J. Kutschera

Alpha 2-macroglobulin enhances prothrombin activation and thrombin potential by inhibiting the anticoagulant protein C/protein S system in cord and adult plasma.

Protein S (PS) is a vitamin K-dependent plasma protein and serves as a cofactor for the anticoagulant activities of activated protein C (APC). We investigated the effects of different PS concentrations on prothrombin activation and thrombin generation in cord and adult plasma containing APC and different amounts of alpha 2-macroglobulin (a2-M). Prothrombin activation was assessed by monitoring the time-course of prothrombin fragment 1+2 (F1+2) generation. Thrombin generation curves were determined by means of a subsampling technique using the chromogenic substrate S-2238. We demonstrate a dose-dependent inhibition of the anticoagulant action of PS by a2-M: suppression of F1+2 and thrombin generation due to addition of PS was stronger in plasma containing low amounts of a2-M than in plasma with elevated a2-M levels. Since no complex formation between a2-M and PS was observed by means of SDS-PAGE, we attribute decreased anticoagulant action of PS at high a2-M levels to enhanced complex formation between APC and a2-M. Thereby, APC is subtracted from its cofactor PS, resulting in suppressed formation of the anticoagulant APC/PS complex. Thus, our data suggest that a2-M, besides its well-known anticoagulant effects, also acts as a procoagulant by suppressing the formation of the anticoagulant APC/PS complex. Our findings have implications particularly on thrombin generation and inhibition in cord plasma, since a2-M levels in newborns are elevated over adult values and the antithrombotic APC/PS pathway is up-regulated at birth. Therefore, elevated levels of a2-M might restrict the up-regulation of the APC/PS pathway.

Absent or reversed end-diastolic blood flow in the umbilical artery and abnormal Doppler cerebroplacental ratio--cognitive, neurological and somatic development at 3 to 6 years.

UNLABELLED The objective of this study was to examine the cognitive, neurological and somatic developments of children who had in utero an absent or reversed end-diastolic blood flow (ARED) in the umbilical artery or an abnormal cerebroplacental ratio (ABF). METHODS 16 children with ARED blood flow and 15 children with ABF were each matched to children with the same gestational age, appropriate for gestational age, the same sex and born within 4 months. Data were assessed at the age of 3-6 years. Children with asphyxia, neonatal infection, malformation or major surgical interventions in the neonatal period were excluded. Each child underwent a neuropediatrical examination; furthermore, a Kaufman Assessment Battery for Children, a Snijders-Oomen Intelligence Scale for Children and a Man-Drawing Test were used to evaluate cognitive development. The socioeconomic status was also assessed. RESULTS Children in the ARED group remained lighter and had a higher frequency of microcephaly. In the Kaufman Assessment Battery for Children and the Snijders-Oomen Intelligence Scale for Young Children, cognitive development was impaired in the ARED and the ABF groups compared to the control group. The ARED and the ABF groups, however, showed no differences. The Man-Drawing Test and the Denver Development Test did not show any differences. DISCUSSION ARED blood flow and ABF showed impaired cognitive development. The degree of impairment was the same in the ARED and the ABF groups. Long-term follow-up studies until adulthood are necessary to see if impaired cognitive development remains significant in these groups of patients.

Bladder voiding in sleeping infants is consistently accompanied by a cortical arousal

The aim of the study was to find out whether bladder voiding in healthy sleeping infants was accompanied by any arousal reaction. Polygraphic recordings were performed in 21 healthy infants (11 female) born at term. The infants’ age at study entry was 42 ± 4 days and actual body weight was 4852 ± 689 g (mean ± SD). Bladder voiding was recorded by an adapted enuresis detector which was connected to the polygraphic computer unit. Arousals were defined as suggested by the ‘International Paediatric Work Group on Arousals’. Awakenings were excluded from the study. Bladder voiding was recorded at a mean time of 68 ± 7 min after the infant had fallen asleep and occurred during quiet sleep (QS). Electroencephalogram frequency (P < 0.01) and heart rate (P < 0.05) were higher during the 5‐s period before and after bladder voiding when compared with a 30‐s interval before voiding. Furthermore, bladder voiding was accompanied by body movements in all infants. Respiratory frequency did not change significantly. We could demonstrate for the first time in sleeping infants, that bladder voiding during QS was accompanied by a cortical arousal.

