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Biomedical subjects

G Fischer

Publications and source records attributed to G Fischer.

At least 595 records · Page 33Linked to original sources
PubMed1976

Incidence study of Down's syndrome in Copenhagen, 1960-1971; with chromosome investigation.

The aim of the study was to obtain incidence figures for Down's syndrome throughout a period where a considerable change in the age distribution of child-bearing mothers has taken place and to study if the expected fall in incidence has occurred. In parts of the Copenhagen Metropolitan area 235 liveborn patients with Down's syndrome were ascertained in the period 1960 to 1971 in a population of 1-2 million with a total of 204771 births. All patients available were examined cytogenetically (75%). In 160 (90-4%) a regular trisomy 21 was observed. In 6-2% of the cases translocations and in 2-3% of the cases mosaics were found. Two double trisomies and a double trisomy mosaic were observed. Throughout the period 1960-71 the percentage of women over 30 years delivering children decreased from 23-4% in the beginning of the period to 16-2% at the end of the period. In the first part of the period 52-6% of the cases were born to mothers over 30, at the end of the period 40% of Down's syndrome mothers were of that age. However, the incidence was unchanged throughout the whole period, about 1-15 per 1000 births. For some age groups a steady rise in incidence of trisomy 21 cases was found throughout the whole period. These findings may be explained by better ascertainment of patients at the end of the period; however, environmental factors may also play a role.

Adolescent↗
PubMed1976

The activator of human cerebroside sulphatase. Activating effect on the acidic forms of the sulphatases from invertebrates.

1) Acidic forms of the sulphatase were partially purified from the following invertebrate species: Tethya aurantium (Porifera), Patella vulgata (mollusca), Maja squinado (Arthropoda), Marthasterias glacialis (Echinodermata) and Microcosmus sulcatus (Tunicata). Enzyme preparations thus obtained cleaved cerebroside sulphates (sulphatides) only in the presence of either specific detergents (e.g. taurodeoxycholate) or an activator protein isolated from human liver. This corresponds to the findings on purified sulphatase A of human origin. 2) At low concentrations, the activating effect was proportional to the amount of activator protein applied; at higher concentrations, proportionality was obtained only in some cases. On a molar basis, less of the activator protein was required to achieve the same activation as taurodeoxycholate. At optimum concentrations of the detergent however, the activation was much higher. 3) The enzyme specificity of the activator and some evolutionary implications are discussed.

Acetylglucosaminidase↗
PubMed1976

The activator of cerebroside sulphatase. Lysosomal localization.

1) An activator protein necessary for the enzymic hydrolysis of cerebroside sulphate could be partially purified from unfractionated rat liver. This activator, which is similar to that of human origin, proved to be a heat-stable, non-dialyzable, low molecular weight protein with an isoelectric point of 4.1. Its activity could be destroyed by pronase. 2) For elucidation of the subcellular localization of the activator, rat liver was fractionated by differential centrifugation. The intracellular distribution of the cerebroside sulphatase activator was compared to the distribution patterns of marker enzymes for different cell organelles and found to coincide with the lysosomal arylsulphatase, thus indicating a lysosomal localization. 3) This was confirmed using highly purified secondary, i.e. iron-loaded, lysosomes. After disruption by osmotic shock, these organelles hydrolyzed cerebroside sulphate when incubations were performed under physiological conditions with endogenous as well as exogenous sulphatase A as enzyme. 4) After subfractionation of the disrupted secondary lysosomes into membrane and lysosol fractions by high speed centrifugation, it was found that the activator protein was exclusively associated with the lysosol, whereas the acid hydrolases were distributed differently between the two fractions. 5) The lysosol was further fractionated by semi-preparative electrophoresis on polyacrylamide gels. Two protein fractions were obtained: a high molecular weight fraction, containing the activator-free acid hydrolases, and a low molecular weight fraction, containing the enzyme-free activator of cerebroside sulphatase. 6) The significance of these findings for the hydrolysis of sphingolipids in the lysosomes is discussed.

Animals↗
PubMed1976

Experimental bypass for sagittal sinus repair. Preliminary report.

