Red Cell Membrane Protein Lateral Mobility in Diabetes Mellitus G. Caimi, A. Serra, R. Lo Presti and A. Sarno Istituto di Clinica Medica e Malattie Cardiovascolari, Universita di Palermo, Palermo, Italy
In a group of 24 diabetics subdivided for type, we evaluated the red cell membrane protein lateral mobility marking intact red cells with pyrene-3-maleimide (3-PM) and calculating the dimer to monomer fluorescence intensity ratio (Iex/Im). The same fluorescent parameter was determined in a group of 13 normal controls. From the obtained data, it is evident that the red cell membrane protein lateral mobility clearly discriminates normals from diabetics of type 1 and 2. In normals and in diabetics of type 1 and 2 no relationship is present between this fluorescent determinant and the glycometabolic parameters (FBGL and HbAlc); considering all the diabetics, a negative relationship is evident between Iex/Im ratio and H b A l c only. Key words Red Cell Membrane Proteins — Diabetes Mellitus
The red cell membrane dynamic property, an essential component of erythrocyte deformability, depends on the lipids and on the proteins (Aloni, Shinitzky and Levin 1974; Chabanel, Flamm, Sung, Lee, Schachter and Chen 1983; Shinitzky and Barenholtz 1978; Cherry 1979). The latter, in diabetes mellitus, have often been neglected because their structural and functional determination is not easy. The red cell membrane proteins interact with the membrane lipids and influence the mechanical stability of the membrane (Borochov, Abbott, Schachter and Shinitzky 1979; Golan, Alecio, Veateh and Rando 1984); the latter property conditions not only the red cell deformability but also the aggregability (Chien and Sung 1987), a macrorheological parameter that in diabetics is altered (Schmid-Schombein and Volger 1976). Our present aim was to verify the behaviour of the red cell membrane protein lateral mobility and also to evaluate the relationships between this aspect and the glycometabolic pattern. Subjects and Methods Subjects
Introduction Previously, employing the fluorescence spectroscopy, we evaluated some parameters reflecting the red cell membrane dynamic properties in diabetic subjects. Using the 1.6-diphenyl-1.3.5-hexatriene (DPH) as probe, we determined the red cell membrane lipid fluidity (Caimi, Catania, D'Asaro, Serra, Catalano, Bono and Sarno 1988). The erythrocyte membrane transverse fluidity gradient was examined employing a set of fatty acid fluorescent probes (Caimi, Serra, D'Asaro, Lo Presti, Grifo, Catania and Sarno 1990). The red cell membrane fluidity was obtained utilizing lO-(l-pyrene) decanoic acid (PDA) as probe (Caimi, Serra, Capobianco, Catania, Romano, D'Asaro and Sarno 1988). In the previous reports we observed that only the red cell membrane fluidity, obtained marking intact red cells with P D A and evaluating the ratio of fluorescence intensity of excimer and monomer in the fluorescence spectrum of PDA, is able to discriminate normals from diabetics. The PDA probe, as well as other pyrenes, during excitation produces a second broad emission peak (excimer spectrum), that depends on the diffusion of the fluorophores in the plane of the membrane (Galla and Sackmann 1974). Horm.metab.Res.24(1992)409-411 © Georg Thieme Verlag Stuttgart • New York
Our research included 12 diabetics of type 1 (mean age 22 ± 10 yrs, range 11 —49 yrs) and 12 diabetics of type 2 (mean age 61 ± 10 yrs, range 40-71 yrs). The diagnosis and the classification of diabetes mellitus was effected according to the criteria of The National Diabetes Data Group (1979). All the diabetics were studied soon after hospital admission, after a fasting state of 12 hours. The means of the venous blood glucose level, determined using an enzymatic method, and the means of the HbAlc red cell level (evaluated using the Auto Ale Analyzer) are reported in Table 1).
Table 1 Means ±SD of glycometabolic parameters in normals and diabetics of type 1 and 2. Normals
FBGL (mg/dl)
HBA1c
(n = 13)
Diabetics of type 1 (n = 12)
Diabetics of type 2 (n = 12)
80.5±7.3 (69-90)
253±85 (108-417)
182±55 (73-288)
4.8 ±0.4 (4.0-5.6)
8.4 ±2.3 (5.2-13.0)
7.9 ±1.6 (6.0-11.6)
FBGL: Fasting Blood Glucose Level HbAlc: Glycated haemoglobin.
