Increased proteolytic activity of erythrocyte membrane in spur cell anaemia.
In a case of 'spur cell anaemia' (SCA) a reduced esterified/free cholesterol ratio was found in plasma, in LDL and HDL fractions and an increased cholesterol/phospholipid (C/PL) molar ratio in erythrocyte membrane. Cation transport was normal with the exception of Li-Na counter-transport was decreased. An increased intrinsic membrane proteolytic activity (IMPA) was demonstrated by the generalized reduction or, sometimes, disappearance of protein bands on SDS-PAGE in patient ghosts when the proteolysis was allowed. This characteristic was found to be transferable to normal cells by incubation in SCA-plasma; moreover membrane C/PL molar ratio was augmented after incubation. Normal plasma was not able to normalize IMPA of SCA cells 'in vitro', even if it induced a remarkable decrease of membrane C/PL molar ratio. Nevertheless IMPA normalization did occur 'in vivo', when the SCA cells were exposed to therapeutic 'plasma exchange' (3.3 litre/week). The results suggest the following conclusions: (a) in our SCA patient there is an increased IMPA; (b) this feature, as well as membrane lipid alteration, is transferable to normal erythrocytes; (c) this case seems to demonstrate, for the first time in our knowledge, a modulating effect of plasma on IMPA in erythrocytes.
Olivieri
O
O
Institute of Pathologia Medica, University of Verona, Italy.
Guarini
P
P
Negri
M
M
Bassi
A
A
Corrocher
R
R
Biffanti
S
S
De Matteis
M C
MC
Vettore
L
L
D000050:Acanthocytes / Q000648:ultrastructure; D000743:Anemia, Hemolytic / Q000097:blood*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000648:ultrastructure; D006801:Humans; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D010447:Peptide Hydrolases / Q000378:metabolism
D008055:Lipids; D008074:Lipoproteins; D008565:Membrane Proteins; D010447:Peptide Hydrolases