Clinical prognostic evaluation of immunocytes in different molecular subtypes of breast cancer.

To retrospectively analyze the relationship between preoperative blood parameters and postoperative clinical outcomes in patients with different molecular subtypes of breast cancer (BC), a cohort of 601 patients with BC in the Third Affiliated Hospital, Sun Yat-sen University, was retrospectively reviewed. They were categorized into four subtypes according to the expression of ER, PR, HER-2, and KI-67%. White blood cell, neutrophil, lymphocyte, monocyte, eosinophil, basophil, and platelet counts, the neutrophil-to-lymphocyte ratio (NLR), the neutrophil-to-monocyte ratio (NMR), the lymphocyte-to-monocyte ratio (LMR), and the platelet-to-lymphocyte ratio (PLR) were recorded. Univariate and multivariate analyses were performed to identify the relationship between parameters and ratios and disease-free survival (DFS) and overall survival (OS). Luminal subtypes of BC had smaller tumor volume, better differentiation degree of invasive ductal carcinoma, less lymph node metastasis, and better clinical outcome than the HER-2 overexpression and triple-negative BC (TNBC) subtypes. In multivariate analysis, age and LMR were the independent prognostic factors of DFS in patients with luminal A (age, p = 0.005; LMR, P = 0.026); PLR in patients with luminal B (DFS; p = 0.032; OS, p= 0.012); LMR in patients with HER-2 overexpression (DFS; p = 0.008; OS, p = 0.017); and NLR for DFS (p = 0.014); and WBC for OS (p = 0.008) in patients with TNBC. LMR was the benign predictor of luminal A and HER-2 overexpression. PLR was the adverse predictor of luminal B. WBC and NLR were the adverse predictors of TNBC. Therefore, these peripheral blood parameters can play an important role in the diagnosis and treatment of patients with different molecular subtypes of BC.

Optimized gating and reference ranges of reticulated platelets in dogs for the Sysmex XT-2000iV.

BACKGROUND: Canine reticulated platelets (r-PLTs) i.e., juvenile PLTs reflecting thrombopoiesis can be measured automatically with the hematology analyzer Sysmex XT-2000iV using manual gating options. However, the impact of interferences on r-PLT measurements performed with the gates published previously (Pankraz et al., Vet Clin Path 38:30-38, 2009; Gelain et al., High fluorescent platelets fraction in macrothrombocytopenic Norfolk terrier, 2010) is largely unknown. The aim was to compare different published gates for measurement of r-PLTs with the Sysmex XT-2000iV with an own, optimized gate ("Oellers-gate") and to establish reference intervals (RIs) in > 120 dogs. Data of 362 measurements of diseased and healthy dogs were analyzed retrospectively. Several gates were applied and RIs for r-PLTs and platelet indices were established for pet dogs and a group of 153 healthy Beagles kept under defined housing conditions. Intra-assay precision (CV) was also assessed. RESULTS: In 30/362 samples, interferences consistent with small erythrocytes/reticulocytes were seen in the previously published gates but not in the "Oellers-gate". Good correlation was found between the different gates (rs: 0.88-1.00). RIs for the "Pankraz-gate", the "Gelain-gate", and the "Oellers-gate" were 0.0-1.2, 0.2-3.7 and 0.2-3.9 % respectively. CVs were ranging between 22 and 41 %. CONCLUSIONS: Optimization of previously published gates minimized interferences of small erythrocytes with r-PLT measurements.

Estimating the residual risk for HIV, HCV and HBV in different types of platelet concentrates in Germany.

