Biomedical subjects

Gábor Kiss

Publications and source records attributed to Gábor Kiss.

8 recordsLinked to original sources

PubMed2006

[Clinical features of the hand-arm vibration syndrome in miners].

INTRODUCTION: It is well known that the vibrating tools used by the miners can cause hand-arm vibration syndrome. However no detailed reports on this field could be found in the Hungarian literature. AIM: The aim of this study was to clarify the clinical features of the hand-arm vibration syndrome of the miners. METHOD: The circulation, the peripheral nerves and the osteoarticular system of the upper extremities of 152 miners were examined by means of cold provocation test, Allen-test, measurement of systolic blood pressure performed by Doppler flowmeter, clinical neurological and neurographic examination and X-ray investigation of the bones and joints. RESULTS: Hand-arm vibration syndrome was diagnosed in 87 patients (57.2%). The most common symptom was the lesion of the circulation which occurred in 78 patients (89.6%). The peripheral nerves were affected in 44 cases (50.5%). Radiological alteration of the bones and joints of the upper extremities was observed in 32 patients (36.8%). Out of 78 damaged cases the frequency of the vascular diseases was as follows: angiopathy (diminished systolic blood pressure in the fingers): 66 patient (84.6%), occlusion of the hand arteries (positive Allen-test) and arterial form of the thoracic outlet syndrome (positive elevation-test) respectively: 28 and 28 cases (35.9%), Raynaud phenomenon (positive cold-provocation test): 26 cases (33.3%). The peripheral nerves were examined in detail in 141 cases. Pathological alterations were observed in 78 patients (55.3%) in the following forms: carpal tunnel syndrome: 66 cases (84.6%), peripheral neuropathy of the upper limbs: 20 patients (25.6%), lesion of the ulnar nerve: 3 cases (3.8%), brachial plexus lesion: one patient (1.3%). Radiological alteration was most common in the carpal region (87 cases, 57.2%). The frequency of the lesion of cubital (40.4%) and shoulder region (40.7%) was practically the same. In the carpal region the most common alterations were the degenerative processes (23 cases, 15.1%) followed by the aseptic osteonecroses (22 patients, 14.5%). In the cubital region the periarticular changes (31 patients, 23.9%) were most common followed by degenerative changes (21 cases, 16.2%) and the osteochondrosis dissecans (13 cases, 10.1%). In the shoulder region the degenerative processes were the most common changes (41 patients, 34.7%), first of all in the acromioclavicular joint (21 cases, 17.8%). Aseptic necrosis was observed in two patients. CONCLUSIONS: The miners are professionally exposed not only to hand-arm vibration, but also to increased physical stress. The symptoms on the upper limbs can develop as the result of both exposures.

Adult↗

PubMed2006

Effect of human organism on the oxide layer formed on titanium osteosynthesis plates: a surface analytical study.

The question of whether or not to remove the titanium osteosynthesis plates used in maxillofacial surgery is not yet answered. These plates can be left a long time in the organism if there is no harmful interaction between the plates and the organism. The authors examined the properties of the surface oxide layers formed on osteosynthesis titanium plates by subsequent thermal and anodic oxidation, together with the properties of plates removed from patients after three years. Surface analytical method Secondary Ion Mass Spectroscopy (SIMS) was chosen. It was found that inside of the about 200-mum thick oxide on the original plates the concentration of impurities is much lower than near the oxide/titanium interface. On the surface of plates removed from the human body, a C (carbon), Ca (calcium) and P (phosphorus) enrichment was detected, suggesting a biological interaction between the organism and the plate. The passivating layer formed with thermal and anodic oxidation has not changed significantly in three years; it resisted to the corrosive effect of the human organism.

Biocompatible Materials↗

PubMed2005

[Basic neurography and its diagnostic importance].

