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Biomedical subjects

M Antal

Publications and source records attributed to M Antal.

At least 55 records · Page 3Linked to original sources
PubMed1992

Synapses on motoneuron dendrites in the brachial section of the frog spinal cord: a computer-aided electron microscopic study of cobalt-filled cells.

Cobalt-labelled motoneuron dendrites of the frog spinal cord at the level of the second spinal nerve were photographed in the electron microscope from long series of ultrathin sections. Three-dimensional computer reconstructions of 120 dendrite segments were analysed. The samples were taken from two locations: proximal to cell body and distal, as defined in a transverse plane of the spinal cord. The dendrites showed highly irregular outlines with many 1-2 microns-long 'thorns' (on average 8.5 thorns per 100 microns 2 of dendritic area). Taken together, the reconstructed dendrite segments from the proximal sites had a total length of about 250 microns; those from the distal locations, 180 microns. On all segments together there were 699 synapses. Nine percent of the synapses were on thorns, and many more close to their base on the dendritic shaft. The synapses were classified in four groups. One third of the synapses were asymmetric with spherical vesicles; one half were symmetric with spherical vesicles; and one tenth were symmetric with flattened vesicles. A fourth, small class of asymmetric synapses had dense-core vesicles. The area of the active zones was large for the asymmetric synapses (median value 0.20 microns 2), and small for the symmetric ones (median value 0.10 microns 2), and the difference was significant. On average, the areas of the active zones of the synapses on thin dendrites were larger than those of synapses on large calibre dendrites. About every 4 microns 2 of dendritic area received one contact. There was a significant difference between the areas of the active zones of the synapses at the two locations. Moreover, the number per unit dendritic length was correlated with dendrite calibre. On average, the active zones covered more than 4% of the dendritic area; this value for thin dendrites was about twice as large as that of large calibre dendrites. We suggest that the larger active zones and the larger synaptic coverage of the thin dendrites compensate for the longer electrotonic distance of these synapses from the soma.

Animals↗
PubMed1992

Hepatic lipid peroxidation and trace elements--nutritional status in streptozotocin-induced diabetic rats.

The aim of this experiment was to study the interrelationships between nutritional status of chosen trace elements (Cu, Zn, Fe) and hepatic lipid peroxidation in streptozotocin-induced diabetic rats. Both copper accumulation and disruption of iron storage were observed in livers of diabetic rats. MDA 0' (baseline) and MDA 30' (produced) levels measured in the liver were negatively correlated with blood glucose levels. MDA 30' levels correlated positively with iron concentration in the liver. It is supposed that the hormonal lability during experimental diabetes caused changes in metabolism of trace elements, and subsequently influenced the rate of lipid peroxidation.

Animals↗
PubMed1992

[Prophylactic administration of selected antibiotics in hospitals in the Slovak Republic].

Over a period of ten years prophylactic administration of selected antibiotics was evaluated three times (in 1973, 1983, and in 1988) in the same ten hospitals of the Slovak Republic. The study was focused on the use of gentamicin (GEN), cotrimoxasol (COT) and cephalosporins (CEP). Prophylactic administration of antibiotics was found to be increasing. GEN is being given less frequently, while CEP are administered more often, which is considered to be a positive trend. The period of prophylactic administration of antibiotics is still inadequately long with an average of 10.7 days. Evaluation of antibiotic administration showed that antibacterial substances have the highest rate of prophylactic administration in patients with oncologic diseases, followed by patients with diseases of the urinogenital system. A positive development was recorded in the perinatal period with a decreasing trend in the prophylactic administration of antibiotics.

Anti-Bacterial Agents↗
PubMed1991

Different populations of parvalbumin- and calbindin-D28k-immunoreactive neurons contain GABA and accumulate 3H-D-aspartate in the dorsal horn of the rat spinal cord.

