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

[Emigration of Quebec physicians: motivation for departure and return].

Since the 80's, outmigration of physicians from Quebec is steadily increasing. About 46 percent of outmigrating doctors explain their move by factors related to their occupational life (higher income, greater opportunity in the academic career, larger amount of resources devoted to the health care system). Nearly 40 percent relate their decision to personal factors (greater job opportunity for their wife/husband, quality of family life...). The factors linked to the context of the receiving place (political climate, linguistic regulations, income tax level...) play a minor role on the migration decision. As concerns the returning physicians, 80 percent explain their decision by personal factors. The factors linked to the occupational life have a lower role. It appears therefore that doctor outmigration from Quebec is not directly determined by manpower policies adopted by the Province during the last two decades, except the policies directly linked to the income level of professionals.

Adult↗

PubMedDate not supplied

[Beyond the statistics: why are Quebec physicians emigrating?].

During the period 1986-1999, about 16% of the annual average number of active physicians in Quebec have left for the US or an other Canadian province. The absolute number was 2367. During the same period, 661 would have returned to Quebec. The majority of the outmigrating doctors were graduated from the anglophone university of the Province (although 44 percent are francophone) whereas the majority of the returning doctors were graduated from the 3 francophone universities of the Province. As a matter of fact, 78 percent of the returning doctors are francophone. The migration decision is equally linked to post-graduate training and occupational opportunities and job satisfaction. This feature should be related to an other: those who have returned to Quebec have had a geographic and occupational mobility level far lower than those who have not returned. Finally, it is noteworthy that there are significant differences between the doctors emigrating to the US and their colleagues going to an other Canadian province.

Adult↗

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

[Study of plasmocytopoiesis. II. Probable scheme of the means of formation of plasmocytes elaborated from the results of the numeration of their mitoses].

Explore the source record for details and available documents.

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↗