Biomedical subjects

P Kolev

Publications and source records attributed to P Kolev.

5 recordsLinked to original sources

PubMed2001

Clinical and electromyographic examinations of patients with tremor after chronic occupational lead exposure.

Tremor is considered to be a clinical sign of patients with chronic lead exposure. However, the type of tremor and its pathophysiological mechanisms are controversial. The aim of this study was to examine the clinical and electromyographic characteristics of tremor in patients with chronic lead exposure. Twenty-three men, 27-49 years old, participated in the study. The tremor activity was detected using surface electrodes from a pair of antagonistic hand muscles. Serum lead concentrations were measured on the day of examination. Our results revealed 12 Hz postural and kinetic tremor, with characteristics of enhanced physiological tremor. Different pathophysiological mechanisms might be responsible for the enhanced physiological tremor of patients with chronic lead exposure. In conclusion, the tremor of patients with chronic lead exposure is an enhanced physiological one. It is probable that this tremor could be influenced by beta-blockers, known to influence the enhanced physiological tremor in anxiety. This will be of benefit for patients disturbed by persistent tremor.

Adult↗

PubMed1990

[Changes in neuropsychic activities during work in clean rooms].

In clean rooms of the system of electronics are carried out work-physiological examinations on two basic professional groups--working in photolithography and operators. At the end of the workings day a considerable prolongation of the sensomotor reactions and deterioration of the dynamometric indices, characterizing the functional status of the neuro-muscular system were found. The time for performing the complex sensomotor reactions (choice of reaction) remains unchanged. At the end of the working day as a result of the performance of a considerably complex work activity, carried out in the clean rooms, was established a significant decrease in the functional state of the central nervous system and development of general and nervous fatigue.

Electronics↗

PubMed1989

[Epidemiological studies of the effect of organophosphate pesticides on health].

The subject of study are agricultural workers applying organophosphorus and other pesticides in an area with intensive agriculture and a control group from the same area having no professional contact with pesticides. The studies include: personal and professional anamnesis, a battery of neurobehavioral tests, electroneuromyography, evoked potentials, neurological status, internal status, hematological tests, liver enzymes, variability of the heart rhythm. The level of the exposure is assessed by: measuring the concentration of PhO compounds in the air of the work environment and deposit on the skin. The biological monitoring is carried out by measuring the level of the cholinesterase activity in serum and erythrocytes, neuropathy target esterase in lymphocytes and alkylphosphates in urine. The tests are performed before and after the active season of spraying. The results from the studies show that at continuous exposure to low concentrations of organophosphorus compounds, applicated in agriculture, no significant health disorders occur. Specific deviations are observed after the season of spraying in the neuro-behavioural tests as increasing the number of incorrectly put dots in the Aiming test, the time of reaction and evoked potentials. The interpretation of the results is impeded because of the large number of interfering factors and considerable quantity of alcohol.

Adult↗

PubMed1988

Selective attention in the presence of music: an event-related potentials (ERP) study.

The present study was aimed at investigating selective attention in the presence of music as expressed by ERPs. The experiments were performed with 7 subjects. A two-channel auditory frequency discrimination task (target - 1000 Hz, standard - 1550 Hz tones) in a dichotic listening environment was employed. The EEG was recorded from Fz, Cz, Pz, C3 and C4. The EOG and performance data were also collected. A smaller and delayed N1 amplitude as well as changes in the two components of the processing negativity in the presence of music were found. N2 and P3 components only delay with music was observed. The changes in the level of performance were not significant.

Adult↗

PubMedDate not supplied

Mental capacity changes in school teachers.

The aim of the present study was to compare the mental capacity changes in school teachers, depending on age and type of school. 120 teachers drawn from the secondary and technical schools of Sofia were divided into two groups of younger (mean 31.5 yrs) and older (mean 47.5 yrs) age. They were given two monotonous visual tasks, which differed in complexity: of discrimination and of categorization. The behavioral measures of performance revealed lower efficiency in categorization due mostly to the so-called "premature" or "impulsive" reactions. Significant positive correlations were found between age and within-individual variability of reaction time, suggesting an earlier onset of the aging processes in the investigated population. The decrease in performance efficiency which was age-related was most expressed in the secondary school teachers. It was concluded that the changes of mental capacity can be regarded as an indirect indicator of the occupational stress of the school teachers.

Adult↗