shapes of the curves (Fig. 6) of each cell preparation were similar, irrespective of the time period of the day the cells were prepared. Comparison of the zymosan-induced chemiluminescence curves of the 3 cell suspensions studied, prepared at the same period of the day, revealed some similarity between the kinetics of blood and spleen samples; the intensity, however, of zymosan-induced chemiluminescence emitted by spleen cells was much higher. The kinetics of zymosan-induced chemiluminescence curves of peritoneal cells differed from the other 2, being slower at the onset, the chemiluminescence lasting for a longer time and declining more slowly. We have shown here circadian variations in the activity of mouse phagocytic cells. The simple and rapid method of chemiluminescence measurements used in this study appears to be a powerful tool for the further investigation of such circadian variations.

Animals↗
PubMed1980

[Influenza A virus infection, a precipitating factor for the major heart attack (author's transl)].

A report on 5 men aged from 53 to 75 years whose clinical symptoms were characterized by a major attack. There was a striking temporal relationship between the onset of this and an influenza infection which, in these 5 patients with chronic heart diseases led to a severe, and in the youngest patient, even to a fatal course. In an acute heart attack it seems rational to take into consideration an acute influenza virus infection as a precipitating factor in existing chronic heart disease and to institute virological studies.

Aged↗
PubMed1980

Bacteriophage T7 DNA replication in vitro. Stimulation of DNA synthesis by T7 RNA polymerase.

Four T7 products, DNA polymerase, gene 4 protein, RNA polymerase, and DNA binding protein, have been purified from phage-infected cells. It has been previously shown (Hinkle, D. C., and Richardson, C. C. (1975) J. Biol. Chem. 250, 5523-5529; Kolodner, R., and Richardson, C. C. (1978) J. Biol. Chem. 253, 574-584) that two T7 products, DNA polymerase and gene 4 protein, catalyze extensive synthesis on duplex T7 DNA containing single strand breaks. However, the T7 DNA polymerase purified by our procedure does not efficiently contribute in this reaction, although the preliminary evidence suggests that this enzyme may be the native form of the DNA polymerase. Such inefficient T7 DNA synthesis is greatly augmented by adding the third T7 product, namely T7 RNA polymerase. This DNA synthesis apparently requires transcription, since each of the four rNTPs must be present. The rate of synthesis is increased about 2-fold by the addition of T7 DNA binding protein. In contrast to the results obtained when DNA synthesis is initiated at single strand breaks in a duplex DNA molecule, essentially none of the DNA synthesized in the presence of T7 RNA polymerase is covalently attached to the T7 DNA template. We postulate that in this in vitro system, T7 DNA replication is initiated using an RNA primer synthesized by the T7 RNA polymerase.

Centrifugation, Density Gradient↗
PubMed1980

Bacteriophage T7 DNA replication in vitro. Electron micrographic analysis of T7 DNA synthesized with purified proteins.

Extensive replication of duplex T7 DNA is catalyzed in reactions contining T7 DNA polymerase, T7 gene 4 protein, and T7 RNA polymerase. When the product of this reaction is analyzed in the electron microscope, many eye form and Y form replication intermediates are observed. Replication in vitro is not initiated at a single region of the T7 genome. However, we tentatively conclude that initiation does occur preferentially at a few specific sites along the DNA, and that these sites may be near promoters at which the T7 RNA polymerase initiates transcription.

DNA Replication↗
PubMed1980

[Anemia in rheumatoid arthritis].

The anaemia in rheumatoid arthritis is apparently of complex origin, in which case an increased accumulation of iron in the RES and the decreased utilisation of storage iron play the quantitatively most important role. According to literary data megaloblastic anaemias shall not appear frequently in rheumatoid arthritis. The frequency of the anaemia is rheumatoid arthritis is clearly depending on the composition of the collective of patients. In our patients anaemia and hypoferraemia do not correlate with the actual activity of the disease, however with the extension of the affection of the joints and the progressing of the basic disease. Anaemia and hypoferraemia may, therefore, be valuated as prognostically unfavourable signs. We could prove decreased vitamin B12-levels in 11.6%. There was no statistically significant relation to the course of the disease. An inhibition of the resportion of vitamin B12 by means of a long-term therapy is discussed.

Anemia↗
PubMed1980

Effects of angiotensin II and of an angiotensin II receptor antagonist on simian virus 40-induced tumor growth in vivo.

The effects of angiotensin II and of the competitive angiotensin II receptor antagonist saralasin on in vivo tumor growth were investigated in hamsters. Angiotensin II strongly inhibited tumor growth while saralasin stimulated it, though the high dose used had partial agonistic angiotensin II-like actions. Lower doses of saralasin were without significant effect on tumor weights.

Angiotensin II↗
PubMed1980

[The effect of bezafibrate on biliary lipids (author's transl)].

The effect of bezafibrate (3 x 200 mg/day) on biliary lipids was studied in 12 healthy male subjects and in 13 patients with hyperlipidemias. In normal subjects, the lithogenic index, with bezafibrate and placebo administered in a double blind cross-over design, was 1.1 and 0.77 respectively. The difference was not significant. In patients, who have been treated with bezafibrate for 6 months to 3 years the index was 0.76, and 0.64 six weeks after discontinuation of the drug. This difference, too, was not significant. It appears, therefore, that contrary to findings with clofibrate, bezafibrate may not be associated with an increased risk of cholelithiasis. This question, however, can ultimately be answered with certainty only on the basis of long-time epidemiologic evidence.

Adult↗
PubMed1980

Chemiluminescence and immune cell activation. II. Enhancement of concanavalin A-induced chemiluminescence following in vitro preincubation of rat thymocytes; dependency on macrophage-lymphocyte interaction.

The immediate chemiluminescence (CL) response to concanavalin A (Con A) of rat thymocytes is enhanced 10 to 20-fold when the cells are preincubated in serum-free medium for 5--20 h. During this period, multiple encounters between lymphocytes and macrophages occur which morphologically appear as rosettes or grape-like cell aggregates. Additionof bone marrow-derived macrophages increases the number of cell aggregates and also the CTL response to Con A. Paradoxically, removal of macrophage-containing cell aggregates after cocultivation leaves a pure thymocyte population which strongly responds to Con A with CL. Our results confirm that macrophage-depleted "competent" lymphocytes are capable of CL and, furthermore, that "competence" is gained during cocultivation with macrophages. We are therefore convinced that measurements of macrophage and lymphocyte CL are a powerful tool for further elucidation of lymphocyte differentiation and of interactions between macrophages and lymphocytes.

Animals↗
PubMed1980

Does PGE1 induce modifications at the membrane level of bone marrow macrophages? A fluorescence study.

The effect of prostaglandin E1 (PGE1), and F2 alpha (PGF2 alpha) on the surface membrane configuration of bone marrow macrophages was studied. We measured the fluorescence intensity of membrane bound ANS in prostaglandin pretreated cells. The effect on fluorescence intensity of a blocker of the prostaglandin binding site (SC19220) and inhibitors of prostaglandin synthesis (aspirin, indomethacin, diclophenate, Eicosa 5,8,11,14 tetraynoic acid) also were studied. Enhancement of the fluorescence intensity of bound ANS in cells pretreated with PGE1 indicates a conformational change localized at the membrane surface. That those changes are confined to the cell surface was shown by the failure of PGE1 or PGF2 alpha to alter the fluorescence polarization of bound DPH used as indicator of membrane core viscosity. Our data indicate that PGE1 could act at the surface of the membrane and that its action causes rapid structural perturbation at strategic points in the molecular organization of the membrane of bone marrow macrophages.

Anilino Naphthalenesulfonates↗