PubMed Health⌕ Search

Biomedical subjects

J Sonntag

Publications and source records attributed to J Sonntag.

At least 19 recordsLinked to original sources
PubMed2001

Capillary leak syndrome in children who undergo cardiopulmonary bypass: clinical outcome in comparison with complement activation and C1 inhibitor.

OBJECTIVES: Capillary leak syndrome (CLS) is associated with significantly increased morbidity and occurs after cardiopulmonary bypass in children with congenital heart disease. We investigated the early clinical parameters that predict the development of CLS and examined the relationship between the presence of CLS and complement and contact activation and C1 esterase inhibitor (C1-INH) during and after bypass. DESIGN: In this prospective study we took serial serological measurements of the complement and contact system and C1-INH in a cohort of 27 infants before, during, and up to 96 h after open-heart surgery. RESULTS: Complement and contact activation and a decrease in C1-INH were measured in all infants during and after CPB. Ten infants developed CLS postoperatively. Younger age and longer bypass time were strongly correlated to the development of CLS. No relationship was found between the degree of hypothermia, weight, gender, or cross-clamp time. C1-INH concentration and activity were lower peri- and postoperatively in the CLS group. Infants with CLS had a more pronounced postoperative increase in the C5a and C3a levels, higher postoperative level of factor XIIa, and lower prekallikrein activity than those without CLS. CONCLUSION: Contact and complement activation occurs during cardiopulmonary bypass and contributes to CLS more frequently in infants of a younger age and with a prolonged bypass time. This activation and decrease in C1-INH was strongly expressed in the CLS group, and therefore early substitution of C1-INH may prevent CLS after open-heart surgery in high-risk infants.

Capillary Leak Syndrome↗
PubMed2001

In-vitro activation of complement system by lactic acidosis in newborn and adults.

INTRODUCTION: Complement activation occurs secondary to a variety of external stimuli. Lactic acidosis has been previously shown to activate the complement factors C3a and C5a. In the present investigation we examined the differential effect of lactic acidosis on anaphylatoxin levels in cord and adult blood. Furthermore we aimed to determine if the entire complement cascade could be activated by lactic acidosis. METHODS: Cord and adult blood samples (n = 20 each) were collected and incubated for one hour in either untreated condition or with the addition of lactate in two concentrations (5.5 mmol/l vs. 22 mmol/l). Following incubation, levels of C3a, C5a and sC5b-9, and blood gas parameters were determined. RESULTS: Anaphylatoxin (C3a and C5a) and sC5b-9 levels increased with the addition of lactate in a dose-dependent manner in cord and adult blood (C3a: 1 h, 5.5 mmo/l, 22 mmol/l: 418/498/622 microg/l in cord blood; 1010/1056/1381 microg/l in adult blood, p<0,05; similar results were found for C5a and sC5b-9). CONCLUSION: Lactic acidosis leads to an activation of the entire complement system in neonates and in adults. This activation is dose-dependent and more pronounced in adults as compared to neonates.

Acidosis, Lactic↗
PubMed2000

Mass Balance of the Greenland Ice Sheet at High Elevations.

Comparison of ice discharge from higher elevation areas of the entire Greenland Ice Sheet with total snow accumulation gives estimates of ice thickening rates over the past few decades. On average, the region has been in balance, but with thickening of 21 centimeters per year in the southwest and thinning of 30 centimeters per year in the southeast. The north of the ice sheet shows less variability, with average thickening of 2 centimeters per year in the northeast and thinning of about 5 centimeters per year in the northwest. These results agree well with those from repeated altimeter surveys, except in the extreme south, where we find substantially higher rates of both thickening and thinning.

Journal Article↗
PubMed2000

Greenland Ice Sheet: High-Elevation Balance and Peripheral Thinning.

Aircraft laser-altimeter surveys over northern Greenland in 1994 and 1999 have been coupled with previously reported data from southern Greenland to analyze the recent mass-balance of the Greenland Ice Sheet. Above 2000 meters elevation, the ice sheet is in balance on average but has some regions of local thickening or thinning. Thinning predominates at lower elevations, with rates exceeding 1 meter per year close to the coast. Interpolation of our results between flight lines indicates a net loss of about 51 cubic kilometers of ice per year from the entire ice sheet, sufficient to raise sea level by 0.13 millimeter per year-approximately 7% of the observed rise.

Journal Article↗
PubMed2000

Changing practices of red blood cell transfusions in infants with birth weights less than 1000 g.

