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Biomedical subjects

G Németh

Publications and source records attributed to G Németh.

At least 145 records · Page 8Linked to original sources
PubMed1984

Fibromuscular dysplasia of the basilar artery. Case report with autopsy verification.

Seven histologically confirmed cases of intracranial fibromuscular dysplasia (FMD) have been published. A new case of intracranial FMD confined to the basilar artery occurred in a 32-year-old man. The proliferation of fibroblasts and smooth-muscle cells could be observed only in the intima detaching from the media. The neurologic symptoms corresponding to akinetic mutism occurred nine days after pulmonary lobectomy for aspergilloma. We believe that this pure intimal type of FMD consisting of cells without elastic and collagen fibers represents a more undifferentiated and therefore more progressive form of the disease. The FMD can be considered as an overwhelming reaction of so-called pluri-potential smooth-muscle cells of the arterial wall to various stimuli.

Adult↗
PubMed1984

The adult form of subacute necrotizing encephalopathy.

The rare adult form of subacute necrotizing encephalopathy in a 49-year-old man is reported. Six months before admission the previously healthy and nonalcoholic patient developed progressive hemiparesis of the left side and instability of gait. Ventriculography revealed marked narrowing of the aqueduct, and after ventriculocisternotomy the patient became akinetic and mute. The post-mortem histologic examination revealed pathologic changes characteristic of subacute necrotizing encephalopathy. This case demonstrates that this rare disease in an adult may cause both akinetic mutism and aqueductal stenosis.

Brain Diseases↗
PubMed1984

Receptor 'memory' in Tetrahymena: does it satisfy the general criteria of memory? An experimental study on induction and extinction by retroactive interference in a unicellular organism.

Diiodotyrosine induced receptor 'memory' at a concentration as low as 10(-18) M. Repeated exposure enhanced cellular responsiveness. Treatment with diiodotyrosine for 1 h, 4 times, induced receptor 'memory' more efficiently than a single uninterrupted treatment for 4 h. Immediately after induction, the receptor 'memory' is subject to retroactive interference by foreign hormonal stimuli, and can be extinguished completely by combined hormone treatment. Thus, the phenomenon of retroactive interference also takes effect at the unicellular level. The experimental observations indicate that receptor 'memory', induced in Tetrahymena by hormonal imprinting, has certain common features with the neuronal memory of higher organisms.

Diiodotyrosine↗
PubMed1984

[Clinical experiences with the radiation sensitizer MTDQ (Sensorad) in advanced malignancies of the head and neck region and in uterine cancer].

33 patients with malignancies of the head and neck and 9 patients with carcinoma uteri received Sensorad combined with megavolt-therapy in a placebo controlled trial. 35% of the Sensorad treated patients with head and neck cancer showed an early radiomucositis. A full regression was achieved in 15 patients and a partial regression in 18 patients thus the drug helped in 79% of the patients treated. No regression was noted in 6 patients and a progression in 3, that means in 21% of patients no benefit was detected. In the placebo control group a benefit was proved for 35% of the patients whereas 65% of the patients showed no benefit. The proportion of benefit to no benefit was 3.66 in the Sensorad group compared to 0.54 in the placebo group. The patients with carcinoma uteri all showed a benefit from the treatment with Sensorad. The number of adverse reactions was small. 4 patients had nausea and gastrointestinal symptoms, 2 allergic reactions and 3 elevated SGOT (21.4%).

Clinical Trials as Topic↗
PubMed1984

On hip and lumbar biomechanics. A study of joint load and muscular activity.

