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2.
Neth J Med ; 65(1): 29-35, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17293637

RESUMO

BACKGROUND: Binge drinking (the consumption of large quantities (>5 units) of alcohol in a short period) is associated with increased cardiovascular mortality. Wine polyphenols are considered to be protective against cardiovascular diseases. We conducted an experimental study to evaluate the acute effects of alcohol consumption on flow-mediated vasodilation and general cardiovascular parameters, using beverages with high polyphenolic content (HPC) and low polyphenolic content (LPC). METHODS: Two groups of ten volunteers were asked to drink two different kinds of beverages. in 45 minutes, three units of red wine or an alcoholic beverage with a low polyphenolic count were consumed. Then 45 minutes were allowed for complete uptake of the alcohol or polyphenolic compounds. Next, all volunteers underwent blood pressure readings, ECG and flow-mediated vasodilation. Blood samples were taken at the same time for routine chemistry, inflammation parameters and lipids. Then the entire cycle was repeated once (in total six units of alcohol in 180 minutes). RESULTS: No differences were found between the two drinks. Alcohol itself dose-dependently increased forearm blood flow by vasodilation of both arterioles and distribution arteries. However, flow-mediated vasodilation (FMD) for the LPC group (n=10) decreased from 7.31 +/- 4.78 (% +/- sd) to 2.82 +/- 2.9 after three drinks and 1.21 +/- 3.25 after six drinks. The FMD values for the HPC group (n=10) decreased from 8.61 +/- 1.78 to 1.78 +/- 3.71 and 1.19 +/- 2.6. There were no significant changes between the LPC and the LPC group at the three time points. CONCLUSION: Although ethanol produces vasodilation at the level of the distribution artery as well as at an arteriolar level, it causes a decrease in flow-mediated vasodilation. This endothelial dysfunction is not corrected by the polyphenols present in wine.


Assuntos
Consumo de Bebidas Alcoólicas/fisiopatologia , Endotélio Vascular/fisiopatologia , Etanol/intoxicação , Flavonoides/farmacologia , Fenóis/farmacologia , Vinho/análise , Adulto , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Eletrocardiografia , Feminino , Flavonoides/análise , Humanos , Masculino , Fenóis/análise , Polifenóis , Vasodilatação/efeitos dos fármacos
3.
Eur J Clin Invest ; 34(12): 818-24, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15606724

RESUMO

BACKGROUND: Moderate and prolonged alcohol consumption has been associated with decreased cardiovascular morbidity and mortality. Inhibition of platelet function in suspension attributes to these effects. Whether alcohol, red wine, or polyphenolic grape extracts (PGE) inhibit platelet adhesion is not known. We investigated platelet adhesion to fibrinogen and collagen in whole blood under standardised flow. MATERIALS AND METHODS: Before perfusion was started, citrated whole blood from 95 volunteers was preincubated for five min with different alcohol concentrations, unfractioned red wine and PGE. Then, blood was perfused in a single-passage flow chamber over coverslips coated with human fibrinogen or collagen type III at shear rates of 300 s(-1) and 1600 s(-1). RESULTS: Alcohol inhibited platelet adhesion to human fibrinogen at high shear rate (concentrations > or = 0.15 per thousand) and low shear rate (only at a concentration of 4.8 per thousand), whereas red wine (concentrations > or = 0.15 per thousand) inhibited platelet adhesion to human fibrinogen at both shear rates. In contrast, PGE (concentrations > or = 0.0225 g L(-1)) inhibited platelet adhesion to human fibrinogen only at low shear rate. None of these incubations affected adhesion to collagen. CONCLUSIONS: Alcohol, red wine and PGE inhibit adhesion to fibrinogen but not to collagen. This inhibition might contribute to the cardioprotective effects of moderate alcohol consumption.


