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Biomedical subjects

M Antal

Publications and source records attributed to M Antal.

At least 73 records · Page 4Linked to original sources
PubMed1989

Transductional analysis of imipenem-ceftazidime-and azactam resistant Pseudomonas aeruginosa strains from nosocomial infections.

Six strains of P. aeruginosa, resistant to IMI, CTZ and/or AZA, or to two of these drugs even to all three antibiotics, have been analysed by transduction by standard transducing phages F116 and G101, propagated on these strains, as well by a wildtype phage isolated from one of P. aeruginosa strains resistant to CTZ and AZA. Analysis of occurrence of resistance determinants in individual sets of transductants allows us to conclude that all three antibiotic-resistance determinants are separable by transduction and, thus, the resistance to any of these three antibiotics is genetically governed by independent determinants. None strain, resistant to these antibiotics, could hydrolyse any of these drugs, with an exception of slow hydrolysis of IMI, observed also by other investigators [8]. In contrast, strains hydrolysed classical, first-generation cephalosporins as well as Cefoxitin, and transferability of these two determinants could be proved by transfers, to Enterobacteriaceae (P. aeruginosa are naturally resistant to these two antibiotics). Thus, resistance to IMI, CTZ and/or AZA, is not co-transferred, with determinants of resistance to more classical cephalosporins.

Aztreonam↗
PubMed1989

[Transmission of resistance to 1st and 2d generation cephalosporins].

The authors investigated the incidence of transferable resistance in bacterial strains resistant to cephalosporins of the first and second generation in the course of two years in materials of the microbiological department of one of the larger district hygiene stations. They recorded the development of the first strains resistant also to cephamandol, although this antibiotic is not used at all in the above area, and in exceptional instances also resistance to cephotaxime. It was revealed that the transferable resistance to cephamandol is due to the presence of an enzyme which hydrolyzes this antibiotic. When using cephalosporins of the first generation, it is important to foresee an increasing incidence of transmitted resistance to these antibiotics and possibly some strains resistant also to cephalosporins of the second generation and in exceptional cases strains resistant to cephalosporins of the third generation.

Cephalosporins↗
PubMed1988

Examination of the interaction of decis and dithane in rats.

Acute (LD50) and short-term (14 days) toxicological examinations were performed in animal experiments on the interaction of a synthetic pyrethroid Decis 2,5 EC (25 g deltamethrin/l) and of ethylene-bisdithiocarbamate/Dithane M-45 (80% mancozeb), using a 1:5 deltamethrin/mancozeb mixture. LD50 value of the mixture was similar to that of the more toxic Decis. In the short-term examination, some pathologically high AST and ALT values were observed in the treated groups and the deltamethrin content of fatty tissue samples increased parallel with the increase of Decis consumption. The chymotrypsin and lipase activities in the small intestinal mucosa and gamma-GT and LAP activities in the content of the bowels were reduced in several treated groups. The administration of Dithane in a dose in accordance with 20% of the LD50 value (3125 mg/kg b.m.) proved to be more toxic than expected and caused the death of the animals.

Adipose Tissue↗
PubMed1988

GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus.

The hippocampus, in particular the neocortex-hippocampus-neocortex circuit, is widely believed to be crucial in memory. Information flow in this circuit is strongly influenced by relatively sparse afferents derived from subcortical centres, such as the septum, involved in arousal, emotions and autonomic control. A powerful mechanism, by which numerically small inputs can produce profound effects, is feed-forward inhibition, that is, the activation of local inhibitory interneurons, which, in turn, control the activity of large populations of principal cells in the hippocampus. An example is the cholinergic input to the hippocampus from the septum, which is likely to be involved in feed-forward operations. Here, we demonstrate the existence of a circuit underlying another powerful mechanism of subcortical control of hippocampal information processing. We show that GABA-containing afferents originating in the septum innervate most of the GABA-containing interneurons in the hippocampus, making many synaptic contacts with each of them. Activation of the GABA-containing neurons in the septum is likely to lead to disinhibition of the principal neurons in the hippocampal formation and so this pathway is probably crucial in the induction of hippocampal electrical activity patterns, and may be involved in NMDA (N-methyl-D-aspartate) receptor-mediated functions, such as memory, in a permissive manner.