Loading moment of force about the hip and lumbo-sacral joints during straight and flexed knee lifting was calculated at regular intervals during the lifts, using a computerized sagittal plane model. Lift with flexed knees and burden moved close to the body was found to induce lower load. Important parameters influencing the induced joint load are discussed. EMG levels from three trunk and seven hip muscles were recorded with surface electrodes and normalized, i.e. expressed as a percentage of the recorded level of each muscle during an isometric voluntary contraction. The erector spinae, gluteus maximus and adductor magnus muscles were more activated initially in the flexed knee lifts than in the straight knee lift, while the hamstrings were more and earlier activated in the flexed knee lifts. In order to estimate what proportion of the maximum hip extensor muscle moment was used to counteract the induced load moments about the hip, assessments of maximum hip extensor muscle moments were made: the highest extensor muscle moment was exerted at 90 degrees hip flexion, decreasing with decreasing hip angle. The knee angle did not significantly influence the muscle moments exerted by the hip extensor muscles. To calculate the magnitude and direction of the hip compressive load from known load moments, the length of the moment arms of three hip extensors was determined at every fifth degree of flexion at hip flexion angles between 0 degrees and 90 degrees by combining data from autopsy specimens and patients, the latter examined by computed tomography. There were significant differences in moment arm length between men and women but there was low correlation between subject's height and length of muscular moment arms. The calculated compressive force during the lifts was about three times body weight and the direction of the compressive force passed through the area described by others as having the most severe osteoarthrotic lesions on the femoral head. Hip joint load moments and normalized EMGs from five hip muscles were assessed during rising exercises for the lower limb in order to determine to what extent joint load and EMG is influenced by adaptive adjustments of the exercise. A multicomponent force-measuring platform and pictures on cine-film were used in the calculations of load moments. Posterior foot position lowered the load moment and slightly increased the level of muscular activity in the hip extensors. The design and use of a force prediction diagram for estimating induced hip extensor muscular forces is described.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Hip load moments and muscular activity during lifting.

The load on the hip joint during lifting was studied. Healthy subjects lifted a 12.8 kg box from floor to table level with straight and flexed knees in four different ways. The loading moment of force about the bilateral hip axis was calculated by means of a computerized static sagittal plane model. The highest load moment, 124 Nm, occurred initially in the straight knee lift and the compressive joint reaction force was 2.7 times body-weight. The lowest load moment, 82 Nm, occurred in the flexed knee lift with the burden moved close to the trunk, the compressive force was 3.2 X bw. The load moment was also discussed in relation to the strength capability. The EMG levels of seven different hip muscles were normalized and expressed as a percentage of the recorded level of each muscle group during an isometric maximum voluntary contraction. The initial activity in the hamstrings was higher in the straight knee lift compared to flexed knees. The gluteus maximus was activated to a moderate level.

Adult↗
PubMed1984

Hip joint load and muscular activation during rising exercises.

The load on the hip joint and activation of the gluteus maximus, hamstrings, adductor magnus and rectus femoris muscles during rising exercises including different adaptive adjustments were investigated in nine healthy subjects. The joint load was calculated from forces recorded with a force-measuring platform and pictures on cine-film. Levels of muscular activity were recorded with rectified, low-pass filtered, time-averaged and normalized EMGs. The loading moment about the hip joint was about 45 Nm during the initial part of the rising exercise, decreasing with smaller hip angle. Increase of the backward inclination of the trunk increased the load moment, which was maintained at about the same level during the rising exercise. Two adaptive adjustments lowered the joint load: foot position further backward and reduced resistance from the device. Foot position further forward increased the joint load. The levels of muscular activity in the hip extensors were low to medium and were slightly increased by posterior foot position and increased resistance from the device. Increased backward trunk inclination increased the activity in the final part of the rising exercise.

Adult↗
PubMed1984

Load on knee joint structures and muscular activity during lifting.

The load on the knee joints during lifting has been less studied than low back load. Healthy subjects lifted a 12.8-kg box from floor to table-level in three different ways; 1) with straight knees, 2) with bent knees and the box in front of the knees, and 3) with bent knees and the box between the knees. The loading moment of force about the bilateral knee axis was calculated by means of a computerized static sagittal plane model. Electromyography was recorded from quadriceps and ischiocrural muscles. The beginning of the flexed-knee lifts caused a flexing loading knee moment of about 50 Nm and a knee angle of 90 degrees. Straight-knee lifts gave all through the lift an extending loading moment. During the final phase of all lifts there was an extending loading knee moment of about 55 Nm and a knee angle of 0 degrees. The three lifts were compared and discussed from a biomechanical and ergonomical point of view.

