Biomedical subjects

P Novák

Publications and source records attributed to P Novák.

14 recordsLinked to original sources

PubMed1992

Increase of slow periodic modulation of EEG in a patient with Alzheimer's disease.

The recently described slow oscillations of amplitude of theta and alpha waves of the EEG (with a frequency below 0.08 Hz) in healthy subjects are attributed to the autonomic nervous system with control at the brain stem level. In the present pilot study, the slow brain rhythms were analyzed in a patient with Alzheimer's disease and were compared to a healthy subject. Dynamic analysis of the EEG was performed using time-frequency mapping which gives simultaneous time and frequency representation of the brain signal. This method comprises a transform of the filtered EEG signal into its analytic form and application of the Wigner distribution modified by time and frequency smoothing. It has been shown that the envelope of both theta and alpha activities oscillates at 0.04 Hz and 0.07 Hz in the healthy subject and at 0.03 Hz and 0.06 Hz in a patient with Alzheimer's disease. The amplitude of the slow oscillations of theta activity was substantially higher in the patient with Alzheimer's disease as compared with the healthy subject. It is being proposed that the increase of slow brain rhythms in the patient with Alzheimer's disease reflects an abnormal activity of the autonomic nervous system. However, the underlying pathophysiological mechanisms need to be further studied.

Alzheimer Disease↗

PubMed1992

[Phacoemulsification. The method of choice in cataract surgery].

Complications and problems in the first 300 patients operated on by phacoemulsification technique are described. In the first 100 cases the procedure began with the creation of the corneoscleral incision and the anterior capsule was opened in a "can opener" fashion. In the second group of 200 patients we preferred the scleral incision, and the anterior capsule was opened mainly by capsulorhexis. The phacoemulsification was predominantly performed in the capsular bag or in the iris plane. The wound was closed with interrupted sutures. The most common and the most serious complication as well in the first 100 cases was posterior capsule rupture (11%). Then the percentage of this most common complication was diminished significantly with increasing experience of the surgeon (2.5% in 200 cases). The same problems which the authors had in their first operations appeared again, though in a smaller amount as soon as they started to work with phacoemulsification as a method of choice of cataract surgery.

Cataract Extraction↗

PubMed1991

Observations on respiratory and cardiovascular rhythmicities during yogic high-frequency respiration.

Yogic high-frequency respiration--kapalabhati (KB)--was studied in 24 subjects from a point of rhythmicity. Respiratory movements, blood pressure and R-R intervals of ECG were recorded in parallel and evaluated by spectral analysis of time series. Respiratory signals during KB were modulated by 0.1 Hz rhythm in 82% of experiments. This component was also present in R-R intervals and blood pressure during KB. Frequency (0.2-0.3 Hz) was observed in 67% of respiratory records. The presence of the component 0.2-0.3 Hz in respiration was dependent on resting respiratory frequency. This frequency component was reduced in R-R intervals but increased in blood pressure during kapalabhati as compared to that at rest. The occurrence of both frequency components in respiration during KB supports the hypothesis about the integrative role of cardiovascular and respiratory rhythms in physiological states characterized by altered respiratory frequency.

Adult↗

PubMed1991

[A program for automated histomorphometry of bone tissue].

A programme for controlled automated histomorphometric evaluation of bone biopsies, connected with authors' results with semiautomated program, introduces new technology as well as new principle. It is based on a digitalization of microscopic picture in videocamera followed by controlled automated computerized processing of the picture. A further simplification of the evaluation process is achieved by eliminating a time consuming and not quite precise over-drawing of the picture on a digitalization desk.

Biopsy↗

PubMed1979

Some new results of investigation of tuberous sclerosis.

The authors describe the case of a patient with tuberous sclerosis. The occurrence of M-protein with antigenous appurtenance of IgM not only in the patient himself but also in some of the healthy blood relations in the family is pointed out. The question of clinical and biochemical-immunological peculiarities occurring in connection with this disease is discussed.

Adenoma↗

PubMed1979