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Damad study research group : Effect of age on ADP-induced platelet aggregation in diabetic and non-diabetic subjects
THROMBOSIS RESRARCH 22; 687-692, 1981 0049-3848/81/110687-06$02.00/O Printed in the USA. Copyright (c) 1981 Pergamon Press Ltd. All rights reserved.
BRIEF
COMMUNICATION
Damad Study Research Groupx : EFFECT OF AGE ON ADP-INDUCED PLATELET AGGREGATION IN DIABETIC AND NON-DIABETIC SUBJECTS.
Report prepared by : P.Y. SCARABIN' and M. SAMAMA2. 1. INSERM - U.21 - Villejuif (New address : INSERM - U.169, 16 Bis Avenue P.V. Couturier - Villejuif. 94800. France). 2. Laboratoire Central d'Hematologie, Hbtel-Dieu, Paris. 75004 France. (Received 19.2.1981; in revised form 25.5.1981. Accepted by Editor C.R.M. Prentice)
INTRODUCTION Increased platelet aggregation (PA) has often been reported in diabetes mellitus especially with vascular complications (1,2,3,4). This topic has extensively been reviewed (5,6). Platelet hyperaggregation was mostly shown from unselected population samples and its role in the genesis of diabetic vascular disease is still not clear. On the other hand, little information is available on a possible link between physiological variables and PA changes. As part of a prospective study of the effects of antiaggregant drugs in diabetic microangiopathy - DAMAD Program (7) - the associations of some cross-sectional haemostatic variables obtained on the first 174 patients screened for this study have been previously analysed. A striking positive relationship was found between age and platelet sensitivity to A.D.P. (8). This report aims to evaluate the extent to which advancing years may contribute to platelet behaviour changes in diabetics. ADP-induced PA and its age-related changes are compared in diabetics from the DAMAD Program and non-diabetics strictly matched for age. X TheDamad Study Research Group consists CLINICCEmRs. France-Paris : Hbtel-DieuHospital : C. J. CANIVLT t'. WESCHI
M.D., M.D.
of
the
P. PASSA M.D. - Great-Britain - cardiff University Hospital
i
following
:
'KfiDBBDUI'SKY M.D.,
: London: of Wales
G. SIAMA Hamersmith : T. HAYES
M.D.
- Saint-Ians
I&spiral
:
:
Hospital E. KCWER M.D., M.D., C. JONES M.D.
OPHTALUOLOCY CENI'SRS. France-Cr&eil Ophtalmlogy Clinic of CrCreil Wuversity : G. COSCAS M.D., G. QUENTBI, N.D., C. SOUBBANE M.D., C. BAIJDOIN U.D. - Great-Britain If-rsmith Hospital E. KDHNER N.D., University Hospital of Wales : T. HAYES M.D., G. JONES M.D. F. CUNESCHI H.D. - Cardiff HAWOSTISIS ‘MGIU'IQRIES : Frame-Paris : Hdtel-Dieu Hospit& : W. SM.D., C. LSCRUSIER PH.D., J. CONAN PH.D., P.Y. SCARABIN M.D. - Great-Britain :Edinburgh : C. LUDLM, PH.D., wp. ~CORDINATING CEmR : Statistical Research Unit - Villejuif - 94800 U.21. INSEBH. PRANCE. - B. ESClWEGE M.D., D. JOB M.D., C. BAUDOIN M.D., P.Y. SCARABIN ".D.