Assuntos
Etanol/farmacologia , Flavonoides/farmacologia , Fenóis/farmacologia , Adesividade Plaquetária/efeitos dos fármacos , Vitis/química , Vinho , Plaquetas/metabolismo , Colágeno/metabolismo , Relação Dose-Resposta a Droga , Fibrinogênio/metabolismo , Humanos , Técnicas In Vitro , Extratos Vegetais/farmacologia , Polifenóis
4.
Eur J Intern Med ; 14(6): 361-366, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14769494

RESUMO

Background: Moderate alcohol consumption reduces the risk of cardiovascular diseases, especially coronary heart disease (CHD). Because of the presence of polyphenols in red wine, this type of beverage may be superior to other alcoholic drinks in the prevention of CHD. Inhibition of platelet aggregation is thought to be one of the mechanisms underlying this favorable effect. The present study analyzes the direct effect of alcohol and red wine polyphenols on platelet aggregation. Methods: Unfractionated red wine, a red wine polyphenolic extract, and alcohol were added in different concentrations to a standardized quantity of blood platelets 2 min before aggregation was induced by different concentrations of ADP. Aggregation was measured in an aggregometer and results were compared to a control 0.9% NaCl solution. Results: Alcohol in concentrations up to 0.24 percent did not inhibit platelet aggregation in vitro initiated with ADP The polyphenolic red wine extract inhibited aggregation dose-dependently and significantly from concentrations of 45 mg/l ( [Formula: see text] ) or more. Red wine only inhibited platelet aggregation at very high concentrations ( approximately 0.24 and 0.48 alcohol%). Conclusions: Consumption of red wine has an inhibitory effect on platelet aggregation, which is caused by the polyphenolic compounds in the wine. Alcohol itself does not have a direct inhibitory effect within a range up to 0.24 percent. Since this effect is only observed at very high concentrations, it is unlikely to be of clinical relevance in a moderate drinking pattern. The results do not exclude platelet inhibition by wine in vivo. However, this must be related to metabolic changes rather than to direct blockade.

6.
Neth J Med ; 60(7): 285-8, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12430575

RESUMO

BACKGROUND: Light to moderate alcohol consumption is associated with a reduced risk of coronary heart disease. Stimulation of fibrinolysis has been suggested as one of the mechanisms involved. The present study analyses the effect of regular alcohol consumption on various parameters of fibrinolysis. The question whether the alcohol-induced plasma increase of plasminogen activator inhibitor (PAI-1) may originate from thrombocytes was also addressed. METHODS: Six healthy male volunteers consumed three glasses of red wine daily during two periods of a week, with a week of abstinence from alcohol in between. PAI-1 antigen and activity levels, t-PA antigen and activity levels and plasmin antiplasmin (PAP) complexes were measured on days 1, 3, 8, 15, 17 and 22 of the experiment period. On the first day, PAI-1 antigen and activity before and after alcohol consumption was also measured in platelet-rich plasma (prp). RESULTS: Although some slight shifts in the various parameters could be noticed during the drinking periods, all favouring impairment rather than stimulation, no significant effect of regular moderate alcohol use could be observed on fibrinolysis. Alcohol did not trigger a release of PAI-1 from platelets. CONCLUSIONS: Regular moderate alcohol consumption has no significant effect on fibrinolysis. The alcohol-induced increase of plasma PAI-1 does not originate from thrombocytes. The cardioprotective effect of moderate alcohol consumption cannot be explained by a beneficial influence on fibrinolysis.


Assuntos
Consumo de Bebidas Alcoólicas/sangue , Fibrinólise/efeitos dos fármacos , Adulto , Antígenos/sangue , Doença das Coronárias/prevenção & controle , Fibrinolisina/análise , Humanos , Masculino , Inibidor 1 de Ativador de Plasminogênio/sangue , Ativador de Plasminogênio Tecidual/sangue , Vinho , alfa 2-Antiplasmina/análise
7.
Blood ; 98(2): 358-67, 2001 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-11435304

