Biomedical subjects
B Maak
Publications and source records attributed to B Maak.
[Vitamin K for newborn infants: why and how?].
Several publications during the past 10-15 years report on the identification of acarboxyprothrombin (PIVKA II) in a varying proportion of examined newborn and babies (1.9 to 81.5%). These findings prove that the relevant infants were suffering from vitamin K deficiency. Hence, the researchers recommend to continue the prophylactic administration of Vitamin K to newborn. Another argument in favour of vitamin K prophylaxis is supplied by the results of epidemiological studies on the frequency of haemorrhages in newborn and babies caused by vitamin K deficiency. In respect of avoidance of haemorrhages, a single intramuscular injection of vitamin K appears to be the safest mode of application, but repeated peroral administration seems to be practically equally effective. The very frequently performed intramuscular injection of vitamin K is criticised not only because of possible local complications but also because of the greatly enhanced vitamin K concentrations in the blood after the injection. This enhanced concentration is accused of being responsible for the increased risk of malignant tumour growth in those babies who received vitamin K via the i.m. route, compared with the children who had not been given any injection or to whom vitamin K had been administered orally. For this reason vitamin K prophylaxis should be effected in newborn via the oral route (repeated administration), whereas the i.m. route should be an exception. Recommendations to this effect are already on record.
[Maternal deficiency of IgG 2 and IgG 4 and neonatal infection caused by B-streptococci].
We describe here an newborn infant born in the 39th week of gestation with an early onset sepsis caused by group B streptococci. The intravenous administration of antibiotics and immunoglobulin preparation was unable to prevent the fatal outcome. The boy died after 16 hours of life. In the maternal serum a marked deficiency of IgG 2 and IgG 4 could be demonstrated. According to the results from the literature it seems possible that partial immunodeficiencies are important factors in the pathogenesis of the B-streptococcal disease of the newborn.
[Hutchinson-Gilford syndrome].
A case report on a 6-year-old boy suffering from the extremely rare Hutchinson-Gilford syndrome (progeria) is presented. The results of histopathological and immunohistological examination of the scar-like skin lesions are reported. Subcutaneous amorphous nodules were eosinophilic, PAS- und elastica-negative und remained unstained with antibodies against collagen type IV, vimentin, and collagenase. The dense perivascular infiltration consisted of CD4+, CD8-, alpha-1-antichymotrypsin-, MAC 387-, and some vimentin-positive cells. Perinodular blood vessels were more abundant and had a thickened wall. Collagen bundles were swollen. The epidermis appeared atrophic with focal basal cell degeneration.
[Malondialdehyde formation by platelets of hemophiliacs].
The platelets of haemophilic patients produce after stimulation with thrombin (5 NIH-units) a significantly reduced amount of malondialdehyde in comparison to the platelets of healthy children of the same age. There is a positive correlation between the platelet count in citrated whole blood and malondialdehyde production in the group of healthy children, however the same correlation is negative in adults and strongly negative in haemophiliacs. Because of the 24 hour-intervals between the last substitution and investigation in the majority of haemophilic patients, the reduced MDA-production of their platelets seems to be the result of side effects of the administration of plasma fractions. On the other hand, the reduced capacity for the MDA-production of the platelets of haemophiliacs can be explained as the result of the release reaction of platelets after haemostasis activation following bleedings.
[Acquired dysfibrinogenemia in a child in the course of a liver disease].
This report documents the results of coagulation studies in a 15-year old boy with hepatic disease of possibly autoimmune origin. Thrombin- and reptilase clotting times were prolonged. The results of fibrinogen determinations with different methods (heat precipitation, kinetic assay according to Clauss) lead to the assumption of a qualitative anomaly of fibrinogen (dysfibrinogenaemia). Investigations with purified fibrinogens from the patient and a healthy control confirmed this assumption. The thrombin clotting time of purified fibrinogen from the patient was clearly prolonged in comparison to the purified fibrinogen from a healthy control. The fibrin monomers of the patient exhibited impaired polymerization. No structural abnormalities were detected by electrophoretic techniques, particularly the thrombin-induced release of fibrinopeptides was found to be normal. The coagulation abnormalities resolved after glucocorticoid administration.
Hereditary dysfibrinogenaemia (fibrinogen Jena)--report of a family study.