Received: 8 Apr. 1991
Accepted: 10 Jan. 1992 after revision
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Summary
Horm. metab. Res. 24 (1992)
G. Caimi, A. Serra, R. Lo Presti and A. Sarno Discussion
Methods The red cell membrane protein lateral mobility was determined on washed intact red cells, marked with pyrene-3maleimide (3-PM). The pyrene-3-maleimide (3-PM) is a thiol agent which interacts with the red cell membrane protein-sulphydryl groups (Weltman 1973). For its characteristic shift in the fluorescence spectrum, it is able to explore a variety of membrane properties, including protein lateral mobility {Betcher-Lange and Leher 1973); Ohyashiki, Yamamoto and Mohri 1989). The 3-PM is different from other pyrenederivatives because a maleimide group is present in its molecule. This group interacts with SH-groups and permits the evaluation of the protein lateral movements employing the excimer/monomer fluorescence. The latter are usually adopted, using the fluorescent lipophylic probes for the evaluation of the lateral diffusion in the hydrophobic region of the membrane (Galla and Sackmann 1974; Eisinger and Flores 1985). The red cells, suspended in PBS at a concentration of 5 x 106 cells/ml, were marked with fluorescent label pyrene-3maleimide (3-PM) (Molecular Probes, Junction City, OR) previously dissolved in tetrahydrofuran. The labelling was effected for 30' at 37 °C with a final concentration of probe of 0.04 mM/1. After incubation, the red blood cells were washed three times with PBS. The fluorescence measurement was effected at a temperature of 37 °C and at a cellular concentration of 5 x 105 cells/ml using the Perkin-Elmer LS5 spectrophotofluorimeter. The excitation wavelength was of 340 nm, while the emission wavelength was of 380 nm for the monomer and 440 for the excimer. The parameter we considered was the dimer (lex) to monomer (Im) fluorescence intensity ratio (Iex/Im); the latter parameter, as it is known, is related to the concentration and to the mobility of the probe in the red cell membrane. The same parameter was evaluated in a group of 13 normal controls (range 22—60 years) matched for sex and smoking habits. Statistical
Analyses
The data were expressed as means + SD; the means difference was evaluated according to the Student's t-test for unpaired data; the relationships between the Iex/Im ratio and glycometabolic parameters were studied employing linear regression. Results From the obtained data, it is evident that: the Iex/Im ratio clearly discriminates normals from diabetics of type 1 and 2 (Table 2); no difference is present between diabetics of type 1 and 2 (Table 2); Table 2 Means + SD of red cell membrane protein lateral mobility (lex/lm) in normals and diabetics of type 1 and 2.
lex/lm (e-PM)
Normals
Diabetics of type 1
Diabetics of type 2
0.529 ±0.090
0.393 ±0.073*
0.365 ±0.090*
*p < 0.001 vs normals.
— in normals and in diabetics there is no significant correlation between Iex/Im ratio, FBGL and HbAlc; considering all the diabetics a significant negative relationship between Iex/Im ratio and HbAlc is present (r=— 0.503; p < 0.05).