The colocalization of parvalbumin (PV), calbindin-D28k (CaBP), GABA immunoreactivities, and the ability to accumulate 3H-D-aspartate selectively were investigated in neurons of laminae I-IV of the dorsal horn of the rat spinal cord. Following injection of 3H-D-aspartate into the basal dorsal horn (laminae IV-VI), perikarya selectively accumulating 3H-D-aspartate were detected in araldite embedded semithin sections by autoradiography, and consecutive semithin sections were treated to reveal PV, CaBP and GABA by postembedding immunocytochemistry. Perikarya accumulating 3H-D-aspartate were found exclusively in laminae I-III, and no labelled somata were found in deeper layers or in the intermediolateral column although the labelled amino acid clearly spread to these regions. More than half of the labelled cells were localized in lamina II. In this layer, 16.4% of 3H-D-aspartate-labelled perikarya were also stained for CaBP. In contrast to CaBP, PV or GABA was never detected in neurons accumulating 3H-D-aspartate. A high proportion of PV-immunoreactive perikarya were also stained for GABA in laminae II and III (70.0% and 61.2% respectively). However, the majority of CaBP-immunoreactive perikarya were GABA-negative. GABA-immunoreactivity was found in less than 2% of the total population of cells stained for CaBP in laminae I-IV. A significant proportion of the GABA-negative but PV-immunoreactive neurons also showed CaBP-immunoreactivity in laminae II and IV. These results show that out of the two calcium-binding proteins, CaBP is a characteristic protein of a small subpopulation of neurons using excitatory amino acids and PV is a characteristic protein of a subpopulation of neurons utilizing GABA as a transmitter. However, both proteins are present in additional subgroups of neurons, and neuronal populations using inhibitory or excitatory amino acid transmitters are heterogeneous with regard to their content of calcium-binding proteins in the dorsal horn of the rat spinal cord.

Animals↗
PubMed1991

Effect of fat and retinol loading on serum triglyceride and retinol levels in patients with ulcerative colitis.

Serum copper, zinc, selenium, magnesium, calcium, cholesterol, triglyceride and retinol contents were determined in 11 patients with ulcerative colitis and in 20 healthy volunteers. Lipid and retinol loadings were performed as well. No differences were found in serum copper, zinc, calcium and selenium levels between the groups. Serum magnesium levels were somewhat lower in the patients than in the volunteers. During the period of loading, cholesterol levels did not differ between the two groups at any time. Triglyceride levels except for two persons, were higher in patients. Triglyceride curves showed pathological courses in each case. Retinol concentrations in patients remained below the values observed in volunteers. Data suggest a disturbed utilization of fat and retinol in patients with ulcerative colitis.

Adolescent↗
PubMed1991

Distribution of GABA immunoreactivity in the optic tectum of the frog: a light and electron microscopic study.

GABA immunoreactivity was studied in the optic tectum of the frog, Rana esculenta, by postembedding immunohistochemical methods at the light and electron microscopic levels. Nearly one-third of the total population of tectal cells appeared to be GABA-immunoreactive. The proportion of stained neurons was highest in layer 9 (61%), and they occurred less frequently in layers 7 (21%) and 6 (27%). Stained perikarya represented a population of small neurons with a diameter of 8-10 microns. Large cell bodies in layer 7 or at the top of layer 6, and cells of origin of the mesencephalic trigeminal tract in layer 2, were devoid of labelling. Axon terminals and dendrites displaying immunoreactivity for GABA were observed in all of the plexiform layers. On the basis of ultrastructural characteristics two types of GABA-positive axon terminals and two variations of GABA-immunoreactive dendrites were distinguished. Synaptic relations of GABA-immunoreactive and GABA-negative axons as well as dendrites were also studied. Besides a wide variety of axodendritic synapses, dendrodendritic synaptic appositions were also revealed. The results suggest that various inhibitory mechanisms are involved in tectal circuits, which have to be incorporated into future neuronal models concerning visual information processing in the optic tectum of the frog.

Animals↗
PubMed1991

Septal GABAergic neurons innervate inhibitory interneurons in the hippocampus of the macaque monkey.

