Kinetic Studies of ⁵¹Cr and DF³²P Labelled Granulocytes

Abstract

In vivo kinetic studies of granulocytes labelled in vitro with 51Cr and DF32P were carried out in nine haematologically normal subjects by isolation of the cells in the blood samples by the Ficoll-Isopaque flotation method. 51Cr and 32P specific activity of blood samples made of 93-98% granulocytes was studied. Distribution between marginated and circulating granulocyte pools was identical for both labelled cells and the marginated pool was similar to the circulating pool, except that it was lower in one subject who had a previous splenectomy. The half-disappearance time (T 1/2) was 16.1+/-2.2 h for 51Cr-labelled and 5.4+/-2.1 hr for DF32P-labelled granulocytes. In one case of a normal subject who previously received multiple transfusion homologous 51Cr-labelled granulocytes had a T 1/2 of less than 1 h.

CXCR4 is a key regulator of neutrophil release from the bone marrow under basal and stress granulopoiesis conditions

“…1 Contributing to the complexity of this process, neutrophils have the shortest survival of any circulating cell, with reported half-lives of 8 to 16 hours under basal conditions. [2][3][4][5][6][7] Despite its importance, the mechanisms regulating neutrophil number in the blood are incompletely understood.…”

Kinetics of reversible-sequestration of leukocytes by the isolated perfused rat lung

“…The half-life of the circulation of leukocytes in the isolated perfused rat lung is approximately 2-1/2 hours, which is of the same order of magnitude as the in-vivo value of 5-6.7 hours (107,52). The difference is most probably due to the greater rate of cell death in the perfusion system than in the body.…”

“…Cells leave circulation randomly, as indicated by the disappearance curves of infused labelled leukocytes in-vivo (107). The magnitude and rate of cell loss demonstrated by these curves includes cell loss due to cell senescence.…”

Technetium 99m Autoradiography of Labelled White Cells

“…13). Briefly, it consists of three steps: (a) sedimentation of 10 ml of normal human venous blood leading to the formation of a suspension rich in leukocytes [13]; (b) preincubation of WBC in a 'cold' tin pyrophosphate solution before (c) labelling with W mTc-pertechnetate [3] 98% of the leukocytes in the initial blood sample were recovered in the final suspension and the final labelling efficiency was therefore 30-35%, for samples from patients with normal granulocyte counts.…”