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Biomedical subjects

G Weissbach

Publications and source records attributed to G Weissbach.

At least 37 records · Page 2Linked to original sources

Diagnostics of septicaemia in childhood by coagulation parameters.

The diagnostic importance of coagulation parameters was tested in 438 children with septicaemia by discriminant analysis. The values of 756 patients with other diseases had been analysed for comparison. After the selection of the parameters by multivariate analyses discriminant functions were calculated for different subgroups. The best discriminant functions were found for septic newborns up to the age of 3 days. Their use may be helpful for diagnostics in practice. A more weak discrimination power was evident in newborns beyond the 3rd day of life. A simultaneous comparison of 7 subgroups of newborns with different illnesses by 3 discriminant functions led to lower sensitivity rate and don't suit for practice. Beyond the postnatal period the diagnostic importance of coagulation parameters for septicemia is even lower. The low reparation capacity of thrombopoiesis in neonates may be a cause for the good discriminant functions for septicaemia. The reason for the better discrimination in the newborns up to the 3rd day could be the more profound defects in the coagulation system.

Blood Coagulation Tests↗

Diagnosis and differentiation of von Willebrand's disease type II.

Out of 113 patients with vWD 15 were of type II. The basic test programme included F VIII:C, vWF-Ag, RCF and BT (Ivy). All type II patients had relatively high vWF-Ag and low RCF values. CIEP proved increased anodal migration velocity. IRMA testing of vWF:Ag was showing narrow correlation with RCF. Thrombocyte count was unchanged after DDAVP infusion and RIPA was always diminished. Finally multimeric sizing was done in 6 patients. From the completely diagnosed patients 5 are of type IIA and one seems to have type IIC. Nobody of the 15 had the characteristics of type IIB.

Antigens↗

Plasma fibronectin concentrations in healthy and septic infants.

The concentration of plasma fibronectin was determined by Laurell's electroimmunoassay in 75 preterm or term newborns within the first 2 days of life, in 97 healthy infants aged from 3 days to 12 months, in 40 septic infants and in 38 healthy adult subjects. The mean fibronectin concentration in citrated plasma of normal adults was 318 +/- 84 ml/l. Healthy eutrophic term newborns 1-2 days old had approximately one-third of the fibronectin concentration of adults. There was no significant difference in the values between healthy term and eutrophic preterm newborns or between eutrophic and hypotrophic newborns. The plasma fibronectin increased strongly over the 1st month of life. No significant difference was observed between fibronectin levels in infant boys and girls. The values in septic newborns and septic older infants were significantly lower when compared with those of age-matched healthy controls. It is speculated that this deficiency, because of linkage to fibrin in disseminated intravascular coagulation or due to increased utilisation as a nonspecific opsonin and sequestration at sites of tissue injury, may contribute to organ failure in septicaemia.

Adult↗

[Iliopsoas hemorrhage in hemophilic children].

Sixty-nine children with hemophilia were treated in our center between 1968 and 1983. About 1 per cent of hemorrhagic complications were bleedings localized in the iliopsoas muscle of 12 patients ranging in age from 9 to 15 years. The typical sign of the bleeding is a tight, palpable tumour above the inguinal fold. Today mass bleedings of the muscle with retroperitoneal localization are diagnosed safely by help of computer tomography or sonography. Psoas muscle bleedings in children are characterized by a high recurrence rate (41.5%) and often by an associated damage of the femoral nerve. Surgery was necessary only in 1 patient where a huge psoas hematoma with cystic transformations had to be removed. High substitution doses led to a complete recovery within 3 weeks in all other children.

Adolescent↗

[Effect on hemostasis and thrombogenesis by septic processes especially in childhood].

In 284 children with sepsis coagulation analyses were carried out. In sepsis in the postnatal period number of thrombocytes, plasminogen, antithrombin III, alpha 2-macroglobulin and factor V were initially decreased on an average, but fibrinogen, alpha 2-antiplasmin, the factors II and X as well as the trypsin inhibitor capacity were increased. The initially on an average reduced parameters often still considerably decreased, in order to increase after this to the norm of age within one to two weeks. The thrombocytopenia longest persists, often to the third week. The components initially found increased on an average in most cases rapidly increase and beyond the norm of age. They behave as acute phase proteins. In sepsis beyond the neonatal period the quality of the acute phase protein is in numerous components still more distinct than in the postnatal period. Several parameters also showed a completely other dynamics: the thrombocytopenia is of lesser size and shorter duration and is very often changed by a thrombocytosis. Here alpha 2-macroglobulin also has the quality of an acute phase protein. From the dynamics observed is concluded that disseminated intravascular coagulation processes frequently accompany the initial phase of the sepsis. They cause an eminent over-production of coagulation components which is limited by their production capacity and partly compensates the defects. The diversity of the constellation is explained by different sizes of consumption and compensation. The parameters in their dynamics have diagnostic valency. As far as the difference from fibrinogen level and number of thrombocytes is concerned it could already proved by simple means.

