Eosinophilic leukaemia: morphological, cytochemical, and electron microscopic studies.

The eosinophils of a patient with eosinophilic leukaemia were studied with 13 different cytochemical methods using light and electron microscopy. Apart from the 'left shift' of the eosinophils in bone marrow and peripheral blood, the following morphological changes were noted: uncoordinated maturation of the nucleus and cytoplasm, changes in size of the specific granules, and hypogranulation to such an extent that some of the cells bore only very few granules. The cytochemical studies showed a strongly positive periodic acid Schiff reaction in the eosinophils, caused by a high content of glycogen, and a relatively strong positive acid-phosphatase reaction. These cells were also tested for aryl sulphatase and coenzyme Q. Electron microscopy confirmed the presence of a high-content glycogen and a strong acid phosphatase response in the cells. Peroxidase reaction, detected in electron microscopy as well, enabled us to trace the maturation of the eosinophil cell line.

Effect of melatonin on active transport of serotonin into blood platelets.

Previous research has demonstrated that the circadian rhythm of melatonin negatively correlates with that of the sensitivity of platelet serotonin uptake sites. Moreover, serotonin has been found to be a competitive inhibitor of melatonin binding to platelets. The goal of the present study was to investigate whether melatonin directly affects platelet serotonin transport. Blood samples from 12 healthy subjects were assayed for both serotonin transport into platelets. Active transport of serotonin (at a concentration of 10(-6) M) into blood platelets was measured in the presence of melatonin at physiological concentrations (10(-12) M to 2 x 10(-9) M) and high nonphysiological concentrations (2 x 10(-8) M to 2 x 10(-3) M). Melatonin inhibited serotonin uptake by blood platelets at the high concentrations only ( > 10(-5) M with IC50 value of 1.1 x 10(-3) M) and had no effect at physiological concentrations.

Lack of association between cholesterol blood levels and platelet serotonin uptake.

It has been suggested that low serum cholesterol interferes with brain serotonergic functioning, which results in increased suicidal and aggressive tendencies. To test this hypothesis we investigated the relationship between serum cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglyceride levels, and serotonin uptake by blood platelets in 17 healthy men aged 39.5 +/- 10.2 years. Platelet serotonin uptake and serum lipids were assayed concomitantly for each individual. Serum cholesterol levels and other serum lipid levels did not correlate with serotonin uptake by platelets at the concentration of 2 x 10(-5) M (a concentration within the maximal uptake capacity range). The results indicate no influence of cholesterol on serotonin uptake, as opposed to some investigators who suggested that high risk of suicide and aggressiveness in hypocholesterolemic individuals is related to impaired serotonin transport.

Phorbol-myristate-acetate-induced platelet aggregation in the presence of inhibitors.

4 beta-Phorbol-12-myristate-13-acetate (PMA) at 100 ng/ml was able to induce platelet aggregation in the presence of agents which inhibited aggregation, triggered by other agonists such as adenosine diphosphate sodium salt (ADP), thrombin and collagen. PMA induced aggregation in acid-citrate-dextrose platelet-rich plasma. 100 microM tetracaine, 5 microM bromophenacyl bromide and 0.2 mM mepacrine decreased PMA-induced aggregation by only 10% in contrast to their high inhibitory effect on other aggregation systems. However, 0.4 mM mepacrine did inhibit PMA-induced aggregation at the same rate as the other aggregation systems. 100 mg/ml vincristine slightly affected PMA-induced platelet aggregation, whereas cytochalasin B rather enhanced it. Nordihydroguaiaretic acid, 5, 8, 11, 14-eicosatetraynoic acid and p-nitrophenyl-phosphorylcholine had no effect on PMA- or collagen-induced platelet aggregation, partially inhibited aggregation triggered by ADP and strongly inhibited aggregation caused by thrombin. It is suggested that PMA exerts its effect on platelets mainly due to its ability to alter their membranes.

5-Hydroxytryptamine uptake by blood platelets of unipolar and bipolar depressed patients.

The active transport of 5-hydroxytryptamine (5HT) by blood platelets of unipolar and bipolar depressed patients was determined. The 5HT uptake by platelets of bipolar patients was determined in depressive, euthymic and manic states. The 5HT uptake was always followed by studying platelets of healthy individuals of the same sex and age. The results confirm the known fact that there is a decreased 5HT active transport in platelets of unipolar depressed patients. On the other hand, the amount of 5HT transported by platelets of bipolar depressed patients was higher than that observed in platelets of healthy individuals. In manic and euthymic bipolar patients the uptake was similar to their matched controls.

Genesis, ultrastructure and cytochemical study of the cat eosinophil.

Eosinophils from cat bone marrow and peripheral blood were studied by electron microscopy and cytochemical procedures. The maturation of eosinophils and formation of typical granules were described. Contrary to the accepted opinion that the core of animal's eosinophilic specific granules have a crytal-like structure, our observations revealed that the core has a myelin-like cylindrical appearance, whose layered formation proceeds from the inside outwards. Electron microscopic observations revealed that localization of reaction product to potassium pyroantimonate and phosphotungstic acid and to acid phosphatase activity was similar to that of eosinophils of man and other animals. Antimonate deposits and acid phosphatase activity were detected between the layers of the myelin-like structure of the core. Eosinophil granules failed to yield a positive reaction for peroxidase activity. The secretory activity of the eosinophil is discussed.

