Showing papers on "Blood Platelet Disorders published in 1972"

The platelet defect associated with albumism.

Abstract: Summary. Investigations on the blood of two albino women with a haemostatic defect have revealed a specific abnormality of their platelets. This consists of an inability of the platelets to store adenine nucleotides in a metabolically inert form, and consequently of an impairment of the release reaction whereby normal platelets are induced to aggregate by agents, including collagen and thrombin, that act indirectly through the release of adenosine diphosphate (ADP). These patients' platelets also have a greatly impaired ability to take up and store 5-hydroxytryptamine (5HT) and adrenaline. It is suggested that the haemostatic failure previously observed in association with albinism is a result of such a defect of storage and release of adenine nucleotides by the platelets. Investigations on seven other albinos without haemorrhagic symptoms have shown no abnormality of platelet aggregation or nucleotide storage.

Platelet Adenine Nucleotide Storage Pool Deficiency In Thrombocytopenic Absent Radii Syndrome

Abstract: To the Editor.— A hemorrhagic diathesis has been described in patients with a platelet functional defect characterized by prolonged bleeding time, normal platelet counts, and abnormal platelet aggregation. The latter is characterized by a poor or absent aggregation with low concentrations of collagen and absence of secondary aggregation with adenosine diphosphate (ADP) and adrenaline. 1 Most of these patients are devoid of other defects and the bleeding disorder has been classified as thrombopathia or thrombocytopathia, terms that are confusing and inaccurate. Similar platelet abnormalities have been found in albinos, 2,3 in one case of Wiskott-Aldrich syndrome, 4 in the Hermansky-Pudlak syndrome, 5 and in some cases of connective tissue disease. 6 Some of these patients have a deficient storage pool of adenine nucleotides and serotonin, and the abnormality has been referred to as "storage pool deficiency" (SPD). 1 This deficiency may be more common than realized, as is evidenced by

A clinical and experimental study of platelet function in chronic renal failure.

Abstract: Coagulation and platelet function studies were performed on 24 normal subjects and 29 patients with chronic renal failure due to various causes. Thrombocytopenia was uncommon in the uraemic patients but there was reduced platelet retention in glass bead columns and platelet aggregation with adenosine diphosphate (ADP) and thrombin was slower and less complete than normal. The rate of platelet disaggregation in uraemic patients was significantly reduced. The abnormalities tended to be more severe in more uraemic subjects. In normal subjects no inter-relationships were observed between the various measurements of platelet activity. In patients there were significant interrelationships between the measurements of platelet aggregation with ADP and thrombin and between the measurements of aggregation and retention in glass bead columns. It is suggested that if a common pathway is involved in these reactions it is adversely affected in uraemia. Plasma coagulation defects were uncommon and present in only five of the uraemic subjects. Impaired prothrombin consumption apparently due to defective platelet function was present in half the patients but was not detected by a kaolin activation method. Although platelet coagulation function was activated during ADP aggregation and disaggregation in normal and uraemic subjects, it did not correlate in the latter with impairment of aggregation. It is suggested that aggregation and activation of platelet coagulant activity are not necessarily related aspects of platelet function. An effect of uraemic plasma on normal platelets was demonstrated by mixing experiments consistent with a humoral cause for the uraemic platelet defects.

The phospholipid and fatty acid composition of platelets in patients with primary defects of platelet function

Abstract: Platelet phospholipid and fatty acid composition was determined in nine normal subjects and in 11 patients with primary defects in platelet function. Two of the patients had thrombasthenia (Glanzmann) and nine had various types of abnormalities in platelet aggregation and platelet factor 3 availability attributed to impairment of the platelet release reaction. The values observed for platelet lipids in the normal subjects were similar to those reported by others. Four of the patients with a disturbance in the platelet release reaction were in the same family and showed the same abnormal pattern of platelet lipid composition. Phospholipid analysis showed a decrease in the relative amount of phosphatidyl ethanolamine (PE) and an increase in lecithin. Abnormalities in fatty acids consisted of an increase in the relative amounts of 18∶1ω9, 20∶0 and 20∶1ω9 and a decrease in the 22∶4ω6+24∶1 fraction. Similar changes in PE and 18∶1ω9 were also observed in another patient with a similar defect in platelet function. In this patient the relative amount of platelet sphingomyelin was also increased. The platelet lipid composition in the other six patients and in one normal subject given aspirin was essentially normal.

Platelet ascorbic acid levels in normal subjects and in disease.

Abstract: The platelet ascorbic acid concentration was measured in 26 normal subjects and found to be 20 times as high as in plasma. This is in agreement with previous reports in the literature. The platelets of patients with uraemia, leukaemia, and megaloblastic anaemia had a lower than normal platelet ascorbic acid content. In uraemia and megaloblastic anaemia the plasma ascorbic acid concentration was normal suggesting that a platelet defect may be responsible for the low platelet ascorbic acid content. In leukaemia the low platelet ascorbic acid content is probably secondary to a low plasma level.

A case of thrombasthenia with a study of platelet aggregation by hydrogen peroxide(H2O2)

Abstract: A six-year-old girl with a congenital hemorrhagic disorder characteristic of thrombasthenia or Glanzmann's disease was reported. A special study on platelet aggregation was performed. It was found that patient's platelets failed to aggregate in response to hydrogen peroxide (H2O2), while normal platelets were readily aggregated by this agent. This H2O2 induced aggregation of normal platelets can be inhibited by adenosine, suggesting a possible mechanism that H2O2 might stimulate platelets to release ADP, which in turn causes platelet aggregation.

Platelet Factor 3 — Properties and Clinical Significance

Abstract: Bounameaux (2) suggested that the periphery of the platelet has a “plasmatic atmosphere” containing many plasma substances, all identified on the basis of their activity Several so-called “platelet factors” have since then been described (Table I) (20); for most of them, however, it is not possible to state at present if they are specific constituents of platelets or if they come from the plasma; in contrast, some other factors such as phospholipid-like activity (platelet factor-3, PF-3) and antiheparin activity (platelet factor-4) seem to be specific platelet constituents

Platelet Factor 3 in Glanzmann’s Thrombasthenia

Abstract: The present paper describes 3 cases of classical thrombasthenia and 3 cases of combined platelet factor 3 defi- 3 ciency and absence of platelet aggregation. The bleeding time and the clot retraction in the latter 3 patients were They, however, did not differ in clinical presentation of classical thrombasthenia. These cases have been designated as thrombopathic thrombasthenia. The possibility of an in vivo platelet activation leading to variable amounts of platelet factor 3 release in thrombasthenia has been raised. Mechanism of PF3 release in vivo in thrombasthenia, however, is not known and needs further study.

The clinical relevance of platelet function tests.

Abstract: Summary. The increasingly used tests of platelet function have been briefly reviewed and an attempt has been made to correlate the result of these tests with their clinical significance. It may be said that the platelet count and bleeding time are still the most important information for the clinician. It has seldom been shown that isolated abnormalities of morphology, adhesion, aggregation or platelet factor 3 release have any clinical relevance unless accompanied by a prolongation of the bleeding time. A long bleeding time in an otherwise healthy patient is most frequently due to aspirin ingestion.

Glanzmann's thrombasthenia and reduced glutathione.

Abstract: PATIENTS with hemorrhagic disorders are usually found to have a diminished platelet count or a demonstrable defect in the activity of one of the clotting proteins, or both. But there is a small gro...