Our results give evidence that in diabetic red cells a reduction of the Iex/Im ratio is present; these results cannot be compared to those of other authors because there is no research regarding the employment of this probe in diabetes mellitus. We retain that this finding expresses the altered red cell membrane composition that accompanies diabetes mellitus. This alteration does not involve the lipid pattern only, but also the membrane proteins, even if their evaluation in this research is only functional. The Iex/Im ratio is not correlated to the FBGL and HbAlc in diabetics subdivided for type, but is significantly correlated to HbAlc in all the diabetics. The latter negative relationship might express the dependence of this red cell membrane microrheological parameter on the glycometabolic pattern. In fact, the HbAlc is negatively related to the red cell glutathione (GSH) content {David, Cerutti, Dianziani, Urbino, Balboni, Fonsati, Sacchetti, Vigo 1986) and the red cell GSH content in diabetes mellitus is reduced {Pescarmona, Bosia and Ghigo 1981; Ghigo, Bosia, Pagani, Pescarmona, Pagano and Lenti 1983; Bono, Caimi, Catania, Sarno and Pandolfo 1987). The latter datum is correlated to the N A D P H decrease caused especially by the increased sorbitol synthesis. The N A D P H decrease limits the reduction to GSH operated by glutathione reductase. As it is known, the red cell GSH decrease favours the peroxidation of the membrane proteins into higher-molecular-weight complexes and the oxidation of the protein-sulphydryl groups; the latter aspect is what was observed employing the fluorescent probe 3-PM. The pyrene-3maleimide (3-PM), in fact, is a thiol agent which interacts with the red cell membrane protein-sulphydryl groups. We think that in diabetes mellitus the erythrocyte membrane protein composition needs further investigation. On the one hand, we know that the red cell membrane protein glycation does not modify the red cell membrane deformability {McMillan and Brooks 1982; Williamson, Gardner, Boylan, Carroll, Chang, Marvel, Gonen, Kilo, Tran-SonTay and Sutera 1985); on the other hand, it may be supposed that in diabetes mellitus the alteration of the red cell membrane protein pattern regards, besides the oxidation of the proteinsulphydryl groups, also the membrane protein phosphorylation. As it is known, an appropriate protein membrane phosphorylaiton is necessary for the physiological erythrocyte deformability {Marchesi 1979). References Aloni, B., M. Shinitzky, A. Levin: Dynamics of erythrocyte lipids in intact cells, in ghost membranes and in liposomes. Biochim. Biophys. Acta 348:438-444(1974) Betcher-Lange, S. L., S. S. Leher: Pyrene excimer fluorescence in rabbit skeletal alpha tropomyosin labeled with n-l(pyrene)maleimide. J. Biol. Chem. 253:3757-3763 (1973) Bono, A., G. Caimi, A. Catania, A. Sarno, L. Pandolfo: Red cell peroxide metabolism in diabetes mellitus. Horm. Metabol. Res. 19: 264-266(1987) Borochov, H., R. E. Abbott, D. Schachter, M. Shinitzky: Modulation of erythrocyte membrane proteins by membrane cholesterol and lipid fluidity. Biochemistry 18:251-255 (1979)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
410
Proteins in Diabetes
Mellitus
Caimi, G., A. Catania, S. D'Asaro, A. Serra, C. Catalano, A. Bono, A. Sarno: Red cell phospholipids and membrane microviscosity in diabetics. Clin. Hemorheol. 8:939-944 (1988) Caimi, G., A. Serra, D. Capobianco, A. Catania, A. Romano, S. D'Asaro, A. Sarno: Red cell membrane fluidity in diabetics. Rev. Port.Hemorrheol.2:139-144(1988) Caimi, G., A. Serra, S. DAsaro, R. LoPresti, G. Grifo, A. Catania, A. Sarno: Diabete mellito: valutazione del gradiente di polarizzazione della membrana eritrocitaria con l'impiego di acidi grassi fluorescentil. In: Atti del 13 Congresso Nazionale della Societa Italiana di Diabetologia, Pisa, 1990; II Diabete 2 (Suppl. 1): 27 (1990) Chabanel, A., M. Flamm, K. L. P. Sung, M. M. Lee, D. Schachter, S. Chen: Influence of cholesterol content on red cell membrane viscoelasticity and fluidity. Biophys. J. 44:171 - 1 7 6 (1983) Cherry, R. J.: Rotational and lateral diffusion of membrane proteins. Biophys. Biochim. Acta559:289-328 (1979) Chien, S., L. A. Sung: Physicochemical basis and clinical implications of red cell aggregation. Clin. Hemorrheol. 7:71—91(1987) David, O., F. Cerutti, I. Dianziani, A. Urbino, R. Balboni, M. Fonsati, C. Saccetti, A. Vigo: Correlazione tra GSH eritrocitario ed emoglobina glicosilata in bambini diabetici insulino-dipendenti. G. Ital. Diabetol. 