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Biomedical subjects

B Boneu

Publications and source records attributed to B Boneu.

At least 181 records · Page 10Linked to original sources
PubMed1983

Platelet density analysis: a tool for the detection of acquired storage pool disease in man.

This study was designed to evaluate the usefulness of platelet density analysis in the detection of acquired storage pool defects in human patients. Two groups of patients were investigated: 19 subjects affected with a myeloproliferative disorder (group I) where abnormal platelets are released from the megakaryocytes and 11 patients hospitalized in an intensive care unit (Group II) where normal platelets are injured in the circulation. Platelet density distribution after isopycnic centrifugation on a discontinuous stractan density gradient, dense granule markers (serotonin, ATP and ADP) and alpha granule markers (intraplatelet beta-thromboglobulin and platelet factor 4) were simultaneously determined. An increased proportion of the percentage of light platelets was observed in 16 patients of group I and nine of group II; an increased ATP/ADP ratio was observed in 12 patients of group I and 10 of group II. Both the tests were abnormal in 11 patients of group I and nine of group II. In group I, the level of serotonin was low and was related to the percentage of light platelets. The alpha granule specific proteins were normal in the two groups. These results indicate that platelet density analysis may serve as a screening test to detect exhausted platelets in human diseases.

Adenosine Diphosphate↗
PubMed1983

[Thrombocytopenia induced by heparin. Apropos of 10 cases].

The authors report ten observations of thrombocytopenia induced by heparin complicated with two arterial thrombosis and four deep venous thrombosis. Two deaths and two amputations are to mention. This retrospective study leads to a review of literature: this iatrogenic disease, which frequency is variously estimated, has no relation with the dose and the mode of administration of Heparin. It's mechanism might be immuno-allergic. It's diagnosis depends mainly on the repetition of platelet numerations at the outset period of treatment, and on the rapid and lasting climbing of platelet countings when heparin is stopped. This uncommon and unforeseeable complication indicates to stop Heparin and to start K antivitamin's if necessary.

Adult↗
PubMed1983

[Evaluation of Owren's thrombotest in the monitoring of treatment with antivitamin K].

The need to standardize the monitoring of oral anticoagulant treatments has led some countries to adopt, generally, Owren's Thrombotest. Apart from needing only one reagent and being perfectly adapted to this type of monitoring, the thrombotest has the advantage of being able to be used on capillary blood and venous blood and of not being influenced by the storage of the blood samples. Its disadvantages are that it is slow to perform, difficult to automate and that it has a therapeutic range which is narrow and close to the limits of precision of the technique. The results of the Thrombotest correlate well with those of the Quick test, the activated cephalin time and the X level measured by the amidolytic technique. Until the chromogenic assays are developed, the Owren's Thrombotest provides a better homogeneity and standardization of the results coming from different laboratories.

Anticoagulants↗
PubMed1982

[A study of antithrombin systems during heparin therapy].

Plasma levels of three thrombin inhibitors (antithrombin III--AT-III-, alpha 2 macroglobulin - alpha 2M -; alpha 1 antitrypsin - alpha 1 AT-) were measured, together with total plasma antithrombin activity (Howie's method), in 19 hospital patients with venous thromboembolic disease before and during heparin therapy. A decrease in AT III levels was observed during treatment and found to correlate significantly with heparin plasma levels, but there were no significant changes in alpha 2M and alpha 1 AT levels. Variations in total plasma antithrombin activity were not significant. In 9 patients whose AT III levels were under 60% a significant increase in alpha 2M level was noted. The therapeutic problems associated with this category of patients are discussed.

Antithrombin III↗
PubMed1982

[Increase in mean platelet volume in shock-related thrombocytopenia].

In a retrospective study the mean platelet volume (MPV) was measured in citrated plasma of 16 patients with hypovolaemic or infectious toxic shock. Bone marrow examination was carried out in most cases. Eighty p. cent of the patients had an increase in MPV, and the increase persisted even after thrombocytopenia had regressed. Cytological examination of the bone marrow failed to provide evidence that bone marrow deficiency was a predominant factor in the pathogenesis of thrombocytopenia in any of these patients. In this particular patient population, bone marrow examination should be reserved to those cases where persistent thrombocytopenia coexists with normal MPV.

