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Biomedical subjects

J Barna

Publications and source records attributed to J Barna.

At least 19 recordsLinked to original sources
PubMed2002

Reorganization of the GABAergic system following brain extirpation in the earthworm (Eisenia fetida, Annelida, Oligochaeta).

The reorganization of the GABAergic system was studied by means of immunohistochemistry after the symmetrical and asymmetrical (unilateral) extirpation of the brain of the annelid Eisenia fetida. GABA-immunoreactive neurons were first observed in the wound tissue on the 3rd postoperative day. Thereafter the number of labelled cells gradually increased, and by postoperative days 76-80 all GABA-immunoreactive cells (approx. 140 neurons) could be found in their final positions in the symmetrically regenerated brain. After asymmetrical brain extirpation, nearly all cells (70-75) could be detected in the regenerating hemisphere by postoperative days 50-56. In the early stages of the asymmetrical regeneration of the brain, more GABAergic cells were concentrated dorsally and laterally in the preganglion than during the symmetrical type of regeneration. In both types of regeneration, the immunoreactive neurons in the regenerated brain originated in part from undifferentiated neuroblasts situated in different parts of the body, and in part from dividing neurons localized mainly in the pharyngeal nerve plexus. Both exogenous GABA and picrotoxin, applied during the early stages (days 10- 12) of brain regeneration, inhibited the development of the wound tissue and the migration of the neuroblasts and the enteric neurons. At the same time, exogenous GABA application accelerated the proliferation of the pharyngeal neurons. No effect on the process of regeneration could be demonstrated when exogenous GABA and picrotoxin were given together.

Animals↗
PubMed2001

Distribution and action of some putative neurotransmitters in the stomatogastric nervous system of the earthworm, Eisenia fetida (Oligochaeta, Annelida).

The chemical neuroanatomy of the stomatogastric nervous system of the earthworm, Eisenia fetida, has been investigated, using antibodies raised against serotonin, tyrosine hydroxylase, octopamine, GABA, FMRFamide, proctolin, Eisenia tetradecapeptide and neuropeptide Y. Neurons immunoreactive to these antibodies can be observed in the stomatogastric ganglia. The labelled cells comprise altogether 95.4% of the total number of neurons in the ganglion. Immunoreactive projections were followed between stomatogastric individual ganglia as well as towards the enteric plexus. Intrinsic neurons containing the different signal molecules examined are present along the entire length of the enteric plexus, but serotonin immunoreactive perikarya were only found in the hindgut. The density of the different immunoreactive neurons, except the serotonin ones, is highest in the pharyngeal plexus, and the number of labelled neurons decreases along the alimentary canal towards the hindgut. A number of epithelial cells also reveal tyrosine hydroxylase, octopamine, GABA and Eisenia tetradecapeptide immunoreactivity. The action of some putative neurotransmitters, such as dopamine, octopamine, serotonin and proctolin was tested on foregut preparations. Dopamine and octopamine (10(-6)-10(-4) M) have an excitatory effect on the musculature, whereas the effect of serotonin depends on the actual muscle tension. Following precontraction evoked by acetylcholine, serotonin in low concentrations (10(-7)-10(-6) M) causes relaxation, whereas in higher (10(-4) M) concentration it evokes slight contractions. In preparations at basal tone, serotonin (10(-7)-10(-6) M) evokes contractions of the foregut. Atropine strongly inhibits the action of acetylcholine but is ineffective against serotonin, dopamine and octopamine. Similarly, the Na+ channel blocker tetrodotoxin fails to influence the contractile effect of dopamine, octopamine and serotonin. These results suggest that dopamine, octopamine and serotonin act directly on the muscle cells of the alimentary tract. Proctolin do not evoke any significant effect on the foregut.

Animals↗
PubMed2000

Distribution of Eisenia tetradecapeptide immunoreactive neurons in the nervous system of earthworms.

A detailed mapping of Eisenia-tetradecapeptide-immunoreactive neurons in the central and peripheral nervous system combined with quantitative morphological measurements was performed in Eisenia fetida and Lumbricus terrestris. In Eisenia, most labelled neurons were observed in the ganglia of the ventral cord (20.38% of the total cell number of the ganglion) and 15.67% immunoreactive cells occurred in the brain, while 6% of the neurons could be shown in the subesophageal ganglion. In the case of Lumbricus, most immunoreactive cells were found in the subesophageal ganglion (16.17%) and in the ventral ganglia (12.54%). The brain contained 122 ETP-immunoreactive cells (5.6%). The size of the immunoreactive cells varied between 35-75 microm. A small number of Eisenia-tetradecapeptide immunoreactive fibres were seen to leave the ventral ganglia via segmental nerves, and labelled processes could also be observed in the stomatogastric system and the body wall. Labelled axon branches originating from the segmental nerves formed an immunoreactive plexus both between the circular and longitudinal muscle layer and on the inner surface of the longitudinal muscle layer. This inner plexus was especially rich in the setal sac. Among the superficial epithelial cells the body wall contained a significant number of immunoreactive cells. Only a few Eisenia-tetradecapeptide immunoreactive neurons and fibres occurred in the stomatogastric ganglia. In the enteric plexus the number of immunoreactive neurons and fibres decreased along the cranio-caudal axis of the alimentary tract. Eisenia-tetradecapeptide immunoreactive cells were also present among the epithelial cells in the alimentary canal. Some of these cells resembled sensory neurons in the foregut, while others showed typical secretory cell morphology in the midgut and hindgut.

