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Biomedical subjects

T Kiss

Publications and source records attributed to T Kiss.

At least 127 records · Page 7Linked to original sources
PubMed1990

Different actions of aconitine and veratrum alkaloids on frog skeletal muscle.

1. The electrophysiological effects of veratridine, cevadine and aconitine (10(-8)-2 x 10(-4), 2 x 10(-7)-2 x 10(-6) and 2 x 10(-6)-10(-4) mol/l, respectively) were compared on frog muscle membrane using conventional microelectrodes. 2. Veratridine and aconitine were equally effective in depolarizing the resting membrane with the threshold concentration of 5 x 10(-5) mol/l. 3. Volleys of repetitive discharges and slow transient depolarizations were observed when single electrical stimuli were applied in the presence of veratridine (5 x 10(-8)-2 x 10(-5) mol/l), but not aconitine. Volleys with aconitine could be evoked only by repetitive stimulation; however no tendency of repolarization was observed following these volleys. Two orders of magnitude more aconitine than veratridine was required to induce volleys with similar parameters. 4. The effects of cevadine were similar to those of the corresponding concentrations of veratridine. 5. The observed differences between the electrophysiological actions of aconitine and veratrum alkaloids may be explained in part with differences in Na+ channel inactivation produced by these toxins, in addition to differences in their use-dependent behavior.

Aconitine↗
PubMed1989

Molecular analysis of eight U1 RNA gene candidates from tomato that could potentially be transcribed into U1 RNA sequence variants differing from each other in similar regions of secondary structure.

From a tomato genomic library we isolated and characterized eight U1 RNA gene candidates (U1.1 to U1.8) all of which possessed the canonical plant U-snRNA transcription signals in their 5' and 3' flanking regions and exhibited nucleotide sequence conservation in the 5' splice site recognition sequence, in the Sm antigen binding site and in Loops B, C, D as well as in Stems III and IV of their coding region. Deviations from the U1 RNA consensus sequence were mainly localized to Loop A and Stems I and II, suggesting that the putative transcripts of the tomato U1.1-U1.8 genes would differ from each other in their capacity of binding to the U1 RNA-specific snRNP proteins.

Animals↗
PubMed1989

Intraoperative balloon angioplasty.

Since 1981 intraoperative balloon dilatation has been performed in 78 patient suffering from occlusive arterial disease of the lower extremities. The indications were claudication in 32, and limb salvage in 46 patients. In most of the 34 patients in whom a proximal iliac stenosis was dilated in association with a femoro-popliteal bypass (10 patients), endarterectomy (19 patients) or profundoplasty (5 patients), the ankle arm index returned to near normal immediately after the procedure. In 44 patients, the femoro-popliteal segment distal to an ilio-femoral reconstruction was dilated. The follow-up period ranged from 1 to 60 months with an accumulated patency rate of 97.6% in aortoiliac and 60.2% in femoro-popliteal segment at 5 years. Fourteen patients were dead at five years after the intervention from concurrent cardiac disease. Balloon angioplasty is a valuable adjunct to vascular surgery either to improve inflow or outflow in association with surgical reconstruction.

Adult↗
PubMed1989

Longitudinal and vertical ultrastructural lesion of crural muscle in post-thrombotic syndrome.

The vertical and longitudinal ultrastructural changes of the crural muscle (triceps surae) were studied in a selected patient material of 18 patients suffering from post-thrombotic syndrome. The transmission and scanning electron microscopic method helped in revealing that the damage had affected the contractile system, the mitochondria and the endoplasmic reticulum and in addition marked degenerative phenomena occurred. It was shown that vertically the impairments of the fine structure were localized in foci and involved the muscle layers to the same extent. Longitudinally--distally--the muscle changes displayed an increasingly aggravating diffuse appearance. Of the several factors responsible for the development of the pathological ultrastructural picture, tissue hypoxia and metabolic disorder, as well as a decreased microcirculation (hypoperfusion) and chronic inactivity are to be emphasized.

Adult↗
PubMed1988

Plant small nuclear RNAs. V. U4 RNA is present in broad bean plants in the form of sequence variants and is base-paired with U6 RNA.

U4 RNA, which is known to play an indispensable role in pre-mRNA splicing, is present in plant nuclei, has a canonical m3 2,2,7 G cap at its 5' end and is associated with U6 RNA in snRNP particles. It occurs in broad bean in the form of a number of sequence variants. Two of these were sequenced: U4A RNA is 154 and U4B RNA is 152 nucleotides long. Sequence similarity of broad bean U4B RNA is 94 per cent to broad bean U4A RNA, 65 per cent to rat U4A RNA, 61 per cent to Drosophila U4A RNA and 50 per cent to snR14, the U4 RNA equivalent of the yeast Saccharomyces cerevisiae. Sequence conservation is much more pronounced in the 5' half of the molecule than in its 3' half. The secondary structure of both variants of broad bean U4 RNA perfectly fits with that of all other U4 RNAs sequenced so far. Nucleotide changes between broad bean U4A and U4B RNAs are restricted to molecular regions that affect the thermodynamic stability of these molecules. A model is proposed for the base pairing interaction of broad bean U4 RNA with broad bean U6 RNA. This is the first report on the structure of a plant U4 RNA.