De novo synthesis of purine nucleotides in human blood platelets.

Human blood platelets were found to carry the complete pathway of de novo purine nucleotide synthesis. The rate of purine synthesis was gauged by the rate of incorporation of precursor (14C)formate into purines. The effect on formate incorporation of several compounds known to inhibit purine synthesis de novo was studied. Adenine, orotic acid and azaserine inhibited purine synthesis, but hypoxanthine and allopurinol did not. Platelet content of phosphoribosylpyrophosphate (PRPP) and of ribose-5-pes. Incubation of intact platelets with high inorganic phosphate concentrations caused an increase in platelet PRPP content but did not affect R-5-P content or the rate of purine synthesis de novo.

Alteration of rat bone marrow megakaryocytes following administration of cytosine arabinoside, daunomycin and hydroxyurea.

The in vivo effects of three cytotoxic agents--cytosine arabinoside, daunomycin and hydroxyurea on rat bone marrow megakaryocytes were studied, specifically the relative count, the type percentage and the morphology. All three agents caused thrombo-cytopenia, a decrease in the number of megakaryocytes relative to the nucleated bone marrow cells, and a decrease in the percentage of megakaryoblasts, associated with an increase in the percentage of granular megakaryocytes. A decreased lobulation of the megakaryocytes was observed following the administration of cytosine arabinoside and of daunomycin. Thrombosthenin, examined immunologically, remained detectable in the bone marrow smears throughout the various stages of megakaryocyte alteration.

Serotonin (5-HT) uptake by blood platelets in anorexia nervosa.

Platelet serotonin (5-HT) uptake was determined in 15 underweight anorexia nervosa patients and a control group of 15 healthy individuals. The Vmax (picomoles/10(8) platelets/5 min) was 424 +/- 103 in patients and 424 +/- 69 in controls. The Km was 1.19 +/- 0.2 microM in patients and 1.08 +/- 0.17 microM in controls. The differences between the groups were not significant. These findings do not support the hypothesis that serotonin metabolism is disturbed in anorexia nervosa.

Serotonin uptake by platelets of suicidal and aggressive adolescent psychiatric inpatients.

Thirty-four adolescent psychiatric inpatients were studied in order to find out whether there is a correlation between serotonin platelet uptake (SPU), suicidality and aggression. The patients were divided into four main diagnostic groups according to clinical data: borderline personality disorder, affective disorder (unipolar) including schizoaffective disorder, schizophrenia and 'others'. These patients were also characterized by the quantitative symptoms profile from K-SADS scale (Children's Version of the Schedule of Affective Disorders and Schizophrenia) and by their behavior: aggression, suicide attempts and violent suicide attempts. In the schizophrenic group, a correlation was found between low Vmax values of SPU and aggressive behavior (p less than 0.05). In addition, in the 'other' group a correlation was found between low Vmax values of SPU and conduct disorder (p less than 0.05). On the other hand, in 'other' patients a correlation was found between low Km values of SPU and violent suicide attempt (p less than 0.05). It is noteworthy that the lowest (20-35%) Vmax values of SPU were found in the patients of the affective group as compared to values of the three other diagnostic groups. These findings are similar to those concerning unipolar depressive adults. It is assumed that there are less binding sites for serotonin on platelets of depressive adolescents than was suggested for depressive adults.

Kinetic values of active serotonin transport by platelets of bipolar, unipolar and schizophrenic patients at 2 and at 8 a.m. Preliminary report.

Serotonin active transport by platelets of psychiatric patients was determined at 2 and at 8 a.m. Kinetic values, Vmax and Km, of serotonin uptake by platelets of bipolar depressive patients at 2 a.m. were higher than those at 8 a.m. Contrary to that, the kinetic values, Vmax and Km, for unipolar patients at 2 a.m. were rather lower than the values at 8 a.m. Serotonin uptake kinetics by platelets of schizophrenic patients at 2 a.m. were similar to those at 8 a.m. The curves of serotonin uptake kinetics by platelets of bipolar patients at 2 and at 8 a.m. were different from those observed for platelets of unipolar and schizophrenic patients. The variability of the kinetics of serotonin uptake by platelets of the three groups of psychiatric patients may offer a clue to the heterogenicity of these disorders.

Room temperature ADP induced first stage hyperaggregation of human blood platelets: a previously undescribed phenomenon and its relationship to spontaneous cold induced platelet aggregation.

ADP induced human platelet aggregation was shown to be accentuated when tested at 20-30 degrees C as increased sensitivity and as a greater change of optical density although second stage aggregation and the release reaction did not occur. This previously undescribed phenomenon is defined as room temperature ADP induced first stage hyperaggregation. Aggregation, which occurs under the above mentioned conditions with a quantity of ADP insufficient to maintain the aggregation (usually less than 1.5 micron), is reversible when the temperature is raised to 37 degrees C. After rewarming to these temperatures, second stage aggregation appeared in the presence of larger quantities of ADP (usually more than 2 microns) and could be blocked by aspirin. The absence of the release reaction was demonstrated with a lumi-aggregometer. Spontaneous cold induced platelet aggregation seen after chilling platelets to 0-4 degrees C is shown to be a distinct phenomenon.