BACKGROUND AND OBJECTIVES: We estimated and compared the residual risks due to window-period donations for pooled and apheresis platelets in Germany using a modification of a previously described statistical model. This model directly utilizes the reported interdonation intervals before a positive donation and reflects in this aspect the look-back procedures used in haemovigilance. MATERIALS AND METHODS: Data from the German National Blood Donor Surveillance System for the years 2006-2012, including reports about donations from repeat donors with confirmed positive test results for HIV, HCV and HBV, were used to estimate the risk of undetected infectious units for both pooled and apheresis platelets. RESULTS: Demographics of whole-blood and apheresis donors differed in age, gender, catchment area and interdonation interval. These differences impact on the prevalence and incidence of transfusion relevant infections and consequently the residual risk. The estimates for the residual risks for pooled and apheresis platelets were comparable. For HIV, there was no significant difference, for HCV apheresis platelets had a lower residual risk, whereas pooled platelets had a lower risk for undetected HBV infections. CONCLUSION: These findings do not support calls for a shift to an apheresis platelets-only policy in Germany.

Neonatal platelets: mediators of primary hemostasis in the developing hemostatic system.

The human hemostatic system is developmentally regulated, resulting in qualitative and quantitative differences in the mediators of primary and secondary hemostasis as well as fibrinolysis in neonates and infants. Although gestational age-related differences in coagulation factor levels occur, the existence of a unique neonatal platelet phenotype remains controversial. Complicated by difficulties in obtaining adequate neonatal blood volumes with which to perform functional assays, ambiguity surrounds the characterization of neonatal platelets. Thus, much of the current knowledge of neonatal platelet function has been based on studies from cord blood samples. Studies suggest that cord blood-derived platelets, as a surrogate for neonatal platelets, are hypofunctional when compared with adult platelets. This relative platelet dysfunction, combined with a propensity toward thrombocytopenia in the neonatal intensive care unit population, creates a clinical conundrum regarding the appropriate administration of platelet transfusions. This review provides an appraisal of the distinct functional phenotype of neonatal platelets. Neonatal platelet transfusion practices and the impact of the relatively hypofunctional neonatal platelet on those practices will be considered.

Ex vivo anticoagulants affect human blood platelet biomechanics with implications for high-throughput functional mechanophenotyping.

Inherited platelet disorders affecting the human platelet cytoskeleton result in increased bleeding risk. However, deciphering their impact on cytoskeleton-dependent intrinsic biomechanics of platelets remains challenging and represents an unmet need from a diagnostic and prognostic perspective. It is currently unclear whether ex vivo anticoagulants used during collection of peripheral blood impact the mechanophenotype of cellular components of blood. Using unbiased, high-throughput functional mechanophenotyping of single human platelets by real-time deformability cytometry, we found that ex vivo anticoagulants are a critical pre-analytical variable that differentially influences platelet deformation, their size, and functional response to agonists by altering the cytoskeleton. We applied our findings to characterize the functional mechanophenotype of platelets from a patient with Myosin Heavy Chain 9 (MYH9) related macrothrombocytopenia. Our data suggest that platelets from MYH9 p.E1841K mutation in humans affecting platelet non-muscle myosin heavy chain IIa (NMMHC-IIA) are biomechanically less deformable in comparison to platelets from healthy individuals.

Prognostic value of platelet-to-lymphocyte ratio in neoadjuvant chemotherapy for solid tumors: A PRISMA-compliant meta-analysis.

INTRODUCTION: Previous research indicates that the platelet-to-lymphocyte ratio (PLR) may be an indicator of poor prognosis in many tumor types. However, the PLR is rarely described in patients undergoing neoadjuvant chemotherapy (NAC) for solid tumors. Thus, we performed a meta-analysis to investigate the prognostic value of this ratio for patients with solid tumors treated by NAC. METHODS: A comprehensive search of the literature was conducted using the PubMed, EMBASE, Cochrane Library, and Web of Science databases, followed by a manual search of references from the retrieved articles. Pooled hazard ratios (HRs) with 95% confidence interval (CIs) were used to evaluate the association between PLR and 3 outcomes, namely, overall survival, disease-free survival, and pathological complete response rate after NAC. RESULTS: Eighteen studies published no earlier than 2014 were included in our study. A lower PLR was associated with better overall survival (HR = 1.46, 95% CI, 1.11-1.92) and favorable disease-free survival (HR = 1.81, 95% CI, 1.27-2.59). A PLR that was higher than a certain cutoff was associated with a lower pathological complete response rate in patients with cancer who received NAC (Odds ratio = 1.93, 95% CI, 1.40-2.87). CONCLUSION: Elevated PLR is associated with poor prognosis in various solid tumors. PLR may be a useful biomarker in delineating those patients with poorer prognoses who may benefit from neoadjuvant therapies.

