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Biomedical subjects

I Pabinger

Publications and source records attributed to I Pabinger.

105 records · Page 6Linked to original sources

1-Deamino-8-D-arginine vasopressin in the treatment of non-haemophilic patients with acquired factor VIII inhibitor.

1-Deamino-8-D-arginine vasopressin (DDAVP) was administered to 3 patients with spontaneous factor VIII inhibitors. In 2 patients with baseline factor VIII levels above 1%, a marked increase of factor VIII activity after DDAVP infusion could be observed. No rise of factor VIII activity after DDAVP was seen in the 3rd patient with a baseline factor VIII level of less than 1%. Daily infusion of DDAVP resulted in a reduction of the efficacy, but the full effect could be retained when DDAVP was given at 48-hour intervals. The effect of DDAVP infusion on factor VIII levels in the 2 responding patients was superior to the treatment with 30 U/kg factor VIII concentrate and approximately equivalent to infusion of 45 U/kg factor VIII concentrate. DDAVP may be a useful and less expensive treatment for patients with acquired factor VIII inhibitors and a baseline factor VIII level of more than 1%.

Aged↗

Evidence for an increased generation of prostacyclin in the microvasculature and an impairment of the platelet alpha-granule release in chronic renal failure.

The formation of prostacyclin (PGI2) and thromboxane A2 and the release of beta-thromboglobulin (beta-TG) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the microvasculature made to determine bleeding time, was studied in patients with end-stage chronic renal failure undergoing regular haemodialysis and in normal subjects. In the uraemic patients, levels of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were 1.3-fold to 6.3-fold higher than the corresponding values in the control subjects indicating an increased PGI2 formation in chronic uraemia. Formation of thromboxane B2 (TxB2) at the site of plug formation in vivo and during whole blood clotting in vitro was similar in the uraemic subjects and in the normals excluding a major defect in platelet prostaglandin metabolism in chronic renal failure. Significantly smaller amounts of beta-TG were found in blood obtained from the site of vascular injury as well as after in vitro blood clotting in patients with chronic renal failure indicating an impairment of the alpha-granule release in chronic uraemia. We therefore conclude that the haemorrhagic diathesis commonly seen in patients with chronic renal failure is--at least partially--due to an acquired defect of the platelet alpha-granule release and an increased generation of PGI2 in the microvasculature.

6-Ketoprostaglandin F1 alpha↗

[Home treatment in hemophilia].

88 patients with severe haemophilia (66 with haemophilia A without inhibitor, 12 with haemophilia A and inhibitor, 10 with haemophilia B) currently receive comprehensive care at the Vienna haemophilia centre. Data available at the centre and a questionnaire answered by the hemophiliacs were used in order to evaluate the current situation of home care. At present, 62 (70%) out of 88 patients receive home treatment (51 with haemophilia A without inhibitor, 5 patients with haemophilia A and inhibitor and 6 with haemophilia B). For treatment of joint and muscle bleeding mean dosages of 15.3 units/kg body weight of factor VIII concentrate, 17.0 units/kg of factor IX concentrate and 30 units/kg of FEIBA were administered by the hemophiliacs. Children and young patients required higher doses (30 and 17.4 units/kg F VIII, respectively). Two thirds of the bleeding episodes were successfully treated by a single infusion. No severe side effects were observed during home treatment. Home treatment has been widely accepted by the patients. It is regarded as a practical and safe therapy and has improved the life quality of haemophiliac patients.

Adolescent↗

[Oral anticoagulant therapy--renaissance of an old therapy?].

Although the antithrombotic potential of oral anticoagulants is undisputed, bleeding complications constitute a serious problem. One of the main causes for these complications has been a lack of standardization of the prothrombin time. The introduction of the International Normalized Ratio (INR) has led to a better standardization of prothrombin time. Thus, the same level of anticoagulation can be reached using different reagents and therefore over- and undercoagulation can be avoided. Furthermore, the benefit/risk ratio can be improved by adapting the intensity of anticoagulation to the indication. The following clinical conditions are established indications for treatment with oral anticoagulants: Prevention of cardiac emboli in acute anterior myocardial infarction with atrial thrombus, in patients with atrial fibrillation with or without mitral valve disease, in patients with prosthetic heart valves and in patients with dilated cardiomyopathy. Furthermore, oral anticoagulants should be given to patients after femoropopliteal bypass. A relatively mild oral anticoagulant treatment (INR 2-3) is sufficient to prevent recurrences of venous thrombosis and pulmonary emboli. The duration of treatment in patients with venous thromboembolism depends on some clinical features and the results of clotting tests which indicate an increased tendency to thrombosis.