The septohippocampal projection was visualized in three Macaca mulatta monkeys by anterograde transport of Phaseolus vulgaris leucoagglutinin. Following injections of the lectin into the medial septal nucleus, P. vulgaris leucoagglutinin-labelled fibres were found in the hippocampal complex, mainly in stratum oriens of the CA1 subfield, throughout the CA3 subfield, and in the hilus and stratum moleculare of the dentate gyrus. The majority of labelled axons were varicose, and formed multiple contacts with cell bodies and dendrites of calbindin D28k- and parvalbumin-immunoreactive non-pyramidal cells. GABA immunoreactivity of P. vulgaris leucoagglutinin-labelled axons and their postsynaptic targets was investigated by sectioning varicose axon segments for correlated light and electron microscopy, and processing alternate ultrathin sections for postembedding immunogold staining for GABA. All P. vulgaris leucoagglutinin-labelled boutons examined were GABA-immunoreactive and the majority of them formed symmetrical synapses with GABA-immunoreactive cell bodies and dendrites. The results demonstrate that a GABAergic septohippocampal pathway exists in the monkey, and, similar to the rat, terminates on different types of GABAergic neurons, including the parvalbumin- and calbindin D28k-containing non-pyramidal cells.

Animals↗
PubMed1991

[Analysis of the use of gentamicin, cotrimoxazole and cephalosporin in selected hospitals].

The authors investigated the administration of monitored antibiotics, i.e. gentamicin, cephalosporins and cotrimoxazol, as well as of other so-called not monitored antibiotics. The investigation was made in the same 10 hospitals in the Slovak Republic three times in the course of 15 years, i.e. in 1978, 1983 and for the last time in 1988. It was revealed that the number of therapeutic administrations of the monitored antibacterial substances in increasing. The excessive gentamicin administration persists in particular on neonatal, premature-infant and surgical departments. The authors evaluate as a positive feature that the structure of administered antibiotics changes, i.e. the amount of gentamicin administration is declining and the cephalosporin administration has a rising trend. The investigated antibiotics were administered for an average period of 10.6 days which is too long, in particular in gentamicin where the period was as long as 9.2 days. The investigated antibiotics were administered most frequently in diseases of the airways and in diseases of the urinary and genital system.

Cephalosporins↗
PubMed1990

Recurrent dorsal root potentials and motoneuron morphology in the frog spinal cord.

About one third of motoneurons stimulated intracellularly evoked dorsal root potentials (DRP) in the lumbar segments of the isolated and perfused frog spinal cord. Axon collaterals were found in one of the 22 motoneurons filled with HRP (horseradish peroxidase) through the stimulating electrode. In further experiments injecting individual motoneurons with cobalt, and filling the ventral roots with HRP or cobalt, the frequency of occurrence of axon collaterals was about 2% of the number of labelled motor cells. It is suggested that the presence of motor axon collaterals is not indispensable in the generation of the DRP evoked by ventral root or motor cell stimulation.

Animals↗
PubMed1990

Calcium-binding proteins, parvalbumin- and calbindin-D 28k-immunoreactive neurons in the rat spinal cord and dorsal root ganglia: a light and electron microscopic study.

