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Biomedical subjects

E Katona

Publications and source records attributed to E Katona.

At least 37 records · Page 2Linked to original sources
PubMed1991

Fibronectin in bronchoalveolar lavage fluid and plasma of dogs with acute inflammation of the lungs.

Bronchoalveolar inflammation, which was generated in dogs by Broncho-Vaxom instilled into the right lower lobe, was characterized first of all by an increased influx of macrophages. In this non-purulent acute-subacute inflammatory reaction, the lavage fibronectin decreased rapidly three hours after the incubation and then a marked gradual elevation was observed, which persisted throughout the whole two-week process, while plasma fibronectin concentrations were not altered significantly. Changes in the levels of lavage fibronectin may be an important sign for the control of the inflammatory reaction activity in the lungs.

Acute Disease↗
PubMed1990

On the use of NHZ-203C Thermoluminescence (TL) reader in clinical dosimetry.

The sensitivity vs. dose characteristics of two TL readers (Harshaw 2000 A + B and NHZ-203C) was compared both in the range of small doses (10 microGy to 100 mGy) as well as in the radiation therapy level by using individually calibrated LiF:Mg, Ti detectors manufactured in Poland. The performance of both systems can be predicted by a three parameter theoretical model. The very good reproducibility of the NHZ-203C reader (sigma/D = 0.6%) is important in radiation therapy while the high sensitivity (the lowest detectable dose limit = 3 S.D. of the background = 27 microGy) is useful for radiation protection measurements.

Evaluation Studies as Topic↗
PubMed1989

Quality control of X-ray orthovoltage therapy units with a dual TL system.

More than 40 orthovoltage X-ray therapy units are monitored by calibrated thermoluminescent dosimeters (TLD). Three pairs of LiF:Mg,Ti and CaSO4:Dy pellets are irradiated in air in a polypropane capsule. The range between 0.2 to 3.0 mm Cu the half-value layer (HVL) is determined from the CaSO4-LiF ratio. In this range, the response of the LiF dosimeters is corrected for energy dependence. We are using a fixed sensitivity for LiF in the MVL range of 2 mm Al to 0.2 mm Cu. In the first two years 173 monitorings were performed by using 485 badges. Usually not more then two different radiation qualities (in the HVL ranges 2 mm Al to 0.2 mm Cu and 0.9-2.5 mm Cu) or two beams used on a therapy unit are measured by using 2-3 badges per monitoring. In 134 cases (77.5%) the dose rates were within acceptable limits (+/- 10%). In 23 cases (13.3%) a failure of the X-ray unit was detected. We think that our system is simple enough and may be used for the dosimetric monitoring of orthovoltage X-ray therapy units. In some cases even the type of malfunction can be determined.

Quality Control↗
PubMed1988

Fibronectin in bronchoalveolar lavage fluid and plasma from children with chronic inflammation of lungs.

Fibronectin/albumin ratios in plasma and in bronchoalveolar lavage fluid were evaluated in patients (1-6 years of age) with recurrent obstructive bronchitis and different interstitial lung diseases. These inflammatory reactions were characterized by increased influx of macrophages on the bronchoalveolar surface, but an increase in the proportion of lymphocytes or neutrophils was also detected in the group of patients with lymphocyte-macrophage or neutrophil-macrophage alveolitis. There was no considerable difference in plasma fibronectin concentrations obtained from healthy children and patients with moderate obstructive bronchitis and slight inflammation of the bronchial mucosa observed bronchoscopically. Levels of plasma fibronectin were elevated in patients with serious bronchial inflammation and different alveolitis, but they were within the normal range. A comparison of lavage fibronectin/albumin ratios with plasma fibronectin/albumin ratios with plasma fibronectin/albumin ratios indicated significant local production of fibronectin in subjects with serious bronchial inflammation and interstitial lung disorders. Fibronectin detected on the bronchoalveolar surface seems to be an important factor in mediating cell-to-cell interactions in the repair of the bronchoalveolar structures, and in tracing the activity of the inflammatory reactions not only in patients with interstitial lung diseases, but also in patients with serious chronic bronchial inflammation.

Bronchitis↗
PubMed1987

Sequential sodium-proton exchange in thrombin-induced human platelets.