6:138-144(1986) Eisinger, J., J. Flores: Fluorometry of turbid and absorbant samples and the membrane fluidity of intact erythrocytes. Biophys. J. 48: 77-85(1985) Galla, H. J., E. Sackmann: Lateral diffusion in the hydrophobic region of membrane: use of pyrene excimers as optical probes. Biochim. Biophys. Acta 339:103-112(1974) Ghigo, D., A. Bosia, A. Pagani, G. P. Pescarmona, G. Pagano, G. Lenti: Alterazioni della deformabilita eritrocitaria conseguenti a modificazioni del metabolismo ossido-riduttivo nel diabete mellito. Res. Clin. Lab. 13 (Suppl. 3): 375-381 (1983) Golan, D. E., M. R. Alecio, W. R. Veateh, R. R. Rando: Lateral mobility of phospholipid and cholesterol in the human erythrocyte membrane: effects of protein-lipid interactions. Biochemistry 23: 332-339(1984) Marchesi, V. T.: Spectrin: present status of a putative cyto-skeletal protein of the red cell membrane. J. Membr. Biol. S1:101 - 1 0 3 (1979) McMillan, D. E., S. M. Brooks: Erythrocyte spectrin glucosylation in diabetes. Diabetes 3 1 : 6 4 - 6 9 (1982) National Diabetes Data Group: Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. Diabetes 28:1039-1057(1979) Ohyashiki, T., T. Yamamoto, T. Mohri: Changes in the fluorescence parameters of bound N-(l-pyrene)maleimide by lipid peroxidation of intestinal brush-border membranes. Biochim. Biophys. Acta981:235-242(1989) Pescarmona, G. P., A. Bosia, D. Ghigo: Shortened red cell life in diabetes. Mechanism of hemolysis. In: Advances in red blood cell biology; Weatherall, Fiorelli and Gorini (eds.), Raven Press, New York(1981),p.391 Schmid-Schombein, H., E. Volger: Red cell aggregation and red cell deformability in diabetes. Diabetes 25:897-902(1976) Shinitzky, M., Y. Barenholtz: Fluidity parameters of lipid regions determined by fluorescence polarization. Biochim. Biophys. Acta 515:367-394(1978) Weltman, J. K.: N-(3-pyrene)maleimide: a long lifetime fluorescent sulphydryl reagent. J. Biol. Chem. 248:3173-3180 (1973) Williamson, J. R., R. A. Gardner, C. W. BoyIan, G. L. Carroll, K. Chang, J. S. Marvel, B. Gonen, C. Kilo, R. Tran-Son-Tay, S. P. Sutera: Microrheological investigation of erythrocyte deformability in diabetes mellitus. Blood 65:283-288 (1985)
Horm. metab. Res. 24 (1992)
411
Requests for reprints should be addressed to: Gregorio
Caimi
Via Leonardo da Vinci, 52 1-90145 Palermo (Italy)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Red Cell Membrane
In a group of 24 diabetics subdivided for type, we evaluated the red cell membrane protein lateral mobility marking intact red cells with pyrene-3-maleimide (3-PM) and calculating the dimer to monomer fluorescence intensity ratio (Iex/Im). The same fluorescent parameter was determined in a group of 13 normal controls. From the obtained data, it is evident that the red cell membrane protein lateral mobility clearly discriminates normals from diabetics of type 1 and 2. In normals and in diabetics of type 1 and 2 no relationship is present between this fluorescent determinant and the glycometabolic parameters (FBGL and HbAlc); considering all the diabetics, a negative relationship is evident between Iex/Im ratio and H b A l c only. Key words Red Cell Membrane Proteins — Diabetes Mellitus
The red cell membrane dynamic property, an essential component of erythrocyte deformability, depends on the lipids and on the proteins (Aloni, Shinitzky and Levin 1974; Chabanel, Flamm, Sung, Lee, Schachter and Chen 1983; Shinitzky and Barenholtz 1978; Cherry 1979). The latter, in diabetes mellitus, have often been neglected because their structural and functional determination is not easy. The red cell membrane proteins interact with the membrane lipids and influence the mechanical stability of the membrane (Borochov, Abbott, Schachter and Shinitzky 1979; Golan, Alecio, Veateh and Rando 1984); the latter property conditions not only the red cell deformability but also the aggregability (Chien and Sung 1987), a macrorheological parameter that in diabetics is altered (Schmid-Schombein and Volger 1976). Our present aim was to verify the behaviour of the red cell membrane protein lateral mobility and also to evaluate the relationships between this aspect and the glycometabolic pattern. Subjects and Methods Subjects