Afferent Pathways↗
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

Longitudinal examinations in the course of dietotherapy of mentally retarded obese in-patients.

Mentally retarded obese in-patients were fed by low-energy diet (4.2-4.6 MJ) for 9 months. During this period, an average of 13 +/- 4.5 kg loss of body mass occurred in men and 16 +/- 2.7 kg in women. Anthropometric measurements were performed before starting the dietotherapy and in the ninth month. Changes of body fat could be followed well when calculated according to BMI. Less reliable results were obtained with skinfold thickness measurements, presumably due to body deformities. Results of clinical laboratory tests, which were carried out before starting the dietotherapy and in the fourth and seventh months, suggested that a low-energy-containing diet with balanced nutrient content and adequate protein intake did not impair protein metabolism, favourably affected serum triglyceride and cholesterol levels, but resulted in an unfavourable decrease in the HDL-cholesterol content.

Adult↗
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

Phagocytosis of myelin sheath fragments by dendrites.

In serial ultrathin sections of the frog spinal cord, profiles of dendritic appearance were identified that contained myelin fragment inclusions and received synaptic contacts. In a number of cases it could be established that the inclusions were derived from adjacent myelin sheaths. It is suggested that the phenomenon may refer to a turnover of the myelin sheath in which the detached myelin fragments are eliminated by dendrites.

Animals↗
PubMed1987

PHA- and Con A-induced chemiluminescence of human blood mononuclear cells and granulocytes in luminol or lucigenin.

Phytohemagglutinin (PHA) and concanavalin A (Con A) can evoke a chemiluminescence (CL) response both in granulocytes and blood mononuclear cells. We have used two parallel systems to compare the quantity and quality of oxygen radicals produced during activation. While the luminol-enhanced CL response is linked to the myeloperoxidase-H2O2-chloride system, the lucigenin-dependent light production measures only the superoxide radical. PHA produced higher CL response in the presence of luminol than with lucigenin. Con A showed high CL response only in the lucigenin-enhanced system. The results suggest that while Con A induces mostly superoxide production, the membrane stimulus evoked by PHA produces light through the myeloperoxidase-H2O2-halide system. Granulocytes are less sensitive to PHA than the blood mononuclear cells. The sensitivity of the responses to several scavengers and enzymes support the differential production of oxygen radicals following activation via these two lectins.

Acridines↗
PubMed1986

Tectal neurons of the frog: intracellular recording and labeling with cobalt electrodes.

With the aid of cobalt-filled intracellular electrodes, responses evoked by electrical and visual stimulation were recorded from tectal neurons. Diffuse light and "edge" and "spot" stimuli were used for visual stimulation; electrical stimuli were delivered by means of bipolar electrodes to the optic tract. The cells were subsequently filled with cobalt for a correlative histological study. The following types of neurons were distinguished: (1) Pear-shaped neurons with restricted and broad dendritic fields occurring in tectal layers 8, 6, 4, and 2. In one group, the dendrites bore beads and small protrusions and the short axon arborized within, or close to, the dendritic arbor. They responded mostly with inhibitory postsynaptic potentials to the various stimulations. This type of neuron was interpreted to be a tectal interneuron. In the second group the dendrites were smooth, the dendritic arbor was large, and the axon could be followed to layer 7 in a few cases. Excitatory activities with frequent spike discharges prevailed in their responses. They were regarded as efferent neurons of the tectum. (2) Large ganglionic neurons showed a greater variation in form than has been described in previous Golgi studies. Their responses to the different stimulations were also very variable. The axons of five neurons could be followed to the dorsal part of the thalamus, to the postoptic commissural system, and to the direct and crossed tectobulbar tract. These axons emitted several collaterals to tectal, pretectal, and tegmental structures. (3) A single stellate neuron was impaled in layer 9. It responded only to electrical stimulation with excitation. (4) Deep bipolar neurons were not mentioned in earlier works. Their somata were found in layer 6; the vertically oriented dendrites arborized in plexiform layers 7, 5, and 3, over a distance of more than 1 mm. These cells were sensitive only to electrical stimulation.

Animals↗