Thrombin stimulation of human platelets initiates a membrane depolarization attributable to a Na+ influx into, and an alkalinization of, the cytoplasm, both of which follow a similar rapid time scale and thrombin-dose dependence. These responses precede secretion of the contents of the dense granules (serotonin) and, after 1 minute, of lysosomes (beta-glucuronidase). We have evaluated these parameters in the presence of 2H2O in order to determine if the Na+ influx and H+ efflux are sequential or simultaneous. NMR evidence indicates that 2H2O equilibration in rapid, and virtually complete within the 3 min prestimulation platelet equilibration period. In response to an 0.05 U/ml addition of thrombin, the rate of depolarization is 70-80% slower in 2H2O than in H2O. The time to reach maximal depolarization is 5 to 10 seconds longer in 2H2O, the extent of depolarization 60% inhibited, and the pH change 85% inhibited. The serotonin secretion is unaltered, while the beta-glucuronidase secretion is 130-180% enhanced. Dimethylamiloride inhibits the Na+ influx and the pH change completely. These results suggest that the Na+ and H+ fluxes across the plasma membrane are interdependent but neither simultaneous nor electroneutral. Furthermore, granule secretion, previously shown by us to be independent of the existent Na+ gradient, depends on the cytoplasmic K+ and H+ concentrations.

Amiloride↗
PubMed1985

The effect of external regeneration on the performance of CaSO4:Dy discs.

The authors have investigated the effect of annealing on the reproducibility of CaSO4: Dy dosimeters. The dosimeters cannot be used without external thermal treatment in high precision therapy level dosimetry while a 600 degrees C-1 h external regeneration resulted in a better reproducibility than a 400 degrees C-1 h treatment (which may be used if the absorbed dose in water does not exceed a few Gy). The background of the dosimeters increased considerably even in a 10 X 1 mGy exposure as a result of irradiation history if no external regeneration was used.

Calcium Sulfate↗
PubMed1981

Kinetics of nerve impulse blocking by protein cross-linking aldehydes. Apparent critical thermal points.

The effect of formaldehyde, crotonaldehyde, butyraldehyde, glutaraldehyde and cinnamaldehyde on the compound action potential of frog sciatic nerve was studied in the temperature domain 20-35 degrees C at various aldehyde concentrations. All these reagents gradually decrease the amplitude of nerve action potential, up to the complete block, the order of effectiveness being: crotonaldehyde greater than cinnamaldehyde greater than butyraldehyde greater than formaldehyde greater than glutaraldehyde. The effect of cinnamaldehyde is almost completely reversible, while all others have irreversible action. The dependence of the blocking time on temperature and concentration is well expressed in all cases by the same empirical equation. This dependence points to the existence of critical temperatures, specific for each aldehyde, at which impulse blocking would be instantaneous, regardless of concentration. These temperatures (obtained by extrapolation) lie between 43 degrees C (for crotonaldehyde) and 57.5 degrees C (for butyraldehyde). The existence of free amino groups within ionic channels, as main sites of aldehyde attack, is inferred.

Action Potentials↗
PubMed1981

Effect of protein cross-linking aldehydes on nerve activity.

The changes in excitability and conduction properties of frog sciatic nerve under the influence of glutaraldehyde (GA), formaldehyde (FA), butyric aldehyde (BA) and crotonic aldehyde (CA) were examined in the concentration domain 0.01-1.00% (w/v) and at 20, 25, 30 and 35 degrees C. All these reagents irreversibly reduce the amplitude of the compound action potential of the nerve and decrease the conduction velocity up to the complete block. These changes occur as approximately exponential time decays. The decreasing order of efficiency is : CA greater than BA greater than FA greater than GA, showing no obvious correlation with the molecular weight of the aldehydes. The rise in temperature activates the decrease of amplitude but has a compensatory affect on the decrease of conduction velocity. The rising phase of the nervogram apparently remains unchanged, while the duration of the falling phase is up to threefold lengthened--more but slower at low temperatures and concentrations. These changes in the electrical response of the nerve are analysed as expressing the diffusion of aldehydes within the tissue, and their specific reactions with the proteins of the ionic channels.

Action Potentials↗
PubMed1979

Water compartments in living, glycerinated and fixed skeletal muscles of the frog.

