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Biomedical subjects

L Balázs

Publications and source records attributed to L Balázs.

At least 19 recordsLinked to original sources
PubMed1992

Computer determination of systolic time intervals based on impedance cardiography.

A computerized system has been developed based on impedance cardiography for processing systolic time intervals (STI) in psychophysiological experiments. The conventional method of STI determination is based on transducing three signals: electrocardiogram, phonocardiogram and pulse tracing (carotid pulse). Because of its negligible pulse transmission time the first derivative impedance cardiogram (dZ/dt) is more reliable than other pulse signals. Since the sharply demarcated points of the dZ/dt waveform occur simultaneously with the cardiac events the dZ/dt makes phonocardiogram processing unnecessary. Computer algorithms for STI assessment are based on processing two signals: the ECG and dZ/dt. The pre-ejection period (PEP), the left ventricular ejection time (LVET) and electromechanical systole (QS2) are derived by recognizing the B and X points on the dZ/dt signal as the endpoints of PEP and LVET respectively. X point identification consists of two steps: (i) the estimation of the QS2 based on the regression relationship between QS2 and heart rate (HR) and (ii) a filtering procedure for exact localization of the X point. The B point is determined by calculating the curvature function of the dZ/dt and employing a clustering procedure. The accuracy and reliability of the software were tested by processing data from 40 subjects under stress condition (cold pressor and mental arithmetic).

Algorithms↗
PubMed1990

Hemispheric preference and obesity.

This study investigated the relationship of hemispheric preference--the tendency to activate one hemisphere rather than the other--and obesity, on 37 right-handed, male university students. Hemispheric preference was assessed by the directionality of conjugate lateral eye movements, and the degree of obesity was determined by the body mass index (BMI). The results showed that right hemisphere preferent subjects ("left-movers") are less obese than left hemisphere preferents ("right-movers").

Adolescent↗
PubMed1990

The effect of lateral visual fixation and the direction of eye movements on heartbeat discrimination.

This study was undertaken to determine whether the asymmetrical activation of the two cerebral hemispheres affects the accuracy of heartbeat perception. Hemispheric preference--the tendency to activate one hemisphere rather than the other--was assessed by the directionality of conjugate lateral eye movements. Actual differential hemispheric activation was achieved by contralateral visual fixation. The results of 44 right-handed male subjects showed that right hemisphere preferent subjects ("left-movers") performed better on a heartbeat discrimination task than left hemisphere preferent subjects ("right-movers"). The direction of lateral visual fixation also influenced heartbeat discrimination: subjects fixating to the left were more accurate than those fixating to the right.

Adolescent↗
PubMed1990

Detection of colon distension in colonostomy patients.

Inborn and learned ability to detect mild, nonpainful distension of the sygmoid colon was examined in 22 patients who underwent colonostomy one year or more before the investigation. The colon was distended by a balloon inserted 10 cm below the orifice of the artificial anus. Each subject participated in three sessions on three consecutive weeks with several experimental tasks in each session. During each task, the patient received the colon stimulus (the "signal") 25 times randomly paired with masking auditory or annular skin stimuli (around the stoma or 15 cm medially to it). The masking (warning) stimuli were administered in series of 50, representing the "noise," according to signal-detection paradigms. The subjects had to indicate after each administration of the warning noise stimulus whether or not they thought the colon stimulus had been presented. In all three sessions, learning tasks were included using reinforcement of successful detection trials. Seven subjects out of 22 were considered good perceivers, 9 persons were considered medium perceivers, and the remaining 6 subjects were considered poor perceivers. According to the data of the first two groups, it can be hypothesized that most patients have some inherent sensitivity of colon distension, and that learning improves this initial ability. However, the role of skin, peritoneal, or interstitial receptors in colon distension detection cannot be excluded.

Adult↗
PubMed1990

[The incidence of Hodgkin's disease: characteristics of its appearance, histological types].

In study of lymphogranulomatosis (LGM), epidemiological surveys and so-called "Rye Classification" for separation of histological types significantly helped to get to know the background and circumscription of etiopathogenesis of the disease. In her paper author analysed histological distribution of types, distribution of sex of patients, their average age, age-specific incidence of disease in LGM registered cases of ten years in Malignant Lymphoma Reference Centre. On basis of rate of histological types, compared to each other, and of number of LGM cases in childhood, it can be established that in MLRC incidence of LGM corresponded to so-called intermediary types (II), namely it showed characteristics of distribution between developed and economically underdeveloped countries. Age-specific incidence of 716 LGM cases studied by author was ot bimodal character, age-specific incidence of nodular sclerosis was different from it. Presumably this fact and different nature of LGMs of other type or its different pathogenesis are in the background.

