Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Formation of thromboxane B2 (TXB2), a metabolite of the potent platelet-aggregating and vasoconstrictor agent thromboxane A2 (TXA2), during ADP-induced platelet aggregation was studied in 10 healthy men and in 10 male alcoholics during the 2-week period of detoxification. None of the alcoholics had anemia or thrombo-embolic disease. The platelets of the alcoholics were more sensitive for ADP and synthesized as much as triple the amount of TXB2 compared to those of the nonalcoholic donors. The effect was most striking during the rebound thrombocytosis and suggests that it could possible contribute to the increased incidence of various thrombotic diseases in the alcoholic.
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PMID:Platelet aggregation and thromboxane B2 formation after ethanol abuse: is there a relationship to stroke? 651 92

The aggregation of normal human platelets in vitro induced by ADP was severely inhibited after preincubation of platelet-rich plasma (PRP) with CoCl2. Platelets from a patient with congenital afibrinogenaemia did not aggregate until fibrinogen was added. This recovered response was also inhibited by CoCl2. The impairment of aggregation seemed to be due to the action of cobalt on surrounding fibrinogen and not to a direct action on the platelets themselves. These results illustrate another aspect of the potential toxicity resulting from the use of cobaltous salts in treating the anaemia of renal failure, in which bleeding disorders have been reported.
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PMID:Effect of cobaltous chloride on aggregation of platelets from normal and afibrinogenaemic human blood. 652 26

Male weanling rats were made copper deficient with a purified diet containing all known essential dietary nutrients except copper. Copper deficiency was verified by indirect (anemia, growth retardation, hypercholesterolemia, gross pathology, and abnormal electrocardiograms) and direct (tissue copper analysis) criteria. His bundle electrographic and electrocardiographic changes detected in the copper-deficient group consisted most notably of depressed His-Purkinje system conductivity and S-T segment depression. Phosphorus-31 nuclear magnetic resonance spectroscopic analysis of cardiac, renal, and hepatic tissue perchloric acid extracts revealed significant metabolic changes associated with the dietary copper deficiency, including a generalized marked decrease in ATP and phosphocreatine levels and a corresponding increase in inorganic orthophosphate and ADP levels in the various tissues. Tissue-specific changes consisting of elevated ribose 5-phosphate (heart), phosphocholine (heart), and inosine monophosphate (kidney) and decreased glycerol 3-phosphorylethanolamine (liver) and glycerol 3-phosphorylcholine (liver) levels were detected in copper-deficient rats. Microscopic examination of heart tissue from copper-deficient rats revealed extensive disruption of mitochondrial fine structure, including fragmentation of cristae and inner and outer mitochondrial membranes, which resulted in pronounced vacuolization throughout the tissue. Although the physiological and metabolic disturbances manifested in hearts from copper-deficient animals generally mimic myocardial responses to chronic ischemia, the observed changes are interpreted in a broader context to represent the appearance of a copper-dependent cardiomyopathy.
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PMID:Physiological and metabolic characterization of a cardiomyopathy induced by chronic copper deficiency. 663 5

Platelet function was measured on 29 occasions in 16 adult patients in the asymptomatic steady state of sickle-cell anaemia. There was a significant increase in platelet number and micro-aggregate formation, and a lower aggregation threshold with adenosine diphosphate, compared with 23 healthy controls. Similar changes were found, however, in 12 splenectomised patients without sickle-cell diseases. The platelet hyperactivity of the sickle-cell steady state therefore reflects an increased circulating population of young, metabolically active platelets resulting from previous autosplenectomy.
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PMID:Platelet hyperactivity in sickle-cell disease: a consequence of hyposplenism. 743 Mar 67