RESUMO

Coagulation factor V (FV) plays an important role in maintaining the hemostatic balance in both the formation of thrombin in the procoagulant pathway as well as in the protein C anticoagulant pathway. FV deficiency is a rare bleeding disorder with variable phenotypic expression. Little is known about the molecular basis underlying this disease. This study identified 5 novel mutations associated with FV deficiency in 3 patients with severe FV deficiency but different clinical expression and 2 unaffected carriers. Four mutations led to a premature termination codon either by a nonsense mutation (single-letter amino acid codes): A1102T, K310Term. (FV Amersfoort) and C2491T, Q773Term. (FV Casablanca) or a frameshift: an 8-base pair deletion between nucleotides 1130 and 1139 (FV Seoul(1)) and a 1-base pair deletion between nucleotides 4291 and 4294 (FV Utrecht). One mutation was a novel missense mutation: T1927C, C585R (FV Nijkerk), resulting in the absence of mutant protein despite normal transcription to RNA. Most likely, an arginine at this position disrupts the hydrophobic interior of the FV A2 domain. The sixth detected mutation was a previously reported missense mutation: A5279G, Y1702C (FV Seoul(2)). In all cases, the presence of the mutation was associated with type I FV deficiency. Identifying the molecular basis of mutations underlying this rare coagulation disorder will help to obtain more insight into the mechanisms involved in the variable clinical phenotype of patients with FV deficiency.


Assuntos
Deficiência do Fator V/genética , Fator V/genética , Mutação , Adolescente , Adulto , Sequência de Bases , Pré-Escolar , Códon sem Sentido , Enzimas de Restrição do DNA , Éxons , Fator V/metabolismo , Deficiência do Fator V/sangue , Feminino , Mutação da Fase de Leitura , Deleção de Genes , Heterozigoto , Homozigoto , Humanos , Íntrons , Masculino , Linhagem , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA
8.
Eur J Clin Invest ; 31(2): 164-70, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11168456

RESUMO

In contrast to a reduced risk of coronary heart disease (CHD) with light to moderate alcohol consumption, heavy alcohol intake and binge drinking are associated with increased cardiovascular mortality. Alcohol has an acute and profound effect on fibrinolysis that may be relevant to the pathogenesis of CHD. The short-term effects of a low (two glasses, 250 mL, 20 g ethanol) and a high (six glasses, 750 mL, 60 g ethanol) intake of red wine were studied in male volunteers and compared to the intake of mineral water. To find a threshold for inhibition of fibrinolysis and to study a binge effect, a second experiment was performed comparing the intake of four (500 mL, 40 g ethanol) and eight (1000 mL, 80 g ethanol) glasses of red wine with mineral water. Plasminogen activator inhibitor-1 (PAI-1), tissue-type plasminogen activator (t-PA), plasmin-antiplasmin (PAP) complexes and clot lysis time were measured. In contrast to the circadian rhythm with an enhanced fibrinolysis in the evening that was found in the mineral water group, an intake above four glasses of wine inhibited fibrinolysis significantly. After the intake of two glasses no significant disturbance of the circadian rhythm was observed. Five hours after the consumption of six glasses of wine, a dramatic increase occurred of PAI-1 antigen (77 +/- 42 microg L-1 vs. - 5 +/- 10 microg L-1 in the mineral water controls; P < 0.001) and PAI-1 activity (27 +/- 15 U mL-1 vs. - 2 +/- 3 U mL-1 in mineral water controls; P < 0.001). Despite a rise in t-PA antigen, t-PA activity dropped (- 0.5 +/- 0.2 U mL-1 vs. - 0.1 +/- 0.2 in controls; P < 0.001) as did PAP complexes (- 103 +/- 55 microg L-1 vs. - 26 +/- 57 microg L-1 in controls; P < 0.01). After the consumption of eight glasses of wine, the clot lysis assay indicated continued inhibition of fibrinolysis the following morning. Drinking a large amount of alcohol in the evening results in an acute inhibition of fibrinolysis, persisting the following morning. This may predispose to accelerated atherosclerosis and set the stage for thrombotic coronary events, explaining the higher cardiovascular mortality risk in binge drinkers.


Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Ritmo Circadiano/efeitos dos fármacos , Doença das Coronárias/etiologia , Fibrinólise/efeitos dos fármacos , Vinho/efeitos adversos , Adulto , Humanos , Masculino
9.
Crit Care Med ; 28(8): 2773-8, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10966249

