Perinatal events and further developmental outcome--assessment of a newborn's individual prognosis. 1. Neonatal period and results of an eight years' follow-up.

The aim of the prospective study described in this paper was to develop a prognostic screening method which permits to give an individual prognostic estimate for every newborn, with an accuracy acceptable for clinical purposes. In the following, the condensed data of the case histories as well as of the clinical and laboratory findings in 47 of initially 60 preterm and term newborns with and without cardiorespiratory distress were analyzed under two different aspects. In the first part, the general statistical relationships are presented in the followed up children, who were classified under various groups according to the clinical course during the first two years of life and to the developmental stage reached at the age of two and six years. It was shown that such a procedure will not suffice in clinical practice for the purpose of individual prognostic estimates. The analysis of the clinical classifications of the six-year-old children in comparison with their school performance at the age of eight years yielded a high accuracy of the previous clinical estimation.

Perinatal events and future developmental outcome--assessment of a newborn's individual prognosis. 2. Prediction of outcome on the basis of perinatological data--results of multivariate discriminant analysis.

The aim of the prospective study described in this paper was to elaborate a prognostic screening method which allows to give an individual prognostic estimate for every newborn, with an accuracy acceptable for clinical purposes. This second part informs about the results of multivariate discriminant analysis, using the data from case histories as well as from the clinical and laboratory findings in the neonates (including "criteria of hypoxia"). According to the kind and number of abnormalities found on the occasion of out-patient consultations during the course of the first two years of life, and according to the developmental status reached at the age of two and six years, the children were classified under two alternative groups. Satisfying results were achieved in the discrimination between the groups of six-year-old children. As compared with the literature, the prognostic method proposed in this paper yields a relatively high accuracy of individual predictions, and therefore promises to become a good tool for clinical practice.

Evaluation of indicators of erythropoiesis stimulated by recombinant human erythropoietin in renal anemia.

Recombinant human erythropoietin (rh-EPO) was administered to 11 anemic children with end-stage renal disease who were undergoing hemodialysis. Hematocrit (Hct), absolute reticulocyte count (retics), creatine concentration of red cells and erythrocyte density test (EDT) were chosen as indicators of rh-EPO effect on erythropoiesis. In the present report the first 9 weeks shall be presented in which all patients received an identical dosage of rh-EPO per kg body weight. The pre-EPO values of retics, creatine and EDT varied considerably. In 10 patients the Hct increased to 0.30 after 9 weeks of rh-EPO treatment. Retics and creatine rose in all cases above the normal range, rates of increase and maximal values differed. Retics, creatine and EDT respond faster to rh-EPO than Hct. Retics and creatine seem to be equally good indicators of rh-EPO stimulated erythropoiesis. The EDT showed an increase only up to the 4th week.

The erythrocyte density test (EDT) and erythrocyte creatine concentration (ECE) as laboratory indexes of perinatal hypoxia.

To study the influence of gestational age and asphyxia on the behaviour of EDT and ECE a group of cuban control and asphyxiated newborns was investigated. A total number of 203 newborns at the age of 0-3 days of life, all with adequate weight for gestational age, were classified into 4 groups according to their gestational age, the 1 min and 5 min Apgar score and the presence of meconium stained amniotic fluid and/or respiratory distress syndrome immediately after birth. In the group of asphyxiated newborns higher values for both parameters were found when they were compared with the respective control groups (p less than 0.05). These techniques could help the neonatologists to more precisely identify newborns with severe perinatal asphyxia and to improve the prognosis of the outcome.

Creatine and density of red blood cells in perinatal hypoxia.

Signs of stimulated erythropoiesis, such as increased creatine and decreased density of red cells are good indicators of hypoxemia in adults and older children. The sensitivity of both tests in perinatal hypoxia was found to be reduced. The causes for this reduction were investigated.

A mathematical model for the cell age-dependent decline of creatine in human cell cells.

A mathematical model is proposed to describe the decline of creatine concentration in red blood cells during the course of cell aging. It is based on experimental data concerning two processes of creatine transport across the red cell membrane: a) an active transport, and b) exchange diffusion. The model corresponds well with data obtained from density-fractionated human red cells in normal steady-state erythropoiesis as well as in acutely and chronically activated erythropoiesis. Degradation of the carrier system for active transport is postulated to be the cause of the time course of decline of the cellular creatine concentration.

[Behavior of creatine in red blood cells and in plasma of children with chronic kidney insufficiency]. / Das Verhalten des Kreatins in roten Blutzellen und im Plasma von Kindern mit chronischer Niereninsuffizienz.

The creatine concentration of red blood cells and plasma in 44 children with chronic renal failure was studied and found to be significantly higher than in healthy children of comparable age. The creatine concentrations of the 31 hemodialyzed children surpassed those of the 13 conservatively treated patients by 30%. A statistically significant correlation was demonstrated between the serum creatinine level and the creatine concentrations in red blood cells. During hemodialysis the plasma creatine concentration decreases by half and reaches the predialysis values within 42 h after the end of dialysis, whereas the creatine concentration of the red cells does not change during a 4-5-h hemodialysis. With increasing number of hemodialyses the creatine concentration of red cells rises, suggesting an improvement of erythropoiesis.

