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Biomedical subjects

S Tóth

Publications and source records attributed to S Tóth.

At least 19 recordsLinked to original sources
PubMed1995

Chronic overcrowding decreases cytoplasmic free calcium levels in T lymphocytes of aged CBA/CA mice.

Intracellular calcium concentration is a sensitive marker of the homeostasis of living cells, and its increase is an essential step of T lymphocyte activation. Changes in the environment provoke an adaptive stress-response of the organism. In our present work we have investigated the effect of chronic overcrowding on resting and lectin-stimulated cytoplasmic free calcium concentration of splenic T lymphocytes from young and aged CBA/CA mice (50 animals total). The animals were kept under 'normal' (68 cm2/animal) or 'overcrowded' (22 cm2/animal) conditions for 3 months. Young animals showed no change in resting and stimulated calcium after overcrowding. T cells from aged mice, however, displayed significantly smaller levels of both resting and lectin-stimulated intracellular calcium concentration (p < 0.01 each), as compared to those of the non-stressed, aged animals. This inadequate adaptation in the calcium metabolism of T lymphocytes may significantly contribute to the diminished immune response of the aged in stress.

Aging↗
PubMed1995

Long-lasting persistence of elevated sister-chromatid exchange frequencies induced by perinatal benzo(a)pyrene treatment in rat bone-marrow cells.

In this work the possibility that a mutagenic factor acting in utero or in the perinatal period might lead to elevated mutagenic rates in bone-marrow cells after a considerable period of time was examined. An aromatic hydrocarbon, benzo(a)pyrene was used as the test substance. Benzo(a)pyrene treatments resulted in significantly higher sister-chromatid exchange (SCE)-frequencies in both fetal and neonatal groups in both sexes, even four months after exposure. In a second experiment we examined whether mutagenic exposure suffered in utero could make the individual more susceptible to mutagenic effects in adulthood. Preliminary results indicate that such a possibility could exist.

Animals↗
PubMed1992

Immunotoxic effects of MPT-IP containing 60% methylparathion in mice.

The effects of a single large and repeated small doses of MPT-IP (the industrial product used to produce Wofatox EC 50) containing 60% methylparathion, on the humoral and cellular immunoreactivity of CFLP mice were investigated. Administration of a single LD50/2 dose 3 d prior to immunization caused a 40% increase in the number of splenic PFC on the 5th day but no significant increase in serum antibody titre on the 7th day after immunization. Treatment for 4 weeks with an LD50/40 dose resulted in a 100% increase in splenic PFC, also not associated with a change in serum antibody titre. Under the same conditions and LD50/20 dose had no effect on these parameters. Neither the single large nor the repeated small doses had any effect on the intensity or time course of a DTH reaction. The results show that MPT-IP has an immunotoxic potential in mice under certain experimental conditions.

Animals↗
PubMed1991

Interactions between human and porcine interferons.

To investigate the possible interactions between human and porcine interferons (IFNs) in vitro, human transformed (FL) and nontransformed (HEF) cells were treated with either HuIFN alpha and/or gamma and porcine alpha and/or gamma. In both cases the antiproliferative activity was measured to determine the effects of different combinations between human and porcine IFNs on cell proliferation. Combinations of human and porcine IFNs acted mostly antagonistically with exception of IFN combination Hu-alpha/Po-gamma which showed a synergic cooperativity in therms of antiproliferative activity on human transformed cells.

Amniotic Fluid↗
PubMed1989

Propagation of focal epilepsies and the timing and targeting of surgical interventions. Illustrative case reports.

The mirror focus conception assumes propagation of epileptic excitation towards a homotopic area of the contralateral hemisphere inducing secondary focal discharges. Later, independent discharges can be initiated by this new area of epileptogenesis but initiation of seizures of the same or altered symptomatology--and not only interictal discharges--from a mirror focus has yet not been proved. Three cases will be presented where dynamism of the development of temporal lobe mirror focus have been followed. All cases give rise to several questions concerning selection and timing of surgical approach.