RESUMO

OBJECTIVES: Critically ill patients often are anemic, which may impair oxygen delivery. Transfusion of red cells and supplementation with vitamins or iron are the usual therapeutic strategies, whereas only sporadic data are available on the use of epoetin alfa in these patients. We investigated endogenous erythropoietin (EPO) production and the response to epoetin alfa in anemic intensive care unit (ICU) patients. DESIGN: Randomized, open trial. SETTING: Multidisciplinary ICU in a single secondary care center. PATIENTS: Thirty-six critically ill patients admitted to the ICU who became anemic (hemoglobin concentration, <11.2 g/dL or <12.1 g/dL in case of cardiac disease) were randomized to one of three study groups. INTERVENTIONS: All patients received folic acid (1 mg) daily. The control group received no additional therapy, the iron group received 20 mg of iron saccharate intravenously (iv) daily for 14 days. The EPO group received iv iron and epoetin alfa (300 IU/kg) subcutaneously on days 1, 3, 5, 7, and 9. MEASUREMENTS AND MAIN RESULTS: Blood and reticulocyte counts were measured daily for 22 days. Serum EPO, C-reactive protein, serum transferrin receptor, and iron variables were measured on days 0, 2, 6, 10, and 21. Blood loss and red cell transfusions were recorded. Serum EPO concentrations were inappropriately low for the degree of anemia at baseline, with no difference between patients with and without renal failure. Exogenous administration of EPO increased EPO concentrations from 23+/-13 to a maximum of 166+/-98 units/L on day 10 (p < .05). Reticulocyte count increased exclusively in the EPO group from 56+/-33 x 10(9)/L to a maximum of 189+/-97 on day 13 (p < .05). Serum transferrin receptor rose only in the EPO group from 3.7+/-1.4 to 8.6+/-3.1 mg/L on day 10 (p < .05) and remained elevated on day 21, indicating an increase in erythropoiesis. Hemoglobin concentration and platelet count remained identical in the three study groups. CONCLUSION: Endogenous EPO concentrations are low in critically ill patients. The bone marrow of these patients is able to respond to exogenous epoetin alfa, as shown by elevated concentrations of reticulocytes and serum transferrin receptors.


Assuntos
Estado Terminal/terapia , Eritropoese/efeitos dos fármacos , Eritropoese/fisiologia , Eritropoetina/uso terapêutico , Ferro/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Eritropoetina/farmacologia , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Proteínas Recombinantes
10.
Med Sci Sports Exerc ; 32(1): 134-42, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10647540

RESUMO

PURPOSE: Studies on the effect of exercise on gastrointestinal (GI) mucosal integrity have been limited to occult-blood tests, which were often nonspecific for human blood. The aim of our study was to investigate more aspects of this integrity. METHODS: We examined the effect of prolonged exercise and carbohydrate (CHO) supplementation on mucosal integrity in 22 male triathletes by measuring fecal lysozyme, alpha1-antitrypsin, and occult-blood loss, which was examined by two tests specific for human blood (Colon-Albumin and Monohaem test). Exercise consisted of two 150-min tests (alternately running, cycling, and running at 70-75% VO2max), either with a 7.0% CHO drink or water (W). Furthermore, GI symptoms during exercise were registered by questionnaire. RESULTS: Three subjects showed human albumin only in the first stool after exercise: twice with W and once with CHO. However, human hemoglobin (Hb) could not be detected in these samples. Four other subjects showed an elevated lysozyme concentration after exercise with CHO but not with W. Elevated alpha1-antitrypsin values were found in three of seven specimens in which either positive albumin tests and/or an elevated lysozyme concentration were demonstrated. Twenty-one subjects (95%) reported one or more GI symptoms during exercise. Incidence rates of different GI symptoms varied from 5 to 68%. Most symptoms were more frequent and lasted longer during running than during cycling but did not differ significantly between supplements and were not related to any mucosal integrity parameter. CONCLUSIONS: GI blood loss during exercise is of no clinical importance, at least in our study design with a group of well-trained male subjects who consumed a relatively high amount of fluid (up to 2.3 L). Nevertheless, an increased alpha1-antitrypsin and lysozyme concentration may indicate a transient local mucosal damage with an inflammatory response.


