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Polymorphonuclear leukocyte transit times in bone marrow during streptococcal pneumonia
T Terashima1, B Wiggs, D English
1Pulmonary Research Laboratory, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.
The American Journal of Physiology
|October 1, 1996
Summary
Bacterial infection significantly reduces the time polymorphonuclear leukocytes (PMN) spend in the bone marrow (BM). This accelerated release may lead to immature PMN entering circulation, potentially increasing inflammation.
Area of Science:
- Hematology
- Immunology
- Cell Biology
Background:
- Polymorphonuclear leukocytes (PMN) are crucial for acute inflammation.
- Bone marrow (BM) stimulation can alter PMN toxicity and behavior.
- Understanding PMN transit time in BM is key to inflammatory response.
Purpose of the Study:
- To measure PMN transit time in the mitotic and postmitotic pools of rabbit bone marrow.
- To investigate the effect of bacterial infection on PMN transit time.
Main Methods:
- Utilized 5'-bromo-2'-deoxyuridine (BrdU) labeling to track PMN.
- Collected blood samples at intervals post-BrdU injection.
- Detected BrdU-positive PMN (PMNBrdU) using immunohistochemistry.
- Quantified BrdU staining intensity to define PMN generations (G1, G2, G3).
Main Results:
- Mean PMN transit time through BM was 95.6 hours (51.1h mitotic, 65.4h postmitotic).
- Streptococcus pneumoniae infection shortened overall BM transit time to 54.0 hours (36.2h mitotic, 34.6h postmitotic).
- Infected PMN transit times were significantly shorter than controls (P < 0.05).
Conclusions:
- Streptococcus pneumoniae accelerates PMN transit through both mitotic and postmitotic bone marrow pools.
- This expedited release may result in immature PMN entering circulation.
- Immature PMN may possess elevated lysosomal enzyme levels, influencing inflammatory responses.