Peripheral oxygenation in term neonates

The aim of this study was to analyse changes in peripheral oxygenation in healthy term neonates within the first week of life with near-infrared spectroscopy and venous occlusion. Oxygen delivery did not change with increasing age. Oxygen consumption and fractional oxygen extraction increased, whereas tissue oxygenation index decreased with increasing age.

Protein S modulates the anticoagulant action of recombinant human activated protein C: a comparison between neonates and adults

Recombinant human‐activated protein C (rhAPC, Drotrecogin alpha (activated), Xigris™) has been shown to reduce organ damage and decrease mortality in severe sepsis. Since protein S (PS) serves as a potentiating cofactor of activated protein C and since PS levels are low in neonatal plasma, we hypothesized that the anticoagulant effect of rhAPC would be decreased in cord plasma compared to adult plasma. We demonstrate that the anticoagulant action of 0.3 μg ml−1 rhAPC (5 nmol l−1) was decreased in cord plasma compared to adult plasma, and dose dependently increased in cord plasma in the presence of increasing activities of PS. Correspondingly, the anticoagulant action of rhAPC decreased in adult plasma in the presence of decreasing activities of PS. The low anticoagulant action of rhAPC in cord compared to adult plasma is attributable to low neonatal levels of PS, and as previously shown, to low neonatal levels of TFPI and AT. Our laboratory experiments do not allow definite conclusions for clinical situations. However, we speculate that the anticoagulant efficacy of rhAPC is impaired in neonates and in clinical situations associated with consumption and/or inhibition of PS, AT, and TFPI, such as severe sepsis.

Collagen/endogenous thrombin-induced platelet aggregation in cord versus adult whole blood.

Background: In previous studies, neonatal platelets have been shown to be hypoaggregable to various agonists when compared with adult platelets. Objectives: It was the aim of this study to investigate the aggregability of neonatal versus adult platelets when the physiological relevant agonist collagen/endogenous thrombin is used. Methods and Results: Whole blood (WB) aggregation experiments employing the impedance method revealed the same responsiveness of neonatal and adult platelets to collagen/endogenous thrombin. Maximum aggregation (13.5 ± 3.2 vs. 13.6 ± 3.2 Ω; p = 0.94), slope (5.8 ± 1.8 vs. 6.2 ± 2.6 Ω/min; p = 0.79) and lag time until the onset of platelet aggregation (38.7 ± 8.9 vs. 42.6 ± 16.5 s; p = 0.59) were similar in cord and adult WB. However, the rise in serotonin plasma levels due to platelet activation was significantly lower in neonates versus adults (227.57 ± 57.65 vs. 473.34 ± 155.75 ng/ml; p = 0.0001). Furthermore, we found a fast capability of cord plasma to generate (the efficient platelet agonist) endogenous thrombin: thrombin generation started significantly earlier in cord compared with adult plasma (215 ± 19 vs. 247 ± 21 s; p = 0.01). Moreover, thrombelastometry revealed significantly shorter coagulation times in cord versus adult WB activated with collagen/endogenous thrombin (229.8 ± 12.5 vs. 256.3 ± 25.3 s; p = 0.003). Conclusions: The efficient platelet aggregation in cord WB provoked by collagen/endogenous thrombin might help to explain the clinically observed well-functioning primary hemostasis of neonates.

Minor neurological dysfunction, cognitive development and somatic development at the age of 3 to 11 years in very‐low‐birthweight infants with transient periventricular echodensities

Aim: To determine, using strict exclusion criteria, whether transient periventricular echodensities (TPE) in very‐low‐birthweight infants lead to minor neurological dysfunction and problems in cognitive and somatic development in children without major neurological impairments. Methods: 23 children with TPE were matched to 23 children without TPE. Exclusion criteria were small for gestational age, microcephaly at birth, diplegia, asphyxia, psychomotor retardation, intraventricular haemorrhage grade III/IV, major surgical interventions and malformations. The Kaufman Assessment Battery for Children, Draw‐a‐Man Test and neuropaediatric examination were used for evaluation. Results: There were no differences in demographic data, growth and socio‐economic status. Significant differences with lower results in the TPE group were found in fine motor skills and in the Draw‐a‐Man Test. In the Kaufman Assessment Battery for Children, all subscales were below average in the TPE group, except the sequential processing scale. In the control group, all subscales were within the average range.

Collagen/endogenous thrombin-induced platelet aggregation in whole blood samples.