Bacterial Infections↗

[Elimination of inhibitors in children with hemophilia A].

In five hemophilic children an attempt was made to eradicate inhibitors by continuous treatment with low doses of cryoprecipitate. All patients were high responders with maximum titers of 25 and 600 U. In four patients the anamnestic response was prevented or diminished by simultaneous treatment with cyclophosphamide. In these patients the inhibitor did not return during the continuous replacement therapy, even not after cessation of cyclophosphamide administration and in three of them not after intensive substitution. In the other child the titer decreased continuously in the beginning, but only to values unsuitable for replacement effects. Attempts to exterminate the inhibitor should be occasionally made by continuous low dose substitution therapy. The importance of the combination with cyclophosphamide cannot be decided until now because of the small number of observations.

Child↗

[Heparin and antiheparin in childhood. 3. Heparin level measurements and their importance in heparin monitoring].

Measurements of the heparin level were made under continuous anticoagulation in a total of 7 patients. For the purpose of monitoring heparin the coagulation time values were determined parallelly. Except a patient with a sepsis and a 7 days old newborn baby the desired prolongation for the partial thromboplastin time and the reaction time of thrombelastogram resulted from heparin titres lying within the range of 0.2-0.7 U/ml of plasma. Even after applying depot preparations there was a relatively good correspondance of heparin level curves and coagulation parameters. In childhood the partial thromboplastin time is primarily suitable for monitoring the heparin therapy. Heparin half-life times calculated during the transumbilical exchange transfusion in 7 children amounted to values ranging between 40-110 minutes. In addition to checking low dose heparinizing, measurements of the level are suitable for deriving dosage standards for neutralizing heparin effects by protamine sulfate.

Adolescent↗

[Alpha 2-antiplasmin in childhood].

In 119 children, predominantly newborns and babies with sepsis, alpha 2-Antiplasmin was determined by the use of the chromogenic substrate S-2251. In healthy newborns, the inhibitor level averaged 65 per cent of the adult level. Already in the initial phase of sepsis, enhanced alpha 2-antiplasmin values were observed. During the further course, they increased markedly. Thus, alpha 2-antiplasmin proved to be an acute phase reactant together with fibrinogen, factors II and X, and alpha 1-antitrypsin measured as trypsin inhibitor capacity. The correlation analysis in all subgroups showed moderately tight binding to fibrin. In patients with shock or in those who decreased, lower levels were measured. The overproduction is assumed to be caused by disseminated intravascular coagulation processes. In other diseases such as respiratory distress, alpha 2-antiplasmin was reduced. In case of disseminated intravascular coagulation that was not caused by sepsis consumption of components dominated. In the probability paper, distribution of the values of the subgroups was found to differ markedly. Thus, the inhibitor proved to be of diagnostic value.

Blood Coagulation Factors↗

[Heparin and antiheparin in childhood. 2. Clinical relevance of the phenomenon of heparin resistance].

Investigations of the content of platelet factor 4 in different thrombocyte lysates and platelet-rich plasma after induced release reaction were aimed at checking the efficiency of the own antiheparin measuring system. In this connection, the age dependent dynamics of platelet factor 4 could be first discovered. In platelet-poor plasma of healthy grown-up test persons there was an evidence of antiheparin titres which were five times higher as compared with those persons born maturely. All patients with disseminated intravascular coagulation processes of different aetiology, however, will have significantly increased values. As demonstrated in two children with hyperpyretic toxicosis, the liberated platelet factor 4 will only show a short plasma half decay period. From investigations made for refinding heparin in the plasma after in vitro addition the conclusion can be drawn that, in addition to platelet factor 4, even unspecific adhesions of heparin to certain plasma proteins may be responsible for increasing heparin resistance.