Assuntos
Hidratação , Mucosa Gástrica/fisiologia , Mucosa Intestinal/fisiologia , Esforço Físico/fisiologia , Adulto , Albuminas/análise , Ciclismo/fisiologia , Dor no Peito/etiologia , Carboidratos da Dieta/administração & dosagem , Eructação/etiologia , Fezes/química , Fezes/enzimologia , Hemoglobinas/análise , Humanos , Masculino , Muramidase/análise , Sangue Oculto , Corrida/fisiologia , Inquéritos e Questionários , Água/administração & dosagem , alfa 1-Antitripsina/análise
11.
Br J Surg ; 85(1): 41-5, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9462381

RESUMO

BACKGROUND: This was a prospective study comparing the effect of major and minor surgery on haematological variables concerning erythropoiesis, iron metabolism and acute-phase response proteins. METHODS: Thirty-one otherwise healthy patients, 15 having major orthopaedic surgery and 16 undergoing minor surgery, were studied. Blood samples were taken before surgery and 1, 4, 10 and 28 days after operation. RESULTS: Haemoglobin concentration was decreased for up to 4 weeks after surgery. Serum erythropoietin concentration and reticulocyte count were raised after major surgery only. Serum iron concentration dropped the day after major (to 23 per cent of its preoperative level) and minor (to 46 per cent of its preoperative level) surgery and remained lower for up to 28 days after major surgery. Serum transferrin concentration and transferrin saturation decreased after both types of surgery while ferritin concentration increased. Serum transferrin receptor concentration increased only 4 weeks after major surgery (P < 0.01). The interleukin 6 peak (day 1) was greater after major than minor surgery, as was the C-reactive protein peak (day 4). CONCLUSION: Both major and minor surgery induce a state of hypoferraemia in the presence of adequate iron stores. The degree of this transient form of 'anaemia of chronic disease' is related to the extent of surgery. Iron supplementation in the first weeks after surgery (if iron stores were normal before operation) is ineffective.


Assuntos
Anemia/etiologia , Eritropoese/fisiologia , Ferro/metabolismo , Complicações Pós-Operatórias/metabolismo , Proteínas de Fase Aguda/metabolismo , Reação de Fase Aguda , Anemia/sangue , Proteína C-Reativa/metabolismo , Feminino , Hemoglobinas/metabolismo , Humanos , Interleucina-6/metabolismo , Masculino , Pessoa de Meia-Idade , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Transferrina/metabolismo
12.
Blood ; 90(12): 4987-95, 1997 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-9389718

RESUMO

We present a novel G1091 to A mutation in the human liver and red blood cell (RBC) pyruvate kinase (PK) gene causing severe hemolytic anemia. In two families, three children were severely PK-deficient compound heterozygotes exhibiting the G1091 to A mutation and a common G1529 to A mutation on the other allele. In one family, the mother, a G1091 to A heterozygote, later had a second baby with a new husband, also a G1091 to A carrier. The baby was homozygous for the G1091 to A mutation and died 6 weeks after birth from severe hemolysis. Both mutant alleles were expressed at the RNA level. The G1091 to A mutation results in the substitution of a conserved glycine by an aspartate in domain A of RBC PK, whereas the G1529 to A mutation leads to the substitution of a conserved arginine residue with glutamine in the C-domain. Molecular modelling of human RBC PK, based on the crystal structure of cat muscle PK, shows that both mutations are located outside the catalytic site at the interface of domains A and C. The mutations are likely to disrupt the critical conformation of the interface by introducing alternative salt bridges. In this way the Gly364 to Asp and Arg510 to Gln substitutions may cause PK deficiency by influencing the allosteric properties of the enzyme.


Assuntos
Anemia Hemolítica Congênita não Esferocítica/genética , Eritrócitos/enzimologia , Modelos Moleculares , Mutação , Piruvato Quinase/química , Sequência de Aminoácidos , Criança , Humanos , Masculino , Dados de Sequência Molecular , Polimorfismo Genético , Piruvato Quinase/genética , Piruvato Quinase/metabolismo
13.
Eur J Clin Chem Clin Biochem ; 34(12): 949-54, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8986398