Erythropoietin corrects anemia and improves hemostasis, but on the other hand bears a risk of thrombotic complications. Therefore in the present study an attempt has been made to evaluate bleeding time, platelet functions and some hemostatic and fibrinolytic parameters in relation to blood and platelet serotonin before and after 1, 2, 4, 8 and 12 weeks of treatment. 22 chronically hemodialyzed patients were administered with human recombinant erythropoietin (rHuEPO) in a dose of 2000 IU s.c. 3 times a week. Bleeding time was shortened significantly as early as after 1 week of the therapy, whereas hematocrit and hemoglobin increased after 2 weeks. These changes lasted throughout the study. Only a transient rise in platelet count, collagen-induced platelet aggregation, beta-thromboglobulin and VIII:C activity were observed during therapy relative to baseline values. ADP- and arachidonic acid-induced platelet aggregation seemed to be unaffected by rHuEPO treatment, whereas a gradual and progressive enhancement in platelet aggregation in response to ristocetin was found, starting from the 2nd week of the therapy. It lasted throughout the study and correlated inversely with the bleeding time and positively with a rise in both blood and platelet serotonin. rHuEPO did not alter plasminogen, fibrinogen, platelet factor 4, alpha 2 macroglobulin levels, protein C activity and euglobulin clot lysis time. A decline in protein C and S concentrations and antithrombin III activity observed during the therapy were counterbalanced by a fall in the activity of alpha 2 antiplasmin, C1 esterase inhibitor and plasminogen activator inhibitor. It is concluded that rHuEPO may improve platelet/vessel wall interactions possibly by means of serotonergic mechanisms. A lowered activity of inhibitors of fibrinolysis may be regarded as a protection against a general tendency to thrombosis during rHuEPO therapy.
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PMID:A study of platelet functions, some hemostatic and fibrinolytic parameters in relation to serotonin in hemodialyzed patients under erythropoietin therapy. 774 May 5

Twenty chronic hemodialysis patients with renal anemia (hematocrit < 25%) received recombinant human erythropoietin (40 IU/kg body weight 3 x weekly) intravenously after each dialysis. Prior to and at 4, 8 and 12 weeks after commencement of erythropoietin therapy, hematocrit together with hemostasis and microhemolysis parameters were determined. There were significant increases in hematocrit, platelet count and platelet retention, but a significant fall in the initial clearly prolonged bleeding time. Free plasma hemoglobin likewise increased. Conversely, lactate dehydrogenase, prothrombin time, fibrinogen, antithrombin III activity, protein C activity and protein S concentration were all unaltered. The positive effect on bleeding time and platelet retention is most probably caused by an increase in adenosine diphosphate due to the hematocrit-dependent rise in the blood shear stress via physiologic microhemolysis (raised free plasma hemoglobin).
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PMID:Influence of recombinant human erythropoietin on hematological and hemostatic parameters with special reference to microhemolysis. 777 78

Uremia may be associated with abnormal hemostasis characterized by a prolonged bleeding time and abnormal in-vitro platelet aggregation. The mechanisms underlying these derangements are not fully elucidated. The present study examined the effect of correction of anemia by recombinant human erythropoietin (r-HuEPO) on these abnormalities in eight dialysis patients. Prior to r-HuEPO therapy the patients had low hematocrits (Hct) (20% +/- 0.7), abnormal bleeding times (23 +/- 1.2 minutes), and marked impairment in platelet aggregation induced by adenosine diphosphate (ADP), epinephrine (Epi), thrombin (Th) and collagen. After correction of the anemia to a Hct of 32% +/- 0.9 over 5 +/- 0.9 months, there were a) significant shortening of the bleeding time (from 23 +/- 1.2 to 10.6 +/- 2.4 minutes, p < 0.01), b) an inverse correlation between the Hct and the bleeding time (r = -0.89, p < 0.001) and c) significant improvement, or normalization of platelet aggregation in response to both concentrations of epinephrine [Epi2 (5.4 x 10(-6) M), 45% +/- 10.5 vs 73.5% +/- 7.3, p < 0.01, and Epi1 (5.4 x 10(-5) M), 49% +/- 10.6 vs 64% +/- 6.6, p < 0.05)], both concentrations of ADP [ADPC'(2 x 10(-6) M), 31% +/- 5.9 vs 60% +/- 9.3, p < 0.05, and ADPB (2 x 10-5), 69.5% +/- 7.6 vs 99% +/- 4.8, p < 0.01], and both concentrations of thrombin [ThC (0.22 u/ml) 28.6% +/- 8.9 vs 80.4% +/- 8.3, p < 0.01, and TH50/50 (0.44 u/ml), 57.8% +/- 6.7 vs 83.3% +/- 9.2, p < 0.01)].(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Recombinant human erythropoietin shortens the bleeding time and corrects the abnormal platelet aggregation in hemodialysis patients. 805 Feb 12

