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Biomedical subjects

S Tóth

Publications and source records attributed to S Tóth.

At least 73 records · Page 4Linked to original sources
PubMed1985

Effect of amino acids on the expression of antiviral activity of different types of human interferon. I. Effect of single amino acids.

It has been observed that certain amino acids may influence the antiviral activity of different types of human interferon (IFN). The effect may be enhancing or inhibitory. A qualitative survey is provided on all three types of human IFN using 23 different amino acids. A more detailed study was carried out with 10 amino acids which proved to be active towards HuIFN-alpha. Their influences on the synergistic antiviral effects of HuIFN-alpha and HuIFN-gamma were also investigated. The dose-dependence curves of their effects on HuIFN-alpha were established.

Amino Acids↗
PubMed1985

Effect of amino acids on the expression of antiviral activity of different types of human interferon. II. Effects of various amino acid pairs.

Seven amino acids which influence the antiviral activity of IFN-alpha were tested in various pairs on human leukocyte and immune IFN and on their synergistic antiviral effect. Different kinds of interactions were observed between amino acids, ranging from extinction through competition to synergism. In some cases, different types of interactions could be observed in relation to HuIFN-alpha and HuIFN-gamma. It has been reported that certain amino acids influence the antiviral activity of human interferons (IFNs). Some of them are even capable of affecting synergistic cooperation between HuIFN-alpha and HuIFN-gamma. In our experiments we tested whether these effects can be modified further by applying two amino acids simultaneously. We hoped to shed light on the problem of their mode of action by analysing their interactions.

Amino Acids↗
PubMed1985

Production of high titre human interferon-gamma in primed leukocyte cultures.

Con A-stimulated leukocytes previously treated with IFN-alpha (1500 IU/ml for 4 h) were very suitable for the production of IFN-gamma with a high titre even under large-scale conditions. The properties of the IFN produced under such conditions were identical to those of IFN-gamma. The IFN-gamma produced in primed cultures showed two peaks of antiviral activity corresponding to molecular weights of 51 000 and 23 000 daltons.

Carcinoma, Squamous Cell↗
PubMed1984

Semi-crude human leukocyte interferon production in a simple medium.

Semi-crude human leukocyte interferon (specific activity at least 10(5) international units per mg protein) was produced by replacement of priming medium with protein poor medium before the production period. A simpler medium than Eagle's medium was suitable to obtain substantial quantities of interferon.

Blood↗
PubMed1983

Different interferon-inducing ability of human adenovirus types in chick embryo cells.

Human adenovirus (Ad) types differ in their ability to induce interferon (IFN) in chick cells. Of 12 types investigated, Ad8, Ad12, Ad 18 and Ad 31 proved to be more effective IFN inducers than Ad2, Ad3, Ad4, Ad5, Ad6, Ad7, Ad15 and Ad19. Ultraviolet (UV) irradiation decreased the IFN-inducing ability of the more effective inducers only, indicating that transcription of viral DNA might play a role in IFN induction by these types. DNAs isolated from Ad2, Ad5 and Ad12 alike induced low amounts of IFN in chick cells. The IFN-inducing capacity of phage DNA was similar to that of adenovirus DNA, but induction by non-viral DNA (prokaryotic and eukaryotic) did not result in detectable IFN production. It is assumed that viral DNA and virus particles promote IFN production in different ways. Probably the viral component responsible for IFN induction by the effective Ad types differs from those having lower IFN-inducing ability.

Adenoviruses, Human↗
PubMed1982

Unusual chromosome aberrations in 3 children with Down syndrome.

In 3 children with Down syndrome extremely rare chromosome aberrations were found. In the first patient, the karyotype showed 46 chromosomes with a de novo duplication of the q22-qter segment. This finding supports that the 21q22-qter band was responsible for the characteristic mongoloid features. In the second case, trisomy 21 was present and out of 78 investigated cells, 60 contained a small, supernumerary marker chromosome in addition to trisomy 21. The parents were cytogenetically and clinically normal. In the third case trisomy 21 with inv(10) (p13q22) occurred. The inversion was inherited from the mother with diminished fertility.