The kinetics of water replacement with heavy water (deuterium oxide) in the gastrocnemius and sartorius muscles of the frog under isotonic conditions, studied both gravimetrically and by infrared photometry, reveals three water compartments: (i) non-exchangeable (approximately 80 ml/kg fresh weight), (ii) slowly exchanging (approximately 500 ml/kg fresh weight), (iii) rapid exchanging--extracellular (approximately 200 ml/kg fresh weight). Exposure to both glycerol and glutaraldehyde increases the permeability coefficients and the amount of rapid exchanging water; glutaraldehyde also increases the amount of non-exchangeable water. Approximately 90% of the water is kept in the tissue only by weak intermolecular forces, the energies of which amount to 1 kcal/mol. The amount of non-exchangeable water is equivalent to about six continuous adsorption layers covering the myofilaments. Approximately 70% of the tissue water appears to be replaced by glutaraldehyde during standard fixation.

Aldehydes↗
PubMed1978

Water compartments in the myelinated nerve. III. Pulsed NMR results.

3 experimentally distinct transverse relaxation components of the water in frog sciatic nerve are obtained by Carr-Purcell-Meiboom-Gill technique. The relative weights of these components: approximately 29%; approximately 50%; approximately 21% fit well with water compartments in this tissue as revealed by previous methods.

Animals↗
PubMed1978

alpha1-Antitrypsin: the presence of excess mannose in the Z variant isolated from liver.

The Z variant of alpha1-antitrypsin was isolated by a new technique from the liver of a patient homozygous for the Z allele of the protease inhibitor locus. The material was homogenous and antigenically competent but had no protease inhibiting capacity. An interesting correlation was found between the subcellular localization and the carbohydrate composition of the Z variant from liver. Carbohydate analysis of this glycoprotein showed an absence of galactose and sialic acid, an appreciable decrease in N-acetylglucosamine, and an almost twofold increase in mannose residues. These data indicate a considerable slowdown in the processing of the oligosaccharides of liver Z variant. In spite of the absence of sialyl residues, the liver Z varant was microheterogeneous by analytical isoelectric focusing. The isoproteins of liver Z variant coincided with those of asialo M variant in the focusing field.

Amino Acid Sequence↗
PubMed1978

The temperature dependence of the surface tension of aqueous solutions of plasma proteins.

The surface behavior of aqueous solutions of fibrinogen, transferrin, gamma-globulin and albumin at the liquid-gas interface has been investigated by a modified Wilhelmy technique. The temperature dependence of the surface tension was studied over a temperature range of 20--80 degrees C and a pH range of 2--12. Most pronounced conformational changes of fibrinogen with this technique were found in physiological conditions: 35--45 degrees C and pH 7--8. A conformational change was found for gamma-globulin and transferrin solutions, but at a higher temperature and less pronounced than fibrinogen. Albumin did not undergo conformational transitions to a significant extent.

Fibrinogen↗
PubMed1976

Incorporation of inorganic sulfate in rat-liver Golgi.

Partial subcellular distribution and specifically the incorporation of 35SO4 in the Golgi apparatus of rat liver was studied. The isolated Golgi fraction was placed on a further sucrose gradient for subfraction and in all samples the total incorporated label, the trichloroacetic-acid-soluble and insoluble, and chloroform/methanol-soluble and insoluble amounts of label were measured. Approximately 2.3% of the total injected 35S was found in the liver, of which 2% was localized in the isolated Golgi fraction. Further subfractionation of the Golgi has shown that the majority of the 35S is localized at densities 1.12-1.13 g/cm3 in the gradient. In the isolated Golgi fraction 85% of the label was present in the trichloroacetic-acid-soluble and 15% in the insoluble part. Approximately 1% of the label in the Golgi fraction was soluble in chloroform/methanol. On the bases of radioactivity per weight of protein and total radioactivity, the Golgi fractions had the highest activity, except the first supernatant which had higher radioactivity. Briefly, a significant amount of the 35SO4 can be found in the isolated rat liver Golgi 15 min after the injection of the label, and the majority of this label is localized in the material sedimenting at density 1.12-1.13 g/cm3 after subfractionation of the Golgi apparatus.

Animals↗