The mechanism of the inhibitory effects of chelators (desferrioxamine, EDTA, rutin, phenanthroline and ADP) on the production of oxygen radicals in the Fenton reaction and on lipid peroxidation of rat brain homogenates has been studied. It was found that the inhibitory effects of the chelators correlated well with their abilities to oxidize ferrous ions in solution and brain homogenates. On these grounds, it was concluded that the oxidation of Fe2+ ions inside a ferrous ion-chelator complex is a major mechanism of inhibitory effects of these chelators on free radical processes. It is proposed that this mechanism is also realized during therapeutic treatment with chelators of patients with "free radical" pathologies such as Fanconi anemia, beta-thalassemia and Diamond-Blackfan anemia.
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PMID:Mechanism of inhibitory effects of chelating drugs on lipid peroxidation in rat brain homogenates. 813 55

Chronic exposure of adult rats to dietary intake of cadmium (15 mg CdCl2/day/kg for 30 days) leads to development of anemia and thrombocytosis. Anemia is characterized by significant reticulocytosis (13.1 +/- 1.0%), anysocytosis, poikilocytosis, iron deficiency and marked alterations of antioxidant and metabolic status of red blood cells. Activities of SOD, catalase, GPx and GR were significantly increased in red blood cells of cadmium-treated rats. In treated animals cadmium induced an increase of red cell reduced and oxidized glutathione with no changes of GSSG/GSH ratio. However, significant reduction of lipid peroxidation was found. Plasma levels of tocopherol and ascorbate, as well as activity of glutathione-S-transferase, were all significantly increased in cadmium-treated rats. The energy metabolism of red blood cells was deeply altered in cadmium-treated rats. The levels of ATP, ADP, AMP and TAN were significantly increased while ATP/ADP ratio and adenylate energy charge (AEC) were significantly reduced. The level of 2,3-BPG was somewhat lower, but 2,3-BPG/Hb ratio was considerably higher, in red blood cells of cadmium-treated rats.
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PMID:Cadmium-induced changes of antioxidant and metabolic status in red blood cells of rats: in vivo effects. 837 Apr 23

Fatigue and lethargy, common symptoms in uraemia, have been attributed to many factors. To assess possible bioenergetic contributions to this, we examined the forearm muscle of five patients in end-stage renal failure using 31P-magnetic resonance spectroscopy. There was a small increase in the ratio of intracellular inorganic phosphate to ATP in resting muscle, suggesting an increased cytosolic phosphate concentration. During exercise, increased phosphocreatine breakdown was accompanied by rapid intracellular acidification and an increase in calculated lactic acid accumulation in the muscle of the uraemic subjects, suggesting glycolysis dominating over oxidative phosphorylation as a source of ATP. After exercise, the half-time of phosphocreatine (PCr) recovery was longer in the uraemic subjects, suggesting diminished mitochondrial function. The initial rate of PCr resynthesis was not significantly decreased, but when account was taken of the high cytosolic ADP concentration (which drives mitochondrial oxidative ATP synthesis) the calculated maximum oxidative capacity was significantly reduced in the uraemic subjects. Thus there was evidence of mitochondrial dysfunction in uraemia due either to limitation of oxygen supply, reduced mitochondrial content, or an intrinsic mitochondrial defect. This resulted in increased phosphocreatine depletion and increased glycolytic ATP production during exercise and there was partial compensation of the mitochondrial abnormality by increased ADP concentration. In three of these patients studied after elevation of haemoglobin with erythropoeitin (from 8 to 12 g/dl), initial phosphocreatine breakdown and lactic acid accumulation during exercise were normalized, while exercise duration and calculated maximum oxidative capacity remained significantly abnormal. This suggests that anaemia contributes to these metabolic abnormalities but does not fully explain them.
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PMID:Effect of chronic uraemia on skeletal muscle metabolism in man. 838 87


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