Adolescent↗
PubMed1989

Decreased cytosolic free calcium concentration of aged human lymphocytes in resting state.

Cytosolic free calcium concentration was measured in lymphocytes from individuals over the age of 80, using quin2 and fura-2 calcium indicators. The average intracellular free calcium concentration of the samples was 62 nM, which value is roughly half the adult (age between 35 and 55) level (116 nM). It is supposed that the decline in immune function of aged individuals is connected to the decrease in free calcium concentration in their lymphocytes. We also discuss the consequences and the adaptive character of this decrease.

Adult↗
PubMed1989

Effect of storage and 60Co irradiation on the antiviral activity and subtype pattern of native human interferon-alpha preparations.

The stability of native human leukocyte IFN-alpha was investigated after one year storage at different temperatures, or after sterilization with 60Co-irradiation by determining the total antiviral activity of samples. Inactivation of VSV and Aujeszky virions by 60Co-irradiation was directly related to the radiolysis of samples, indicating the uselessness of this procedure for sterilization of IFN-alpha preparations. The presence and proportion of subtypes in the stored or irradiated preparations (with 50 and 25-70% inactivation, respectively) was analysed by chromatofocusing, comparing their patterns with that of the untreated controls. A logarithmic correlation was found between the pI values and temperature/irradiation sensitivity of subtypes.

Antiviral Agents↗
PubMed1989

Some basic features of the pathological and normal motor system studied by chronic deep electrodes.

Our stereotactic experiences in agreement with the literature showed, that different target points could influence the same motor disturbance. To choose the best target point or target point combinations we generally implant the electrodes into VL, Vim, CM, P, dentate nucleus and motor cortex. To ensure the correct sequence of therapeutic lesions we developed an investigation system, taking into consideration the resting and the working state of the motor system. We elicited events centrally (stimulation of the different target points) and peripherally (reflexes) and recorded the evoked potentials at the non-stimulated sites along with the motor and motor modulation effects in the appropriate muscles. The elicited events depend on the site of stimulation and registration and on the state of muscle activity. The centrally and peripherally elicited events influence each other. With our technique the elicited events and their functional dependency is most explicit within the motor system. The results help to explain some basic motor functions and help to answer some of our therapeutic questions.

Athetosis↗
PubMed1988

Further experiences in the treatment of cystic craniopharyngeomas with yttrium 90 silicate colloid.

20 patients suffering from cystic craniopharyngioma were treated with intracavitary irradiation on 25 occasions. The beta emitting radionuclide 90Y silicate colloid was instilled into the cyst or cystic part of the tumour. 17 patients on 22 occasions underwent follow-up CT and ophthalmological examinations 1 to 144 (average: 34) months after the intracavitary radioisotope therapy. An 23 occasions there was an average of 82 to 90% volume decrease of the craniopharyngioma cysts. On two occasions the volume has remained unchanged and the result of the 90Y therapy cannot be evaluated yet. The neuroophthalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, it is the fibrotic tissue that is responsible for the shrinkage of the cyst.

Brain Neoplasms↗
PubMed1987

Investigation of trigeminal SEP with scalp and deep electrodes.

A special technique for stimulating and recording trigeminal somatosensory evoked potential (SEP) is described. Eleven healthy subjects and seven patients with chronically implanted deep electrodes have been investigated. Characteristic polyphasic waves were repeatedly observed. The recording of somatosensory evoked potential following trigeminal stimulation is a more difficult technique. This paper describes data in control subjects with scalp electrodes and data on patients with electrodes in the nucleus ventralis posteromedialis and cortical white matter. Depth recording may provide useful information about the origin, nature, and properties of trigeminal SEP.

Electrodes, Implanted↗
PubMed1987

Overlapping imprinting of oligopeptides in Chang liver cells. Data on the mechanism of hormone evolution.

