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Biomedical subjects

J J Veltkamp

Publications and source records attributed to J J Veltkamp.

At least 19 recordsLinked to original sources
PubMed1985

The functional defect of factor VIII Leiden, a genetic variant of coagulation factor VIII.

Factor VIII Leiden is a genetic variant of coagulation factor VIII which has been detected in the plasma of a patient with mild haemophilia A. In this patient's plasma factor VIII procoagulant antigen was in 5-fold excess over factor VIII procoagulant activity, indicating the presence of an abnormal factor VIII molecule. The variant factor VIII was isolated from the patient's plasma, and its functional properties were studied in a factor X-activating system consisting of purified components. The isolated factor VIII Leiden was normally activated by factor Xa and by thrombin, but the activity of the factor VIIIa was about 3% of normal. The defect of factor VIIIa Leiden was studied by comparison with normal factor VIIIa in kinetic experiments of factor Xa formation. The results support the hypothesis that factor VIIIa Leiden has a reduced affinity for phospholipid-bound factor IXa in the intrinsic factor X-activating complex.

Calcium↗
PubMed1985

Carrier detection of haemophilia B by using an intragenic restriction-fragment length polymorphism.

We analysed DNA from individuals of five families with haemophilia B, including nineteen potential carriers. A gene-specific probe was used to reveal a TaqI restriction-fragment length polymorphism. Segregation analysis of the polymorphic marker and the deleterious mutation within families allowed diagnosis at the gene level for 16 out of the 19 potential carriers, two proving to be carriers and 14 non-carriers. The obvious advantage is that lyonisation, which is a limiting factor when gene product (clotting factor IX) measurements are used for carrier detection, does not interfere with this procedure and that the result is a definitive diagnosis instead of a risk estimate. The method also permits prenatal diagnosis on chorionic villi in the first trimester of pregnancy. Restriction-fragment length analysis, based upon the probe and restriction enzyme used in this study, will be informative for approximately 45% of the individuals at risk of carrying or transmitting the haemophilia B mutation.

DNA Restriction Enzymes↗
PubMed1985

Intermediate and high-dose ARA-C and m-AMSA (or daunorubicin) as remission and consolidation treatment for patients with relapsed acute leukaemia and lymphoblastic non-Hodgkin lymphoma.

27 patients (aged 15-55 years) with relapsed acute myelogenous (AML) and lymphoblastic leukaemia (ALL), and with lymphoblastic non Hodgkin's lymphoma (NHL) have been treated with intermediate dose cytosine arabinoside (AraC, 1 g/m2 q 12 h X 12) and 3 d of m-AMSA (20 patients), 90-115 mg/m2 daily, or daunorubicin (7 patients). 18 of them attained a complete remission (AML 10/14, ALL 3/5, NHL 5/8). 7 patients received consolidation treatment with 1-2 courses comprising 4 d of AraC (3 g/m2 q 12 h X 8) and m-AMSA (90-115 mg/m2) on d 5 of each course. 2 patients underwent allogeneic bone marrow transplantation and 9 received no further treatment after remission induction. In addition to vomiting, fever and conjunctivitis, toxicity in 6 patients included a combination of severe diarrhoea, fever and signs of paralytic ileus. 3 of them died during the pancytopenic phase. The pancytopenic period ranged from 16-25 d (median 21 d) after the remission induction and 14-21 d (median 19 d) after the consolidation course. Median remission duration was 5 months for those patients who received no treatment after remission induction and greater than 9 months (4+ - 16+ months) for the patients who received consolidation courses. Increased dosages of AraC are active in relapsed leukaemia and lymphoma, although optimal dose and schedule are still undetermined.

Adolescent↗
PubMed1985

Coagulation factors in the premature infant born after about 32 weeks of gestation.

In plasma samples from 10 premature infants born after about 32 weeks of gestation, a number of coagulation factors have been determined. For 9 infants, who were healthy, mean values are given: fibrinogen-antigen, 311 mg/dl; factor II, +/- 0.46 U/ml; factor V, 0.80 U/ml; factor VII, 0.59 U/ml; factor VIII coagulant activity, 0.93 U/ml; factor VIII-related antigen, 1.66 U/ml; procoagulant factor VIII antigen, 1.15 U/ml; factor IX coagulant activity, 0.41 U/ml; factor IX antigen, 0.42 U/ml; factor X coagulant activity, 0.52 U/ml; factor X antigen, 0.61 U/ml, and antithrombin III-antigen (AT-III), 0.43 U/ml. In 5 infants a second sample was taken a week after the first one; for most values there was no significant rise, except for factor II and AT-III. The values we found in this group of premature infants are within the range of those reported in earlier literature. They are higher than the ones we found in early fetal samples and most of them are similar to those we found in early fetal samples and most of them are similar to those we found in the cord blood of full-term newborns.

Blood Coagulation Factors↗
PubMed1983

Congenital protein C deficiency and venous thromboembolism. A study of three Dutch families.

Protein C is the zymogen of a vitamin K-dependent serine protease involved in blood coagulation. In the absence of protein C the inactivation of activated factors V and VIIIC is impaired, and the fibrinolytic capacity of the circulating blood is reduced. These conditions promote excessive fibrin formation and thus constitute a risk factor for thrombosis. Using an immunologic assay for protein C, we identified 18 patients (11 male and 7 female) in three unrelated Dutch families as fulfilling the criteria for an isolated protein C deficiency. In 12 patients who were not receiving oral anticoagulant treatment the mean protein C antigen concentration was 0.48 +/- 0.09 U per milliliter (+/- S.D.), and in 6 patients who were receiving adjusted doses of oral anticoagulants and had stable anticoagulation, the mean value was 0.17 +/- 0.05 U per milliliter. (The value in healthy subjects is 0.98 +/- 0.19 U per milliliter.) Fourteen of the 18 patients had a history of venous thromboembolism, with superficial thrombophlebitis as the hallmark of this condition (in 13 patients). These data are consistent with an autosomal dominant trait with variable expressivity.