:
:
: London:
Key words : Platelet aggregation - Diabetes - Vascular aging. 687
:
688
PA AGGREGATION, AGE, DIABETES
vo1.22, No.5/6
MATERIAL AND METHODS For this study, 30 diabetic outpatients (19 men, 11 women) were selected according to criteria detailed elsewhere (7). They had recently been enrolled from the Diabetic Unit of HBtel-Dieu Hospital in Paris into the DAMAD Program. Mean age (m f s.d.) was 43.6 + 11.8 years (range : 26-62). 19 required insulin-treatment, the rest of them was taking an oral hypoglycemic agent or was on diet alone. Mean duration of diabetes was 12.9 + 6.9 years (range : 3-29). All the patients had to show a background retinopathy assessed by fundus angiofluorography (at least 5 microaneurysms and/or one area of capillary non-perfusion at the posterior pole without proliferative lesions). No evidence of macrovascular disease was found (hypertensive syndrome, past history of angina pectoris, E.C.G. abnormalities, abolished peripheral vascular pulses). Patients with overt neuropathy or renal failure (creatininemia > 133 mol/l) were excluded. Findings in the diabetics were compared with those of 30 age-matched non-diabetic outpatients (21 men, 9 women) selected in a diabetic screening center of the same hospital. Mean age was 43.8 f 12.3 years (range : 26-62). Fasting blood sugar ranged from 3,22 to 5,76 mmol/l. All the subjects were carefully questionned about any intake of drug which might influence PA and were excluded if they had taken such drugs during the past week. Each diabetic patient and his age-matched control were investigated on the same day. Platelet aggregation was measured according to the photometric method of Born (9). Blood was collected in 0,l mol/l trisodium citrate, in nonwettable tubes (1 vol. of citrate to 9 vol. of blood), and centrifuged 10 mn at 1509. Aggregation tests were performed within 3 hours following blood collection, using a Labintec Aggregometer and non-siliconized material at 37'C. For each assay, 0.04 ml of A.D.P. serial dilutions (Stag0 Laboratories) giving final concentrations of 0.33, 0.66, 1.32, 2.64 pM/l were added to 0.2 ml of platelet-rich plasma stirred at 1.100 t-pm and previously adjusted to 3 x lo5 platelet/v1 with platelet-poor plasma. The platelet reactivity threshold (PRT) was determined by the lowest ADP concentration still able to induce irreversible aggregation. Non parametric Mantel's test (lo), Student's t test and Pearson's correlation coefficient test were used for statistical evaluation of results. RESULTS The distribution of ADP threshold levels in both groups is given in Table I. PRT is significantly decreased in the diabetic group (p < 0.01). TABLE I Distribution of platelet reactivity threshold to A.D.P. in diabetic and non-diabetic patients. A.D.P. Threshold Levels (PM)
0,33
0,66
1,32
2,64
>2,64
Diabetic patients
4
8
10
8
0
Non-Diabetic patients
3
2
7
13
5
vo1.22, No.516
PA AGGREGATION, AGE, DIABETES
689
PRT age-related changes are shown in Fig. 1. When the ADP threshold levels are expressed in logarithmic form (base2), a negative correlation between PRT and age is found in both the non-diabetic and diabetic groups (respectively r = -0.47, p < 0.01 and r = - 0.50, p < 0.01). For this computation, 5.28 PM was used as the ADP threshold level in the 5 non-diabetic subjects having a PRT over 2.64 pM (i.e. value 4 in the scale of Fig. 1). Besides, as indicated by the slopes of regression lines, PRT decreases with age in the same extent for both groups (respectively s = - 0.46 + 0.16 and s = - 0.42 f 0.14). Although this result is based on cross-sectional data, the effect of advancing years on platelet behaviour in both groups can be evaluated as follows : a same value of PRT should be expected in a diabetic patient and in a 17 years older non-diabetic patient. No significant relationship between PRT and sex, insulin-treatment, duration of diabetes was found.
n
:9
. 25 - 31
n:7
l-l:6
. 35-44
. L5 - 54 AGE
fl:E . 55 - 51
(Years)
FIG. 1 Regression lines of platelet reactivity threshold to ADP on age in 30 diabetics (solid line) and 30 non-diabetics (broken line). PRT values are expressed in a logarithmic form. Mean values of log2 (PRT/0.33)+ s.e.m. are plotted for various age ranges.
