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Mononuclear cell-membrane "fluidity": a study in some haematological malignancies
Abstract:
The polarization of fluorescence from diphenyl hexatriene embedded in the membranes of intact peripheral-blood mononuclear cells has been measured and used to assess the "microviscosity" or fluidity of the membrane. Cell preparations were examined from patients with various types of leukaemia and related conditions in which circulating primitive cells may occur. Significantly lower fluorescence polarization values were obtained in all samples from patients with chronic lymphocytic leukaemia, but normal results were obtained in cases of chronic granulocytic leukaemia, myelosclerosis, solid lymphomas and in acute leukaemias in remission. In relapsed acute leukaemia, fluorescence polarization indicated reduced "microviscosity" of the cell membrane when large numbers (greater than 10(9)/1) of primitive cells were present; normal "microviscosity" was indicated when less than 10(9)/1 primitive cells were present. However, exceptions occurred in both cases, and the technique failed to give warning of imminent relapse in one case. Our findings suggest that a reduction in "microviscosity" as indicated by this technique is not a general property of the blood leucocytes in all types of leukaemia, and that the technique cannot, at present, be regarded as an alternative method for detecting circulating primitive cells.
Insights
Fluorescence polarization measurements reveal altered cell membrane fluidity in chronic lymphocytic leukemia. This technique, however, is not a reliable indicator for detecting primitive cells in all leukemia types.
Area of Science:
- Biophysics
- Hematology
- Cell Biology
Background:
- Cell membrane fluidity is crucial for cell function.
- Alterations in membrane properties are associated with various diseases, including leukemia.
- Diphenyl hexatriene is a fluorescent probe used to assess membrane microviscosity.
Purpose of the Study:
- To investigate the relationship between cell membrane microviscosity and different types of leukemia.
- To evaluate the potential of fluorescence polarization as a diagnostic tool for leukemia and detection of primitive cells.
Main Methods:
- Measurement of fluorescence polarization of diphenyl hexatriene in peripheral-blood mononuclear cells.
- Analysis of cell samples from patients with various leukemias and related conditions.
- Correlation of fluorescence polarization values with clinical status and cell counts.
Main Results:
- Significantly lower fluorescence polarization (increased fluidity) was observed in chronic lymphocytic leukemia.
- Normal fluorescence polarization was found in chronic granulocytic leukemia, myelosclerosis, solid lymphomas, and acute leukemias in remission.
- In relapsed acute leukemia, reduced microviscosity correlated with high primitive cell counts, but exceptions and false negatives occurred.
Conclusions:
- Reduced cell membrane microviscosity is not a universal characteristic of all leukemias.
- Fluorescence polarization is not currently a reliable alternative method for detecting circulating primitive cells.
- The technique shows potential for characterizing specific leukemia subtypes, like CLL, but requires further validation.