Red cell creatine in term and preterm, adequate and small for gestational age newborns after normal pregnancy or risk conditions. I. Statistical analysis of creatine in various groups of newborns.

The red cell creatine concentration was determined in 174 newborns (cord blood) and in 50 healthy adults. Normal values for term adequate for gestational age newborns without intrauterine and perinatal risk (n = 53) were established to lie significantly above those for adults. Newborns after risk pregnancies had higher mean creatine concentrations than those born after uneventful gestation. Small for gestational age (SGA) infants proved to have the lowest creatine concentration of all newborn groups. The creatine values of our SGA children suggested that not more than 20% of them had chronic intrauterine hypoxia. It is concluded that red cell creatine at birth may serve to characterize in retrospect erythropoietic dynamics in cases of intrauterine growth retardation and intrauterine risk.

Red cell creatine in term and preterm, adequate and small for gestational age newborns after normal pregnancy or risk conditions. II. Mathematical analysis of 12 risk conditions in relation to the creatine level at birth.

Univariate and multivariate analysis of variance and discriminant analysis were performed on newborns with respect to the level of red cell creatine at birth (cord blood) and 12 risk conditions occurring during the last trimester of gestation and birth. 111 of the 174 newborns studied had been at risk. The factor "small for gestational age" (SGA) showed to have a negative coefficient of discriminant function, i.e. it contributes to lower creatine values at birth. Other risks are shown to raise the creatine level. For "adequate for gestational age" (AGA) newborns "Rh-incompatibility", "toxoplasmosis", "premature and/or prolonged rupture of the membranes", "complications of the umbilical cord" and - to a minor degree - "pyelonephritis of the mother", "threatened premature labour", and "toxemia of pregnancy" were shown to be significant risks leading towards high red cell creatine concentrations in cord blood. For the SGA infants "preterm birth", "threatened premature labour", "green amniotic fluid" and "toxemia of pregnancy" were the most important risks relating to high creatine levels of red cells at birth.

A simple method for the approximation of the behaviour of marker constituents in density-fractionated red blood cells by means of normalized cumulative distribution functions.

The present paper proposes a mathematical approach for the approximation of the relation between the concentration (or activity) of a cell constituent and the cumulative red cell distribution after density gradient centrifugation by means of normalized cumulative distribution functions (NCDF). With only one parameter (easily obtained on a programmable pocket calculator) and the mean concentration of the substance in the total red cell population this functional relation can be described in good approximation. The goodness of fit expressed by v2 (= square of correlation coefficient) to the experimentally obtained data is demonstrated for the cell constituents creatine (v2 = 0.85-0.97), RNA (v2 = 0.82-0.87) and G-6PD (v2 = 0.60-0.95). The method of NCDF is shown to be superior to an exponential function. It permits the estimation of a concentration (or activity) of a cell constituent for any chosen density-fractionated cell portion and thus gives information on the ratio of standardized portions of young: old cells.

Red cell creatine in steady state and stimulated erythropoiesis.

Intra- and interindividual variances as well es the age dependency of red cell creatine were studied. Following a single erythropoietic stimulation creatine can stay elevated for many months. A rise of creatine may not only reflect a shift towards a younger cell population but also different erythropoietic sites. The creatine concentration of red blood cells (rbc) has been shown to be an excellent indicator of cell age (1,2,3) and of dynamics of erythropoiesis (3). Intra- and interindividual variances were determined. Fig. 1 (designed according to 4) shows the variance of the method (3)-both for serial determinations and for repeated analyses of the same sample after storing up to 19 days--as well as the variances for the individual person and for a group. It is shown, that the values for one individual are remarkably constant. Fig. 2 illustrates values obtained from presumably healthy persons without evidence of hematological pathology--from newborn to old age. The fat bar represents the values for adults with a mean of 6,64 mg/dl cells and a rather small standard deviation. The mean creatine concentration for very old persons (bar to the utmost right) appears to be higher with a larger standard deviation. However, these values probably should be taken with caution, since some of the persons might have had some minor cardiac or pulmonary difficulty or occult blood loss from the gastrointestinal tract--even though they were declared healthy by the physician of the seniority home. From the age of 6 months on there appears to be no age dependency of rbc creatine concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

[Erythrocyte creatine concentration in infants and children with congenital heart disease and left-to-right shunts (author's transl)]. / Kreatinkonzentration in den roten Blutzellen bei Säuglingen und Kleinkindern mit angeborenen Herzfehlern der Links-Rechts-Shunt-Gruppe.