Does the preoperative platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio predict morbidity after gastrectomy for gastric cancer?

BACKGROUND: Gastric cancer is the 2nd most common cause of cancer-related deaths, and the morbidity rate after surgery is reported to be as high as 46%. The estimation of possible complications, morbidity, and mortality and the ability to specify patients at high risk have become substantial for an intimate follow-up and for proper management in the intensive care unit. This study aimed to determine the prognostic value of the preoperative platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) and their relations with clinical outcomes and complications after gastrectomy for gastric cancer. METHODS: This single-center, retrospective cohort study evaluated the data of 292 patients who underwent gastrectomy with curative intent between January 2015 and June 2018 in a tertiary state hospital in Ankara, Turkey. A receiver operating characteristic curve was generated to evaluate the ability of laboratory values to predict clinically relevant postoperative complications. The area under the curve was computed to compare the predictive power of the NLR and PLR. Then, the cutoff points were selected as the stratifying values for the PLR and NLR. RESULTS: The area under the curve values of the PLR (0.60, 95% CI 0.542-0.657) and NLR (0.556, 95% CI 0.497-0.614) were larger than those of the other preoperative laboratory values. For the PLR, the diagnostic sensitivity and specificity were 50.00 and 72.22%, respectively, whereas for the NLR, the diagnostic sensitivity and specificity were 37.50 and 80.16%, respectively. The PLR was related to morbidity, whereas the relation of the NLR with mortality was more prominent. This study demonstrated that the PLR and NLR may predict mortality and morbidity via the Clavien-Dindo classification in gastric cancer patients. The variable was grade ≥ 3 in the Clavien-Dindo classification, including complications requiring surgical or endoscopic interventions, life-threatening complications, and death. Both the PLR and NLR differed significantly according to Clavien-Dindo grade ≥ 3. In this analysis, the PLR was related to morbidity, while the NLR relation with mortality was more intense. CONCLUSION: Based on the results of the study, the PLR and NLR could be used as independent predictive factors for mortality and morbidity in patients with gastric cancer.

Platelet transfusion thresholds in neonatal medicine.

Thrombocytopenia is common in preterm neonates. Thresholds for prophylactic platelet transfusion vary widely due to lack of evidence. The results of the PlaNet-2/MATISSE Study identified harm in the form of mortality and major bleed in babies prophylactically transfused below a platelet count of 50 × 109/L compared to 25 × 109/L. Neonatal platelet transfusions are administered at volumes based on historical practice which greatly exceed those routinely used in adults. Rate of transfusion is also based around practice in trauma and does not take into account the physiology of the preterm infant. There are multiple ways in which platelets may be mediating harm and this review discusses these potential mechanisms including immunological, inflammatory and blood group incompatibility. Much of the difficulty in assessing harm relates to problems in classification of transfusion-associated adverse events in babies. Thrombocytopenia and timing, efficacy and adverse effects of platelet transfusion are poorly understood. Further research is essential.

99m Technetium-HMPAO-labeled platelet scan in practice: Preparation, quality control, and biodistribution studies

Abstract There is no biodistribution or imaging data on 99mtechnetium (Tc)-hexamethyl propylamine oxime (HMPAO)-labeled platelets in the literature. The current study aimed to present updated information about the clinical procedures for preparation and use of labeled platelets. Following two-step centrifugation at 1500 and 2500 rpm, the platelets were extracted from whole blood into platelet-rich plasma (PRP) above the buffy coat and then from PRP into a platelet pellet at the bottom of the tube. The 99mTc-HMPAO-labeled platelets were inspected for purity, viability, release of 99mTc from platelets, and sterility. Also, microscopic examination and thin layer chromatography (TLC) were performed. Biodistribution was assessed following necropsy in BALB/c mice and through imaging of New Zealand rabbits. The separation ratio was estimated at 98%, and radiochemical purity was measured to be 80%. The labeling efficiency was above 30% in more than half of the assays (range: 17-43%). The release of 99mTc from platelets was 9% per hour at 37ºC. After 24 hours, stability was estimated at 54% in the human serum. The target organs of mice included the spleen and liver. In rabbits, the imaging results indicated liver as the target organ. Thyroid uptake was negligible up to 90 minutes. Based on the findings, extraction of platelets and labeling them with 99mTc-HMPAO is a feasible and safe approach in routine practice.

