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Biomedical subjects

G Fischer

Publications and source records attributed to G Fischer.

At least 559 records · Page 31Linked to original sources
PubMed1980

[Histamine reduction by means of oncolytically active and oncolytically non-active clostridial strains (author's transl)].

Spores and vegetative forms of oncolytically active and oncolytically non-active clostridial strains were tested for histamine reducing activity (isolated ileum of guinea pig used for testing, waterbath method acc. to Magnus, Fig. 1). Culture media and the washed intact material did not show any or only very little effectiveness. On the other hand the fractionated, charges diminished histamine standard solutions except for very little remaining activity in the case of all strains. This effect was stronger in vegetative forms than in spores (Fig. 2). The histamine effect on the isolated organ was generally increased by means of culture media as well as by the washed intact material. In this respect, preparations of non-lytic strains showed a slightly higher effectiveness than preparations of lytic clostridial strains (Fig. 2). It was shown in earlier investigations (cf. bibliography) that the charges of clostridial strains decompose plasmakinin (synthetic bradykinin) at varying rates. Reduction of histamine activity by means of clostridia could lead to a decrease of the microcirculation and capillary-permeability in the tumor tissue (as hypothesized for bradykinin) and thereby favour its disintegration.

Animals↗
PubMed1980

Total removal of intramedullary ependymomas: follow-up study of 16 cases.

With microsurgical techniques, most intramedullary ependymomas may be totally removed. Such a complete surgical removal has been performed in 16 patients with intramedullary ependymomas. Of the 14 patients with benign tumors, 3 have no sequelae, 7 are able to walk, and 4 with preoperative paraplegia remain unchanged. The two other patients had malignant ependymomas and died within three years following surgery, in spite of chemotherapy and radiotherapy. Besides the histological and clinical factors, the prognosis depends largely on the surgical technique. The technical points that are important for locating the medullary posterior sulcus, for opening of the spinal cord, and for removal of the tumor are described.

Adolescent↗
PubMed1980

[The effect of experimentally induced histamine deficiency on growth and rate of taking of model tumours (author's transl)].

From oncolytically effective clostridial strains, the intact washed or fractionated material of the spores and vegetative forms and culture media were examined for histamine decomposing activity in previous in vitro experiments (14). In a fractionated state, all strains cause a reduction of histamine activity. Therefore histaminases are present as endozymes. When the spores germinate to vegetative forms on the tumour following i.v. injection, the cell wall breaks open and the enzymes are released. Möse et al. (13) described rapid and nearly complete decomposition of plasmakinins (specifically bradykinin) by means of the above mentioned special preparations of clostridial strains with oncolytical effect (culture media partially excepted). Bradykinin and histamine are vasoactive substances, which are significant in terms of fine regulation of the capillary circulation. Continuous inactivation of these tissue hormones effected by the (clostridial) vegetative forms concentrated in the tumour may decrease the capillary circulation and thereby favour necrotization or decomposition of the tumour. In this animal experiment the effect of this biogenic amine on growth and rate of taking of tumours by means of artificially produced changes in the flowing equilibrium of the histamine metabolism was to be shown. Mice: While feeding mice a pyridoxal phosphate-free diet, a Harding-Passey melanoma was inoculated: The tumour weights were slightly lower in the case of animals put on the diet than in controls. Rats: Histamine-free diet and treatment with semicarbazide (in the course of the treatment implanzation of a Walker tumour). The taking of the tumours was significantly delayed or their growth reduced as a result of the diet or the treatment with semicarbazide or both.

Animals↗
PubMed1979

Inhibition of lymphocyte function in rats fed higher-fat diets.

Concanavalin A-induced blastogenesis of spleen lymphocytes was significantly inhibited when lymphocytes from rats on a high-polyunsaturated-fat diet were compared to lymphocytes from rats on a low-fat diet. Responsiveness was dependent on source of serum since lymphocytes from rats fed a low-fat diet were suppressed in serum from rats fed a high-polyunsaturated-fat diet. Alternatively, lymphocytes from rats on a high-polyunsaturated-fat diet were more responsive in serum from low-fat-fed rats compared to their response in autologous serum. One of the inhibiting factors in serum was the lipoprotein fraction; however, rats on a high-polyunsaturated-fat diet probably had additional inhibitors in their serum. While tumor incidence was highest in rats with the least responsive lymphocytes was highest in rats with the least responsive lymphocytes and lowest in rats with the most responsive lymphocytes, the significance of the observation is not known.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1979

Revascularization of the spinal cord by micro-anastomoses in dogs.