Introduction Previously, employing the fluorescence spectroscopy, we evaluated some parameters reflecting the red cell membrane dynamic properties in diabetic subjects. Using the 1.6-diphenyl-1.3.5-hexatriene (DPH) as probe, we determined the red cell membrane lipid fluidity (Caimi, Catania, D'Asaro, Serra, Catalano, Bono and Sarno 1988). The erythrocyte membrane transverse fluidity gradient was examined employing a set of fatty acid fluorescent probes (Caimi, Serra, D'Asaro, Lo Presti, Grifo, Catania and Sarno 1990). The red cell membrane fluidity was obtained utilizing lO-(l-pyrene) decanoic acid (PDA) as probe (Caimi, Serra, Capobianco, Catania, Romano, D'Asaro and Sarno 1988). In the previous reports we observed that only the red cell membrane fluidity, obtained marking intact red cells with P D A and evaluating the ratio of fluorescence intensity of excimer and monomer in the fluorescence spectrum of PDA, is able to discriminate normals from diabetics. The PDA probe, as well as other pyrenes, during excitation produces a second broad emission peak (excimer spectrum), that depends on the diffusion of the fluorophores in the plane of the membrane (Galla and Sackmann 1974). Horm.metab.Res.24(1992)409-411 © Georg Thieme Verlag Stuttgart • New York
Our research included 12 diabetics of type 1 (mean age 22 ± 10 yrs, range 11 —49 yrs) and 12 diabetics of type 2 (mean age 61 ± 10 yrs, range 40-71 yrs). The diagnosis and the classification of diabetes mellitus was effected according to the criteria of The National Diabetes Data Group (1979). All the diabetics were studied soon after hospital admission, after a fasting state of 12 hours. The means of the venous blood glucose level, determined using an enzymatic method, and the means of the HbAlc red cell level (evaluated using the Auto Ale Analyzer) are reported in Table 1).
Table 1 Means ±SD of glycometabolic parameters in normals and diabetics of type 1 and 2. Normals
FBGL (mg/dl)
HBA1c
(n = 13)
Diabetics of type 1 (n = 12)
Diabetics of type 2 (n = 12)
80.5±7.3 (69-90)
253±85 (108-417)
182±55 (73-288)
4.8 ±0.4 (4.0-5.6)
8.4 ±2.3 (5.2-13.0)
7.9 ±1.6 (6.0-11.6)
FBGL: Fasting Blood Glucose Level HbAlc: Glycated haemoglobin.
Received: 8 Apr. 1991
Accepted: 10 Jan. 1992 after revision
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Summary
Horm. metab. Res. 24 (1992)
G. Caimi, A. Serra, R. Lo Presti and A. Sarno Discussion
Methods The red cell membrane protein lateral mobility was determined on washed intact red cells, marked with pyrene-3maleimide (3-PM). The pyrene-3-maleimide (3-PM) is a thiol agent which interacts with the red cell membrane protein-sulphydryl groups (Weltman 1973). For its characteristic shift in the fluorescence spectrum, it is able to explore a variety of membrane properties, including protein lateral mobility {Betcher-Lange and Leher 1973); Ohyashiki, Yamamoto and Mohri 1989). The 3-PM is different from other pyrenederivatives because a maleimide group is present in its molecule. This group interacts with SH-groups and permits the evaluation of the protein lateral movements employing the excimer/monomer fluorescence. The latter are usually adopted, using the fluorescent lipophylic probes for the evaluation of the lateral diffusion in the hydrophobic region of the membrane (Galla and Sackmann 1974; Eisinger and Flores 1985). The red cells, suspended in PBS at a concentration of 5 x 106 cells/ml, were marked with fluorescent label pyrene-3maleimide (3-PM) (Molecular Probes, Junction City, OR) previously dissolved in tetrahydrofuran. The labelling was effected for 30' at 37 °C with a final concentration of probe of 0.04 mM/1. After incubation, the red blood cells were washed three times with PBS. The fluorescence measurement was effected at a temperature of 37 °C and at a cellular concentration of 5 x 105 cells/ml using the Perkin-Elmer LS5 spectrophotofluorimeter. The excitation wavelength was of 340 nm, while the emission wavelength was of 380 nm for the monomer and 440 for the excimer. The parameter we considered was the dimer (lex) to monomer (Im) fluorescence intensity ratio (Iex/Im); the latter parameter, as it is known, is related to the concentration and to the mobility of the probe in the red cell membrane. The same parameter was evaluated in a group of 13 normal controls (range 22—60 years) matched for sex and smoking habits. Statistical
Analyses
The data were expressed as means + SD; the means difference was evaluated according to the Student's t-test for unpaired data; the relationships between the Iex/Im ratio and glycometabolic parameters were studied employing linear regression. Results From the obtained data, it is evident that: the Iex/Im ratio clearly discriminates normals from diabetics of type 1 and 2 (Table 2); no difference is present between diabetics of type 1 and 2 (Table 2); Table 2 Means + SD of red cell membrane protein lateral mobility (lex/lm) in normals and diabetics of type 1 and 2.
lex/lm (e-PM)
Normals
Diabetics of type 1
Diabetics of type 2
0.529 ±0.090
0.393 ±0.073*
0.365 ±0.090*
*p < 0.001 vs normals.