Nerve conduction studies are fundamental elements of the neurophysiological investigation of neuromuscular diseases. They provide information on peripheral nerve function. Knowledge of the biological and technical basis of the method is essential for the clinician to understand the place of nerve conduction testing in the diagnostic process. A characteristic feature of the nerve fibers is their ability to conduct electrical potentials. This conductivity changes in pathologic circumstances; therefore, the patient's nerve conduction data may be important if a neuromuscular disorder is suspected. The electrical activity spreading along the nerve fibres can be detected with special techniques and instruments. To perform an examination, a stimulator, a high quality amplifier and a computer with various accessories are necessary. The examination is usually carried out by surface stimulation and recording electrodes and requires some cooperation. By supramaximal stimuli all nerve fibers in the peripheral nerve are activated, and their summated activity is recorded bipolarly. For technical reasons the procedures for the motor and the sensory nerve conduction measurements are somewhat different, but their principles are similar. A number of parameters, such as the latency, the amplitude, the area and the shape of the evoked potentials are analyzed. These parameters are influenced by many biological (age, gender, body height, etc.), physical (such as limb temperature) and technical factors. The results are compared with the reference data. Nerve conduction studies may help distinguish between normal and diseased nerve function. The latter has two main categories; axonal lesion and demyelinisation. Axonal lesion is characterized by relatively normal conduction velocity and lower than normal amplitude of the potentials. Demyelinisation is almost the opposite with long latencies, slow conduction velocity and relatively spared potential amplitudes. Nerve conduction studies help differentiate between these two forms. Abnormalities found by nerve conduction measurement may reflect the severity of the disease. Repeated studies are suitable for quantitative follow-up. The anatomical, physiological, pathophysiological and technical details are discussed below. The characteristic neurographic findings of various diseases are also summarized.

Electromyography↗

PubMed2005

Molecular forms of acetylcholinesterase in the rat extensor digitorum longus and soleus muscles regenerating from notexin-induced necrosis.

The activity of acetylcholinesterase molecular forms were examined after separation on sucrose gradients during notexin-induced necrosis and the following regeneration in rat extensor digitorum longus (EDL) and soleus (SOL) muscles. All forms dropped rapidly in both muscles in the first few days after single notexin injection. After a delay small globular forms (G1+G2) started to regenerate from day 7 and larger forms (G4 and A12) from day 10 in EDL. The A8 form which cannot be detected in normal EDL was present between day 7 and day 28. In SOL the recovery of AChE forms begun already on day 3. The small globular forms displayed a more rapid increase between day 3 and day 7 then the other forms. In SOL we observed a temporary overshooting peak at day 7 in the activity of all molecular forms. Both muscles recovered their normal AChE pattern by that time when muscle fibres regained their normal diameter (day 28). Most of the events of regeneration of AChE forms resembled those of normal myogenesis.

Acetylcholinesterase↗

PubMed2004

[Surface analysis of interaction between titan implants treated with anod oxidation and the human organism].

UNLABELLED: The examination of interaction between the titan implants treated with anod oxidation and the human organism carried out with surface analytical methods. The favourable properties of metallic titanium have led to its widespread use as an implant material. These properties can be further improved by surface treatment. We have been using anodically oxidized titanium plates for purposes of osteosynthesis for more than 15 years. A specially produced surface oxide layer (TiO2) improves the properties of the metal considerably, increasing the physical and chemical resistance of the plates to the aggressive effects of the organism. Thanks to this, it is now very rare for the plates to have to be removed after the bone healing. The present aim was to use XPS, SIMS and AES surface analytical methods to study the extent to which the positive charactheristics of the TiO2 coating are altered by the aggressive action of the organism during the years following implantation. In practice, we sought to establish the length of time during which the good properties of the plates do not change, and to determine when, it at all, the plates need to removed. MATERIAL AND METHODS: In our present work we studied titanium (ostheosynthesis) plates, removed from 3 patients, with XPS, AES and SIMS method. RESULTS: It was observed that the basic metal remained covered by a TiO2 layer. In consequence of the osseintegration, the Ca and P contents of this layer had increased, which may be explained by incorporation from the organism. CONCLUSION: The Ti implant with is modified surface was covered by a TiO2 layer 120-150 nm thick, which exhibited a homogeneous oxygen distribution. During many years, this had provided protection against the chemical and physical effects of the organism.

