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Biomedical subjects

G Németh

Publications and source records attributed to G Németh.

At least 127 records · Page 7Linked to original sources
PubMed1986

Moment arm lengths of trunk muscles to the lumbosacral joint obtained in vivo with computed tomography.

Computed tomography is valuable in obtaining in vivo length of muscular moment arms, which can be used in biomechanical models. Using computed tomography, the authors measured lengths of the muscular moment arms of the erector spinae, psoas, oblique abdominal, and rectus abdominis muscles to the bilateral motion axis (about which flexion/extension movements occur) and to the anteroposterior motion axis (about which lateral bending occurs), both axes running through the lumbosacral joint. The subjects were 21 patients. Examinations were performed on a General Electric CT/T 7800 scanner. The average erector spinae moment arm to the bilateral motion axis was 68 mm, which is greater than the moment arm used earlier. The results also revealed significant differences in moment arm length between men and women for several muscles. The authors conclude that for some muscles different moment arm lengths should be used for men and for women. The moment arms reported are proposed for use in biomechanical models for calculating lumbosacral joint load.

Aged↗
PubMed1986

Joint forces in extension of the knee. Analysis of a mechanical model.

A two-dimensional model of the tibio-femoral joint was constructed by using the results of cadaver knee dissections together with radiographic landmarks on healthy knees loaded at various angles of flexion. The tibio-femoral compressive force during isometric knee extension had the same magnitude as the patellar tendon force. The tibio-femoral shear force changed direction from posterior at full flexion to anterior when the knee was extended, indicating that high forces may arise in the anterior cruciate was extended, indicating that high forces may arise in the anterior cruciate ligament in the straight knee. Women developed some 20 per cent higher knee joint forces than men for the same extending muscular moment higher knee joint forces than men for the same extending muscular moment, since women's patellar tendon moment arms were found to be shorter. The model presented may be used for quantifying tibio-femoral forces during knee extending activities.

Adult↗
PubMed1986

Source localization in intracavitary 60Co therapy with semiconductor and TL detectors.

Thermoluminescence and p-type semiconductor detectors were used for localization of the source in intracavitary (modified Stockholm method) treatment. The results were compared with X-ray films, and especially good agreement was obtained if the detectors were positioned on both sides of the patients. The measurements performed on Stage III to IV carcinoma cervix uteri patients indicate that the intracavitary source can deviate to both sides with equal probability. The magnitude of the deviation is described by a Gaussian distribution with an expected value of zero and S.D. of 8mm.

Brachytherapy↗
PubMed1986

Shoulder joint load and muscular activity during lifting.

The aim of this study was to investigate load on shoulder joint and muscles in healthy adults during four different ways of lifting a moderate burden (12.8 kg) from floor to table level. The methods used were surface electrode EMG with linear envelope, and calculation of loading moments of force using a static biomechanical model. The shoulder load at the beginning of the lift was lowest for the straight knee lift. The peak load occurred in the late phase of all lifts. On completion of the lift, load and activation were considerably lower when the subject was allowed to step forward before putting the box down. The most activated shoulder muscles were the anterior and lateral parts of the deltoid, and the serratus anterior. Around 80% of the shoulder load moment was caused by the weight of the burden. Some 75% of maximum shoulder strength was required for lifting the burden.

Adult↗
PubMed1986

Load moments about the hip and knee joints during ergometer cycling.

The aim of the study was to calculate the magnitudes of moments of force acting about the bilateral hip and knee joint axes during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at different workloads, pedalling rates, saddle heights and pedal foot position. During cycling at 120 Watts, 60 revolutions per minute with mid-saddle height and anterior pedal foot position, the mean peak flexing and extending hip load moments were 34.3 and 8.9 Nm, respectively. Mean peak flexing knee load moments was 28.8 Nm and extending moment was 11.9 Nm. Hip load moments were significantly increased by increasing the ergometer workload or pedalling rate. For knee load moments, workload was the most important factor. The flexing knee load moment did not change with changes in pedalling rate. Different saddle heights or pedal food positions had a slight but not always statistically significant influence on the hip and knee joint loads. The maximum hip and knee joint load moments induced during cycling were small compared with those obtained during other exercises or normal activities such as level walking, stair climbing, and lifting.

Adult↗
PubMed1985

In vivo moment arm lengths for hip extensor muscles at different angles of hip flexion.