Hodgkin Disease↗
PubMed1990

[Immunohistology of Hodgkin's disease. Use of monoclonal antibodies in the analysis of the pathomorphology of Hodgkin's disease].

Author studied cryostatic sections of lymph node biopsy of 45 untreated patients suffering in lymphogranulomatosis by known T and B lymphocyte, macrophage-histiocyte, Ia and HLA-DR and transferrine receptor specific monoclonal antibodies (moats). In HK-LP, HK-NS, HK-MC and HK-LD the infiltrations were formed by phenotyped lymphocytes contrary to HK-NP, where HK nodules were composed of B-cells. In HK-LPs T lymphocytes were of T-helper phenotypes, and these T-cells were observed in cases of HH-NS and HK-MC, abounding in lymphocytes, besides a few T-suppressor cells. The number of lymphocyte of latter type increased in HK-NS and and HK-MC, poor in lymphocytes and in HK-LD. The giant cells had positive reaction with Leu3a, Leu5, OKIa, HLA-DR and transferrine receptor specific moats. SR cells are such anaplasic cells or probably tumorous cells developed by cell hybridization, which are able to antigen expression characteristic of various hemopoietic cell line and of activated cells, respectively.

Antibodies, Monoclonal↗
PubMed1987

Lymphocyte subpopulations and immunoglobulins in idiopathic thrombocytopenic purpura (ITP).

Data gained from observations of the humoral and cellular immunity of 22 patients with ITP (11 in remission and 11 splenectomised) are presented. The amount of T-lymphocytes according to E-rosetting decreased significantly. In tests performed with monoclonal sera the amount of OKT-4 cells was significantly lower then normal, and the ratio of OKT-4/OKT-8 was also reduced. The C-4 complement fraction showed a significant reduction, and a rise was observed in the three Ig classes. No differences could be found, however, between patients in remission and in relapse, and between the splenectomised cases, those treated with prednisolone, and those who had no such treatment. Apart from the primary role of antiplatelet antibodies that cause thrombopenia, a complex disturbance in immune regulation also occurred in ITP, and this manifested with changes in the T-lymphocyte subpopulations. Its pathological progress still remains to be justified, but the plasma of healthy individuals and gammaglobulin have a favorable effect by blocking their receptors and they result in the cessation of the symptom and thrombocytopenia.

Adult↗
PubMed1985

Increased NK activity is responsible for higher cytotoxicity to HEF cells by lymphocytes of women with threatened preterm delivery.

Recently we have shown that lymphocytes of pregnant women with threatened preterm delivery (risk group) exerted significantly higher cytotoxic activity to human embryonic fibroblast (HEF) cells than those of healthy pregnant women. The purpose of this study was to get information on the mechanism of this cytotoxicity. The possibility of prior sensitization to embryonic antigen was excluded, since no difference could be demonstrated between cytotoxic activity of lymphocytes obtained from women with two or more previous pregnancies and that of lymphocytes from never-pregnant women. For determining the effector cell type responsible for cytotoxicity, lymphocytes of 50 healthy pregnant women and those of 50 risk patients were tested in different cytotoxicity tests using HEF and K-562 target cells. The proportion of NK cells among lymphocytes was determined by counting large granular lymphocytes (LGL), IgG Fc receptor bearing cells, and cells positively stained by NK specific monoclonal antibody. Though no difference in the proportion of NK cells between the two groups was found, risk patients' lymphocytes were significantly more cytotoxic to K-562 target cells than those of healthy pregnant women. Investigations at the single-cell level made it obvious that this higher cytotoxic activity originated from increased target cell lysing ability of their lymphocytes, while their conjugating capacity did not differ significantly from that of lymphocytes obtained from healthy pregnant women.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1985

[Angiosarcoma of the liver following brief arsenic therapy].

Hepatic angiosarcoma developed in a 46-year-old man, who had had 7-months of arsenic therapy 24 years before. The role of arsenic in the etiology of angiosarcoma of the liver is well know, although rarely has it followed such a brief period of arsenic therapy.

Arsenic↗
PubMed1984

Isolation of the human myelin basic protein by immunoaffinity chromatography with a monoclonal antibody.

Immunoaffinity chromatography has been developed for the isolation of the human myelin basic protein (MBP). The method is based on the use of a monoclonal antibody which was produced to bovine MBP, cross-reacting with human MBP. The protein isolated from acidic extracts of the brain proteins was shown to be native MBP by its immunochemical reactivity, by its ability to elicit experimental allergic encephalomyelitis and by its mol. wt (18,600 +/- 400). It represented a single-band purity after hypersensitive silver staining. The MBP isolated by the method described represents a higher purity than that of the MBP purified by conventional multistep biochemical separation techniques.

Animals↗