b
690
PA AGGREGATION,AGE, DIABETES
vo1.22,
No.516
DISCUSSION The possible role of an increased PA in the vascular complications of diabetes is presently under intensive scrutiny (11). Aztiologic approach to this topic was for many years based on retrospective studies. In this regard, the results are more in agreement than in conflict. However, by contrast with general epidemiology of other haemostatic variables (12), the influence cf personal and environmental characteristics on PA has been little emphasdied until now. This may be due to both great variability in measures of this parameter and heterogeneity of population samples studied. While our data show a significant decrease of PRT to ADP in the diabetic group as often described, the present report points out that advancing years account for increased platelet sensitivity to ADP in both diabetic and non-diabetic patients. Thus, PA related to age previously reported in diabetes (8) does not appear as a characteristic of the diabetic state. Some authors (13,14,15) using turbidimetric methods have suggested such a relationship in normal subjects but this was not clearly determined especially in respect of vascular disease. Our findings deserve attention for at least two reasons. First, differences in PA could be partly or entirely explained by disparity of age. A review of main retrospective case-control studies in diabetes (5) show that the patient populations have not always been ideally standardized regarding age ; in many instances, control patients were mostly younger than diabetic ones. The actual differences in PA between groups were almost certainly fewer and less marked. This underlines that age is an important factor to be taken into account in studying PA to ADP. Secondly, since there is evidence that advancing years and diabetes both increase the incidence of thrombotic disease (16), our results raise once more the question whether increased PA is a cause or is secondary to vessel wall damage (17). In this study, if we make allowance for patients selection in respect to vascular disease, vascular state of subjects would appear as the results of two processes : one unrelated to age deterioration of microcirculation unique to diabetic patients and a large vessels aging process advancing with atherosclerosis development in both diabetic and non-diabetic patients. Thus, the findings that PRT is lower in diabetic patients and similarly decreases with age in both groups may indicate that its changes simply reflect the underlying vascular process. However, according to this hypothesis, the well known accelerated atherosclerosis in diabetes (16) should enhance the PRT decrease with age in the diabetic group. Small sample size and/or particular selection of diabetic patients can explain the inability to detect this effect. Longitudinal data are clearly needed to determine the pathogenic relevance of platelet abnormalities to diabetic vascular complications and arterial disease in general. ACKNOWLEDGMENTS This work was supported in part by a grant from INSERM (Contrat ASR-5 78). We wish to thank A. GRADELET and C. LECRUBIER for their technical assistance.
Vol.22, No.516
691
PA AGGREGATION, AGE, DIABETES
REFERENCES POLLOCK, J., HUNTER, P.R., 1. HEATH, M., BRIDGEN, W.D., CANEVER, J.V., KESLEY, J., BLOOM, A. Platelet adhesiveness and aggregation in relation to diabetic retinopathy. Diabetologia,l, 308-315, 1971. 2. LEONE, G., BIZZI, B., ACCORA, F., BONI, P. Functional aspects of platelets in diabetes mellitus. In : Platelet aggregation and drugs. L. CAPRINO and F.C.ROSSI (Ed.'j.Academic Press New-York, 19/4, 49-61. 3.
BENSOUSSAN, D., LEVY-TOLEDANO, S., PASSA, P., CAEN, J., CANIVET, J. Platelet hvDeraPareaation and increased level of von Willebrand factor in diabetics widthr&inopathy. Diabetologia, 11, 307-312, 1975.
4.
COLWELL, J.A., HALUSHKA, P.V., SARJI, K., LEVIN, J., SAGEL, J. NAIR, R. Altered platelet function in diabetes mellitus. Diabetes 826-831, 1976.
5.
27,
BERN, M.M. Platelet function in diabetes mellitus. Diabetes, 27, 342-362, 1978.
6. COLWELL, J.A. and HALUSHKA, P.V. Platelet function in diabetes me litus. Brit. J. Haematol., 4_4,521-526, 1980. 7. VERSTRAETE, M. Registry of Prospective Clinical trials - Fourth Report. Thrombos. Haemostas., 43, 176-181, 1980. 8.