Leaf extract of Coffea arabica L. reduces lipid peroxidation and has anti-platelet effect in a rat dyslipidemia model

Abstract This study aimed to evaluate the antioxidant potential of the Coffea arabica Lineu (L.) leaf extract and its effects on platelet aggregation of dyslipidemic rats. The extract was obtained by the percolation of C. arabica L. leaves in hydroethanolic solution 70% (v/v). The mass spectrometry FIA-ESI-MS² suggested the presence of chlorogenic acid, rutin acid, and quinic acid. The DPPH• radicals scavenging capacity was demonstrated (IC50 = 0.06 mg/mL). The extract was administered to rats by gavage (300 mg/kg/day) for 56 days. Dyslipidemia was induced by administering Triton WR-1339 (300 mg/kg body weight) on the 54th day. On day 56, blood was collected by puncturing the abdominal aorta artery and the aortic artery was removed. Lipid profile, markers of renal and hepatic injury, lipid peroxidation, and platelet aggregation tests were carried out. The ingestion of extract reduced the lipid peroxidation (aorta and plasma) and platelet aggregation in dyslipidemic rats. The extract did not affect markers of renal and hepatic function as analyzed in this study, suggesting neither impaired liver nor kidney function in these animals. Therefore, our results demonstrate that the extract of leaves of C. arabica L. show antioxidant potential in vitro and in vivo as well as anti-platelet aggregation in dyslipidemic animals

Platelet count, mean platelet volume and thrombocytopoietic indices in healthy women and men.

UNLABELLED: Gender-dependent differences in platelet count have been demonstrated in few studies. In women platelet count is higher than in men, which seems to reflect different hormonal profiles or a compensatory mechanism associated with menstrual blood loss. The aim of the study was to assess platelet count, mean platelet volume and thrombocytopoietic indices in women and men. The study was conducted on healthy blood donors divided into groups: F - 60 women and M - 65 men. Platelet count and mean platelet volume were determined on a haematological analyser Advia 120, Bayer. The following thrombocytopoietic indices were measured: thrombopoietin concentration (ELISA), percentage of reticulated platelets (flow cytometry, COULTER EPICS XL) and absolute reticulated platelet count. RESULTS: Higher platelet count was noted in the group of women 252.35 +/- 41.25 x 10(9)/l as compared to men 221.87 +/- 37.63 x 10(9)/l (p = 0.0002). At the same time women had lower thrombopoietin concentration 156.50 +/- 57.18 pg/ml compared to men 180.46 +/- 60.98 pg/ml, (p = 0.03). No statistically significant differences were found in the mean platelet volume, percentage of reticulated platelets or absolute reticulated platelet count between group F and M. CONCLUSIONS: Platelet count is gender-dependent, being higher in women than in men. Thrombopoietin concentration is gender-dependent and is lower in women than in men. In physiological conditions, there is no correlation between platelet count and thrombopoietin concentration in women (r = -0.155) and men (r = -0.2586).

A simple technique to determine thrombopoiesis level using immature platelet fraction (IPF).