Bone Plates↗

PubMed2003

[Hand-arm vibration syndrome in foundry workers].

INTRODUCTION: The hand-arm vibration syndrome of the foundry workers using chipping hammers and grinders were analysed in Hungary last in 1950th-s years. Therefore it seemed necessary to consider the present situation of the disease. AIM: To study of the signs of the hand-arm vibration syndrome of the foundry workers using chipping hammers and grinders. METHOD: Retrospective analysis of the clinical findings of 154 foundry workers using chipping hammers and grinders. The examination included the vascular, neurological and musculoskeletal systems of the upper extremities in 95 patients. RESULTS: The first symptoms referring to hand-arm vibration syndrome appeared on the average after seven years exposure. The signs of the 95 patients were as follows: vascular disorders: 75 cases (78.9%), peripheral neurologic lesion: 62 cases (65.3%), osteoarticular damage: 35 patients (36.8%). The Raynaud's phenomenon developed more commonly on the left than the right hand. The rate of the improvement of the Raynaud's phenomenon on the average 6.5 years after the cessation of the exposure on the basis of the result of the cold provocation test was 32.8%. Lesion of the peripheral nerves of the upper limbs, mostly of distal type was experienced in 41, whereas tunnel syndromes of the upper extremities in 21 cases. The most common amongst the latter (18 cases) was the thoracic outlet syndrome. Osteoporosis of the carpal bones was detected in 36 patients (37.9%), but osteoarthrosis of the joints of the upper limbs in 12 cases (12.6%). There was no aseptic necrosis of the bones. Fatigue fracture of the spinous process of the cervical VII vertebra occurred in one single case. CONCLUSIONS: Using chipping hammers and grinders in foundry is one of the most dangerous hand-arm vibration exposure in Hungary. The most frequent signs are the vascular and neurological lesions. Due to relatively rare occurrence of osteoarticular damages X-ray examinations are not necessary during periodical medical follow up. The most effective possibility of the prevention is the diminishing of the daily exposure time.

Adult↗

PubMed2003

Equilibria of mononuclear oxomolybdenum(VI) complexes of triethanolamine. A multinuclear dynamic magnetic resonance study of structure and exchange mechanisms.

1D and 2D 1H and 13C NMR spectra of the assumed [MoO(4)(TEA)](2-) complex recorded in DMSO at variable temperatures clearly indicate one free and two bound hydroxyethyl arms. The free arm of the ligand readily exchanges with the two metal-bound arms. Under such conditions the triethanolamine (TEA) acts as a bidentate ligand. The presence of water accelerates the exchange, which at higher water content involves the free ligand too. In organic solvents the binding strength of the hydroxo groups to the molybdenum is weaker than that of the water molecules. A plausible structure is confirmed by 14N, 17O and 95Mo measurements and an exchange mechanism based on the existence of an eight-membered relatively rigid chelate ring is suggested.

Ethanolamines↗

PubMed2003

[SIMS (secondary ion mass spectroscopy) and XPS (x-ray photoelectron spectroscopy) study of titanium implant surfaces coated with anodic titanium-oxide layer].

The demands that must be satisfied by titanium implants applied in medical practice include chemical and physical durability. An anodic oxide protective layer formed on the surface of titanium implants serves for the better attainment of this aim. The composition of the passivizing layer and the changes in its thickness and binding state can be studied by method of material science, e.g. by secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS). In this way a possibility arises for the material technological classification of the Ti-TiO2 layer structure and for the observation of the physical and chemical reactions that occur between the implants and the tissues in the organism. The present XPS examinations revealed that the binding state of the titanium forming the surface of the plates involve neither significant quantities of titanium oxide nor impurities. In the SIMS investigation the thickness of the titanium oxide layer was found to be 120-150 nm. Determination of the thickness of the surface, the binding state of the titanium and the exact proportions of the impurities and additives furnishes a possibility for a subsequent comparison with the surface structure of plates removed from the organism. It is important for the assessment of the practical value of the protective layer.

Dental Implants↗