胎羊肺泡液的成分

Composition of alveolar liquid in the foetal lamb.

Adamson T M, Boyd R D, Platt H S, Strang L B

J Physiol. 1969 Sep;204(1):159-68. doi: 10.1113/jphysiol.1969.sp008905.

Abstract

Experiments were performed on foetal lambs at gestations between 125 days and term. The foetus was exteriorized at Caesarean section with the umbilical cord and placental attachment maintained intact. Samples of liquid from the alveolar parts of the lung were withdrawn through a tracheal cannula and samples of lung lymph, plasma and amniotic liquid were also obtained. Measurements were made of total osmolality, concentrations of electrolytes and urea, pH and P(CO2). Titrations were carried out with N/10 HCl and N/10 NaOH. The water content of the liquids was estimated and concentrations expressed per kg H(2)O.2. In alveolar liquid [H(+)], [K(+)] and [Cl(-)] were higher and [Ca(2+)], [phosphates] and [HCO(3) (-)] were lower than in plasma or lymph. In amniotic liquid osmolality [Na(+)], [Cl(-)] and [Ca(2+)] were lower and [phosphates] higher than in plasma or lymph. Alveolar liquid/plasma ratios of [HCO(3) (-)], [Ca(2+)], [Cl(-)] and [K(+)] differed from ultra filtrate/plasma ratios of these ions.3. Titration curves demonstrated a very small amount of buffering in alveolar liquid at its in vivo pH of 6.27 mostly due to HCO(3) (-) at an average concentration of 2.8 mM/kg H(2)O.4. It is concluded that foetal alveolar liquid is not an ultrafiltrate of plasma nor a mixture of amniotic liquid and plasma ultrafiltrate, but a special material elaborated by the foetal lung.

摘要

实验在妊娠125天至足月的胎羊身上进行。通过剖宫产将胎儿取出，保持脐带和胎盘附着完整。经气管插管抽取肺肺泡部分的液体样本，同时获取肺淋巴、血浆和羊水样本。测量总渗透压、电解质和尿素浓度、pH值及P(CO2)。用N/10 HCl和N/10 NaOH进行滴定。估算液体的含水量，浓度以每千克H(2)O表示。
肺泡液中的[H(+)]、[K(+)]和[Cl(-)]高于血浆或淋巴液，而[Ca(2+)]、[磷酸盐]和[HCO(3)(-)]低于血浆或淋巴液。羊水中的渗透压、[Na(+)]、[Cl(-)]和[Ca(2+)]低于血浆或淋巴液，而[磷酸盐]高于血浆或淋巴液。肺泡液/血浆中[HCO(3)(-)]、[Ca(2+)]、[Cl(-)]和[K(+)]的比值与这些离子的超滤液/血浆比值不同。
滴定曲线表明，肺泡液在体内pH值6.27时的缓冲量非常小，主要是由于平均浓度为2.8 mM/kg H(2)O的HCO(3)(-)。
得出的结论是，胎儿肺泡液既不是血浆的超滤液，也不是羊水和血浆超滤液的混合物，而是胎儿肺产生的一种特殊物质。