Adult↗
PubMed1983

Attempt to disturb receptor memory in a unicellular (Tetrahymena) model system.

The effect of a hormone-like substance first reaching a receptor is of decisive importance in the unicellular (Tetrahymena) model system. The effect of the similar or dissimilar molecule after the first or second pretreatment depends to a great extent on pretreatment if it was carried out by a similar substance, but it does not depend on it if the agent used for pretreatment was different chemically. Receptor memory developing after hormonal imprinting can thus be disturbed by molecules of similar nature, but the effect of a different molecule--if it acts immediately after the imprinting--cannot be neglected, either.

Alkaloids↗
PubMed1983

Load moment, muscle strength and level of muscular activity during internal rotation training of the shoulder.

Existing studies of shoulder joint loading, muscle strength and muscular activity do not, from the point of view of clinical application, adequately cover these factors, knowledge of which is important for the design of optimal exercises for training shoulder impairments. In the present study, exercises using a weight-and-pulley device have been analysed in order to map the resistance moments of force in relation to the muscular strength capacity of shoulder internal rotators , and to map the activation of these muscles in response to the resistance from the device. The relationships established in the study provide a basis for optimising various types of shoulder training exercises. For example, an angle of 40 degrees between frontal plane and shoulder-pulley line has been found to give the best adaptation of resistance to strength. The study also demonstrates the possibility of using a pulley apparatus for shoulder inward rotator muscle training.

Adult↗
PubMed1983

Knee load and muscle activity during exercises in rising.

Knee joint loading and the level of knee muscle activation during rising exercises have been evaluated and methods have been developed for such studies. Floor-to-foot forces were recorded using a force-measuring platform. The loading moment of force representing the resistance for the knee joint was calculated. It was shown that the initial knee loading moment with much flexed knees was high at large knee angles. The loading moment showed a marked decrease with decreasing knee angles. For small knee angles there was no resistance to knee extension. Muscular activity level was studied using EMG. The levels of activity in the quadriceps muscles were high at large knee angles and low at small angles. The hamstrings and gastrocnemius showed only low activity. The magnitude of change in knee extension resistance due to adaptive adjustment of the exercise device was mapped. These rising exercises will increase strength mainly for large knee angles and only for quadriceps muscles.

Adult↗
PubMed1983

Influence of knee flexion on isometric hip extensor strength.

The maximum isometric extensor muscle strength was measured in 10 healthy subjects of different combinations of hip and knee angles. An ordinary exercise device was used for the measurements and the method could be useful in clinical work. The results revealed that the knee angle does not affect the hip extensor strength. The highest extensor muscular moments occurred at 90 degrees hip flexion, decreasing with decreasing hip angle. The distribution of the strength over the motion sector differed between male and female. The weight of the body segments was found to utilize 10-24% of the maximum strength at hip angles 60 degrees-0 degrees with subjects in a prone position.

Adult↗
PubMed1982

Involvement of selection and amplification mechanisms in hormone receptor development in a unicellular model system.

It was demonstrated earlier, that long lasting exposure of Tetrahymena to a hormone (histamine) resulted in an increased responsiveness to a later re-exposure. However, it was difficult to establish whether selection or amplification plays a role in receptor differentiation. As diiodotyrosine (T2) enhances the growth of Tetrahymena, in the present experiment the effect of T2-treatment on a long-term culture of Tetrahymena pyriformis was analysed by mathematical-statistical methods to differentiate the effects of selection and amplification mechanisms on hormone receptor development. Although continuous and periodic treatment with T2 enhanced cell division equally, the resulting populations differed in structure. On continuous treatment the population tended to become inhomogenous. The variance tended to increase for 9 days and decreased afterwards without, however, returning to the control level. On periodic treatment the variance was the same as in the control group, but the second and third exposure were significantly more effective than the first treatment, suggesting that the primary encounter with the hormone had given rise to lasting alterations (hormonal imprinting). It follows that continuous exposure involves a selection process which does not, however, account for a steady increase of the growth rate; for initial amplification, taking place also in this condition, and selection which takes effect later, compensate one another's effects. Regarding the unicellular experimental system as a phylo- and ontogenetic model, the conclusion lies close at hand that the selection and amplication mechanisms promote hormone receptor development by joint rather than alternate action.

