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Biomedical subjects

J Vanková

Publications and source records attributed to J Vanková.

9 recordsLinked to original sources
PubMed2005

[Heart rate variability during sleep].

BACKGROUND: Changes in the tone of the autonomic nervous system during sleep occur and characterize individual sleep stages and probably also sleep cycles. The spectral analysis of the heart rate variability (SA HRV) is a tool for exact assessment of autonomic nervous activity giving us precise information on the activity of the autonomic nervous system--on its sympathetic and parasympathetic component. METHODS AND RESULTS: All night polysomnographic recording was performed in 11 healthy subjects, during which the SA HRV was carried out. The total spectral power of the heart rate variability and relative values of its individual components were evaluated: the very low frequency component (VLF), the low frequency component (LF), and high frequency component (HF). The absolute value of the RR-interval duration was assessed. The LF spectral band in normalized units was significantly higher during REM sleep than in non-REM sleep. On the other hand, the HF spectral band in normalized units was significantly higher during non-REM sleep compared to REM sleep. The LF/HF ratio, which reflects the sympathovagal balance, had a maximal value during REM sleep and reached its minimum in non-REM sleep. A gradual lengthening of the RR-interval and lowering of the LF/HF ratio during night was observed. CONCLUSIONS: The SA HRV showed to be a sensitive method for detection of activity of the autonomic nervous system during sleep. The sympathovagal balance was shifted to prevailing sympathetic activity in REM sleep. On the contrary, during non-REM sleep this balance was shifted towards prevailing parasympathetic influence. A gradual increase of parasympathetic influence during night was also observed.

Adolescent↗
PubMed2004

Spectral analysis of the heart rate variability in sleep.

Spectral analysis of heart rate variability (HRV) during overnight polygraphic recording was performed in 11 healthy subjects. The total spectrum power, power of the VLF, LF and HF spectral bands and the mean R-R were evaluated. Compared to Stage 2 and Stage 4 non-REM sleep, the total spectrum power was significantly higher in REM sleep and its value gradually increased in the course of each REM cycle. The value of the VLF component (reflects slow regulatory mechanisms, e.g. the renin-angiotensin system, thermoregulation) was significantly higher in REM sleep than in Stage 2 and Stage 4 of non-REM sleep. The LF spectral component (linked to the sympathetic modulation) was significantly higher in REM sleep than in Stage 2 and Stage 4 non-REM sleep. On the contrary, a power of the HF spectral band (related to parasympathetic activity) was significantly higher in Stage 2 and Stage 4 non-REM than in REM sleep. The LF/HF ratio, which reflects the sympathovagal balance, had its maximal value during REM sleep and a minimal value in synchronous sleep. The LF/HF ratio significantly increased during 5-min segments of Stage 2 non-REM sleep immediately preceding REM sleep compared to 5-min segments of Stage 2 non-REM sleep preceding the slow-wave sleep. This expresses the sympathovagal shift to sympathetic predominance occurring before the onset of REM sleep. A significant lengthening of the R-R interval during subsequent cycles of Stage 2 non-REM sleep was documented, which is probably related to the shift of sympathovagal balance to a prevailing parasympathetic influence in the course of sleep. This finding corresponds to a trend of a gradual decrease of the LF/HF ratio in subsequent cycles of Stage 2 non-REM sleep.

Adolescent↗
PubMed2001

Increased REM density in narcolepsy-cataplexy and the polysymptomatic form of idiopathic hypersomnia.

The present work is focused on REM sleep density in patients with primary hypersomnia in comparison with non-hypersomnia subjects. 28 unmedicated patients with narcolepsy-cataplexy (NC) and 10 unmedicated patients suffering from the polysymptomatic form of idiopathic hypersomnia (IH) and their age- and sex-matched controls were included in the study. The clinical diagnosis was confirmed by MSLT and nocturnal PSG, HLA typing was performed in a respective group of narcoleptic patients. Polygraphical recordings were visually scored with particular regard to the two most characteristic phasic features of REM sleep: the number of rapid eye movements (REMs) and chin muscle twitches (Tws) per minute. These events were evaluated according to recognized criteria; a closer look was taken at both their frequency and their distribution across all the nocturnal REM periods (REMPs). The following main differences between hypersomniac patients (of both groups examined) and healthy controls were found in terms of phasic activity: (I) REM density (expressed in REMs/min and Tws/min in each REM period) was significantly increased in the hypersomniac patients in comparison with the controls. (p>0.05).(II) The intra-night phasic activity distribution was found rising more conspicuously in the hypersomniacs than in the controls.

Adult↗
PubMed2000

[Hypocretin (orexin) deficiency in narcolepsy-cataplexy].

A mutation in the HCRT locus was proved in 18-yrs old male suffering from narcolepsy-cataplexy. He has demonstrated cataplectic attacks (brief spells of head dropping provoked by laughter) as well as imperative sleep in spells of several minutes up to one hour since the age of six months. He has suffered from severe bulimia since five years; later hypnagogic hallucinations, sleep paralysis and unquiet nocturnal sleep accompanied by periodic limb movements appeared. Symptoms are partially controlled with methylphenidate and either imipramine, clomipramine or fluoxetine. Periodic leg movements poorly responded to L-DOPA and clonazepam treatment. He is HLA-DQB1*0602 negative. Repeated MSLT (over 16 years followed-up period) showed extremely short latency with predominant SOREMPs and also nocturnal PSG recordings revealed fragmented sleep with SOREMPs. This case report demonstrates that hypocretin (orexin) mutations in human can produce the full narcolepsy phenotype and validates data recently reported in dog and mouse models suggesting a role for hypocretin (orexin) in the pathophysiology of narcolepsy and the regulation of REM sleep.

Adolescent↗
PubMed1976

Application of Bathurin and borax in the biological control of Monomorium pharaonis in housing estates.

Of two apartment houses infested with ants of the species Monomorium pharaonis, one was treated with a biological, the other with a chemical substance. In the first case we used Bathurin in combination with borax at a concentration of 1.3% for both substances. In the first week, borax was added to the bait (minced beef), within the next three weeks, the bait was mixed with Bathurin. The procedure was repeated 5 times. After this period, we achieved complete control of the ants on the infested premises.--Our results obtained with the chemical substance (the insecticide Anthrix) were less successful. This indicates that the first method, although time-consuming and requiring a perfect collaboration with all inhabitants, is safer, because it leads to the complete eradication of ants in the infested premises.

Animals↗
PubMedDate not supplied

Determination of exotoxin in Bacillus thuringiensis cells.

The presence of exotoxin in Bacillus thuringiensis was demonstrated and its quantity in the cells determined. The concentration of exotoxin in the producing microorganism is approximately half the concentration of ATP. Exotoxin is produced at such a rate that the cell excretes 1/5 to 1/4 of its exotoxin content into the medium per minute.

Adenosine Triphosphate↗