Animals↗
PubMed1988

Effect of deltamethrin on transient outward currents in identified snail neurons.

1. The effect of a pyrethroid insecticide deltamethrin was investigated on transient outward potassium currents of identified snail (Helix pomatia) neurones LPa1 and RPa3. 2. In 5 x 10(-5)M concentration the deltamethrin decreased the IA amplitude and the slope of I-V curve. The activation variable was shifted left along the voltage axis by 10-20 mV, while the inactivation variable remained unchanged. 3. Time constant of inactivation decreased, and the relaxation of IA described by one exponential. "Modified" ionic channel fraction was not observed. 4. It is suggested that deltamethrin acts on IA channels through a different molecular mechanism to INa channels, since not only the gating machinery but the permeability of the channels were influenced.

Animals↗
PubMed1988

Comparative studies of single Na-channels in different neuroblastoma cell lines.

Single sodium channel currents were compared in two neuroblastoma (N1E 115, N18) and in two neuroblastoma x glioma (108CC5, 108CC15) hybrid clonal cell lines. Similar single channel parameters were reached from every cell line. The single channel conductance was 11 pS for N1E 115 and N18 cells, and was 10 pS for both hybrid cells at 7-8 degrees C. Except for N18 cells, the amplitude histograms could be best fitted by the sum of two Gaussian functions. The mean channel open time was 1.5-2.0 ms for N1E 115 and the hybrid cells and it was shorter than 1 ms for N18 cells. Open time histograms from N18 cells could be fitted by a single exponential at most potentials, but the sum of two exponentials resulted in a best fit for N1E 115 and the hybrid cells. Differentiation of N1E 115 cells elicited by dibutyryl cAMP instead of dimethylsulfoxide caused only a slight increase in the single channel conductance and open time. The results indicate a certain uniformity of the sodium channels in these cell line.

Animals↗
PubMed1987

Plant small nuclear RNAs. II. U6 RNA and a 4.5SI-like RNA are present in plant nuclei.

Two small nuclear RNA species (U6 RNA and a 4.5SI-like RNA) not described so far for plants were detected in broad bean (Vicia faba L.) nuclei. U6 RNA is 98 nucleotides long, contains psi and methylated nucleotides and shows a surprisingly high degree of sequence homology (80%) with its rat counterpart, particularly in the middle part (a 57 nucleotide-long stretch) of the molecule, where it amounts to 98%. The 4.5SI-like RNA, similar in its structure to 4.5SI RNA detected so far only in rodent nuclei, is 94 nucleotides long, contains psi and an unidentified nucleotide and exhibits 52% overall sequence homology with rat 4.5SI RNA. A block of 20 consecutive nucleotides at the 5' end of the molecule is conserved between broad bean 4.5SI-like RNA and rat 4.5SI RNA. The presence of the two RNA polymerase III internal promoter consensus sequences in 4.5SI-like RNA suggests that it is an RNA polymerase III transcript.

Animals↗
PubMed1987

Isolation of high molecular weight plant nuclear DNA suitable for use in recombinant DNA technology.

Nuclei isolated from leaf cells of broad bean (Vicia faba L) by a newly developed method based on the use of citric acid in the isolation medium and flotation on a Percoll cushion yielded high molecular weight plant nuclear DNA which was suitable for (i) analysis by restriction endonucleases, (ii) molecular cloning and (iii) genomic blot hybridization. Starting from nuclear preparations obtained by this method, U2 small nuclear RNA-specific DNA sequences were detected in Vicia faba L. This is the first report on the demonstration of small nuclear RNA-specific DNA sequences in plant material.

DNA↗
PubMed1985

Plant small nuclear RNAs. Nucleolar U3 snRNA is present in plants: partial characterization.

Nuclei, isolated from a number of plant species by either of two independent, newly developed methods, regularly contained a common set of low-molecular-mass RNAs. Partial characterization of these RNAs, based on cell fractionation, polyacrylamide gel electrophoretic and chemical sequencing techniques, as well as comparison with literature data, revealed that, in addition to tRNA, 5S RNA and 5.8S RNA, plant nuclei contain two families of low-molecular-mass RNAs, that are counterparts of vertebrate U1 and U5 RNAs respectively, and three individual low-molecular-mass RNA species. One of these may be related to vertebrate U6 RNA. The two others are true eukaryotic U2 and U3 RNAs, respectively, on the basis of the following lines of evidence obtained from analyses of broad bean nuclear RNAs. The 3'-end portion (121 nucleotides sequenced) of broad bean U2 RNA shows a nearly perfect sequence homology with that of authentic pea U2 RNA. Broad bean U3 RNA is localized in the nucleolus and its 3'-end portion (164 nucleotides sequenced) (a) shows sequence homology with that of both rat U3 RNA (48%) and Dictyostelium D2 RNA (39%), (b) has a secondary structure which fits perfectly that proposed for both rat U3 RNA and Dictyostelium D2 RNA, and (c) contains the specific sequence which, in a model based on the primary structure of rat U3 RNA, is supposed to be involved in the processing of eukaryotic 32S pre-ribosomal RNA. This is the first report on the occurrence in plants of nucleolar U3 RNA.

Animals↗