RESUMO

A single nucleotide substitution and the effect on the phenotype in an Indonesian family with beta-thalassaemia, HbE-trait and HbE-beta-thalassaemia is described. In the proposita (female, age 20 (Hb 7.4 mmol/l; MCV 72 fl; MCH 1.45 fmol; HbA2 3.5%; HbF 2.4%)). An A/G mutation in the RNA cleavage and polyadenylation sequence was detected (AATAAA/AATAGA). Her sister (Hb 8.2 mmol/l; MCV 77 fl; MCH 1.60 fmol; HbA2/HbE 32.4%), carried a different mutation in the beta-globin gene (codon 25; G129/A), and consequently had HbE-trait. Their mother had a haemoglobin concentration of 6.4 mmol/l (MCV 56 fl; MCH 1.20 fmol; HbA2/HbE 55.8%). She was compound heterozygous for the mutation in the poly A-signal and HbE-trait. Using restriction enzyme analysis and linkage studies, we subsequently identified six family members with HbE-beta-thalassaemia, five with beta-thalassaemia and six with HbE-trait. Two individuals were unaffected. The mutation in the polyadenylation sequence causes a mild form of beta (+)-thalassaemia. The MCV and MCH in individuals with both beta-thalassaemia and HbE-trait were significantly lower, yet on average they were only slightly more anaemic than those carrying only the thalassaemic gene.


Assuntos
Globinas/genética , Hemoglobina E/genética , Hemoglobinúria/genética , Adolescente , Adulto , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutagênese , Linhagem
15.
Eur J Clin Invest ; 25(6): 383-9, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7656915

RESUMO

The decrease in haemoglobin concentration commonly observed after major surgery is usually corrected by red cell transfusions or oral iron medication. The increased awareness of blood-transmissible diseases has led to the restrictive use of homologous blood and to interest in alternatives for correcting anaemia. We investigated the pathophysiology of postoperative anaemia by studying variables of erythropoiesis, iron metabolism, and inflammation in 48 consecutive patients who underwent total hip replacement. Haemoglobin concentration remained low during 14 days after surgery with only a mild increase in erythropoietin concentration and reticulocyte count. No increase in serum transferrin receptor concentration was observed during the first 2 weeks after surgery. Postoperative serum ferritin increased, whereas serum iron, transferrin and transferrin saturation decreased significantly. There was a marked increase in interleukin-6 and C-reactive protein with maximal values on the 1st and 4th post-operative day, respectively. At 6 weeks after surgery, haemoglobin concentration and variables of iron metabolism were almost at the preoperative level and serum transferrin receptor concentration was significantly increased, indicating increased erythropoietic activity. These changes were preceded by the normalization of interleukin-6 and C-reactive protein levels. Haemoglobin, iron, transferrin, and ferritin concentrations were not influenced by iron therapy during the postoperative period and no differences of erythropoietic and iron variables were observed between transfused and non-transfused patients. In conclusion, post-operative erythropoiesis is associated with an inflammatory effect of surgery on iron metabolism, which can explain, despite a slightly increased production of erythropoietin, the persistence of anaemia and the lack of effect of iron supplementation after surgery.


Assuntos
Anemia/etiologia , Eritropoese , Inflamação/metabolismo , Ferro/metabolismo , Complicações Pós-Operatórias/etiologia , Idoso , Anemia/terapia , Transfusão de Eritrócitos , Feminino , Humanos , Ferro/administração & dosagem , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/terapia
16.
Br J Haematol ; 90(1): 56-64, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7786796

RESUMO

Hereditary spherocytosis (HS) is a congenital haemolytic anaemia which is characterized by a great variety of structural defects in the red cell's membrane skeleton and/or deficiencies in particular membrane (skeletal) proteins. Enhanced (Mg2+)-dependent adenosine triphosphatase (Mg(2+)-ATPase) activities, varying from 115% to 160%, were invariably found in erythrocyte ghosts derived from 13 HS patients. Similarly, an enhancement of Mg(2+)-ATPase activity by 30% is observed in normal red cell ghosts that have been stripped of the greater part of their membrane skeletal proteins by treatment with a low ionic strength buffer. Reassociation of those stripped ghosts with spectrin reduces the enhanced Mg(2+)-ATPase activity to its original level. Since in both cases, HS ghosts and stripped normal ghosts, the stabilizing effects that the membrane skeleton exerts on the maintenance of an endofacial localization of the aminophospholipids are impaired, the enhanced Mg(2+)-ATPase activity is interpreted to reflect an increased activity of the aminophospholipid translocase. The present observations therefore support a role of the membrane skeleton in the stabilization of phospholipid asymmetry in the red cell membrane and consequently in reducing the energy consumption of the translocase.