Animals↗
PubMed2000

Reorganization of peptidergic systems during brain regeneration in Eisenia fetida (Oligochaeta, Annelida).

After the extirpation of the brain reorganization of the peptidergic (FMRFamide, neuropeptide Y, proctolin) systems was studied in the newly forming cerebral ganglion of the annelid Eisenia fetida. During regeneration, all immunoreactive fibres appear on the 1st-2nd postoperative day. At the beginning of regeneration, immunoreactive neurons and fibres form a mixed structure in the wound tissue. On the 3rd postoperative day, FMRFamide positive and neuropeptide Y-immunoreactive, while on the 7th postoperative day proctolin-immunoreactive neurons appear in the loose wound tissue. From the 25th postoperative day a capsule gradually develops around it. The neurons of the preganglion move to the surface of the newly appearing preganglion. The number of these cells gradually increase, and by the 72th-80th postoperative days the localization and number of peptide-immunoreactive neurons is similar to that in the intact one. The neurons of all examined peptidergic systems may originate from the neuroblasts, situated on the inner and outer surface of the intact ganglia (e.g. suboesophageal and ventral cord ganglia). In addition FMRFamide and proctolin immunoreactive neurons may take their derive by mitotic proliferation from the pharyngeal neurons, too.

Animals↗
PubMed1998

Effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa in vitro.

The effects of taurine on the motility and intracellular free Ca2+ concentration of fowl spermatozoa were investigated in vitro. The addition of taurine, within the range of 0-5 mmol l(-1), did not appreciably affect the motility of intact fowl spermatozoa. Motility remained almost negligible at 40 degrees C, while vigorous movement was observed at 25 degrees C. Even with the addition of Ca2+ before the addition of taurine, neither stimulation nor inhibition of motility was observed compared with the control (no addition of taurine). Similar results were obtained by the addition of taurine and calyculin A, a specific inhibitor of protein phosphatases. There were no changes in intracellular free Ca2+ concentrations, measured by a fluorescent Ca2+ indicator, fura-2, in taurine-treated spermatozoa. These results suggest that taurine is not involved in the regulation of fowl sperm motility and metabolism by intracellular Ca2+ mobilization in vitro.

Animals↗
PubMed1997

Octopamine-containing neurons in the alimentary tract of the earthworm (Eisenia fetida).

Octopamine-containing nerve cells have been demonstrated in the enteric plexus of the earthworm (Eisenia fetida), applying immunocytochemistry and HPLC assay. A few octopamine-immunoreactive neurons occurred in the fore- and hindgut, whereas their number in the midgut was considerably greater. Octopamine levels detected by HPLC correlated with the distribution of octopamine-containing nerve cells. A regulatory role for these intrinsic octopaminergic neurons is suggested in the enteric plexus in the earthworm alimentary tract. This is the first report on the occurrence of octopamine-containing nerve cells in the peripheral nervous system of an invertebrate.

Animals↗
PubMed1996

Unchanged intestinal absorption in rats fed a high sweet paprika-containing diet.

The absorption rate of radiolabelled nutrients (22Na, 45Ca, [35S]methionine, [3H]leucine) was investigated in vivo in Sprague-Dawley rats at the end of a feeding period of 135 days on a semisynthetic diet containing 32% sweet paprika powder. No effect was seen on the intestinal absorption of these compounds, nor on the nutritive experimental parameters in these animals.

Animals↗
PubMed1996

Motility and agglutination of fowl spermatozoa in media of different amino acid content and pH value in vitro.

The objective of the present experiments was to study some properties of fowl spermatozoa which may play a role in the sperm storage and emptying mechanism of the uterovaginal sperm storage tubules (SST) of the hen. The effects exerted by different amino acids (aspartic acid, Asp; glutamic acid, Glu; gamma-aminobutyric acid, GABA; glycine, Gly) and by the pH of the environment at 24 and 39 degrees C on the motility and agglutination of cock spermatozoa were studied in vitro. The spermatozoa did not show agglutination in the presence of Asp and Glu, and became immobilised if the concentration of Glu or the acidity of the environment was increased. In neutral solutions of GABA and Gly or in a faintly alkaline solution characteristic plait-like conglomerations could be seen. The motility of spermatozoa immobilised by Glu could be restored in a varying degree by the addition of GABA or Gly. At a temperature of 24 degrees C, the spermatozoa became immobilised in a medium of pH 6.0 while showed maximum motility at pH 7.1. At 39 degrees C, the spermatozoa were immobilised at higher pH (6.2) and required a pH value as high as 7.4-7.5 to show the highest motility. Spermatozoa inactivated in an acidic solution could be immediately mobilised by alkalisation of the medium, irrespective of the Ca2+ content of the solution. Thus, Ca2+ was not found to play a role in the reactivation of spermatozoa. Nevertheless, marked differences were observed in the maintenance of sperm motility between solutions either containing or lacking Ca2+. As the concentration changes of the above-mentioned amino acids and the pH changes were found to affect the motility and agglutination of spermatozoa in vitro, they may influence also the regulatory mechanism of the uterovaginal SST during the egg-formation cycle in vivo.