Blood Platelets↗
PubMed1982

Platelet arachidonic acid metabolism in severe cerebrovascular disease.

The ability of platelets to synthetise thromboxane B2 and hydroxylated fatty acids from arachidonic acid was studied simultaneously with arachidonic acid-induced aggregation in 42 patients suffering from severe cerebral atherosclerosis and also in 34 healthy controls. Additionally, phospholipase-A2-induced aggregation was performed as a probe for arachidonic acid located at the platelet surface. All the assays were performed with washed platelets, eliminating a possible influence of plasma. Platelets from patients were found responsive to significantly lower concentrations of arachidonic acid whereas thromboxane and hydroxylated fatty acid biosynthesis did not differ from controls. In the experimental conditions used, 75% of the control platelets underwent aggregation with phospholipase A2 plus sphingomyelinase C, in comparison to only 50% for the patients, indicating the necessity for further analysis of the platelet membrane lipids in atherosclerosis.

Adult↗
PubMed1982

Factor II related antigen and antithrombin III levels as indicators of liver failure in consumption coagulopathy.

In order to detect impaired synthesis of blood coagulation factors associated to consumption coagulopathy, a simultaneous evaluation of factor II-related antigen (II rAg) and of antithrombin III (AT III) was carried out in 16 patients affected with severe defibrination. An in vitro preliminary study on plasma and serum demonstrated that the levels of II rAg and of AT III, assessed by the Laurell technique with Behring antisera, were not reduced by the coagulation process. The patients were, a posteriori, classified into two groups according to the absence (group A) or the presence (group B) of factors predisposing to liver failure such as metastasis, cirrhosis, and prolonged shock. II rAg and AT III levels are significantly correlated; they are in the normal range in group A but reduced in group B. Thus II rAg or AT III level determinations are useful markers in the detection of liver failure associated to the consumption phenomenon. These results also suggest that part of the decreased AT III levels reported in severe cases of disseminated intravascular coagulation may be the consequence of an associated liver failure.

Antigens↗
PubMed1982

Further studies on the relationship between platelet buoyant density and platelet age.

The relationship between platelet buoyant density and platelet age was investigated in eight human subjects submitted to an autologous chromium labeled platelet survival study. Platelets were isolated after isopycnic centrifugation using eight discontinuous isoosmotic stractan gradients (five subjects), or various continuous and linear isoosmolar gradients (three subjects). A paradoxical radioactivity enrichment of the dense platelets and a premature loss of radioactivity in the light platelets were observed. These results are explained by a shift of the radioactivity distribution curve toward higher densities during the 3-4 days after platelet injection, while the standard deviation of the distribution was conserved throughout the platelet life span. These results suggest that young platelets are heterogeneous and slightly less dense than the total platelet population.

Blood Platelets↗
PubMed1982

Serotonin uptake and storage in human platelet density subpopulations.

Serotonin uptake and storage were studied in human platelet density subpopulations which were isolated after isopycnic centrifugation on a discontinuous iso-osmolar stractan gradient. Kinetic parameters of the serotonin uptake were calculated (Km, Vi max) and the granular storage capacity was determined by comparing the total amount taken up in the presence or absence of reserpine, a specific inhibitor of the uptake at the granular level. Mean platelet volume and the number of mepacrine-labelled dense bodies were also determined. The results show that the active metabolic process of serotonin uptake is identical whatever the platelet subpopulation but the storage capacity is greater in the densest fraction which contains more dense bodies than the lightest one. Thus active serotonin uptake appears as another well-defined platelet metabolic process which is independent of platelet density; this argues against the conception that light platelets could be old platelets with reduced functional capacities.

Blood Platelets↗
PubMed1982

[Importance of synoviorthesis using osmic acid in the treatment of hemophilic arthropathy. Apropos of 19 cases].