Adolescent↗
PubMed1983

Hemostasis and intracranial surgery.

Preoperative and postoperative coagulation studies were performed in 25 patients undergoing various intracranial surgical procedures. Coagulation abnormalities, mostly consisting of an increase of fibrin/fibrinogen degradation product concentration, either appeared or increased postoperatively in 18 patients. This incidence of postoperative appearance or increase of coagulation abnormalities is higher than that reported in a comparable study of patients after general surgical procedures, and also higher than that of coagulation abnormalities in a previous study of patients after blunt head injury. Although the coagulation abnormalities after intracranial surgery were usually small, they tended to be larger in patients with more extensive intracranial procedures.

Adolescent↗
PubMed1982

Heterogeneity of haemophilia A: a study with three different antisera.

One human and one rabbit antibody against VIII:C--in a fluid-phase, inhibitor neutralization assay (INA)--and one human antibody--in a solid-phase, immunoradiometric assay (IRMA)--were used to investigate a group of 59 patients with severe, moderate and mild haemophilia A. Patients were classified as haemophilia A+ when the VIII:C/VIIIAG ratio was less than 0.4 while the absolute VIII:C antigen (VIIICAG) value exceeded 0.25 u/ml. Three haemophiliacs (from two pedigrees) were classified as A+ in all three assay systems. 50% of the patients were classified as haemophilia A+ on the basis of at least one assay. The other 50%, including 66% of the patients with severe haemophilia, were shown to be A- by all three assay systems. Combining the data obtained with the three different antibodies four different categories could be distinguished, in addition to the classification based on severity.

Antigens↗
PubMed1982

Combined hereditary deficiency of the sixth component of complement and factor VIII coagulant activity in a Dutch family.

Prompted by previous observations of defective blood clotting in rabbits deficient in the sixth component of complement (C6), and the discovery of a patient with both C6 and factor VIII deficiency, an evaluation was made of the haemostatic functions in this individual and his family members. The family contained three members homozygous for C6 deficiency (C6D); two of them were deficient also in factor VIII. In addition, one other member of the family was only deficient in factor VIII. The only C6D member without haemophilia A had a normal recalcification time without clinical symptoms of a bleeding disorder. Reconstitution of factor VIII and C6 deficient plasma from the various members of the family in this study with purified human C6 did not result in a change in the recalcification time. The results obtained from this study also indicate that there is no linkage between the inheritance of C6 and factor VIII.

Adult↗
PubMed1981

Hemostasis and computerized tomography in head injury. Their relationship to clinical features.

Coagulation studies (plasma fibrinogen, ethanol gelation test, and fibrin-fibrinogen degradation product concentration) and computerized tomography (CT) scan examinations were performed in 55 patients with blunt head injury. The frequency of abnormalities in both coagulation study results and CT scans was higher in patients with severe clinical features and clinical course than in less severely injured patients; in these same patients the coagulation results were abnormal (64%) more frequently than the CT scans (40%). Very high fibrin-fibrinogen degradation product (FDP) concentrations were found to be associated with combined hemorrhagic lesions and mass effect on CT scans, but not with a specific localization of brain-tissue damage. It was concluded that: 1) FDP concentration reflects the amount of brain-tissue damage rather than its location, and 2) in the absence of other possible causes of disseminated intravascular coagulation, coagulation studies may be more sensitive than CT scanning in demonstrating brain contusion.

Adolescent↗
PubMed1981

Bartter's syndrome: an autosomal recessive disorder? Study of four patients in one generation of the same pedigree and their relatives.

The diagnosis of Bartter's syndrome was established in four patients of one generation of the same pedigree. The proband affected with Bartter's syndrome appeared to have a brother and two first cousins, who are siblings, with the same condition. All four patients had hypokalemia, hyperreninemia, normal blood pressure and a diminished pressor sensitivity to angiotensin II. In contrast to most cases of Bartter's syndrome, the urinary excretion of prostaglandin (PG) E2 was not elevated. The parents and the siblings of the patients were studied in order to detect asymptomatic carriers of the disorder. Abnormal serum potassium levels, plasma renin activities, urinary PG excretions and pressor responses to angiotensin infusion were not found in these relatives. Although consanguinity could not be established between the parents of any of the couples, the distribution of the disorder in the two related families confirms the hypothesis that genetic factors play an important role in Bartter's syndrome and that it is inherited as an autosomal recessive trait.

Adult↗
PubMed1980

Immunoradiometric assay of procoagulant factor VIII antigen (VIIICAG).

An immunoradiometric assay of procoagulant factor VIII antigen was developed using a human antibody to the procoagulant activity of factor VIII (VIII:C). The assay measures specifically the antigen related to factor VIII procoagulant activity (VIIICAG) both in plasma and in serum. VIII:C and VIIICAG were measured in a group of healthy individuals and in a group of haemophilia A patients. In haemophilia A at least four groups can be recognised on the basis of the presence or absence of VIII:C and VIIICAG and the VIII:C/VIIICAG ratio.

Adult↗