Size distributions of chylomicrons from human lymph from dynamic light scattering measurements

Abstract

Chylomicrons, the vehicles for the transport of exogeneous triglycerides and cholesterol in the lymph and the blood, were characterized by their size from dynamic light scattering measurements. To achieve an appropriate resolution, correlation data were collected over several hours. Analysis was performed with an extended version of the regularization method CONTIN, and special attention was given to errors in the experimental baseline and to randomness of the residuals. The solutions selected by means of Fisher's F-test by CONTIN agreed with those obtained with the stability plot of Schnablegger and Glatter, when in the case of data of lower statistical accuracy the solution was taken from the lower part of the confidence interval of the F-test. The intensity-weighted size distributions indicated two classes of particle, their mean diameters being 100-140 nm and 330-350 nm. The ability to resolve two peaks of such a size ratio is demonstrated. The numbers of particles associated with the two peaks were estimated by means of the scattering properties of the particles, which showed that the overwhelming majority were small ones. This estimation also suggested that the mean size of the first peak of the number distribution is significantly smaller than the typical size of chylomicrons. This was consistent with the finding that the sample contained not only apolipoprotein B-48 but also a similar amount of apolipoprotein B-100, which is associated with lipoproteins of smaller size. The larger particles of the second peak are probably dietary triglyceride-rich chylomicrons.

Systemic and Forearm Triglyceride Metabolism

“…However, the inconsistencies may relate more to species differences. Human chylomicrons are reported to have particle diameters of 316 -352 nm (10,21,22); this correlates well with commercial lipid emulsions, which have particle sizes in the 286-to 340-nm range (10,23). In contrast, rat chylomicrons have been found to have mean diameters of 130 -160 nm (24 -26).…”

Lipid Metabolism and Fatty Liver in Poultry

“…조류의 경우, 포유류와 같은 림프계가 발달 되어 있지 않기 때문에 사료의 지방이 소장에서 흡수되면 lipoprotein 형태로 간문맥(hepatic portal vein; 위 장관에서 나온 혈액이 간으로 들어가는 혈관)으로 바로 유입되는데, 이를 "protomicron"이라 한다 (Bensadoun and Rothheld, 1972). Protomicron의 크기(평균 지름 약 150 nm)는 포유류인 사람 의 chylomicron(평균지름 약 350 nm; Ruf and Gould, 1999) 보다 작고, 조성(약 80∼90%의 중성지방)은 사람과 유사하 다 (Griffin et al, 1982). Griffin 등(1992)에 의하면 proto-micron과 VLDL 중성지방의 6∼7%만이 육계의 복부지방 조직에서 흡수된다고 한다.…”

Information-weighted constrained regularization for particle size distribution recovery in multiangle dynamic light scattering

“…These include the regularization method [9,10], the CONTIN constrained regularization method [11,12], Bayesian strategies method [13,14], and the neural network method [15], for example. These methods generally work well for unimodal PSDs, but less well for bimodal PSDs with a peak position ratio less than ~2:1, although bimodal PSDs with a peak position ratio larger than ~3:1 can be recovered accurately with the CONTIN method [16,17]. Zhu et al [18] proposed a weighted constrained regularization (WCR) method, and applied it to single-angle DLS measurements, in which a bimodal PSD with peaks at 200nm and 350nm was successfully recovered giving resolution for a peak position ratio of ~1.7:1, and in spite of considering particle sizes <350nm.…”