LECRUBIER, C., SCARABIN, P.Y., GRAUSO, F., SAMAMA, M. Platelet aggregation related to age in diabetes mellitus. Haemostasis,z, 43-51, 1980.
9.
BORN, G.V.R. and CROSS, M.J. The aggregation of blood platelets. J. Physiol. (Lond), 168, 178-195, 1963.
10.
SCARABIN,P.Y., MOREAU, T., DUCIMETIERE, P. An application of Mantel's test to the analysis of some biological assays. Rev. Epid&n. et Sante Publ, 28, 373-377, 1980. --
11. GANDA, OM. P. Pathogenesis of macrovascular disease in the human diabetic. Diabetes. 2, 931-942, 1980. 12.
BENNET, B. and OGSTON, D. Physiological variations in coagulation, fibrinolysis and platelet behaviour. In : Haemostasis : biochemistry, physiology and pathology. D. Ogston and B. Bennet (Ed.) London : Wiley Ed1t., 1977, 354-369.
13.
JOHNSON, H., RAMEY, E., RAMWELL, P.W. Sex and age difference in human platelet aggregation. Nature (Lond.), 253, 355-357, 1975.
14.
COUCH, J.R., HASSANEIN, R.R. Platelet aggregation, stroke an transient ischemic attack in middle aged and elderly patients. Neurology, 26, 888-895, 1976.
15.
GORMSEN, S., NIELSEN, J.O., ANDERSEN, L.A.A.D.P. induced platelet aggregation in vitro in patients with ischemic heart disease and peripheral thromboartherosclerosis. Act. Med. Stand., 201, 509-513, 1977.
692
PA AGGREGATION, AGE, DIABETES
Vo1.22, No.5/6
16. WEST, K.M., Specific morbid effects (complications) : atherosclerosis and related disorders. In : Epidemiology of diabetes and its vascular lesions. K.M. West (Ed.) New-York : tlsevier, 1978, 353-391. 17. MUSTARD, J.F., PACKHAM, M.A. Platelet and diabetes mellitus. New Engl. J. Med., 297, 1345-1347, 1977.
BRIEF
COMMUNICATION
Damad Study Research Groupx : EFFECT OF AGE ON ADP-INDUCED PLATELET AGGREGATION IN DIABETIC AND NON-DIABETIC SUBJECTS.
Report prepared by : P.Y. SCARABIN' and M. SAMAMA2. 1. INSERM - U.21 - Villejuif (New address : INSERM - U.169, 16 Bis Avenue P.V. Couturier - Villejuif. 94800. France). 2. Laboratoire Central d'Hematologie, Hbtel-Dieu, Paris. 75004 France. (Received 19.2.1981; in revised form 25.5.1981. Accepted by Editor C.R.M. Prentice)
INTRODUCTION Increased platelet aggregation (PA) has often been reported in diabetes mellitus especially with vascular complications (1,2,3,4). This topic has extensively been reviewed (5,6). Platelet hyperaggregation was mostly shown from unselected population samples and its role in the genesis of diabetic vascular disease is still not clear. On the other hand, little information is available on a possible link between physiological variables and PA changes. As part of a prospective study of the effects of antiaggregant drugs in diabetic microangiopathy - DAMAD Program (7) - the associations of some cross-sectional haemostatic variables obtained on the first 174 patients screened for this study have been previously analysed. A striking positive relationship was found between age and platelet sensitivity to A.D.P. (8). This report aims to evaluate the extent to which advancing years may contribute to platelet behaviour changes in diabetics. ADP-induced PA and its age-related changes are compared in diabetics from the DAMAD Program and non-diabetics strictly matched for age. X TheDamad Study Research Group consists CLINICCEmRs. France-Paris : Hbtel-DieuHospital : C. J. CANIVLT t'. WESCHI
M.D., M.D.
of
the
P. PASSA M.D. - Great-Britain - cardiff University Hospital
i
following
:
'KfiDBBDUI'SKY M.D.,
: London: of Wales
G. SIAMA Hamersmith : T. HAYES
M.D.