— in normals and in diabetics there is no significant correlation between Iex/Im ratio, FBGL and HbAlc; considering all the diabetics a significant negative relationship between Iex/Im ratio and HbAlc is present (r=— 0.503; p < 0.05).
Our results give evidence that in diabetic red cells a reduction of the Iex/Im ratio is present; these results cannot be compared to those of other authors because there is no research regarding the employment of this probe in diabetes mellitus. We retain that this finding expresses the altered red cell membrane composition that accompanies diabetes mellitus. This alteration does not involve the lipid pattern only, but also the membrane proteins, even if their evaluation in this research is only functional. The Iex/Im ratio is not correlated to the FBGL and HbAlc in diabetics subdivided for type, but is significantly correlated to HbAlc in all the diabetics. The latter negative relationship might express the dependence of this red cell membrane microrheological parameter on the glycometabolic pattern. In fact, the HbAlc is negatively related to the red cell glutathione (GSH) content {David, Cerutti, Dianziani, Urbino, Balboni, Fonsati, Sacchetti, Vigo 1986) and the red cell GSH content in diabetes mellitus is reduced {Pescarmona, Bosia and Ghigo 1981; Ghigo, Bosia, Pagani, Pescarmona, Pagano and Lenti 1983; Bono, Caimi, Catania, Sarno and Pandolfo 1987). The latter datum is correlated to the N A D P H decrease caused especially by the increased sorbitol synthesis. The N A D P H decrease limits the reduction to GSH operated by glutathione reductase. As it is known, the red cell GSH decrease favours the peroxidation of the membrane proteins into higher-molecular-weight complexes and the oxidation of the protein-sulphydryl groups; the latter aspect is what was observed employing the fluorescent probe 3-PM. The pyrene-3maleimide (3-PM), in fact, is a thiol agent which interacts with the red cell membrane protein-sulphydryl groups. We think that in diabetes mellitus the erythrocyte membrane protein composition needs further investigation. On the one hand, we know that the red cell membrane protein glycation does not modify the red cell membrane deformability {McMillan and Brooks 1982; Williamson, Gardner, Boylan, Carroll, Chang, Marvel, Gonen, Kilo, Tran-SonTay and Sutera 1985); on the other hand, it may be supposed that in diabetes mellitus the alteration of the red cell membrane protein pattern regards, besides the oxidation of the proteinsulphydryl groups, also the membrane protein phosphorylation. As it is known, an appropriate protein membrane phosphorylaiton is necessary for the physiological erythrocyte deformability {Marchesi 1979). References Aloni, B., M. Shinitzky, A. Levin: Dynamics of erythrocyte lipids in intact cells, in ghost membranes and in liposomes. Biochim. Biophys. Acta 348:438-444(1974) Betcher-Lange, S. L., S. S. Leher: Pyrene excimer fluorescence in rabbit skeletal alpha tropomyosin labeled with n-l(pyrene)maleimide. J. Biol. Chem. 253:3757-3763 (1973) Bono, A., G. Caimi, A. Catania, A. Sarno, L. Pandolfo: Red cell peroxide metabolism in diabetes mellitus. Horm. Metabol. Res. 19: 264-266(1987) Borochov, H., R. E. Abbott, D. Schachter, M. Shinitzky: Modulation of erythrocyte membrane proteins by membrane cholesterol and lipid fluidity. Biochemistry 18:251-255 (1979)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
410
Proteins in Diabetes
Mellitus
