It is known that the lung has the ability to synthesize and metabolize vasoactive substances and to alter their physiologic activity during passage through the pulmonary circulation.
The present study was conducted to compare the effects of various vasoactive substances and to examine the interactions between vasoactive substances and dibutyryl cyclic AMP in the guinea-pig trachea.
Male guinea-pigs (200-300g) were killed. The trachea was removed, suspended isotonically in the tissue bioassay system superfused with Krebs-Hensleit solution (gassed with 95% oxygen, 5% carbon dioxide and heated to 37°C).
1) Acetylcholine (50ng/ml) contracted guinea-pig trachea, and the response to acetylcholine was increased by 220% with continuous infusion of neostigmin (500ng/ml). (p<0.001).
2) Bronchodilating effect of isoproterenol was increased with continuous infusion of prednisolone hemisuccinate (50μg/ml).
3) Acetylcholine (50ng/ml) and angiotensin II (50ng/ml) caused an initial cntraction and then some relaxation (negative phase). This negative phase was decreased with continuous infusion of propranolol (2μg/ml).
4) Bronchodilating effect of PGE₂ is about 2-5 fold stronger than that of PGE₁, (p<0.001).
5) Dibutyryl cyclic AMP (5-50μg/ml) partially inhibited the contractions elicited by 50ng/ml of acetylcholine, serotonine, PGF_2α, histamine and by 500ng/ml of angiotensin II.
Acetylcholine, Serotonin p<0.001
PGF_2α, Histamine p<0.01
Angiotensin II p<0.1

抄録全体を表示

In order to elucidate the physiological significance of triglyceride metabolism in lung, effects of nutritional condition on triglyceride content, lipolytic activity and lipase activity in rat lung were examined, and incorporations of long-chain fatty acids, administered orally, into the lipid fractions in mouse lung and liver were measured.
(1) The triglyceride content in rat lung decreased significantly with fasting, and increased 1 to 4 hours after oral administration of triolein.
(2) The production of nonesterified fatty acid from rat lung incubated in vitro was not increased by fasting for 24 to 48 hours, and it was not stimulated by the addition of adrenaline to the incubation medium.
(3) The lipoprotein lipase activity in rat lung showed no significant change in fasting for 24 to 48 hours, and 1 to 4 hours after oral administration of triolein.
(4) Palmitate-9, 10-³H and oleate-9, 10-³H were administered orally into mice. After 1 to 3 hours the lungs and livers were removed, and the lipids were extracted.
The amounts of these labelled fatty acids incorporated into the total lung lipids were below 4% of those i corporated into the total liver lipids.
The amounts of these fatty acids incorporated into the lung phospholipid (lecithin+sphingomyelin+cephalin) fraction were larger than those incorporated into the lung triglyceride fraction. The ratio of the amount of isotope in phospholipid fraction to that in triglyceride fraction of the palmitate-³H was about 2.5, and that of the oleate-³H was 1.24 to 1.36. On the other hand, these fatty acids were much incorporated into the liver triglyceride fraction than into the liver phospholipid fraction.

抄録全体を表示

36歳女性, 体動時息切れと乾性咳で発症し, 増強する呼吸困難と低酸素血症を認め, 開胸肺生検にて間質性肺炎と診断したが, 経過中約5ヵ月して四肢の脱力と血中諸酵素 (CPK, GOT他) の高値を認め筋電図, 皮膚筋生検で多発性筋炎と診断された. 多発性筋炎に肺病変が合併する事は稀ではないが, 筋病変を思わせる所見がなく肺病変が先行する例は少ない.

抄録全体を表示