The effect of repeated exposure to carbon monoxide (CO) on the response of middle-age rats to an acute CO exposure combined with a low dose of a sympathomimetic agent was studied. A group of 12 rats (male albino, Wistar, age 9 months) without ECG abnormalities was divided into two subgroups matched for weight, heart rate and ECG: one subgroup was exposed to 500 ppm CO for 6 h/d, 5 d/w, for 6 weeks (peak COHb 31.5%, SD 3.5); the other one (controls) was exposed to fresh air. Two or three days after the last exposure both groups underwent combined challenge with 0.025 mg/kg isoproterenol s.c. and 90 minute exposure to CO in a concentration increasing from 500 to 1500 ppm; ECG was recorded continuously. The hearts were examined morphometrically and histologically. The CO-preexposed subgroup had, as compared to controls: 1) significantly higher blood hemoglobin (by 25%), erythrocyte count (by 28%) and volume (by 6%), and hematocrit (by 33%); 2) the same peak COHb; 3) lower basic heart rate and an earlier decrease after isoproterenol, 4) significantly smaller increase in ECG abnormalities and arrhythmias after isoproterenol and during CO exposure; 5) nonsignificantly higher heart weight indexes; 6) a nonsignificantly lower score of histological abnormalities. The global score of ECG pathology during CO exposure (abnormal pattern or arrhythmia) correlated best (multiple corr. coef. >0.9) with end-exposure free (non CO bound) hemoglobin (negatively) and with mean heart rate during exposure (positively): the lower score in the preexposed subgroup was attributable primarily to the increased hemoglobin. Six-week intermittent CO exposure induced marked compensatory processes (hematological) but only a tendency to adaptational changes in the heart (by gross morphometry), and decreased the ECG response to CO+ isoproterenol challenge at the same COHb.
- MeSH
- elektrokardiografie * účinky léků MeSH
- hematokrit MeSH
- hemoglobiny metabolismus MeSH
- isoprenalin * farmakologie MeSH
- krysa rodu rattus MeSH
- lékové interakce MeSH
- objem erytrocytu účinky léků MeSH
- oxid uhelnatý * toxicita MeSH
- počet erytrocytů MeSH
- potkani Wistar MeSH
- srdce * fyziologie patofyziologie účinky léků MeSH
- srdeční arytmie chemicky indukované patofyziologie MeSH
- srdeční frekvence účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
To test liposome penetration through the skin the authors used liposomes with encapsulated protein G with gold conjugate in a gel vehicle. Skin specimens were taken 2, 4, 24,48 and 72 hours after application and were examined histologically and by electron microscopy. The findings indicate that the passage through the skin depends above all on liposome size. Liposomes with a diameter of 600 nm penetrate easily through the skin while liposomes with a diameter above 1000 nm remain in the stratum corneum. The main penetration of liposomes takes place along hair follicles as indicated by a larger amount of free liposomes in the corium of furred guinea pigs.
- MeSH
- adenin analogy a deriváty farmakologie MeSH
- histokompatibilita - antigeny MeSH
- homologní transplantace imunologie MeSH
- imunosupresiva farmakologie MeSH
- krysa rodu rattus MeSH
- nemoc štěpu proti hostiteli patofyziologie prevence a kontrola MeSH
- transfuze lymfocytů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- MeSH
- antidota MeSH
- kadmium metabolismus MeSH
