Developmental age estimated by bone-length measurement in human fetuses

The lengths of 491 long bones of the extremities derived from 193 freshly delivered human fetuses of 7 to 22 weeks fertilization age were measured. Fetuses delivered after spontaneous abortion, twin pregnancy, or known maternal disease were excluded. The correlation between fetal age (measured by crown-rump length) and bone length was linear. The term "developmental age" was used for bone length-derived age values. Developmental age can be determined from the length of even a single bone, i.e., when mechanical injury of the delivered fetus inhibits crown-rump length measurement. The results could aid researchers dealing with human embryology, clinicians performing fetal tissue transplantation, and could be applied in forensic medicine as well.     

The repopulation of lymph nodes of dogs after 1200 R whole-body x-irradiation and intravenous administration of mononuclear blood leukocytes.

Fresh and cryopreserved autologous or allogeneic mononuclear blood cells (MBCs) intravenously injected in 1200 R total-body x-irradiated dogs repopulated lymph nodes within 10 days after tranfusion. Several parameters of the lymphopoietic regeneration were correlated with the number of cells transfused and with the number of colony-forming units contained in the cell suspension when they were cultured in agar (CFUc). Values within the normal or close to normal range were reached in the mesenteric nodes of most of the animals transfused with 10 X 10(9) MBC or more. These values were obtained when 5 X 10(5) CFUc or more were transfused. Axillary nodes showed lower values than mesenteric nodes. They were mostly under the normal range but well over those of the irradiated controls. Frozen and thawed MBCs seem to be as effective as fresh cells for lymphopoietic restoration. The mesenteric nodes of dogs transfused with allogeneic MBCs showed higher cellularity and larger cortical-paracortical areas than those of dogs tranfused with approximately the same number of autologous cells. The repopulation of lymph nodes parallels that of the marrow.