Adolescent↗

[Heparin and antiheparin in young children. 1. Report: development of a method for determining heparin and antiheparin in the antithrombin-thrombin system].

A new method of determining the biological activity of heparin and antiheparin is described. The principle is based on measuring the coagulation time in the antithrombin-thrombin system. By using a partially purified antithrombin III preparation and after coagulating the plasma samples with small amounts of thrombin the measuring system proves to be mostly independent on the inhibitory content of the test plasmas to be investigated. Heat defibrinated plasma cannot be used because it has essential properties with a close affinity to heparin. Additions of sodium and calcium ions will make the system more sensitive. Criteria of reaction kinetics are used for standardizing the antithrombin-thrombin system. The heparin level of up to 0.01 U/ml and the antiheparin titre of up to 0.005 U/ml can be covered by the procedure presented. Thus, it has a high sensitivity. The quality controls which were performed give evidence of the high precision of this method.

Antithrombin III↗

[Genetic questions of hemophilia].

Haemophilia A and B are X-chromosomally recessively inherited. In the GDR the frequency of these genuine haemophilias is 1 to 6,500 male births. The frequency of sporadic haemophilias is still in dispute and certainly depends on the intensity of genealogic examinations. The mutation rate for haemophilia A is estimated to 1.3 to 3.6 x 10(-5). In secure female conductors the lyonisation evokes a considerable dispersion of the factor VIII coagulation activity, wherefore this is able to prove also only a small proportion, about 20-50%. The lyonisation apparently takes place in a critical anlage of less than 32 cells. Bleeding female conductors are in the first place the sequel of extreme lyonisation, more infrequently homozygotes or such ones with anomalies of the X-chromosomes. The state of female conductors is best characterized by th discrepancy between decreased factor VIII coagulation activity and the normal factor VIII associated antigen. At present numerous variants of this female conductor test are used, particularly concerning its calculatory evaluation. In many places only quotients from the two parameters are formed. Discriminancy-analytical methods brings without doubt better results. They allow to coordinate a certain probability to each result, which with the help of genealogic criteria may be combined to an evidence. Immunochemical determinations of the factor IX are certainly not of value for the proof of the state of female conductors of haemophilia B. The prenatal diagnostics of sex is recommended for pregnant conductors by amniocentesis in the 14th week of pregnancy. Only in few countries the prenatal diagnostics of haemophilia is possible. In blood tests taken by means of fetoscopy beginning with the 18th week of pregnancy the factor VIII coagulation property is determined by immunoradiometrical methods or recently even by means of a coagulation method. Though for the genetic consultation only female conductors in the reproductive phase are of importance, for the search of female conductors the whole lineage must be worked up genealogically, at least over four generations and with the help of archives material. The genetic consultation of haemophils and female conductors should be performed early and directedly, for important reasons also repeatedly.

Amniocentesis↗

[Hemostasis disorders after transfusions].

Disturbances of haemostasis caused immunologically and non-immunologically were observed after transfusion of blood and blood derivatives. Transfusion of heparin blood increased the bleeding susceptibility only in case of pre-existing high-degree defects of haemostasis or if they were performed as massive or exchange transfusions. Massive transfusions with blood stored for a long time will induce complex defects. Under intensive substitution therapy of haemophilia A the so-called paradoxical bleeding will occur in spite of a high factor VIII level. These bleedings are supposed to be disturbances of the thrombocyte function and are caused by fibrin(ogen) derivatives. Post-transfusional thrombocytopenias may be brought to remission by repeated plasmapheresis. Factor specific inhibitory bodies will appear after substitution in a small percentage of haemophilic patients. 5 to 7 days after the onset of therapy an anamnestic reaction can be observed as a titre increase by leaps. Usually, the inhibitory titre will decrease to a mostly low basal value in the course of three to five months. The therapy with cyclophosphamide simultaneously started with the substitution will more frequently prevent the anamnestic reaction or reduce it. Titres with more than 5 units cannot be overcome at the beginning even by higher concentrations of preparations. The substitution therapy should be preceded by exchange transfusions or plasmapheresis of up to 25 units. With still higher titres only procedures of inhibitor-bypassing are possible with factor VIII preparations of animal origin or better with activated prothrombin complex preparations, such as FEIBA. Recent reports give evidence that permanent substitution with factor VIII concentrates at a highest dosage can eliminate the production of inhibitors completely.

Blood Coagulation Disorders↗