- Saint-Ians
I&spiral
:
:
Hospital E. KCWER M.D., M.D., C. JONES M.D.
OPHTALUOLOCY CENI'SRS. France-Cr&eil Ophtalmlogy Clinic of CrCreil Wuversity : G. COSCAS M.D., G. QUENTBI, N.D., C. SOUBBANE M.D., C. BAIJDOIN U.D. - Great-Britain If-rsmith Hospital E. KDHNER N.D., University Hospital of Wales : T. HAYES M.D., G. JONES M.D. F. CUNESCHI H.D. - Cardiff HAWOSTISIS ‘MGIU'IQRIES : Frame-Paris : Hdtel-Dieu Hospit& : W. SM.D., C. LSCRUSIER PH.D., J. CONAN PH.D., P.Y. SCARABIN M.D. - Great-Britain :Edinburgh : C. LUDLM, PH.D., wp. ~CORDINATING CEmR : Statistical Research Unit - Villejuif - 94800 U.21. INSEBH. PRANCE. - B. ESClWEGE M.D., D. JOB M.D., C. BAUDOIN M.D., P.Y. SCARABIN ".D.
:
:
: London:
Key words : Platelet aggregation - Diabetes - Vascular aging. 687
:
688
PA AGGREGATION, AGE, DIABETES
vo1.22, No.5/6
MATERIAL AND METHODS For this study, 30 diabetic outpatients (19 men, 11 women) were selected according to criteria detailed elsewhere (7). They had recently been enrolled from the Diabetic Unit of HBtel-Dieu Hospital in Paris into the DAMAD Program. Mean age (m f s.d.) was 43.6 + 11.8 years (range : 26-62). 19 required insulin-treatment, the rest of them was taking an oral hypoglycemic agent or was on diet alone. Mean duration of diabetes was 12.9 + 6.9 years (range : 3-29). All the patients had to show a background retinopathy assessed by fundus angiofluorography (at least 5 microaneurysms and/or one area of capillary non-perfusion at the posterior pole without proliferative lesions). No evidence of macrovascular disease was found (hypertensive syndrome, past history of angina pectoris, E.C.G. abnormalities, abolished peripheral vascular pulses). Patients with overt neuropathy or renal failure (creatininemia > 133 mol/l) were excluded. Findings in the diabetics were compared with those of 30 age-matched non-diabetic outpatients (21 men, 9 women) selected in a diabetic screening center of the same hospital. Mean age was 43.8 f 12.3 years (range : 26-62). Fasting blood sugar ranged from 3,22 to 5,76 mmol/l. All the subjects were carefully questionned about any intake of drug which might influence PA and were excluded if they had taken such drugs during the past week. Each diabetic patient and his age-matched control were investigated on the same day. Platelet aggregation was measured according to the photometric method of Born (9). Blood was collected in 0,l mol/l trisodium citrate, in nonwettable tubes (1 vol. of citrate to 9 vol. of blood), and centrifuged 10 mn at 1509. Aggregation tests were performed within 3 hours following blood collection, using a Labintec Aggregometer and non-siliconized material at 37'C. For each assay, 0.04 ml of A.D.P. serial dilutions (Stag0 Laboratories) giving final concentrations of 0.33, 0.66, 1.32, 2.64 pM/l were added to 0.2 ml of platelet-rich plasma stirred at 1.100 t-pm and previously adjusted to 3 x lo5 platelet/v1 with platelet-poor plasma. The platelet reactivity threshold (PRT) was determined by the lowest ADP concentration still able to induce irreversible aggregation. Non parametric Mantel's test (lo), Student's t test and Pearson's correlation coefficient test were used for statistical evaluation of results. RESULTS The distribution of ADP threshold levels in both groups is given in Table I. PRT is significantly decreased in the diabetic group (p < 0.01). TABLE I Distribution of platelet reactivity threshold to A.D.P. in diabetic and non-diabetic patients. A.D.P. Threshold Levels (PM)
0,33
0,66
1,32
2,64
>2,64
Diabetic patients
4
8
10
8
0
Non-Diabetic patients
3
2
7
13
5
vo1.22, No.516
PA AGGREGATION, AGE, DIABETES
689