Administration, Oral↗

Incidence of inhibitors in patients with severe and moderate hemophilia A treated with factor VIII concentrates.

Recent data published on the prevalence of inhibitors to factor VIII in hemophiliacs on treatment show great variations, with prevalence rates ranging from 3.6 to 14.2%. We have studied the cumulative risk of inhibitor development in a cohort of 62 patients with hemophilia A. All patients were born after 1960, were natives of the Vienna area, had a factor VIII activity of less than 5%, and were treated at least once. Using the method of Cutler and Ederer, the cumulative risk of inhibitor development was found to be 24% at the age of 25 years. Most inhibitors developed between the ages of 3 and 7 years. The current prevalence of F VIII inhibitors in the group of patients studied is 17.5%. It is concluded that prevalence data underestimate the true risk of inhibitor development.

Adult↗

Trisomy 14 in refractory anemia with excess of blasts in transformation.

Trisomy 14 was demonstrated on four occasions over a 2-year period in the bone marrow cells of a 63-year-old patient with refractory anemia with excess of blasts in transformation (RAEB-t). Trisomy 14 as the sole karyotype abnormality has been documented in only six malignancies, namely, in two cases of acute leukemias, one Philadelphia-negative chronic myeloid leukemia, one pancytopenia, and in two colonic polyps. In hematologic neoplasms, this rare primary change preferentially occurs in elderly adults and seems exclusively associated with the myeloid cell lineage.

Anemia, Refractory, with Excess of Blasts↗

Coumarin induced acral skin necrosis associated with hereditary protein C deficiency.

Hemorrhagic skin necrosis of the toes was observed in a patient with heterozygous protein C deficiency (protein C:Ag 32% and protein C activity 30%) on the 4th day of coumarin treatment overlapping with effective intravenous anticoagulation with heparin. Family studies revealed protein C deficiency in two sisters of the proposita without a history of thromboembolic disease. Immunologic studies in the proposita at the time of coumarin necrosis revealed slight depression of complement factor C4 and the presence of immune complexes. The present case and review of the literature show that the pathogenetic mechanism leading to coumarin necrosis in patients with protein C deficiency seems not yet to be fully understood.

Adult↗

Clinical relevance of protein C.

Protein C is, after activation by thrombin, a potent inhibitor of blood coagulation. An isolated deficiency of protein C increases the risk of thrombosis. The two forms of protein C deficiency, the heterozygous and the homozygous deficiency state, have different clinical features. Patients with heterozygous protein C deficiency are at a high risk to develop venous thrombosis and pulmonary embolism. In newborns with homozygous protein C deficiency with very low protein C levels (1%) a purpura fulminans like syndrome was observed. Heparin and coumarin derivatives are effective drugs in heterozygous protein C deficiency, homozygous patients may be treated either by replacement of protein C or coumarin derivatives. Decreased protein C levels were observed in various other diseases: Chronic and acute liver disease, disseminated intravascular coagulation, malignancy, postoperatively and during treatment with asparaginase. The role of protein C in these diseases to trigger thrombosis is not yet established.

Animals↗

Erythrocytes as carriers for heparin. Preliminary in vitro and animal studies.

Encapsulation of heparin into resealed carrier erythrocytes may be useful in the prevention of thromboembolism because heparin may be released locally during retraction of fresh thrombi. Heparin encapsulation in human and canine erythrocytes was achieved by hypo-osmotic dialysis with 44% and 36% encapsulation, respectively. Encapsulated heparin did not leak from carrier erythrocytes in vitro. In vivo survival of heparin-loaded carrier erythrocytes in dogs was biphasic: After an initial phase of cell loss the carrier cells survived in circulation with a half-life of 28 h. The present results seem to warrant clinical studies with heparin-loaded carrier erythrocytes.

Animals↗

The prevalence of hereditary antithrombin-III deficiency in patients with a history of venous thromboembolism.