The severity of ischemic lesions in the spinal cord justifies attempts at its surgical revascularization. The experiments consisted of: (1) creating devascularization of the conus medullaris by ligation of all the lumbo-sacral collaterals of the aorta, and (2) revascularizing the lumbo-sacral rachidian circulation by performing an end-to-side anastomosis between the caudal mesenteric artery and the 5th left lumbar artery (from which in the dog the Adamkiewicz artery generally arises). After two-months, the patency rate of the 20 cases was 85%. Such a procedure of revascularization could be useful in man in cases of interruption of the arterial supply of the spinal cord.

Angiography↗
PubMed1979

[Preliminary physiological and psychological results under various electroclimatic conditions (author's transl)].

Before the start of a research project which was to stretch over a period of several years, characteristics of the control space were to be defined. Therefore the influence of spherics and 50 Hz-alternating fields in the unscreened control space were studied.--Pupils (Foster children) were the test subjects. Each test subject was subjected to the conditions of the control space as well as the testing space.--Two classes of parameters were studied. Blood sugar, blood pressure and pulse rate were recorded as physiological dimensions. Short-term memory, powers of concentration as well as the subjective well-being were the psychological parameters.--As to the parameters examined, no significant difference between testing and control space conditions was recorded. In order to examine whether the climatic factors of the control space have an antagonistic effect on the variables in question, their influence was studied separately in two further investigations. In order to clarify this problem, spherics-impulses in the 10 Khz range were given in screened space ("Vorversuch 2"/preliminary experiment 2), then--in, "Vorversuch 3"/preliminary experiment 3 - a 50 Hz-alternating field was applied. For each of the climatic factors under examination the influence on each single parameter was negative. The assumption of an antagonistic effect which would hinder the definition of standard spatial conditions was thereby shown to be incorrect.

Adult↗
PubMed1978

The activator of cerebroside-sulphatase. A model of the activation.

The activator of cereboroside-sulphatase (cerebroside-3-sulphate-3-sulphohydrolase, EC 3.1.6.8) is necessary for the enzymic hydrolysis of sulphatides (cerebroside sulphates) at ionic concentrations in the physiological range. The pH optimum of the reaction is 4.5--4.8. Under similar incubation conditions, a complex is formed between activator and sulphatides which is partially inhibited, due to competitive binding in the presence of cerebrosides of phosphatidylserine. Inhibition depends upon the concentration of the lipids and is of the same order of magnitude as the inhibition (by these lipids) of enzymic sulphatide hydrolysis in the presence of activator. Complex formation between activator and sulphatides is reversible since the complex dissociates partially when certain concentrations of phosphatidylserine are added. Moreover, the rate of sulphatide hydrolysis increases with the concentration of the activator.sulphatide complex in the reaction mixture. This indicates that the activator.sulphatide complex is the substrate for the enzyme and a model for this activation is presented.

Cerebroside-Sulfatase↗
PubMed1978

Studies on the function of the activator of sulphatase A.

The activator of sulphatase A is necessary for the enzymic degradation of sulphatides to cerebrosides at ionic concentrations in the physiological range (1). Activation is probably due to the reversible formation of a one-to-one complex between activator and sulphatides (1,2). Formation of this complex is partly inhibited by cerebrosides due to competitive binding (2), as well as by phospholipids (e.g. lecithin or phosphatidylserine). Inhibition of the complex formation between activator and sulphatides by cerebrosides and phosphatidyl-serine depends on the concentration of the lipids and is of the same order of magnitude as the inhibition (by these lipids) of the enzymic degradation of sulphatides in the presence of activator (1). Moreover the degradation rate of sulphatides increases with the concentration of activator-sulphatide complex in the reaction mixture (1) indicating that the activator-sulphatide complex is the substrate for the enzyme in the degradation of sulphatides by sulphatase A.

Cerebroside-Sulfatase↗
PubMed1978

A new approach to spike detection using a combination of inverse and matched filter techniques.

For the detection of spikes and other types of transient signal, a combination of inverse and matched filter techniques can be used. The inverse filter improves the signal to noise (spike to EEG) ratio; the matched filter makes it possible to classify different types of spikes. When compared, the combined inverse matched filter techniques gave a higher detection rate than the inverse filter technique alone, for the same error probability. Both simulated and patient data were used for testing the methods.

Electroencephalography↗