Caimi, G., A. Catania, S. D'Asaro, A. Serra, C. Catalano, A. Bono, A. Sarno: Red cell phospholipids and membrane microviscosity in diabetics. Clin. Hemorheol. 8:939-944 (1988) Caimi, G., A. Serra, D. Capobianco, A. Catania, A. Romano, S. D'Asaro, A. Sarno: Red cell membrane fluidity in diabetics. Rev. Port.Hemorrheol.2:139-144(1988) Caimi, G., A. Serra, S. DAsaro, R. LoPresti, G. Grifo, A. Catania, A. Sarno: Diabete mellito: valutazione del gradiente di polarizzazione della membrana eritrocitaria con l'impiego di acidi grassi fluorescentil. In: Atti del 13 Congresso Nazionale della Societa Italiana di Diabetologia, Pisa, 1990; II Diabete 2 (Suppl. 1): 27 (1990) Chabanel, A., M. Flamm, K. L. P. Sung, M. M. Lee, D. Schachter, S. Chen: Influence of cholesterol content on red cell membrane viscoelasticity and fluidity. Biophys. J. 44:171 - 1 7 6 (1983) Cherry, R. J.: Rotational and lateral diffusion of membrane proteins. Biophys. Biochim. Acta559:289-328 (1979) Chien, S., L. A. Sung: Physicochemical basis and clinical implications of red cell aggregation. Clin. Hemorrheol. 7:71—91(1987) David, O., F. Cerutti, I. Dianziani, A. Urbino, R. Balboni, M. Fonsati, C. Saccetti, A. Vigo: Correlazione tra GSH eritrocitario ed emoglobina glicosilata in bambini diabetici insulino-dipendenti. G. Ital. Diabetol. 6:138-144(1986) Eisinger, J., J. Flores: Fluorometry of turbid and absorbant samples and the membrane fluidity of intact erythrocytes. Biophys. J. 48: 77-85(1985) Galla, H. J., E. Sackmann: Lateral diffusion in the hydrophobic region of membrane: use of pyrene excimers as optical probes. Biochim. Biophys. Acta 339:103-112(1974) Ghigo, D., A. Bosia, A. Pagani, G. P. Pescarmona, G. Pagano, G. Lenti: Alterazioni della deformabilita eritrocitaria conseguenti a modificazioni del metabolismo ossido-riduttivo nel diabete mellito. Res. Clin. Lab. 13 (Suppl. 3): 375-381 (1983) Golan, D. E., M. R. Alecio, W. R. Veateh, R. R. Rando: Lateral mobility of phospholipid and cholesterol in the human erythrocyte membrane: effects of protein-lipid interactions. Biochemistry 23: 332-339(1984) Marchesi, V. T.: Spectrin: present status of a putative cyto-skeletal protein of the red cell membrane. J. Membr. Biol. S1:101 - 1 0 3 (1979) McMillan, D. E., S. M. Brooks: Erythrocyte spectrin glucosylation in diabetes. Diabetes 3 1 : 6 4 - 6 9 (1982) National Diabetes Data Group: Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. Diabetes 28:1039-1057(1979) Ohyashiki, T., T. Yamamoto, T. Mohri: Changes in the fluorescence parameters of bound N-(l-pyrene)maleimide by lipid peroxidation of intestinal brush-border membranes. Biochim. Biophys. Acta981:235-242(1989) Pescarmona, G. P., A. Bosia, D. Ghigo: Shortened red cell life in diabetes. Mechanism of hemolysis. In: Advances in red blood cell biology; Weatherall, Fiorelli and Gorini (eds.), Raven Press, New York(1981),p.391 Schmid-Schombein, H., E. Volger: Red cell aggregation and red cell deformability in diabetes. Diabetes 25:897-902(1976) Shinitzky, M., Y. Barenholtz: Fluidity parameters of lipid regions determined by fluorescence polarization. Biochim. Biophys. Acta 515:367-394(1978) Weltman, J. K.: N-(3-pyrene)maleimide: a long lifetime fluorescent sulphydryl reagent. J. Biol. Chem. 248:3173-3180 (1973) Williamson, J. R., R. A. Gardner, C. W. BoyIan, G. L. Carroll, K. Chang, J. S. Marvel, B. Gonen, C. Kilo, R. Tran-Son-Tay, S. P. Sutera: Microrheological investigation of erythrocyte deformability in diabetes mellitus. Blood 65:283-288 (1985)
Horm. metab. Res. 24 (1992)
411
Requests for reprints should be addressed to: Gregorio
Caimi
Via Leonardo da Vinci, 52 1-90145 Palermo (Italy)
Downloaded by: Universite de Sherbrooke. Copyrighted material.
Red Cell Membrane