Assuntos
ATPase de Ca(2+) e Mg(2+)/sangue , Proteínas de Transporte/sangue , Proteínas do Citoesqueleto , Membrana Eritrocítica/enzimologia , Proteínas de Membrana/sangue , Neuropeptídeos , Proteínas de Transferência de Fosfolipídeos , Esferocitose Hereditária/enzimologia , Actinas/sangue , Adolescente , Adulto , Soluções Tampão , Criança , Pré-Escolar , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Masculino , Proteínas de Membrana/fisiologia , Pessoa de Meia-Idade , Concentração Osmolar , Espectrina/análise
17.
Lancet ; 344(8919): 367-70, 1994 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-7914307

RESUMO

The risk of blood-borne diseases has substantially increased the use of autologous blood transfusion. Many autologous donors, however, still need homologous transfusions. To find out whether recombinant erythropoietin (rhEPO) reduces requirements for homologous blood transfusion, we carried out a randomised, controlled trial, in which patients were stratified according to blood volume. We studied 95 autologous blood donors undergoing elective hip surgery. 50 patients were randomly assigned 500 U/kg rhEPO subcutaneously twice a week for 3 weeks, and 45 patients received no treatment (control group). The patients each donated two units of blood before surgery. Only 5 (10%) rhEPO-treated patients received homologous transfusions compared with 16 (36%) controls (p < 0.01). rhEPO was most useful in patients with a blood volume below 4 L and an estimated blood loss below 2 L or with a blood volume of 4-5 L and blood loss of 1-2 L. Continued administration of rhEPO caused no further increase in reticulocyte counts after the fourth injection, which was accompanied by a pronounced depletion of storage iron. rhEPO treatment had no effect on renal function, platelet count, or blood pressure. Subcutaneous rhEPO is an effective and safe way to reduce exposure to homologous blood in autologous donors. Its use can be restricted to a subpopulation of autologous blood donors, which improves the cost-effectiveness of this expensive approach.


Assuntos
Transfusão de Sangue Autóloga , Procedimentos Cirúrgicos Eletivos , Eritropoetina/uso terapêutico , Idoso , Transfusão de Sangue/estatística & dados numéricos , Transfusão de Sangue Autóloga/estatística & dados numéricos , Volume Sanguíneo , Feminino , Hematócrito , Prótese de Quadril , Humanos , Ferro/sangue , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/uso terapêutico , Contagem de Reticulócitos
18.
J Lab Clin Med ; 124(1): 42-7, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8035101

RESUMO

Treatment with recombinant human erythropoietin (rhEPO) for the anemia of end-stage renal disease has been associated with thrombotic complications. To detect prothrombotic changes in autologous blood donors given 500 U/kg rhEPO subcutaneously (twice weekly during a 3-week period), changes in variables of hemostasis and fibrinolysis and in blood rheology before and at the end of treatment were investigated. In 21 patients, platelet count increased from 272 +/- 55 x 10(9)/L to 313 +/- 55 x 10(9)/L (p < 0.05). Although activated partial thromboplastin time and protein C antigen decreased significantly during rhEPO treatment, these changes remained within normal ranges. No changes in the hemostatic variables prothrombin time, fibrinogen, factor V, von Willebrand factor antigen, antithrombin III activity, protein S antigen, and prothrombin fragments F 1 + 2 were found. Measurements of plasminogen activity, alpha 2-antiplasmin activity, tissue plasminogen activator, and plasminogen activator inhibitor-1, representing variables of fibrinolysis, were normal and constant during the study. In 5 patients no changes in red cell deformability and whole blood viscosity, corrected for differences in hematocrit, were observed. Plasma viscosity showed a slight but clinically not relevant increase in 4 out of 5 patients. The absence of evident (pro)thrombotc changes in this study confirms the safety of high-dose rhEPO therapy in autologous blood donors, who donate 2 units (i.e., 2 x 450 ml) of blood.