Bypasses of the sagittal sinus, 2.5 mm in diameter, were carried out in 25 dogs with venous (13 cases) and arterial (12 cases) autogenous grafts, by classical microtechniques. Animals were sacrificed 10 to 75 days after the operation, average 40 days. The patency rate was 54% in the venous autograft group; in all cases, thrombosis occurred early and was due to technical factors. The immediate postoperative patency rate was 100% in the arterial graft group, but this type of graft showed a tendency to progressive occlusion because of extensive fibrosis of the arterial wall; thus the patency rate was 75% at the time of autopsy. This preliminary work demonstrates the technical feasibility of bypass procedure which could be used for sagittal sinus repair.

Animals↗
PubMed1976

[Age-specific distribution of beta-glucuronidase and beta-galactosidase in the humeral epiphysis of rats].

The chondrocytes of the humeral epiphysis and of the articular cartilage of newborn, 8-, 30-, and 60-day-old albino rats contain beta-glucuronidase and beta-galactosidase. Both enzymes were found to be rare in the before mentioned cells. The reactions begin in the cells of the column cartilage and of the osteoblasts of the metaphysis on the 8th day of life and demonstrate an additional activity in 40- to 60-day-old animals. The results mark the activity of the degrading enzymes of the carbohydrate metabolism.

Animals↗
PubMed1976

[Positive and negative ions influence on the activity of the adrenal cortex (author's transl)].

The cortisol level in the serum of mice, which had been exposed to the influence of negatively or positively ionized air for 30 minutes, was determined by means of competitive protein fixation. Under the influence of both ion moieties, the cortisol level rose to twice the physiological norm (p less than 0,001 in both cases). - Theoretically the inhaled air ions might exert influence on the regulatory cycle hypothalamus - hypophysis - ACTH - adrenal cortex both neurogenically and directly via the circulatory system, thereby changing the cortisol level. For this reason, the determination of ACTH, as well as of cortisol after hypophysis exstirpation, must be regarded as a prerequisite for further investigations.

Adrenal Cortex↗
PubMed1976

[Positive und negative ions influence on the activity of the adrenal cortex (author's transl)].

The cortisol level in the serum of mice, which had been exposed to the influence of negatively or positively ionized air for 30 minutes, was determined by means of competitive protein fixation. Under the influence of both ion moieties, the cortisol level rose to twice the physiological norm (p less than 0,001 in both cases). - Theoretically the inhaled air ions might exert influence on the regulatory cycle hypothalamus - hypophysis - ACTH - adrenal cortex both neurogenically and directly via the circulatory system, thereby changing the cortisol level. For this reason, the determination of ACTH, as well as of cortisol after hypophysis exstirpation, must be regarded as a prerequisite for further investigations.

Adrenal Cortex↗
PubMed1976

[Influence of line frequency electric fields on the heart rate of rats (author's transl)].

At present, the few published research results concerning the effect of 50 HZ fields on biological measurements, for instance on circulatory parameters, show only slight correlation. In order to find objective criteria for the infleunce of a field on heart frequency physically defineable observation conditions must first be created. In the interpretation of the results, it had to be taken into consideration that the measurements were taken immediately after application of the field in both brief and extended exposure. The effect of narcosis during derivation of cardiac activity was also a factor to be considered in this context. Keeping these facts in mind, rats were exposed for up to 50 days to a 50 Hz field with a field-strength of 50 V/m resp. 5300 V/m. Under both field-strength ranges, the heart frequency sank significantly. The intensity and the temporal development of the influence were dependent on the field-strength and the length of application. The comparatively strong frequency drop after 15 min treatment time in the 5300 V/m field points to a stress effect, whose persisting influence determines the development of the biological reaction over a longer period of time. The stronger field is comparable to the value found in the middle of the potential field of a 380 kV high-tension line. For this reason, the experimental results are interesting from the point of view of industrial hygiene as well.

Animals↗
PubMed1975

The kininase activity of Ehrlichs' ascites solid tumor after treatment with oncolytic clostridia.

For the first time the effect of bacterial kininases of Cl. oncolyticum M 55 ATCC 13.732 could be demonstrated in the tumor itself. This is shown by an increased degradation of kinins by spore-treated tumor tissue in comparison with respective controls. The results indicate the influence of kininases on the capillary circulation of the tumor tissue as one of the fundamental reactions of oncolysis.

