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Biomedical subjects

P Gróf

Publications and source records attributed to P Gróf.

At least 37 records · Page 2Linked to original sources
PubMed1983

Lipid-protein interaction in frog nerve membrane as studied by spin-labelling.

Molecular dynamics of membrane proteins in frog nerve was studied by the spin labelling technique. By varying the reaction conditions three protein domains were identified which differ in polarity of the micro-environment of the labelled sites (polarity index, h = 0, 0.6 and 1.2) and in mobility (apparent rotational correlation times, tau 2 = 1 ns, 35 ns and 62 ns, respectively). The protein domains reflect different structural stabilities towards specific and non-specific membrane perturbants. One part of the labels has an anisotropic distribution. Modification of the membrane components with different chemicals leads to a change in conformation and/or segmental motion of proteins, as well as to an alteration in the degree of ordering of the attached labels. The experiments support the fact, that the state of the lipid matrix strongly influences the overall conformation of the embedded proteins and their functions in biological processes.

Anesthetics↗
PubMed1983

Microbiological findings and protein concentration in gastric juice.

From 17 patients subjected to pentagastrin test, 136 samples of gastric juice (fasting sample, basal secretion, fractions after stimulation) were collected. The concentration of the protein components (IgG, IgA, IgM, C3 and albumin) in the fasting samples were in excess of those found in the basal secretion, but protein output (volume X concentration) was nearly identical in the two samples. The protein concentration of the fractions obtained in response to pentagastrin stimulation were too low to be measurable. According to correlation analysis, protein concentration in the gastric juice is primarily the function of the microbiological finding. The allergic effect of microorganisms in the gastric juice may give rise to an increase in its immunoglobulin and albumin concentrations.

Albumins↗
PubMed1981

Protein content of gastroduodenal juice: concentration and significance.

IgG, IgA, IgM, C3 and albumin were measured in 572 samples of gastric juice and the bile fractions A, B and C obtained by a duodenal tube from 143 dermatological patients. The results were correlated to gastric acidity. The findings are consistent with the barrier function of gastric acid secretion, it having been found that, unless hypacidity or anacidity is present, the proteins in the gastric and duodenal fluid show neither high concentrations nor a wide variety. The finding that the fairly high IgA was nearly equal to the amount of IgG in the samples and that the concentration of albumin was much lower (IgG: albumin approximately equal to 2 : 1), seems to indicate that the immunoglobulins were produced by the local immune system.

Adult↗
PubMed1980

Actin-myosin interaction in oriented F-actin filament system.

The decorated actin technique combined with the spin label method was used to study the interaction of skeletal muscle actin and myosin in synthetic filament system. If follows from the orientation dependence of the EPR spectra of the rigidly attached spin label in F-action filaments that the spin-label is sensitive to the dynamic state of the filaments. The interaction of myosin heads with actin reduces the intrinsic order of the F-actin filaments. The interaction seems to be cooperative.

Actins↗
PubMed1979

The study of nitroxide radical active esters as spin labels on muscle protein actin.

Nitroxide radical active esters were used to label the muscle protein actin and to study the orientation dependence of the EPR spectra of the labelled protein. It is concluded that the labels are located at least at two different sites of the protein with strong polar environment and different mobilities. The EPR spectrum of the strongly immobilized labels exhibits orientation dependence, the N--O bond axis of the spin labels is nearly perpendicular to the long axis of the F-actin threads, and the labels undergo a rapid rotational motion about an axis directed perpendicular to the filament axis. The application of the nitroxide radical active esters may be useful in the study of ordered systems as muscle or muscle protein systems.

Actins↗
PubMed1978

Surgery of venous leg ulcers.

Numerical data are presented to prove the endemic nature and importance of the varicose and postthrombotic syndrome. The fact that even in the most fortunate cases conservative therapy can bring about only temporary improvement, has directed attention to surgical methods. The surgical methods of treatment of varicos (VS) and postthrombotic (PS) syndrome are reviewed. The surgical procedure considered adequate is described. It consists of the following steps. After phlebography, in the case of satisfactorily functioning deep veins, the superficial venous system is extirpated according to Trendelenburg, Madelung and Babcock, the insufficient perforants are exposed and ligated, the ulcer is excised deeply and broadly into the intact tissue. The effect is covered at a later date with a semi-thick skin graft. The importance of supplemental conservative methods (preparation and postoperative treatment) is stressed. This complex therapy was applied in 112 severe cases of venous failure; in 96% the result was excellent, in 3% adequate and in 1% poor. The guiding principles for the successful solution of chronic venous failure are a correct diagnosis and a correctly performed operation. Only proper care can guarantee good results.

Humans↗
PubMed1976

Investigation of hydration of macromolecules. II. Studies on poly-(vinyl-alcohol) solutions by microwave dielectric method.

Microwave conductivity and dielectric condstant of poly-(vinyl-alcohol) (PVA) solutions of 0--10 per cent were determined at 2--4 GHz frequency in the temperature range from 25 degrees C to 35 degrees C. The low-frequency conductivities of the solutions were measured at 20 kHz in the same concentration and temperature range. Microwave conductivity was proportional to the square of frequency, and the axial section extrapolated to zero frequency was higher than low-frequency conductivity. This difference in conductivity can probably be attributed to the relaxation processes of water molecules interacting directly with macromolecules. The relaxation wavelength calculated from the frequency dependence of microwave conductivity increased and the dielectric constant of the solutions decreased with increasing macromolecular concentration in a linear way. The activation energy calculated from its temperature dependence was 4.0 +/- 1.0 kcal/mol. The products of self-diffusion coefficient and macroviscosity were compared with that of self-diffusion coefficient and microviscosity calculated from relaxation wavelength. From this the conclusion can be drawn that the self-diffusion of water is influenced by the concentration dependent microviscosity. The hydration numbers calculated by different methods give divergen results the discussion of which requires further investigations.

Binding Sites↗
PubMed1967

Carotenodermia.

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Adult↗