Antithrombin-III activity was determined in 752 patients with a history of venous thrombosis and/or pulmonary embolism. 54 patients (7.18%) had an antithrombin-III activity below the normal range. Among these were 13 patients (1.73%) with proven hereditary deficiency. 14 patients were judged to have probable hereditary antithrombin-III deficiency, because they had a positive family history, but antithrombin-III deficiency could not be verified in other members of the family. In the 27 remaining patients (most of them with only slight deficiency) hereditary antithrombin-III deficiency was unlikely. The prevalence of hereditary antithrombin-III deficiency was higher in patients with recurrent venous thrombosis.

Antithrombin III Deficiency↗

Prevention of arterial and pulmonary embolism by oral anticoagulants in patients with dilated cardiomyopathy.

The incidence of arterial embolism (AE) and pulmonary embolism (PE) during treatment with oral anticoagulants (OA) or without OA therapy was studied in 38 patients with dilated cardiomyopathy (DCMP). AE/PE occurred in 17 patients (44.7%) before initiation of OA treatment. The severity of DCMP was a risk factor for AE/PE, but not the presence of atrial fibrillation or intracardial thrombi. No AE/PE episodes occurred during the period of OA therapy. No major bleeding complications were seen, probably due to the moderate intensity of OA therapy (therapeutic range 5-15% Thrombotest [TT], 2.1-4.8 International Normalized Ratio [INR], median TT value 11%, median INR 2.6). Recurrence of AE was observed in 4 of 5 patients in whom treatment with OA had been discontinued.

4-Hydroxycoumarins↗

Deficiency of fibrinogen and factor VII following treatment of severe aplastic anaemia with anti-thymocyte globulin and high-dose methylprednisolone.

In 4 patients with SAA treated with ATG and high-dose MP, an as yet unrecognized acquired deficiency of fibrinogen and factor VII was observed. The plasma level of fibrinogen fell to 39% (34-51%) and of factor VII:C to 50% (31-55%) of the pretreatment value. The nadirs were between days 10 and 35 (fibrinogen) and d 3 and 11 (factor VII) after the 1st dose of ATG/MP. From additional clotting studies it is concluded that disseminated intravascular coagulation, fibrinolysis, liver cell damage and synthesis of abnormal clotting factors are unlikely causes of these clotting abnormalities. The most probable explanation seems to be a selective inhibition of the synthesis of fibrinogen and factor VII by an as yet unknown mechanism. These clotting abnormalities might, to some extent, increase the bleeding tendency in these patients, which up to now had been solely attributed to thrombocytopenia.

Adult↗

Four year follow-up of the Duromedics Edwards bileaflet valve prostheses.

The Duromedics Edwards (DE) bileaflet valve prosthesis was withdrawn from the market after 12 leaflet escapes had been reported in 20,000 implants. Effort is necessary to identify the failure mode to improve valve design or production, but the rate of other valve related complications will tell if it is worthwhile reintroducing this prosthesis. Five-hundred and sixty-four DE valves have been implanted in 508 patients between September 1983 and May 1988. Two-hundred and sixty-eight had aortic valve replacement (AVR), 183 mitral valve replacement (MVR) and 56 double valve replacement (DVR); the perioperative mortality was 6.9%. Follow-up has been 98.7% complete for a total of 1064 patient years and a mean follow-up of 26 months (range 3 to 54 months). Late mortality was 3.7%/yr and actuarial survival was 85 +/- 3% without and 78 +/- 3% including operative mortality after 54 months. Event free actuarial rates (linearized rates in parenthesis) were 93 +/- 2% (1.5%/yr) for thromboembolism, 91.7 +/- 1.9% (2.3%/yr) for anticoagulant related hemorrhage, 89 +/- 4.8% (2.3%/yr) for valve failure, 93 +/- 2% (1.8%/yr) for valve related mortality, 72 +/- 4.8% (6.3%/yr) for all valve related morbidity and mortality and 83 +/- 4.4% (3%/yr) for treatment failure. Two leaflet escapes occurred in the study group (0.18%/yr), both patients survived reoperation. The concept of reducing thrombus formation by a specially designed irrigating hinge mechanism was proven by a low rate of thromboembolism in our clinical follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