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Biomedical subjects

M Kuna

Publications and source records attributed to M Kuna.

7 recordsLinked to original sources

[Carbomers and their use in pharmaceutical technology].

Carbomers, high-molecular polymers based on acrylic acid, are employed in the technology of drugs as auxiliary substances acting as emulsifiers, gel-forming substances, stabilizers of suspensions, and binders in tablets. Their properties are utilized to control release as well as to improve biological availability of drugs. They are physiologically inert, non-sensitizing, and possess excellent thermal stability. They are used for various routes of administration: topical, oral and peroral, vaginal and rectal.

Acrylic Resins↗

The polycyclic musk 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthaline lacks liver tumor initiating and promoting activity in rats exposed to human-relevant doses.

7-Acetyl-1,1,3,4,4,6-hexamethyl- 1,2,3,4-tetra-hydronaphthaline (AHTN) is one of the two most widely used fragrances of a group of substances known collectively as the polycyclic musks. In the last few years evidence has been accumulating that AHTN is hepatotoxic when administered at high doses. In the present study the subchronic hepatotoxicity of AHTN administered to rats at doses within the human exposure range was evaluated. For this purpose female and male juvenile Wistar rats were exposed to AHTN (300 microg/kg body weight per day, i.p.) alone or to a single dose of diethylnitrosamine (DEN) (100 mg/kg body weight, i.p.) followed by AHTN (1, 10, 100 or 300 microg/kg body weight per day, i.p.) for 90 days. Thereafter the liver architecture as well as the presence of placental glutathione S-transferase (GST-P)-positive hepatic lesions was assessed. In male animals receiving AHTN alone or in combination with DEN the number of GST-P-positive single hepatocytes was similar to that in untreated rats, while GST-P-positive mini-foci and foci were not observed. In the case of female rats the number of GST-P-positive single hepatocytes and mini-foci in AHTN-treated rats was similar to that in untreated animals, whereas in those animals receiving AHTN either alone or in combination with DEN, GST-P-positive foci could not be detected or were present in a number as similar to that in untreated rats. In conclusion, in the present study it has been shown that AHTN administered over a 90-day period in concentrations similar to those taken up daily by humans does not lead to hepatotoxicity.

Animals↗

EEG changes during forced alternate nostril breathing.

The effects of 10 min forced alternate nostril breathing (FANB) on EEG topography were studied in 18 trained subjects. One type of FANB consisted in left nostril inspiration and right nostril expiration and the other type in right nostril inspiration and left nostril expiration. Mean power in the beta bands and partially in the alpha band increased during FANB irrespective of the type of nostril breathing. In addition, hemisphere asymmetry in the beta 1 band decreased in the second half of FANB suggesting that FANB has a balancing effect on the functional activity of the left and right hemisphere.

Adult↗

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↗

Kapalabhati--yogic cleansing exercise. I. Cardiovascular and respiratory changes.

We studied cardiovascular and respiratory changes during yogic breathing exercise kapalabhati (KB) in 17 advanced yoga practitioners. The exercise consisted in fast shallow abdominal respiratory movements at about 2 Hz frequency. Blood pressure, ECG and respiration were recorded continuously during three 5 min periods of KB and during pre- and post-KB resting periods. The beat-to-beat series of systolic blood pressure (SBP) and diastolic blood pressure (DBP), R-R intervals and respiration were analysed by spectral analysis of time series. The mean absolute power was calculated in three frequency bands--band of spontaneous respiration, band of 0.1 Hz rhythm and the low-frequency band greater than 15 s in all spectra. The mean modulus calculated between SBP and R-R intervals was used as a parameter of baroreceptor-cardiac reflex sensitivity (BRS). Heart rate increased by 9 beats per min during KB. SBP and DBP increased during KB by 15 and 6 mmHg respectively. All frequency bands of R-R interval variability were reduced in KB. Also the BRS parameter was reduced in KB. The amplitude of the high-frequency oscillations in SBP and DBP increased during KB. The low-frequency blood pressure oscillations were increased after KB. The results point to decreased cardiac vagal tone during KB which was due to changes in respiratory pattern and due to decreased sensitivity of arterial baroreflex. Decreased respiratory rate and increased SBP and low-frequency blood pressure oscillations after KB suggest a differentiated pattern of vegetative activation and inhibition associated with KB exercise.

Adult↗

Kapalabhati--yogic cleansing exercise. II. EEG topography analysis.

Topography of brain electrical activity was studied in 11 advanced yoga practitioners during yogic high-frequency breathing kapalabhati (KB). Alpha activity was increased during the initial five min of KB. Theta activity mostly in the occipital region was increased during later stages of 15 min KB compared to the pre-exercise period. Beta 1 activity increased during the first 10 min of KB in occipital and to a lesser degree in parietal regions. Alpha and beta 1 activity decreased and theta activity was maintained on the level of the initial resting period after KB. The score of General Deactivation factor from Activation Deactivation Adjective Checklist was higher after KB exercise than before the exercise. The results suggest a relative increase of slower EEG frequencies and relaxation on a subjective level as the after effect of KB exercise.

Adult↗