Assuntos
Doadores de Sangue , Transfusão de Sangue Autóloga , Viscosidade Sanguínea/efeitos dos fármacos , Eritropoetina/farmacologia , Fibrinólise/efeitos dos fármacos , Hemostasia/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Deformação Eritrocítica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes
19.
Eur J Clin Invest ; 24(6): 426-32, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7957497

RESUMO

The use of recombinant human erythropoietin (rhEPO) to intensify the erythropoietic response in autologous donors may reduce homologous blood requirement. We studied the effect of subcutaneous rhEPO (500 U kg-1 body weight twice weekly during a 3 week period) on variables of erythropoiesis and iron metabolism in 62 autologous blood donors, of whom 32 received rhEPO (epo group) and 30 did not (control group). Patients donated only 2 units of blood and received oral iron in order to restrict phlebotomy-induced decrease of iron stores. Pre-phlebotomy haemoglobin concentration (14.0 +/- 0.8 g dl-1) was completely regenerated in the epo group at surgery (13.7 +/- 1.3 g dl-1); haemoglobin concentration in the control group fell from 13.5 +/- 1.4 g dl-1 to 11.6 +/- 1.4 g dl-1 after the phlebotomies and did not improve during the pre-operative phase. Total erythropoietic activity expressed as serum transferrin receptor concentration (sTfR) showed a 4-fold increase from 3.8 +/- 0.9 micrograms ml-1 to 14.9 +/- 4.8 micrograms ml-1 in the epo group. Effective erythropoietic activity measured by absolute reticulocyte count, however, declined after the fourth rhEPO injection in the epo group. Serum ferritin was lower in the epo group, but no differences in serum iron, transferrin concentration and transferrin saturation were observed between the groups. A marked increase in free erythrocyte protoporphyrin (FEP) was observed in the epo group, whereas FEP levels in the controls remained within normal ranges. Despite oral iron supplementation and the limited number of phlebotomies, the effect of rhEPO therapy in autologous donors is restricted by iron depletion.


Assuntos
Transfusão de Sangue Autóloga , Eritropoese/fisiologia , Eritropoetina/uso terapêutico , Prótese de Quadril , Ferro/sangue , Idoso , Volume Sanguíneo , Eritropoese/efeitos dos fármacos , Eritropoetina/sangue , Feminino , Ferritinas/sangue , Hemoglobinas/análise , Humanos , Masculino , Período Pós-Operatório , Receptores da Transferrina/análise , Proteínas Recombinantes/uso terapêutico , Contagem de Reticulócitos , Fatores de Tempo , Transferrina/análise , Transferrina/metabolismo
20.
Br J Haematol ; 86(1): 30-5, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8011544

RESUMO

A dose-finding study of recombinant human erythropoietin (rhEPO) was performed in 60 autologous donors who donated 2 units of blood prior to orthopaedic or vascular surgery. The correction of phlebotomy-induced anaemia was studied in four groups of 15 patients who received 500 U/kg, 250 U/kg, 125 U/kg or no (controls) rhEPO subcutaneously twice per week during a 3-week period. Haemoglobin concentration in the 500 U/kg, 250 U/kg and 125 U/kg group and in the controls reached respectively 99.2, 98.8, 91.9 and 87.1% of pre-phlebotomy value. Flow cytometric analysis of reticulocytes showed a steady increase of reticulocyte count as the dose increased. Maximal levels of high fluorescence reticulocytes which represent early changes of erythropoiesis were reached after 7 d and decreased thereafter in each group. Serum ferritin decreased significantly to approximately 50% of baseline values in all groups; no differences in the decrease of serum ferritin were observed between the patients who received rhEPO and the controls. No severe adverse events were observed. This study demonstrates a dose-related effect of rhEPO on erythropoiesis in autologous donors during the first 2 weeks. No further increase of reticulocytes was observed despite continued rhEPO therapy, which may be due to the inability of the mononuclear phagocytic system to release additional iron. To restore pre-phlebotomy haemoglobin concentration, a dose of 250 U/kg rhEPO was sufficient.


Assuntos
Anemia/terapia , Transfusão de Sangue Autóloga , Sangria/efeitos adversos , Eritropoetina/administração & dosagem , Idoso , Anemia/sangue , Anemia/etiologia , Estudos de Coortes , Relação Dose-Resposta a Droga , Eritropoetina/sangue , Eritropoetina/uso terapêutico , Feminino , Ferritinas/efeitos dos fármacos , Hemoglobinas/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico , Contagem de Reticulócitos/efeitos dos fármacos
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