Immature platelet fraction (IPF) has been measured by fully automated analyzer (XE-2100) as reticulated platelet (RP) which is reflected with thrombopoiesis in bone marrow. IPF value in the healthy volunteers was 3.3% (1.0-10.3) and upper 95% confidential interval (95% CI) of IPF was determined as 7.7%. IPF was significantly high in the patients with idiopathic thrombocytopenic purpura (ITP; 17.4%, 1.2-53.2%) and recovery phase of post-chemotherapy, and significantly low in nadir phase of post-chemotherapy, and within normal range in the patients with ITP in complete remission (CR) and with aplastic anemia (AA). Total count of IPF was significantly low in patients with ITP, AA or post-chemotherapy. Mean platelet volume (MPV) was significantly high in only patients with ITP. IPF 7.7% is best point for highest sensitivity (86.8%) and specificity (92.6%) in diagnosis of ITP and recovery phase of post-chemotherapy. In receiver operating characteristic curve for diagnosis of ITP and recovery phase of post-chemotherapy, IPF was significantly more useful than MPV. These results show that IPF reflects the pathology of thrombocytopenic disorders, and that measurement of IPF is useful for the differential diagnosis and analysis of platelet kinetics.

[Does menopause affect thrombocytopoiesis and platelet activation?]. / Czy menopauza wplywa na trombocytopoeze i aktywacje plytek krwi?

BACKGROUND: Menopause has been postulated to increase the risk of cardiovascular disease. We try to analyse wheather lack of estrogens in postmenopausal women (without oestrogen replacement therapy) can change any of the platelet parameters. In the current study, blood samples of healthy woman before (group K) and after menopause (group Km) were analysed with respect to platelet count (PLT), mean platelet volume (MPV), large platelet count (LPLT), percentage of reticulated platelets (RP), absolute count of reticulated platelets (BLR) and plasma levels of thrombopoietin (TPO) and beta-thromboglobulin. RESULTS: The mean platelet count in group Km (230.12 +/- 49.5 x 10(9)/l) was significantly lower than in group K (252.35 +/- 41.25 x 10((9)/l, p = 0.025). Percentage of reticulated platelet in group Km (1.35 +/- 0.4%) was higher than in group K (1.13 +/- 0.47%, p = 0.02). Also P-TG concentration in group Km (245.64 +/- 29.55 IUI ml) was significantly higher (p = 0.02) than in group K (221.79 +/- 42.20 IU/ml). The MPV, LPLT, TPO and BLR values were similar in both groups. CONCLUSIONS: Lower platelet count in woman after menopause than in young woman probably was a result of a decreased concentration of estrogens. Higher percentage of reticulated platelet in group of woman after menopause than in the group before menopause suggests that it is a more sensitive parameter of thrombocytopoiesis than others. Higher beta-thromboglobulin level confirms platelet activation in postmenopausal women.

Subpopulations in purified platelets adhering on glass.

Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process.

Platelet-derived chemokines in atherosclerosis.

In atherosclerosis, activated platelets have been recently recognised not only to participate in thrombotic events but also to play an essential role in the development of atherosclerotic lesions. Upon their activation, platelets release several pro-inflammatory mediators including chemokines. Chemokines are key molecules in inflammation as they are able to recruit leukocytes, modulate their activation/differentiation and control their proliferation/apoptosis. In this review we will discuss recent findings regarding the specific roles of chemokines released by platelets on leukocytes and their effects on atherosclerosis.

Genetic determinants of platelet large-cell ratio, immature platelet fraction, and other platelet-related phenotypes.

INTRODUCTION: Platelets play a significant role in arterial thrombosis and are involved also in venous thrombosis. The genetic determinants of several platelet-related phenotypes have been studied previously. However, to the best of our knowledge, the genetic determinants of other platelet phenotypes have not been reported such as platelet-large-cell ratio (P-LCR) index, immature platelet fraction (IPF) parameters and overall platelet function measured through the PFA-100 system. MATERIALS AND METHODS: As part of the GAIT-2 (Genetic Analysis of Idiopathic Thrombophilia 2) Project, 935 individuals from 35 large Spanish families, ascertained through a proband with thrombophilia, were studied. Using variance component methods, implemented in the SOLAR package, the heritability of the following sets of platelet-related phenotypes was determined: platelet count and indices, IPF, and platelet function. RESULTS AND CONCLUSIONS: High heritabilities of the platelet count and index phenotypes (from 0.41 to 0.64) were found, especially for those related to platelet volume. The heritabilities of the IPF phenotypes, as a measure of platelet turnover, were the highest (from 0.65 to 0.69). The heritabilities of the platelet function phenotypes were high also (0.45 and 0.62). The covariate age influenced all of the platelet phenotypes. Smoking influenced the platelet indices related to platelet volume and all the IPF phenotypes. Venous thrombosis showed a heritability of 0.67. We did not find a genetic correlation between any of the platelet-related phenotypes and venous thrombosis. The high heritabilities found for all of the platelet phenotypes provid promising data for the identification of new genes that underly these phenotypes.

