Biomedical subjects

F S Peng

Publications and source records attributed to F S Peng.

39 records · Page 3Linked to original sources

PubMedDate not supplied

Migration of intramediastinally injected thymocytes in draining nodes.

The present study investigated the migration, in the lymph node, of cells entering the organ via the subcapsular sinus. Thymocytes of rats were labelled with 3H-thymidine and injected into the mediastinal cavity of syngeneic recipients. These animals were sacrificed at various intervals after injection. Five minutes after injection, labelled cells were found in the subcapsular sinus, and even in the peripheral cortex, of the draining mediastinal lymph nodes. The overall of the radioautographic observations reveals a migration of cells from the peripheral cortex towards the deep cortex, and into the medullary cords. The observations indicate that such migration can occur in less than 12 hours. Nevertheless, six hours after the injection, some labelled cells had escaped already the draining nodes and migrated into the other lymphoid organs. It is a fact that some of our results suggest that cells may pass directly from the subcapsular into the medullary sinuses without previously migrating into the nodal parenchyma. As to folliculo-nodules and pseudo-follicles, they exhibited relatively few labelled cells. Moreover, some of our findings indicated that cell migration was much slower in the pseudo-follicles than in the extrafollicular zone.

Animals↗

PubMedDate not supplied

A study of the mode of lymphocyte recirculation in the dog.

Current view of lymphocyte recirculation holds that lymphocytes enter the nodes by migrating across the wall of their postcapillary venules, not by way of their subcapsular sinus. Having explained elsewhere our reasons to question the validity of the concept, we undertood to reinvestigate the problem. Lymphocytes were collected from the thoracic duct of dogs and labelled with3 H-cytidine. Each suspension of labelled cells was transfused to the dog having provided it. Analysis of radioautographs revealed that a significant amount of the labelled cells, which had migrated in the nodes, were present in their subcapsular sinus and the peripheral layer of their cortex. Among the nodes, the mesenteric nodes showed the greatest concentration of labelled cells. In addition, a substantial percentage of the injected lymphocytes, mostly small ones, were found in the lamina propria of intestinal villi and crypts. The findings indicate that, at least in the dog, a large fraction of the lymphocytes recirculate by entering the nodes via the afferent lymph, mostly that of the mesenteric nodes.

Animals↗

PubMedDate not supplied

Histological observations on the deep cortex of the lymph nodes of the germ-free mouse.

The deep cortex of the node was previously shown to be composed by semi-rounded "units", each one comprising a centre and a periphery. The periphery was considered to a site of migration of lymphocytes circulating through a node and the centre a site where some of these migrating cells collect for a certain time. The present work compared the units of the nodes of germ-free and normal mice at age eight-weeks. The units differed in the two groups of animals. The main finding was that the units of mesenteric nodes of germ-free mice differed from those of the other nodes found in the same animals. Unlike in the mesenteric nodes of normal mice, the periphery of a unit was clearly demarcated from its center due to a greater lymphocyte density in the periphery. This fact fits a previous proposal that each part of the unit functions separately. Observations of the peripheral cortex and medulla of the germ-free nodes support other previous proposals on various aspects of the functioning of the organ in normal animals.

Animals↗