PRT age-related changes are shown in Fig. 1. When the ADP threshold levels are expressed in logarithmic form (base2), a negative correlation between PRT and age is found in both the non-diabetic and diabetic groups (respectively r = -0.47, p < 0.01 and r = - 0.50, p < 0.01). For this computation, 5.28 PM was used as the ADP threshold level in the 5 non-diabetic subjects having a PRT over 2.64 pM (i.e. value 4 in the scale of Fig. 1). Besides, as indicated by the slopes of regression lines, PRT decreases with age in the same extent for both groups (respectively s = - 0.46 + 0.16 and s = - 0.42 f 0.14). Although this result is based on cross-sectional data, the effect of advancing years on platelet behaviour in both groups can be evaluated as follows : a same value of PRT should be expected in a diabetic patient and in a 17 years older non-diabetic patient. No significant relationship between PRT and sex, insulin-treatment, duration of diabetes was found.
n
:9
. 25 - 31
n:7
l-l:6
. 35-44
. L5 - 54 AGE
fl:E . 55 - 51
(Years)
FIG. 1 Regression lines of platelet reactivity threshold to ADP on age in 30 diabetics (solid line) and 30 non-diabetics (broken line). PRT values are expressed in a logarithmic form. Mean values of log2 (PRT/0.33)+ s.e.m. are plotted for various age ranges.
b
690
PA AGGREGATION,AGE, DIABETES
vo1.22,
No.516
DISCUSSION The possible role of an increased PA in the vascular complications of diabetes is presently under intensive scrutiny (11). Aztiologic approach to this topic was for many years based on retrospective studies. In this regard, the results are more in agreement than in conflict. However, by contrast with general epidemiology of other haemostatic variables (12), the influence cf personal and environmental characteristics on PA has been little emphasdied until now. This may be due to both great variability in measures of this parameter and heterogeneity of population samples studied. While our data show a significant decrease of PRT to ADP in the diabetic group as often described, the present report points out that advancing years account for increased platelet sensitivity to ADP in both diabetic and non-diabetic patients. Thus, PA related to age previously reported in diabetes (8) does not appear as a characteristic of the diabetic state. Some authors (13,14,15) using turbidimetric methods have suggested such a relationship in normal subjects but this was not clearly determined especially in respect of vascular disease. Our findings deserve attention for at least two reasons. First, differences in PA could be partly or entirely explained by disparity of age. A review of main retrospective case-control studies in diabetes (5) show that the patient populations have not always been ideally standardized regarding age ; in many instances, control patients were mostly younger than diabetic ones. The actual differences in PA between groups were almost certainly fewer and less marked. This underlines that age is an important factor to be taken into account in studying PA to ADP. Secondly, since there is evidence that advancing years and diabetes both increase the incidence of thrombotic disease (16), our results raise once more the question whether increased PA is a cause or is secondary to vessel wall damage (17). In this study, if we make allowance for patients selection in respect to vascular disease, vascular state of subjects would appear as the results of two processes : one unrelated to age deterioration of microcirculation unique to diabetic patients and a large vessels aging process advancing with atherosclerosis development in both diabetic and non-diabetic patients. Thus, the findings that PRT is lower in diabetic patients and similarly decreases with age in both groups may indicate that its changes simply reflect the underlying vascular process. However, according to this hypothesis, the well known accelerated atherosclerosis in diabetes (16) should enhance the PRT decrease with age in the diabetic group. Small sample size and/or particular selection of diabetic patients can explain the inability to detect this effect. Longitudinal data are clearly needed to determine the pathogenic relevance of platelet abnormalities to diabetic vascular complications and arterial disease in general. ACKNOWLEDGMENTS This work was supported in part by a grant from INSERM (Contrat ASR-5 78). We wish to thank A. GRADELET and C. LECRUBIER for their technical assistance.