The creatine concentration of red blood cells was determined in 58 children with congenital acyanotic malformations of the heart at the age of 3 weeks to 3 1/2 years. It was correlated to the severity of the hemodynamic changes, the physical development of the children and number of reticulocytes. The average creatine concentration in the red cells of all patients was 12.8 +/- 4.80 mg/100 ml cells, i.e. twice as high as that of the control group (6.61 +/- 1.19 mg/100 ml cells). Particularly high creatine values were found in children, who died in consequence of their heart disease without previous operation (18.49 +/- 4.25 mg/100 ml cells, n = 11) and those children who had to be operated on as a life-saving measure (17.88 +/- 3.43 mg/100 ml cells, n = 10). The highest creatine concentration was found in a 4 weeks-old infant with hypoplastic left heart syndrome (25.3 mg/100 ml cells). In children with a systolic pressure in the pulmonary artery of greater than 50 torr the creatine concentration was significantly higher than in those with pressures less than 50 torr. Increased creatine values correlated well with the poor physical development and increased reticulocyte numbers of the children. There was no correlation found between capillary pO2 and creatine concentration. It is concluded that the determination of erythrocyte creatine in children with congenital heart disease of the left-right shunt type furnishes additional objective information on the general condition of the organism and its adaptation capacities to hypoxia. It may serve as a valuable diagnostic and prognostic measure.

Separation and characterization of red blood cells from newborns and infants during the first trimenon of life using a dextran density gradient: mean cellular volume and mean cellular haemoglobin concentration.

The adaptation of cell physiological parameters of erythrocytes of the newborn to erythrocytes in later life was studied by cell separation in an isopycnic dextran density gradient. The cell characteristics during the first trimester of life were followed by repeated determinations. The mean cellular haemoglobin concentration of the lightest cells is remarkably less than that of the cells of median density. This is probably due to the ongoing synthesis of haemoglobin in reticulocytes, which are highly concentrated in the top fractions. It was shown that the young cells released from the bone marrow become progressively smaller during this period with a decrease of mean cellular volume (MCV) from 104 micrometer3 at birth to 85 micrometer3 at the end of the first trimester. It has been established that this process commences during the first week of life. No difference concerning the alterations of cell parameters, especially MCV, in premature and mature infants was found. It is therefore probable that these alterations are due to changes in the external milieu following birth.

Criteria of maturity and age of red blood cells.

Any work on red blood cells requires information about the characteristics of a cell population. Using buoyant density separation of red blood cells (RBC) in a dextran medium during a bleeding anemia of rabbits cell-physiological, ribosomal, mitochondrial and cytoplasmic criteria were estimated in order to select parameters useful for the characterization of a given RBC population according to its developmental stages. Useful criteria for an unknown overall RBC population are reticulocyte count and aspartate amino transferase, or glucose-6-phosphate dehydrogenase activity or creatine concentration. Useful additional criteria for reticulocytes are the mean cellular volume and the RNA concentration.

Creatine in density-fractionated red cells, a useful indicator of erythropoietic dynamics and of hypoxia past and present.

Creatine in density-fractionated red cells is not only a useful criterion of cell age but also an excellent indicator of erythropoietic dynamics particularly under the influence of present and past hypoxia. This is documented on patients with cardiac hypoxia. A histogram is proposed which permits the simultaneous evaluation of four parameters: (1) the creatine concentration of each separate fraction, (2) the absolute density of a given cell fraction, (3) the percentage distribution of cells over the whole gradient and within the different fractions and (4) the general position of the red cell population with respect to its median density, which serves to characterize the overall age of a red cell population. Creatine histograms on fractionated red cells are shown to be useful aids for diagnosis and prognosis in hypoxic clinical states. They may also give retrograde information on past stimulation of erythropoiesis.

Creatine transport into red blood cells.

The permeation of creatine from plasma into normal human red blood cells was investigated by means of 1-[14C]-creatine. Two statistically different Vmax and Km values were found for lower and for higher creatine concentrations of the plasma, respectively, indicating two types of transport with different affinities and capacities. It is suggested that the high affinity process, which accounts for 1/4 of the capacity and has an affinity constant of 0.087 +/- 0.032 mM is an active transport, while the low affinity transport represents an exchange diffusion. There is little, if any, effect of pH in the range of 6.9-7.9 on the transport. The total creatine concentration of the red cells did not change significantly even with high creatine concentration of the plasma during 6 h incubation at 37 degrees C. The in vitro experiments showed a daily exchange of cellular creatine of 20%, the t0.5 being about 2.5 days.

[Creatine content in erythrocytes and blood plasma of chickens before and following stimulation of erythropoiesis by anemia]. / Kreatingehalt in Erythrozyten und Blutplasma des Huhns vor und nach Erythropoiese-Stimulation durch Anämie.

The red blood cells of chicken have a lower creatine concentration than those of man (1 mg/100 ml vs 5-6 mg/100 ml cells). No creatine phosphate was found in either erythrocytes or reticulocytes. With anemia produced by phenylhydrazine and bleeding a young cell population appeared with a higher creatine concentration.

[Behavior of creatine in red blood cells and blood plasma of adult rats following exposure to hypoxia]. / Das Verhalten von Kreatin in roten Blutzellen und im Blutplasma bei erwachsenen Ratten nach Hypoxie-Exposition.

Adults rats exposed to hypoxia showed a definite increase of creatine concentration in red cells and plasma. The rise in cell creatine 37 h after the beginning of hypoxia had disappeared 2 days after the end of hypoxia. It is explained by the expulsion of preformed reticulocytes from the bone marrow. The increase of plasma creatine is supposed to be due to hypoxic damage to the muscles, which release creatine into the blood stream.