Analysis of Variance↗
PubMed1982

Influence of hormone concentration and time factor on development of receptor memory in a unicellular (Tetrahymena) model system.

1. Treatment of Tetrahymena pyriformis cells with diiodotyrosine (T2) gave rise to a considerable, concentration-dependent increase of the growth rate within the range of 10(-15) and 10(-9) M, but did not influence it at the level of 10(-18) M. 2. Re-exposure of the cells 1, 2 and 4 weeks later to the hormone concentrations originally used accounted for a marked increase of growth rate at all hormone levels tested, indicating that the extremely low concentration of 10(-18) M, which failed to stimulate growth on first exposure, did nevertheless give rise to hormonal imprinting, which caused the cells to "remember" the hormone, as judged from their increased responsiveness to it on re-exposure. 3. The degree of growth response was concentration-dependent on both first and second exposure: higher levels of treatment gave rise to firmer imprinting, and to greater response on re-exposure. 4. The length of exposure time proved to be more decisive than the level of treatment in respect of the development of hormonal imprinting. 5. Short-term exposures up to 60 min, although they stimulated cell growth by direct effect, gave rise to lasting inhibition of cellular response to re-exposure(s) rather than to hormonal imprinting.

Animals↗
PubMed1982

Development and persistence of receptor 'memory' in a unicellular model system.

A single exposure of Tetrahymena to diiodotyrosine stimulated replication of the unicellular organism significantly relative to the control. The stimulatory effect tended to decrease with progressing time, but was still demonstrable after as many as 500 generations. Reexposures to diiodotyrosine also enhanced cell growth, indicating the existence of a receptor 'memory' in respect to the initial exposure, but their effect tended to decline soon after initial stimulation, and did not, in all probability, contribute to the preservation of the 'memory' which itself tends to vanish gradually in due course.

Animals↗
PubMed1982

[Therapy result of malignant tumors of the paranasal sinuses in patients treated at the metropolitan onco-radiologic centre of Budapest. Period under review: 1946-1974 (author's transl)].

A report is given on the therapy results of 301 patients with ethmoidomaxillary tumors treated at the Metropolitan Onco-Radiologic Centre of Budapest between 1946 und 1974. Most of these patients were in an advanced stage when the first diagnosis was established. The five-year survival rate of all stages was 27%, which does not strongly differ from the average value of 30% mentioned in literature. The five-year survival rate of the patients submitted to a combined surgical and radiologic treatment was 33%, that of the patients treated by irradiations only was 16%. 81 patients received an intracavitary brachycurietherapy after having undergone a non-radical operation. The five-year survival rate of this group was 38%. The intracavitary brachycurietherapy is most favorable and should always be applied in case of this not very radiosensible, often even radioresistant tumor.

Adenocarcinoma↗
PubMed1982

Experimental observations on the mechanism of hormonal imprinting: influence of actinomycin D, methylamine and colchicine on receptor memory in a unicellular model system.

The first interaction between target cell and hormone gives rise to hormonal imprinting, which accounts for greater responsiveness of the cell at later interactions. The mechanism of hormonal imprinting is obscure; we based experimental approach to its closer study on combined treatment of Tetrahymena, as model cells, with diiodotyrosine (T2), which stimulates the division, and cell growth inhibitors, which interfere with different stages of cell reproduction, and methylamine, which inhibits cluster formation in the membrane. Of these, actinomycin D and methylamine inhibited the growth of the Tetrahymena, while colchicine did not, and all three suppressed the division stimulating action of T2, but could not prevent hormonal imprinting, as demonstrated on later re-exposure to T2 of cells preexposed and not preexposed to T2 in combination with the inhibitors. It appears that the underlying mechanism of hormonal imprinting is highly complex, and involves many subcellular mechanisms and structures, but suppression of, or gross interference with, one or another of these cannot delete, only quantitatively reduce, the consequence of the first interaction with the hormone, i.e. hormonal imprinting.

Animals↗