The intranodal distribution of lymph-borne particles injected intravenously

The sequential distribution of lymph-borne, i.v. injected particles of tantalum in hepatic hilar lymph nodes was studied in rats in an attempt to determine which structural compartments of a node are responsible for mechanical filtration. The injected particles reached these nodes via liver lymph but the i.v. route of administration eliminated any possibility of disturbing either lymph flow or pressure. Particles began to enter hepatic hilar nodes only after an interval of 7-8 h. They were subsequently redistributed from marginal, trabecular and medullary sinuses to the paracortex and finally to medullary cords. Particles accumulated predominantly in the paracortex at 12-24 h and thereafter in medullary cords. This sequential pattern of distribution differed significantly from that observed previously in other lymph nodes after either intralymphatic or intratissue injection.