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Biomedical subjects

J Frenzel

Publications and source records attributed to J Frenzel.

17 recordsLinked to original sources
PubMed1992

[School performance of former premature infants in the first four years of school].

School achievement during the first four grades was analysed by means of subject marks in 203 prematurely born and in 140 maturely born children. In subjects referring to behaviour in the classroom, no statistically significant differences in average marks could be found between prematurely born children and the control group. The average marks in performance subjects were slightly higher in the subgroup of very prematurely born children. However, statistically significant lower marks were observed in the subject of sports only, and for formerly immature children also in the subject of manual training. The higher the educational level of the mothers, the better the average marks without sports. No relationships between school performance and manifestation of postnatal risk factor like Apgar score, blood gas values and duration of oxygen dependency could be seen. These results demonstrate that school performance of former premature infants lies within the normal variance of their grade.

Brain Damage, Chronic↗
PubMed1978

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.

Age Factors↗
PubMed1978

Calorimetric, 13C NMR, and 31P NMR studies on the interaction of some phenothiazine derivatives with dipalmitoyl phosphatidylcholine model membranes.

1. The dipalmitoyl phosphatidylcholine/water system was employed to study the interaction of phenothiazines with model membranes. In particular the effects of the drugs upon the lipid phase transition were examined using differential scanning calorimetry and NMR spectroscopy. The studied phenothiazines have peripheral (diethazine) or central (chlorpromazine) properties. 2. Both drugs were observed to lower the phase transition temperature of dipalmitoyl phosphatidylcholine. The molar activity of chlorpromazine is somewhat higher than of diethazine. At low concentrations the drugs affect the dipalmitoyl phosphatidylcholine pretransition endotherm. 3. In the 13C NMR spectra of the drug-containing samples the signal of the trimethylammonium group of dipalmitoyl phosphatidylcholine is broadened, whereas a narrowing of the signal of the fatty-acid chain methylene groups is observed. Further, addition of the phenothiazines causes higher values of the effective chemical shift anisotropy of the 31P in the phosphate group, in comparison to the pure dipalmitoyl phosphatidylcholine sample. 4. The results obtained by three different techniques indicate a higher fluidity in the fatty-acid chain region and a mobility reduction of the polar headgroup of the dipalmitoyl phosphatidylcholine molecules in the presence of the phenothiazines. These phenomena can be well accounted for by a model for the incorporation of the phenothiazines in the dipalmitoyl phosphatidyl-choline bilayer, in which the dialkylaminoalkyl chains are located near the polar headgroups and the ring system does not penetrate far beyond the glycerol backbone into the hydrocarbon phase.

Calorimetry, Differential Scanning↗
PubMed1977

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.

Antigens↗
PubMed1977

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.

Age Factors↗
PubMed1977

Effect on maturation of kidney function in newborn infants of repeated administration of water and electrolytes.

In newborn infants of various ages, the influence of repeated administration of water and electrolytes on renal excretion of urine, sodium, potassium, free and bound hydrogen ions and on urine osmolarity was studied. In 14- and 21-day-old infants the repeated administration of water and electrolytes was followed by diminution of renal excretion of hydrogen ions and potassium, possibly caused by stimulation of hormonal regulation of ion exchange in the kidney. In animal studies performed with a larger water and electrolyte load, stimulation of renal excretion of sodium was caused by the pretreatment.

Acetates↗
PubMed1975

[Methodological studies on the immunologic determination of proconvertin (factor VII)].

The influence of the different determinations of factor VII activities on the determination of the concentrations of the immunoreactive factor VII in the neutralizing test according to Good-Night were re-examined. The measurement of activity was performed with Seitz filtered cattle plasma as a complex proof of factor VII and X and with a specific artificial deficiency plasma. The examinations had the following results: In the plasma of healthy grown-up people there is a considerable, apparently physiologic range of dispersion of the immunoreactive concentration of factor VII within its normal activity which can be traced irrespective of the used measurements of activity. In plasma samples with a decreased activity of factor VII the values of measurement of the complex evidence will surpass those of the specific determination. The extent of neutralizing the activity in factor VII is not only dependent on the antibody concentration, but will mostly depend on the antibody-antigen relation. The findings obtained prove that the natural deficiency plasma of factor VII used in the original method of Goodnight can be replaced by an artificial substrate plasma.

Adult↗