D. Boda et al., MEASUREMENT OF SURFACE-TENSION IN BIOLOGICAL-FLUIDS BY A PULSATING CAPILLARY TECHNIQUE, Journal of perinatal medicine, 25(2), 1997, pp. 146-152
Ever since the discovery of the antiatelectatic function of the pulmon
ary surfactant, the measurement of surface tension (ST) has been of in
creasing importance in respiration physiology and clinical research. F
or the determination of ST, the elevation of the level of a fluid arti
ficially pulsated in a capillary glass tube was monitored, and ST was
calculated with the digitalized video-computerized picture analysis pr
ogram Surftens. The biological relevance of the method is given by the
Gibbs-Thomson principle, according to which surface-active lipids str
eam towards the surface by an adsorptive process; on pulsation of the
fluid in a capillary glass tube, therefore, ST is gradually decreased
to a minimal value. ST values of 60 amniotic fluid samples collected f
rom pregnancies with different gestation times were determined. A mult
iple regression analysis of the results, including other parameters (t
otal protein content, total lipid content, phospholipid content and mi
croviscosity), indicated that this method may enhance the precision of
the determination of gestation time. Precision analysis of various sa
mples proved that this technique gives well-reproducible results under
the given standardized conditions. The main field of application of t
he method may be in clinical practice and in studies on as yet inadequ
ately known factors affecting the ST of biological fluids.