The distribution of two calcium-binding proteins, parvalbumin (PV) and calbindin-D 28K (CaBP), was studied by the peroxidase-anti-peroxidase immunohistochemical method at the light and electron microscopic level in the rat spinal cord and dorsal root ganglia. The possible coexistence of these two proteins was also investigated. PV-positive neurons were revealed in all layers of the spinal cord, except lamina I, which was devoid of labelling. Most of the PV-positive cells were found in the inner layer of lamina II, lamina III, internal basilar nucleus, central gray region, and at the dorsomedial and ventromedial aspects of the lateral motor column in the ventral horn. Neuronal processes intensely stained for PV sharply delineated inner lamina II. With the electron microscope most of them appeared to be dendrites, but vesicle containing profiles were also found in a smaller number. CaBP-positive neurons appeared to be dispersed all over the spinal gray matter. The great majority of them were found in laminae I, II, IV; the central gray region; the intermediolateral nucleus; and in the ventral horn just medial to the lateral motor column. Laminae I and II were densely packed with CaBP-positive punctate profiles that proved to be dendrites and axons in the electron microscope. A portion of labelled neurons in lamina IV and on the ventromedial aspect of the lateral motor column in the ventral horn disclosed both PV- and CaBP-immunoreactivity. All of the funiculi of the spinal white matter contained a large number of fibres immunopositive for both PV and CaBP. The highest density of CaBP-positive fibres was found in the dorsolateral funiculus, which was also densely packed with PV-positive fibres. PV-positive fibres were even more numerous in the dorsal part of the dorsal funiculus. The territory of the gracile funiculus in the brachial cord and that of the pyramidal tract in its whole extent were devoid of labelled fibres. In the thoracic cord, the dorsal nucleus of Clarke received a large number of PV-positive fibres. Dorsal root ganglia displayed both PV- and CaBP-immunopositivity. The cell diameter distribution histogram of PV-positive neurons disclosed two peaks--one at 35 microns and the other at 50 microns. CaBP-positive cells in the dorsal root ganglia corresponded to subgroups of small and large neurons with mean diameters of 25 microns and 45 microns, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

[Transfer of resistance to the newer beta-lactam antibiotics in Czechoslovakia].

Transmitted resistance to recent cephalosporin antibiotics of the third generation was first proved in 1983 by the authors. Approximately five years later the authors revealed during systematic monitoring of bacterial strains resistant to cephtazidime, cephtriaxone and cephotaxim also transmitted resistance to these and other more recent beta-lactam antibiotics in Czechoslovakia. The authors advocate rational use of new cephalosporins and other beta-lactams (e. g. aztreonam) as reserve antibiotics.

Anti-Bacterial Agents↗
PubMed1990

Retrograde transport of the lectin Phaseolus vulgaris leucoagglutinin in frog central nervous system.

The transport properties of the lectin Phaseolus vulgaris leucoagglutinin (PHA-L) were tested in the frog central nervous system. After delivery of the lectin to the lower brainstem by iontophoresis, stained axons and axon terminals, as well as neurons with richly arborizing dendrites, were observed indifferent regions of the brain and spinal cord even far away from the site of application. The large number and the Golgi-like appearance of labeled neurons situated rostral and caudal to the site of PHA-L deposit indicate that PHA-L is transported equally in both the anterograde and the retrograde direction in the central nervous system of the frog. This is in contrast with the mammalian nervous system, in which PHA-L is transported predominantly in the anterograde direction and the retrograde transport is poor.

Animals↗
PubMed1989

Subacute toxicological examination of Dithane M-45.

A subacute toxicological study of the effects of the ethylene-bisdithiocarbamate-containing fungicide Dithane M-45 (80% mancozeb) was carried out in male Wistar rats. The rats were given Dithane mixed in the feed at doses of 0, 10, 50, 75, 113, 169, 253 or 379 mg/kg body weight for 12 wk. One-third of the rats given 379 mg Dithane/kg body weight died, and doses of greater than or equal to 169 mg/kg decreased the growth of the rats as well as the nutrient utilization. The relative weights of the liver and thyroid were significantly increased in rats given greater than or equal to 75 mg Dithane/kg body weight, and those of the kidneys, adrenals and testes were significantly increased in the two highest dose groups. The serum cholesterol level was increased significantly in groups given greater than or equal to 75 mg/kg, and doses of 113, 169 or 253 mg/kg caused the elevation of the triglyceride content of the liver. The two highest doses of Dithane decreased the detoxicating capacity of the liver. The function of the thyroids was impaired even by very small doses of Dithane: at a dose of 10 mg/kg body weight the quantity of iodine stored in the thyroids was decreased by 20%. At doses of greater than or equal to 50 mg/kg statistically significant decreases in thyroid iodine content were observed. Histological examination of the thyroids showed dose-dependent hyperplasia in rats treated with Dithane.

Animals↗