Amino Acids↗
PubMed1996

Amino acid secretion of the hen's oviduct during the egg formation cycle.

The free amino acid content of 34 hens' oviducts was determined in different phases of the egg formation cycle. In addition, quantitative changes of transmitter-type amino acids (glutamic acid, aspartic acid, taurine, glycine) were monitored in comparison with those of other amino acids participating in protein synthesis (e.g., lysine, tyrosine, valine). Different portions of the hen's oviduct, primarily the magnum and the uterus, were characterised by substantial amino acid secreting activity. The amino acids detectable in the highest quantity were taurine, glutamic acid, glycine and aspartic acid. These amino acids were present in high concentrations throughout the egg formation cycle, but their quantity abruptly decreased at the time of oviposition and ovulation. The quantitative changes of transmitter-type amino acids are mostly independent of those of other amino acids participating in protein synthesis. Since in our earlier in vitro studies the concentration changes of the transmitter amino acids studied were found to affect the motility and agglutination of spermatozoa, they--besides other factors--can be assumed to exert an influence on the sperm storage and release processes of the uterovaginal sperm storage tubules located in the oviduct of birds.

Amino Acids↗
PubMed1994

The number of ganglion cells in the intact and regenerated nervous system in the earthworm (Lumbricus terrestris).

1. The nerve cell number is higher in the cerebral ganglion than in the subesophageal or segmental ganglia of Lumbricus terrestris. 2. The nerve cell number of the subesophageal ganglion is similar to that of the segmental ganglia in spite that the latter developed from a fusion of several ganglia. 3. Segmental ganglia in front and behind the clitellum can be considered as "typical" ganglia. 4. The most caudal segmental ganglia are less differentiated and resembles to the embryological state. 5. Nerve cells of the regenerating ganglia, at least in part, originate from undifferentiated nerve cells of the intact ganglia.

Animals↗
PubMed1994

Evaluation of testosterone response to intramuscular injection of GnRH and its correlation with sperm quality parameters in cockerels.

Eight 40-week-old New Hampshire cockerels (average liveweight: 3.10 +/- 0.2 kg) were used for studying the testosterone response to a single intramuscular dose (5 micrograms/kg b.w.) of exogenous 6D-Phe gonadotropin releasing hormone (GnRH). Serum samples were collected at 15-min intervals during the first hour and at half-hour intervals up to two hours post injection. The semen samples were collected 24 h before GnRH treatment. Testosterone peaks were found 45 to 60 min after the treatment. The coefficient of correlation between the semen quality parameters and the testosterone response to GnRH was evaluated both by Rank correlation and by multiple regression analyses. Rank correlation showed moderate but not significant values while multiple regression analyses showed a close correlation (multiple R = 0.72). The results show that testosterone response to GnRH may be used as a marker of semen quality in cockerels.

Animals↗
PubMed1982

Hind limb somatosensory evoked potentials in the monkey: the effects of distal axonopathy.

Computer-averaged short-latency somatosensory evoked potentials (SLSEP) to unilateral stimulation of the peroneal nerve were recorded from surface electrodes overlying the peripheral nerve, cauda equina, spinal cord, brainstem, and contralateral sensorimotor region. Seven monkeys were studied under normal conditions and at various stages of distal axonopathy induced by systematic acrylamide intoxication. With the use of a noncephalic reference, a series of five small-amplitude positive components were identified that precede the initial cortical activity. On the basis of timing and topography of the components, the source of the first one, SLSPEP1, was localized to the lumbar dorsal root fibers and that of the second, SLSEP2, to the ascending spinal tracts, principally gracile fasciculus. Bipolar recordings of the SLSEP2 overlying the rostral extreme of the cervical spinal cord provided a sensitive measure of the onset of distal axonopathy. Changes in the timing of this component antedated both abnormalities of spinal or peripheral nerve conduction and behavioral signs of intoxication. The initial alteration was specific to stimulation of the hind limb and was associated with early morphological change limited to the terminal and preterminal portions of the long axons in the gracile fasciculus.

Acrylamide↗
PubMed1981

[Roentgen diagnosis of congenital hip dysplasia].

The X-ray of 4000 infants between the age of 4-6 months have been examined, regarding correlations between the measured Hilgenreiner's acetabular roof angle and the position of the pelvis during X-raying. Faulty positioning often was found, and only in 34,2% was the pelvis symmetric and the pelvic inclination normal, when the photos were made. The change of the acetabular roof angle due to the incorrect pelvic position is not always significant. The geometrical correction of these values is therefore not important and the other radiological signs of CDH can be relied on.

Hip Dislocation, Congenital↗