Animals↗
PubMed1975

The activator of cerebroside sulphatase. Purification from human liver and identification as a protein.

1) A heat-stable activator of human sulphatase A (cerebroside sulphatase) was purified from human liver. It is required for the enzymatic degradation of cerebroside sulphates (sulphatides) in buffers (ionic strength greater than or equal 0.2) with osmolarity in the physiological range. 2) The purification steps involve extraction, acetone precipitation, heat treatment, isoelectric focusing and gel filtration. 3) Based on the definition of a specific activator unit, the purification of the final preparation was approximately 2000-fold over the acetone precipitation and several thousand-fold in the overall procedure. 4) The purified activator migrated as a single protein band when subjected to gel electrophoresis. Its effect was abolished after treatement with pronase E. The apparent molecular weight as determined by gel filtration was 21 500 +/- 1500; the isoelectric point was 4.3. 5) The activating effect of this protein factor and of taurodeoxycholate on cerebroside sulphatase activity was compared on a weight and molar basis.

Cerebroside-Sulfatase↗
PubMed1975

[Studies on the culture of clostridium butyricum strain M 55 ATCC 13.732. 4th Communication: The influence of peptone quality upon kininase activity (author's transl)].

Studies of the oncolytic effect of Cl. butyricum strain M 55 resulted in the hypothesis of oncolysis to be an effect of a continuous production of kinin-decomposing enzymes. A decomposition of bradykinin will reduce capillary permeability and microcirculation in the tumour tissue, thus releasing and maintaining the process of necrotization. To achieve an optimal oncolytic effect of Cl. butyricum M 55, in addition to conditions already demanded in preceding papers, also an abundant production of kininase is required. Experience has shown peptone-containing media to be most suitable for culturing the M 55 strain, kininase formation being dependent upon peptone quality. The best yield of kinine-decomposing enzymes was achieved with the following peptones: peptone from Gelatine Merck, Tryptose Merck, Microbiotone Oxoid, Proteose Oxoid and Trypticase BBL. To obtain the greatest possible kininase production by the spores of Cl. butyricum M 55 applied for oncolytic therapy, the peptones mentioned are recommended for culture.

Bradykinin↗
PubMed1975

[Kininases from yeasts (author's transl)].

Practically no studies are available on the presence of kinin-decomposing enzymes in yeasts. Different preparations (intact washed cell suspensions, cell-homogenised blastospores, nutrient media, supernatant of raw fungus suspensions) of Candida strains sampled from foci of disease and from the environment were studied qualitatively and quantitatively fro the presence of kinin-inactivating enzymes. The parameter measured is the time-dependent inactivation of bradykinin by the test strain preparations as determined in the isolated guinea-pig ileum by the water-bath test. Preceding surveys of the basic presence of kinin-decomposing enzyme activity in 10 Candida strains from foci of disease revealed that only undiluted, intact washed suspensions of spores were capable of bradykinin inactivation. Intact washed blastospores from 4 other strains sampled from foci of disease (Candida tropicalis B5, Candida tropicalis B12, Candida albicans C10, Candida albicans A23) diluted 1:10 by volume did not exhibit bradykinin decomposition at the concentration studied. In contrast to this, identical preparations of three strains from the environment (Candida tropicalis E2, Rhodotorula rubra H14, Saccharomyces lactis R15) were exhibiting kinin-inactivation of partially high intensity which was still enhanced by cell homogenisation. The Candida brumptii Q6 strain, however, did not induce kinin breakdown. In the case of Candida tropicalis E2, the enzymes could be demonstrated also in the nutrient diluted 1 : 2. Supernatants obtained by centrifugation of raw fungus suspensions were ineffective in respect of strains from foci of disease as well as such from the environment. Bradykinin was protected against inactivation by treatment of all kinin-decomposing preparations with 1,10 phenanthroline, acid and heat. Thus, the kinin-decomposing enzymes involved were kininases. In a general view, species-specific differences in the presence of kininases among Candida strains were recognizable.

Bradykinin↗