Vol.22, No.516
691
PA AGGREGATION, AGE, DIABETES
REFERENCES POLLOCK, J., HUNTER, P.R., 1. HEATH, M., BRIDGEN, W.D., CANEVER, J.V., KESLEY, J., BLOOM, A. Platelet adhesiveness and aggregation in relation to diabetic retinopathy. Diabetologia,l, 308-315, 1971. 2. LEONE, G., BIZZI, B., ACCORA, F., BONI, P. Functional aspects of platelets in diabetes mellitus. In : Platelet aggregation and drugs. L. CAPRINO and F.C.ROSSI (Ed.'j.Academic Press New-York, 19/4, 49-61. 3.
BENSOUSSAN, D., LEVY-TOLEDANO, S., PASSA, P., CAEN, J., CANIVET, J. Platelet hvDeraPareaation and increased level of von Willebrand factor in diabetics widthr&inopathy. Diabetologia, 11, 307-312, 1975.
4.
COLWELL, J.A., HALUSHKA, P.V., SARJI, K., LEVIN, J., SAGEL, J. NAIR, R. Altered platelet function in diabetes mellitus. Diabetes 826-831, 1976.
5.
27,
BERN, M.M. Platelet function in diabetes mellitus. Diabetes, 27, 342-362, 1978.
6. COLWELL, J.A. and HALUSHKA, P.V. Platelet function in diabetes me litus. Brit. J. Haematol., 4_4,521-526, 1980. 7. VERSTRAETE, M. Registry of Prospective Clinical trials - Fourth Report. Thrombos. Haemostas., 43, 176-181, 1980. 8.
LECRUBIER, C., SCARABIN, P.Y., GRAUSO, F., SAMAMA, M. Platelet aggregation related to age in diabetes mellitus. Haemostasis,z, 43-51, 1980.
9.
BORN, G.V.R. and CROSS, M.J. The aggregation of blood platelets. J. Physiol. (Lond), 168, 178-195, 1963.
10.
SCARABIN,P.Y., MOREAU, T., DUCIMETIERE, P. An application of Mantel's test to the analysis of some biological assays. Rev. Epid&n. et Sante Publ, 28, 373-377, 1980. --
11. GANDA, OM. P. Pathogenesis of macrovascular disease in the human diabetic. Diabetes. 2, 931-942, 1980. 12.
BENNET, B. and OGSTON, D. Physiological variations in coagulation, fibrinolysis and platelet behaviour. In : Haemostasis : biochemistry, physiology and pathology. D. Ogston and B. Bennet (Ed.) London : Wiley Ed1t., 1977, 354-369.
13.
JOHNSON, H., RAMEY, E., RAMWELL, P.W. Sex and age difference in human platelet aggregation. Nature (Lond.), 253, 355-357, 1975.
14.
COUCH, J.R., HASSANEIN, R.R. Platelet aggregation, stroke an transient ischemic attack in middle aged and elderly patients. Neurology, 26, 888-895, 1976.
15.
GORMSEN, S., NIELSEN, J.O., ANDERSEN, L.A.A.D.P. induced platelet aggregation in vitro in patients with ischemic heart disease and peripheral thromboartherosclerosis. Act. Med. Stand., 201, 509-513, 1977.
692
PA AGGREGATION, AGE, DIABETES
Vo1.22, No.5/6
16. WEST, K.M., Specific morbid effects (complications) : atherosclerosis and related disorders. In : Epidemiology of diabetes and its vascular lesions. K.M. West (Ed.) New-York : tlsevier, 1978, 353-391. 17. MUSTARD, J.F., PACKHAM, M.A. Platelet and diabetes mellitus. New Engl. J. Med., 297, 1345-1347, 1977.