Child, Preschool↗
PubMed1981

Advantages and drawbacks of some ERG stimulation and data-processing methods.

In each group of diseases, electroretinographic (ERG) diagnosis requires optimal stimulation parameters and detection techniques that clearly evidence any deviations from normal values. Television tube light stimulator assemblies and stimulation techniques applying methods of the control theory are very suitable for the dynamic separation of gross ERG components. The advantages and drawbacks of flicker ERG, frequency-characteristic methods and the frequency ranges that provide useful information in data processing are discussed.

Animals↗
PubMed1980

Evoked responses by physiological sensory inputs in human central motor structures.

In human with chronic implanted electrodes physiological evoked responses could be detected from those structures they were thought to be parts mainly of central motor system. Investigating the functional changes of evoked responses to motor states and attention the results have suggested the responses do not sign the centres to treat as directly the sensory inputs i.e. auditory, visual, somatosensory stimuli as motor stimuli.

Attention↗
PubMed1980

The function of the human cerebellum studied by evoked potentials and motor reactions.

The authors investigated the cerebellar function of patients with chronic implanted electrodes. The investigations were carried out using elicited compulsion events--evoked potentials and motor reactions--in different functional motor states, i.e., rest and contraction. The compulsion events are the result of motor control processes which eliminate the transient effect of stimuli. In connection with the cerebellum, these motor control processes in some ways mirror the function of the cerebellum. The evoked potentials recorded in the cerebellum have specific features and specific functional dependence as well. On stimulation of the cerebellum, the first effect on motor activity is always inhibitory. Altering the cerebellar function by high frequency stimulation appears to cause cerebellar symptoms such as hypotonia and ataxia.

Cerebellum↗
PubMed1980

Multitarget technique in Parkinson surgery.

In the past 10 years, experience has been gained with combined VL-thalamotomy, pallidotomy and dentatomy using chronically implanted electrodes in Parkinson's disease. In the vast majority of cases, symptoms ceased surprisingly for 10-14 days just after stereotactic exploration of these motor centers. Clinical neurophysiological investigations (evoked responses, motor effects) show where consecutive lesions will be permanently effective at definitive coagulation. The physiological basis of these findings are discussed and a sophisticated therapeutic protocol is advised.

Electrodes, Implanted↗
PubMed1979

Frequency resonance investigation of the H reflex.

Results of a previous study demostrated transformation of the sustained activity of a muscle into rhythmic, tremor-like activity by stimulation of different motor centres. The optimum for this transformation was in the 4-7 Hz frequency band (resonance band). Sustained rhythmic stimulation with stimuli at 0.1-20 per second caused a normal frequency curve of the H reflex in subjects with intact motor systems. The resonance phenomenon of the frequency curve of the H reflex was in agreement with that found in previous studies stimulating the different motor centres. As this requires connections between spinal and higher motor centres, it is suggested that this investigation is appropriate for a detailed functional study of spinal cord lesions.

Electric Stimulation↗
PubMed1977

The study of recovery and modification of the evoked potentials and motor answers in the motor system.

After an electrical stimulus within the motor system there will follow a compulsion, a reflexlike process in functional dependency, naturally in illness (function disturbance) dependency as well. We can detect this process with the evoked potentials at the non-stimulated sites of the motor system and with the motor answers at the periphery. Because the motor system acts as a whole, it is certain that every process at a site has its correlates at the other sites, but the different part of the same process will be in a different grade pronounced (many times in opposite direction) at the different sites. If we want to know something from the basic process and to find the real correlates, we have to compare different evoked potentials within the motor system and motor responses at the periphery, or we have to enhance or depress the whole process or its parts. For the latter the double stimulation technique is suitable, but we have to take into consideration that during this investigation two alternating processes affect each other and therefore the result will not be direct.

Brain↗