The aim of the study was to investigate the individual and combined effects of collagen (3.5 μg/ml) and endogenously generated thrombin (due to addition of 0.35 pmol/l tissue factor) on platelet aggregation in the physiological environment of whole blood by means of the impedance method. Lag times were significantly shorter when a combination of collagen and endogenous thrombin was used to provoke platelet aggregation (41.9 ± 16.3 s) compared with collagen (173.8 ± 52.1 s, P < 0.0001) or endogenous thrombin (94.3 ± 43.6 s, P < 0.001). Amplitudes and slopes were the lowest in collagen-induced experiments (2.83 ± 1.59 Ω and 1.79 ± 0.45 Ω/min, respectively), whereas they were approximately the same in endogenous thrombin-induced experiments whether collagen was present or not (13.7 ± 3.1 versus 11.2 ± 4.0 Ω and 6.3 ± 2.8 versus 5.6 ± 2.3 Ω/min, respectively). No synergistic effect of collagen and endogenous thrombin on the clot formation process was observed by means of thrombelastometry. Moreover, thrombin potentials in tissue factor-activated plasma samples were approximately the same whether collagen was present or not (834 ± 67 versus 809 ± 63 nmol/l.min). In conclusion, endogenously generated thrombin is a potent platelet agonist in whole blood, and a combination of collagen and endogenous thrombin synergistically shortens the lag time until the onset of platelet aggregation.

Clot strength: a comparison between cord and adult blood by means of thrombelastometry.

Objective To evaluate the clot strength in cord versus adult blood. Method Thrombelastometry (TEM) was the method of choice as it provides information on the clot strength in terms of the maximum clot firmness (MCF) and on the fibrin polymerization process in terms of the clot formation time and the α angle. Results The MCFs were significantly lower in cord versus adult platelet rich plasma (PRP, 63.0±3.8 vs. 67.0±3.9 mm, P=0.006) and in cord versus adult whole blood (WB, 55.3±3.8 vs. 59.3±3.6 mm, P=0.001) employing the thrombelastometry with extrinsic activator assay. We suggest that the diminished clot strength in cord versus adult blood and plasma samples is attributable to an impaired polymerization of neonatal fibrin: (i) the thrombelastometry with extrinsic activator and inactivated platelets (FIBTEM) assay revealed significantly lower MCFs in cord versus adult PRP (23.0±3.1 mm vs. 27.3±3.9 mm, P=0.002) and in cord versus adult WB (11.6±2.3 mm vs. 15.3±3.3 mm, P<0.001); (ii) the α angle in the FIBTEM assay was significantly lower in cord versus adult WB (39.0±12.8 degrees vs. 55.5±12.3 degrees, P=0.02); (iii) the clot formation times in the FIBTEM assay were significantly longer in cord versus adult PRP (248.0±143.5 s vs. 81.5±39.8 s, P=0.001). Conclusions Neonatal fibrin shows impaired polymerization properties under our experimental conditions resulting in reduced clot strength compared with fibrin of adult origin.

Akupunkturpunkte am Ohr bei Neugeborenen mit Neonatalem Abstinenzsyndrom (NAS) aufgrund mütterlicher Substitutionstherapie

BACKGROUND This is a prospective observational study performed at a university teaching hospital. The aim of the study was to determine the presence and absence of acupuncture ear points in neonates with neonatal abstinence syndrome (NAS). PATIENTS AND METHOD The patients are neonates with neonatal abstinence syndrome. The examination took place on the third day (mean value: 72.3 h) after delivery and was performed by a neuronal pen (PS 3 Silberbauer, Vienna, Austria). A integrated optical and sound signal detects the ear points that were assigned to the ear map. RESULTS We investigate 5 neonates (3 males, 2 females, mean gestational age: 37+3, mean birth weight: 2,655 g). All investigated neonates showed the presence of active ear acupuncture points. The psychovegetative rim was the most common point in 100% of the children. In all neonates we found the presence of psychic ear points. The detectable psychic ear points are frustration point, R point and the psychotropic field nasal from the incisura intertragica. CONCLUSION Ear points are detectable in neonates with NAS and do not depend on the side of the ear lobe. The most important point is the psychovegetative rim and, in all neonates with NAS, psychic ear points were detectable. So for the first time it is possible to identify psychic ear acupuncture points in neonates. In the future it could be possible to use active ear points in neonates for diagnostic and therapeutic options.