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Biomedical subjects

F Wolf

Publications and source records attributed to F Wolf.

At least 127 records · Page 7Linked to original sources
PubMed1984

[Combined bone marrow and skeletal scintigraphy in osseous and myelogenous diseases].

In 87 patients with proved diagnosis and a normal or pathologic bone scan (BS) in addition a bone marrow scan (BMS) was performed using a 99mtechnetium-labelled microcolloid. The analysis of scintigraphic findings included those obtained by other investigations shows that in these selected patients a false normal or false positive interpretation would have been resulted in 18% performing the BS only. Both methods BS and BMS were capable of diagnosing the correct stage of disease in all patients. The results indicate an augmentation of diagnostic facilities by the BMS in diseases affecting bone or bone marrow.

Adult↗
PubMed1984

[Results of scintigraphic studies with 131I-meta-benzylguanidine in space-occupying lesions of neuroectodermal origin].

Between 1982 and 1984, 48 studies with 131I-meta-benzylguanidine were carried out in Erlangen in patients with suspected pheochromocytoma or neuroblastoma. Scintigraphy with MIBG was found to be highly specific. False positive findings can be avoided if with weak uptakes an exact correlation with the results of morphological studies such as CT or sonography is sought and if follow-up observations ensure that they are not caused by activity residues in the biliary, intestinal or urinary pathways. False negative findings are made in 5-10% of the investigations in pheochromocytoma and in 41% of those in neuroblastoma patients. In pheochromocytoma the uptake rates are generally low (1-2%), whereas in neuroblastoma they may reach 10% and more.

3-Iodobenzylguanidine↗
PubMed1983

Increased serum concentration of free L-triiodothyronine in patients treated with L-thyroxine.

This study demonstrates that in spite of measured normal concentrations of carrier proteins one cannot deduce in all cases a normal fT3 from a normal level of TT3 when l-thyroxine given for diagnostic or therapeutic purposes is present in excess. The displacement of l-triiodothyronine from its binding sites is shown in 35 patients with non-toxic goitre who received an oral dose of 200 micrograms l-thyroxine/die for two weeks. Apart from a significant increase of TT4 (from 7.85 to 14.21 micrograms/dl equal + 81%) and of fT4 (from 1.58 to 3.7 ng/dl equal + 134%) there is only a slight increase in TT3 from 148 to 158 ng/dl (equal + 10%) after 14 days of treatment. By contrast fT3 rises clearly from 4.97 to 8.07 pg/ml equal + 63% (normal range: 2.8-5.6 pg/ml). Compared with the increase of TT3 (+ 10%) the free T3 rises by a factor of 6.3 (63%/10%). On account of higher affinity of l-thyroxine to binding proteins the free T4 is influenced to a lesser degree. Compared with the increase of TT4 (+ 81%) free T4 rises by a factor of 1.6 (134%/81%). It is supposed that the serum concentration of free T3 can be increased despite a normal concentration of TT3 when l-thyroxine is present in excess. Therefore, for laboratory work fT3 should be assigned a higher validity than TT3 when patients are treated with comparatively high doses of l-thyroxine.

Adult↗
PubMed1982

Calcium permeability of Ehrlich ascites tumour cell plasma membrane in vivo.

Passive Ca2+ entry into Ehrlich ascites tumour cells has been investigated. Passive equilibrium of Ca2+ takes place in ascites tumour cells only under conditions of exhaustive energy depletion. The specific Ca2+ ionophore A23187 does not affect Ca2+ entry into ascites tumour cells under active metabolic conditions, but it increases the rate of Ca2+ equilibration in ascites tumour cells in the early stages of energy depletion. The results of the present experiments lead to the conclusion that in ascites tumour cell plasma membrane Ca2+ permeability is not a limiting step in the regulation of intracellular calcium content, while the energy-dependent Ca2+ extrusion is the main mechanism that prevents uncontrolled intracellular Ca2+ increase. The results taken together support the hypothesis that increased Ca2+ influx into the cell, caused by plasma membrane alteration, is responsible for permanently elevated mitotic activity and for deranged metabolic behavior of these neoplastic cells.

Anaerobiosis↗
PubMed1981

Lack of effect of the Ca2+ ionophore A23187 on tumour cells.