Ultrastructural morphometric observations on serial sectioned human blood platelet subpopulations.

The relationships between the volume of human platelets and their cytoplasmic organelles were studied by morphometric analysis. Platelets were separated into four density-dependent subpopulations on an arabino-galactan gradient. In vitro activation of platelets was effectively prevented by maintaining them at a constant ambient temperature of 37 degrees C. Serial sections were cut through platelets, morphometrically analyzed and the platelets reconstructed. The volumes of the individual platelets and their constituent granules, mitochondria and open canalicular systems (OCS) were calculated. Individual organelles were counted. The mean volumes of the platelets of the subpopulations decreased significantly as density decreased (p = 0.01). Also, as the density of platelets decreased, there was a decrease in the mean unit volume of their granules (p = 0.003). In contrast, independent of platelet volume or density, the OCS occupies about 10% of the platelet volume. These findings indicate that it is possible to prevent in vitro platelet activation by maintaining their environment at 37 degrees C. Our study confirms the direct relationships between platelet volume and density; and platelet density and granule content. There is no ready explanation for the constant relationship between platelet volume and that of the OCS.

Relationship between mepacrine-labelled dense body number, platelet capacity to accumulate 14C-5-HT and platelet density in the Bernard-Soulier and Hermansky-Pudlak syndromes.

We have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 +/- 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients' platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bernard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

Functional fractionation of platelets: aggregation kinetics and glycoprotein labeling of differing platelet population.

Platelet heterogeneity has been studied with a technique called functional fractionation which employs gentle centrifugation to yield subpopulations ("reactive" and "less-reactive" platelets) after exposure to small doses of aggregating agent. Aggregation kinetics of the different platelet populations were investigated by quenched-flow aggregometry. The larger, "reactive" platelets were more sensitive to ADP (Ka = 1.74 microM) than the smaller "less-reactive" platelets (Ka = 4.08 microM). However, their maximal rate of aggregation (Vmax, % of the platelets aggregating per sec) of 23.3 was significantly lower than the "less-reactive" platelets (Vmax = 34.7). The "reactive" platelets had a 2.2 fold higher level of cyclic AMP. Platelet glycoproteins were labeled using the neuraminidase-galactose oxidase--[H3]-NaBH4 technique. When platelets were labeled after reversible aggregation, the "reactive" platelets showed a two-fold decrease in labeling efficiency (versus control platelets). However, examination of whole cells or membrane preparations from reversibly aggregated platelets revealed no significant difference in Coomassie or PAS (Schiff) staining. These results suggest that the large, "reactive" platelets are more sensitive to ADP but are not hyperaggregable in a kinetic sense. Reversible aggregation may cause a re-orientation of membrane glycoproteins that is apparently not characterized by a major loss of glycoprotein material.

Platelet abnormalities in muscular dystrophy.

Platelets which have complex membranes and calcium shifts similar to those in muscles were investigated in 14 patients with muscular dystrophy and 20 suitable controls. In 4 Duchenne and one limb-girdle dystrophy aggregations were done and found to be depressed with adrenaline and ADP. Electron microscopic and chemical examinations revealed an increased number of dense bodies, changed permeability and/or binding of cations and elevated intracellular calcium in all the 9 cases of Duchenne dystrophy while the 2 limb-girdle and 3 myotonic dystrophies varied. A two phase polymer separation system applied to fixed platelets of all patients and controls showed no abnormality of surface negative charge.