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F Palecek

Publications and source records attributed to F Palecek.

80 records · Page 5Linked to original sources
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Pulmonary hypertension in silicotic rats.

In male rats, pulmonary hypertension was found 9, 17 to 18, and 30 wk after an intrapulmonary injection of 50 mg quartz dust suspended in saline. Pulmonary arterial blood pressure increased progressively with time, and in the oldest group, the weight of the right heart ventricle was increased.

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Effect of vagal cooling on lung functional residual capacity in rats with pneumonia.

We examined the effect of cold vagal block on the functional residual lung capacity (FRC) in control rats and in rats with experimental pneumonia induced by intratracheal administration of the herbicide paraquat. The measurements were performed in a body plethysmograph in anaesthetized and intubated rats. Rats with pneumonia had tachypnoea and increased minute ventilation. Their FRC was 3.6 +/- 0.7 ml in comparison with 2.5 +/- 0.6 ml in controls (mean +/- SD). Cooling the cervical vagi, so that the Hering-Breuer inflation reflex was abolished (approximately 8 degrees C), resulted in a marked decrease of the rate of breathing and an increase of tidal volume in both groups of animals. The value of FRC did not change during vagal cooling (3.7 +/- 0.9 ml in rats with pneumonia, 2.8 +/- 0.8 ml in controls). In rats with model pneumonia, bilateral cervical vagotomy was followed by a normalization of the FRC (2.3 +/- 0.7 ml). In control animals, the FRC did not change after vagotomy (2.5 +/- 0.6 ml). We conclude that increased FRC in rats with paraquat pneumonia depends on intact conduction through thin, slowly conducting vagal fibres.

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Effect of alpha-methyldopa on lung microembolism in the rat.

The effect of chronic pretreatment with alpha-methyldopa on acute pulmonary hypertension induced by lung microembolization with Sephadex particles in the rat was studied. Alpha-methyldopa was administered twice a day for 10 days by oesophageal gavage (20 mg X kg-1 of body weight) prior to embolization. Rats were anaesthetized with urethane. A catheter was positioned in closed chest rats in the pulmonary artery and 50 microliter of Sephadex suspension in saline were injected. The control group was not pretreated with alpha-methyldopa. In a subgroup of control and pretreated rats, the cardiac output was measured by the dye dilution technique before and after lung microembolization. Rats pretreated with alpha-methyldopa had less pulmonary hypertension, higher cardiac output and more severe arterial hypoxaemia 15 min after lung microembolization than untreated animals. There was no difference in platelet counts prior and after embolization. We suggest that pulmonary hypertension after lung microembolization in the rat includes a vasoconstrictor component which can be suppressed by alpha-methyldopa, and that severe arterial hypoxaemia in pretreated rats is probably the result of a decrease of the ventilation/perfusion ratio in unobstructed areas, which in untreated rats may be prevented by active vasoconstriction.

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Enlargement of carotid bodies in rats with lung emphysema or silicosis.

Volume of carotid bodies was measured morphometrically in rats with experimental lung emphysema or silicosis. The mean volume of the left carotid body was 19.9 +/- (SD) 12.4 in 13 control rats, 30.7 +/- 12.5 in 9 rats with lung emphysema, and 41 +/- 18.9 . 10(6) micrometer 3 in 10 rats with lung silicosis. There was no correlation between carotid body volume and pulmonary arterial blood pressure. A good correlation was found between the volume of carotid body and partial pressure of oxygen in arterial blood. The functional meaning of the increase of volume of carotid bodies in rats with chronic respiratory insufficiency remains unclear.

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