The Ca2+ ionophore A23187 increases intracellular calcium content in normal thymic cells, while it is without effect on the corresponding neoplastic cell (Ascites thymoma) and on Ehrlich ascites tumour cells. The A23187-induced total cell calcium increase in normal thymocytes takes place both in control and energy-depleted cells, while it is lacking in neoplastic cells. In addition the ionophore stimulates aerobic glycolysis of normal thymocytes, whereas it is ineffective on neoplastic cells. The study of intracellular calcium exchange properties reveals that in normal cells the ionophore A23187 provokes a 60% increase of the exchangeable pool together with a more significant, 4-fold enlargement of the unexchangeable pool. These effects are lacking in cancer cells. The data give rise to interesting considerations concerning the regulation and compartmentalization of calcium in neoplastic cells. The results will be also discussed in relation to the models that predict altered cell calcium metabolism as a cause of cancer cell high aerobic glycolysis and uncontrolled growth.

Animals↗
PubMed1981

Further observations on calcium and other divalent cations metabolism in intact Ehrlich ascites tumour cells.

The metabolism of calcium has been investigated in the Ehrlich Ascites Tumour Cells (ATC). ATC extrude Ca2+ actively by an energy-dependent mechanism, supported by both respiration and glycolysis. Extrusion takes place even against a very steep concentration gradient (10 mM Ca2+). Cell calcium content is decreased by monovalent cations (Na+,K+ and Li+), which act independently from their metabolic effects. La3+ inhibits ATC Ca2+ extrusion whereas Ruthenium Red slightly decreases cell calcium content. The antibiotic ionophore A 23187 strongly increases ATC Ca2+ level. the metabolism of other divalent cations (Mg2+, Sr2+ and Mn2+) has been studied. Mg2+ does not show appreciable changes in the various metabolic conditions tested, while Mn2+ and Sr2+ behave quite differently from Ca2+, suggesting a different distribution of these cations in ATC. The experimental findings indicate that Ehrlich Ascites Tumour Cells regulate their calcium content by mechanisms related to plasma membranes while the size and activity of mitochondrial compartment is of minor importance.

Animals↗
PubMed1980

Assessment of regional blood flow by intravenous injection of 99m-technetium-pertechnetate.

A general method for computation of regional blood flow from time-activity curves obtained after intravenous injection of 99m-TC pertechnetate is presented. The method is based on the well-known principle of Meier and Zierler, but, it also considers the dispersion of an intravenously injected activity-bolus as well as the recirculation of the nondiffusible tracer. The problems arising from the use of a nondiffusible indicator concerning the partition coefficient lambda are discussed. This method of blood flow determination is adopted for measurements of cerebral blood flow and some first results are discussed.

Adult↗
PubMed1978

A correlation between shortened life span and UV-sensitivity in some strains of Saccharomyces cerevisiae.

From a UV-irradiated sample of diploid cells several clones were isolated, which produced cells with a shortened life span. A closer examination of three of these clones showed among other deviations from the wild type a higher sensitivity to UV-irradiation. Three other clones, which were selected from a haploid strains as UV-sensitive mutants, proved to be shortlived as well. In all these strains photoreactivation and liquid holding reactivation were unimpaired. There was no cross-sensitivity to X-irradiation. The correlation between shortened life span and UV-sensitivity is discussed.

Clone Cells↗
PubMed1978

Infant botulism.

Explore the source record for details and available documents.

Botulism↗
PubMed1977

Calcium metabolism in Ehrlich Ascites tumour cells.

Ehrlich ascites tumour cells are able, under the proper experimental conditions, to extrude a substantial amount of Ca2+ from the intracellular space. The Ca2+ extrusion mechanism, probably located at the plasma membrane level, appears to be similar to that found in red blood cells. It is energy-dependent and both respiration and glycolysis are able to drive it. The use of some inhibitors and uncouplers, besides showing that this activity is different from that linked to the mitochondrial Ca2+ pump which acts in the opposite direction, proposes some speculations on the energy compartmentation in the Ehrlich ascites tumour cells.

Animals↗
PubMed1977

[Immobilization of proteins on macroporous glasses involving maleinimide as the anchoring group].

Macroporous glasses with pore sizes from 400-1000 A appropriate for protein binding were produced and characterized by a thermal demixing procedure and alkaline after treatment. To achieve a covalent binding capacity relative to proteins, the gamma-aminopropyl derivative was allowed to react with 4-maleinimido benzoylic chloride to give preparations containing, in addition to maleinimide residues, acid chloride structures for the protein binding. A preparation of 400 A pore size was tested for its protein binding capacity relative to bovine serum albumin and trypsin. Furthermore, the capacity of binding glucoamylase from Endomycopsis bispora in active form was studied.

Animals↗