A qualitative abnormality of fibrinogen was found in a boy aged 3 years and 6 months. It was recognized by prolonged prothrombin-, thrombin- and reptilase clotting times. There was also a difference between the results of different fibrinogen assays. The same constellation was identified in additional 7 members of the family belonging to 3 generations. No bleeding or thrombotic symptoms exist. The mode of inheritance of the fibrinogen variant (fibrinogen Jena) seems to be autosomal-dominant.
[Behavior of antithrombin III activity in children with diabetes mellitus].
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[Results of thrombelastographic studies in obese children].
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[Relations between hemostasis parameters and fatty acid composition of serum lipid fractions--results of a study in obese children].
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[Thrombocytopenias and thrombocytopathies in the newborn infant].
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Acceleration of coagulation by spectrin-free erythrocytic vesicles. Evidence for lipid flip-flop during vesicle formation.
Spectrin-free erythrocytic vesicles isolated from outdated liquid-preserved blood samples show a distinct increase of the clot-promoting activity compared with membrane phospholipid equivalents of intact erythrocytes. We suppose that, among other remodelling processes, local spectrin detachment from the inner membrane surface may trigger a flip-flop-mediated disturbance of the membrane lipid asymmetry. The interactions of spectrin with the cytoplasmic membrane surface seem to be essential for the structural membrane integrity including the lipid asymmetry.
[Factor VIII activity and factor VIII-associated antigen in healthy newborns and in newborns with stressing perinatal factors].
Factor VIII coagulation activity (VIII:C) and factor VIII associated antigen (VIII:AGN) were determined in healthy newborns and in children with charging perinatal factors ("risk children"). VIII:C values of healthy newborns may be compared with those of grown-ups with normal coagulation. Risk children have somewhat higher values than newborns, the difference, however, being statistically not significant. The concentration of VIII:AGN is clearly increased in both groups on the first day of life. Moreover, VIII:AGN is being eliminated more slowly in risk children. The increased VIII:AGN concentrations are considered as a sequel of stress conditions caused by birth, whereas the discrepancy between VIII:C and VIII:AGN is due to a thrombin effect.
[Consumption coagulopathies in childhood].
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[Thrombocytes during the neonatal period].
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Factor VIII activity and factor VIII related antigen in newborns.
Factor VIII procoagulant activity and factor VIII related antigen were examined in 20 full-term and preterm newborn infants during the first days of life. The control group involved 15 adults volunteers. Factor VIII activity was estimated by a one-stage test and factor VIII related antigen was determined by immunelectrophoresis according to Laurell, using our own rabbit antiserum. The following results were obtained:--Factor VIII activity during the first 3 days of life did not differ from the normal range of the adult controls.--The concentration of factor VIII related antigen in newborns was markedly higher than in adults on the first, and to a lesser extent on the second, day of life.--The antigen concentration decreases on the second and following days of life to adult levels. The cause of this discrepancy cannot be completely explained but possible reasons are discussed.
Antibody neutralizing material of factor VII during the first weeks of life.
In a study on 66 newborns and infants, factor VII activity and factor VII related antigen were investigated on 110 occasions. A normal range was calculated by testing plasma from 12 healthy male volunteers at various dilutions. Most of the values in the newborns and infants fell within this range but 18.2% of the factor VII proteins showed a significantly different specific activity.
The influence of perinatal risk factors on the incidence of atypical coagulation factor VII during the first days of life.
The correlation between the appearance of functionally-atypical factor VII and perinatal complications was investigated in 66 newborn infants. The presence of an abnormal clotting factor was assumed if the ratio between clotting activity and antigen-related factor VII material exceeded the normal range for adult plasma. The newborns were divided into a risk group of infants threatened by adverse conditions of labour or post-natal adaptation, and a control group of newborns without perinatal complications. The findings were as follows: The incidence of atypical factor VII was significantly higher in the risk group. There was no difference between prenatal and postnatal complications in this respect. Infants born by caesarian section or with cord complications, as well as those with delayed respiratory adaptation, showed a higher incidence of atypical factor VII than the risk group as a whole. Atypical factor VII was not detected until the third day of life, irrespective of the prenatal or postnatal complications. These findings suggest that perinatal risk factors are associated with an alteration of factor VII synthesis.