While getting synovial sclerosis and articular drying, the synoviorthesis breaks the circulus vicious which comes from iterative hemarthrosis to articular destruction. With 25 cases and a follow up of 6 years, we have got 39% of good results, 35% of medium and 26% of bad ones. The therapeutic efficiency requires a certain latent time (0 to 15 days for isotopical synoviorthesis, 2 to 3 months for those ones with osmical acid.) A new synoviorthesis can be made if needed. Neither age nor radiological stage are of any influence. The radiological worsening uses to go on unchanged. The synoviorthesis should be performed at an early stage, previous to the cartilage and bone destructions.

Adolescent↗
PubMed1982

Coulter Counter studies of hypotonic-induced macrothrombocytosis in normal subjects and in idiopathic thrombocytopenic purpura patients.

The addition of distilled water to platelet rich plasma converts the platelets into large spherocytes without lysis. This phenomenon implies an evagination of the platelet membrane which participates in the surface connecting system. An adaptation of the direct microscopic method (Milton & Frojmovic, 1979) to the Coulter Counter is reported. The maximum increase in platelet volume without platelet lysis was obtained for 120 mOsm. These volume changes are a consequence of a shift in the platelet volume distribution curve towards higher values without loss of log normality, while the volume dispersion is only slightly modified. This suggests that the amount of evaginable platelet membrane is correlated to the size of the platelet. The size parameters (volume, surface, diameter) of hypotonic-induced spherocytes closely agree with those reported in the original microscopic method. Application of this technique to ITP-platelets suggests a reduced evaginable platelet membrane; this fact probably reflects the abnormal demarcation of platelet territories at the megakaryocytic level.

Blood Platelets↗
PubMed1981

Evaluation of some platelet parameters in a group of elderly people.

Platelet production time (PPT), plasmatic beta-thromboglobulin (beta-TG), platelet density distribution, and mepacrine labelled granular content of the platelets were simultaneously determined in a group of elderly subjects. Vascular deterioration, assessed by the history and clinical examination, was variable in extension and severity. PPT was slightly but not significantly shortened, whereas the raised beta-TG level and diminished platelet density and granular content suggested an in vivo release reaction process. The results are not correlated with the apparent severity of vascular deterioration, and the release reaction may not be solely related to enhanced platelet-vessel wall interactions.

Adult↗
PubMed1981

Factor VIII complex in normal pregnancy, pre-eclampsia and fetal growth retardation.

The levels of the three components of factor VIII complex (VIII R:AG, VIII R:WF, VIII:C) were measured during normal late pregnancy, in pre-eclampsia and in pregnancies complicated by fetal growth retardation. In late normal pregnancy, there was a steady increase in factor VIII complex and the highest level was reached at delivery; in primary fetal growth retardation, the values were similar. In pregnancies complicated by pre-eclampsia, with or without fetal growth retardation, there was a significant increase of VIII R:AG VIII R:WF; the more severe the course of the disease, the greater the increase. The level of VIII R:AG-VIII R:WF appears to be an indicator of vascular pathology and it is suggested that this assessment may be of value in monitoring high risk pregnancies.

Factor VIII↗
PubMed1981

Platelets in myeloproliferative disorders. III: Glycoprotein profile in relation to platelet function and platelet density.

Membrane glycoproteins (GP) are implicated in platelet functions. In myeloproliferative diseases (MD), some of these functions are known to be perturbed. 16 patients with various MD were investigated for platelet functions (retention to glass beads, epinephrine- and ristocetin-induced aggregation), platelet density distribution and PAS-staining glycoprotein profile on SDS-polyacrylamide-gel-electrophoresis. An abnormal GP pattern (moderate reduction of GP (Ib + Is) and GP IIb with corresponding increase in GP IIIb) was demonstrated but no relation to platelet dysfunction or density distribution was observed. No differences between the various types of MD were noticed although the group of polycythaemia vera was the less perturbed for platelet function, platelet density and also GP profile.

Blood Platelets↗