Moment arm lengths of three hip extensor muscles, the gluteus maximus, the hamstrings and the adductor magnus, were determined at hip flexion angles from 0 degrees to 90 degrees by combining data from ten autopsy specimens and from twenty patients, the latter examined by computed tomography. A straight-line muscle model for muscle force was used for the hamstrings and adductor magnus, and for the gluteus maximus a two-segment straight-line muscle force model was used. With the joint in its anatomical position the moment arm of the gluteus maximus to the bilateral motion axis averaged 79 mm, for the hamstrings 61 mm and for the adductor magnus 15 mm. The moment arm of gluteus maximus decreased with increasing hip flexion angle. The hamstrings showed an increase in moment arm length up to an average of 35 degrees hip flexion and then a decrease with increasing hip flexion angle. The corresponding figures for the adductor magnus moment arm showed an increase up to 75 degrees and then a decrease. Statistical analysis revealed significant differences in moment arm length between men and women.

Aged↗
PubMed1985

Chemical reception mechanisms at a low level of phylogeny. Influence of polypeptide hormones and non-hormone polypeptides on the growth of Tetrahymena.

The polypeptide hormones insulin, glucagon, thyrotropin (TSH), pregnant mare serum gonadotropin (PMSG) and adrenocorticotropin (ACTH) stimulated the growth of the Tetrahymena, and the non-hormone polypeptides (bovine serum albumin (BSA), protamine) had a similar effect. Re-exposure after 24 h accounted for a greater growth stimulation than pre-exposure alone in cultures treated with TSH and PMSG, and re-exposure after 7 days had such effect in all polypeptide-treated cultures. It follows that the non-hormone polypeptides had a similar imprinting potential to the polypeptide hormone. The non-hormone polypeptides were also able to cross-imprint for one another, i.e. pre-exposure to one enhanced the binding capacity of the cells for the other on re-exposure, and vice versa. A single treatment with a polypeptide hormone or a non-hormone polypeptide did in itself stimulate the growth of the Tetrahymena for as long as 1 week.

Animals↗
PubMed1985

Influence of hormone treatment applied or begun in different phases of the cell cycle on hormonal imprinting in Tetrahymena.

Primary exposure to a hormone (hormonal imprinting) alters--in the case of the Tetrahymena increases--cellular response to re-exposure(s) to the same hormone. The intensity of hormonal imprinting depends on the phase of the cell cycle in which the primary exposure has taken place. The effect of imprinting was greater on the cells exposed to the hormone in phase G1 than on those exposed in phase S or G2. The response pattern of the progeny generations corresponded to that of the primarily exposed (imprinted) ancestor cell, irrespective of their own pre-exposure in phase G1, G2 or S of their cycle.

Animals↗
PubMed1985

Influence of low and high temperature on diiodotyrosine imprinting in Tetrahymena.

Hormonal imprinting takes place at the primary interaction between target cell and hormone, and alters cellular response to the hormone for lifetime (at the unicellular level in many subsequent generations). Imprinting induced in Tetrahymena cells by diiodotyrosine at the optimum temperature of 25 degrees C took effect on re-exposure to the hormone at 25 degrees C and 15 degrees C, but failed to take effect if the cells were first exposed to the hormone at 15 degrees C or 32 degrees C.

Animals↗
PubMed1985

Post mortem uterine arteriography and in vivo angiographic diagnosis.

Arteriography of the small pelvis was done to obtain exact data on the extension of uterine tumours. Some findings were useful in differential diagnostics in vivo. The borderline between the uterine corpus and collum cannot be characterized by the elbow of the uterine artery (the end of its parametrian part) but by the most medial loop of the ascending part of the vessel, coinciding with the end of the cervical canal. The cervix gets its blood supply from the uterine artery only in two-thirds of the cases and even if so, the cervico-vaginal branch takes its origin not from the isthmic but from the parametrian part of the uterine artery. Visualisation of small arteries in the parametrium is difficult in vivo mostly because of their modest vascularity.

Angiography↗
PubMed1985

Shoulder externally rotating exercises with pulley apparatus. Joint load and EMG.

The mechanical load on the gleno-humeral joint and the muscular activity during shoulder external rotation resisted by a pulley apparatus were analysed using normalized, low-pass-filtered EMG recorded from the infraspinatus, deltoid, pectoralis major and trapezius muscles. The load moment about the longitudinal axis of the joint was compared with the distribution of maximum muscle moment over different angles throughout the range of motion. The effect of subject positioning on the joint load and the muscular activity was studied. The best adaptation between the curves for load moment and maximum muscle moment was obtained when the subject was positioned sitting with the pulley located 20 degrees posterior to a frontal plane through the shoulders at a distance of 1.3 m from the joint. Of the four muscles investigated, the infraspinatus was the most active. The method described might be used to find optimal designs of shoulder external rotation exercises with special regard to avoiding unintentional overloading of joint structures weakened by disease or trauma.

Adult↗