Imprinting was induced with synthetic oligopeptides in Chang liver cell cultures to test these molecules for signal molecule value. Investigations into imprinting overlaps (cross-imprinting) have shown that all oligopeptides (di-, tetra- and pentapeptides) carrying a terminal proline group were able to imprint the cells for the pentapeptide Tyr-D-Met-Gly-Phe-Pro-NH2, which displayed an outstanding imprinting potential for itself and an extraordinary opioid activity as well. The fact that exclusively the proline-deficient oligopeptide (a tetrapeptide) failed to imprint for the pentapeptide in question, indicates a decisive role of proline in the transformation of molecules to signal carriers (hormones). The pentapeptide in question did imprint for the related molecules (except the dipeptide) but to a much lesser degree than for itself. The marked inferiority of the pentapeptide's cross-imprinting potential to its self-imprinting potential supports the hypothetical implication that a considerable difference between the specific and non-specific binding capacities of a molecule, if not the loss of non-specific binding was an essential prerequisite of transformation to a signal molecule, i.e. of hormone evolution.

Animals↗
PubMed1986

Surgical treatment of multiple intracranial aneurysms.

Patients with multiple intracranial aneurysms present a great challenge to neurosurgical practice. The presence of one or more additional aneurysms, whether recognized or unrecognized, along with the source of the haemorrhage profoundly changes the outcome. It also alters the timing and strategy of surgery. In this study the experiences gained from 138 cases with a total of 317 aneurysms are discussed. The analysis of the clinical data, our results and the factors influencing the outcome suggest that the risk of clipping all aneurysms simultaneously are less than the risk of a rebleed from an untreated, previously silent sac even in the early postoperative period.

Adolescent↗
PubMed1986

The surgery of middle cerebral artery aneurysms.

Aneurysms of the middle cerebral bifurcation represent an interesting entity among intracranial saccular aneurysms. Their shape, size, situation, and in particular their relation to the middle cerebral trunk and its branches show wide variations. Topographical analysis of the angiograms offers a great deal of interest in planning surgery. Our experience with 289 patients with middle cerebral artery aneurysms operated on since 1977 are presented. Factors such as number of previous haemorrhages, timing of surgery, preoperative condition, major intraoperative bleeding or brain oedema and delayed postoperative deterioration play a major role in the outcome. Others such as severity of the subarachnoid bleed, age, size of the sac seem to have much less influence.

Adult↗
PubMed1986

Computer analysis of some bacteriological, biological and physiochemical parameters of the coastal water of Lake Balaton.

Some 61 coastal water samples were taken at four definite points of Balaton Lake. Seventeen parameters of each sample characterizing the quality of the water were studied by means of multiple correlation and regression analysis, one-way variance analysis and by factor analysis with the help of BMD computer program. Uni- and multilateral relationships could be observed among the single parameters. On the basis of the results of factor analysis six factors--phytoplankton system, anthropogenic effect, own bacterial system of the lake, nitrogen circulation, hydrocarbonate and reactive phosphate system and NH+4 circulation--could be separated. Significant qualitative differences could be found along the longitudinal axis of Balaton. It could be also demonstrated that the water of the lake in its present condition is suitable for the proliferation of bacteria. Further and deeper examinations are necessary for a better understanding of the biochemical and biological processes.

Analysis of Variance↗
PubMed1985

The radiotherapy of cystic craniopharyngioma with intracystic installation of 90Y silicate colloid.

The authors describe the intracavital treatment with 90Y silicate colloid in 9 cases of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery, Budapest. The intracavital treatment was only one among several applied treatment forms. In all patients a partial removal of the tumour has also been performed. The possibilities of evaluation of the effectiveness of the internal cyst irradiation are therefore limited. In most cases the intracavital treatment resulted in shrinkage of the cyst, or even was followed by its practical disappearence and the condition of the patients shows a decisive improvement. The growth of solid tumour parts is not influenced by this kind of treatment. Therefore the clinical improvement of the patient's condition depends also on the ratio between cyst and solid tumour volume. The optic nerve impairment did not improve in all cases. As a side-effect an oculomotor nerve paresis developed in several patients. Its possible explanations have been discussed, including lasting damage from tumour pressure.

Adolescent↗