OBJECTIVE: Extremely low birth weight (ELBW) infants frequently undergo transfusion because they are critically ill, often need artificial ventilation, and have the highest blood sampling loss in relation to their weight. During the last decade our transfusion guidelines were changed 3 times to become more restrictive. We hypothesized that these modifications substantially decreased the number of transfusions in our ELBW infants. METHODS: We performed a single-center analysis of 256 infants with birth weights from 500 to 999 g who were admitted from 1989 to 1997 and included 3 study periods, each starting with newly modified transfusion guidelines in April 1989, September 1991, and January 1995. We evaluated prospectively recorded clinical data and retrospective chart analysis for transfusion-related information. RESULTS: The median number of transfusions per infant decreased from 7 in the first period to 2 in the third period, whereas donor exposure decreased from 5 to 1 and blood volume transfused decreased from 131 to 37 mL/kg birth weight (P <.01). The median venous hematocrit measured before transfusion decreased from 43% to 35% in infants who underwent ventilation and from 41% to 31% in spontaneously breathing infants. The median birth weight decreased from 870 to 740 g and the median gestational age from 27 to 25 completed weeks (P <.01). The overall survival rate was 75% and did not change. The incidences of retinopathy, intraventricular hemorrhage, and patent ductus arteriosus remained unchanged. CONCLUSION: Over this 9-year period with increasingly restrictive transfusion guidelines, the transfusion number decreased by 71% and the donor exposure by 80% in ELBW infants without adverse clinical effects.

Blood Donors↗
PubMed2000

Growth and neurodevelopmental outcome of very low birthweight infants with necrotizing enterocolitis.

UNLABELLED: The aim of the study was to assess the effect of necrotizing enterocolitis (NEC) on neurodevelopmental outcome and growth. Neurodevelopmental outcome of 20 out of 22 suriviving very low birthweight infants (VLBW) diagnosed with NEC between 1992 and 1996 was compared with 40 control infants matched for gestational age and year of admission. Follow-up studies were performed at 12 and 20 mo of corrected age. The German revision of the Griffiths' scales was used for development assessment. Neurodevelopment was significantly delayed in infants with NEC at 12 mo (median general developmental quotient: 90.0 vs 97.8; p = 0.04) and 20 mo (86.4 vs 97.7; p = 0.004) of age. Somatic growth did not differ between infants with and without NEC. Fifty-five percent of infants suffering from NEC but only 22.5% of the infants without NEC were severely retarded (developmental quotient < -2 SD of a control group of healthy newborns) at 20 mo of corrected age. CONCLUSION: Preterm infants developing NEC are at risk for neurodevelopmental impairment and need close neurodevelopmental follow-up for the first years of life.

Developmental Disabilities↗
PubMed2000

Endotracheal surfactant atomization: an alternative to bolus instillation?

OBJECTIVE: To investigate the effect of an intratracheal surfactant fog on oxygenation, blood pressure, distribution, and recovery rate as a pilot study to intratracheal surfactant aerosol. DESIGN: Prospective, randomized study. SETTING: University laboratory. SUBJECTS: A total of 15 New Zealand White rabbits. INTERVENTIONS: The anesthetized ventilated rabbits were surfactant-deprived by repeated lung lavages and then received 200 mg/kg of a 99mTc-labeled porcine surfactant (Curosurf) either as bolus or as intratracheal surfactant fog. MEASUREMENTS AND MAIN RESULTS: Blood gases and pressure were measured and distribution as well as recovery rate of the surfactant determined by means of the radio label (gamma camera images and lung processing with subsequent gamma counter measurements). Respiratory function normalized immediately, no difference could be found between the two groups with regard to PaO2, PaCO2, and blood pressure. Even distribution of the radiolabel was found with both methods, the bolus group showing a higher percentage of lung pieces with label concentrations of double average or more. Recovery rates were 82.5%+/-13.1% (mean +/- SD) in the bolus group and 86.5%+/-7.7% in the fog group. CONCLUSION: Endotracheal surfactant fog application is as effective as bolus instillation and may have a role in the treatment of adult respiratory distress syndrome. It has to be considered as a first step in producing an effective aerosol.

Aerosols↗
PubMed1999

Rapid thinning of parts of the southern greenland ice sheet

Aircraft laser-altimeter surveys over southern Greenland in 1993 and 1998 show three areas of thickening by more than 10 centimeters per year in the southern part of the region and large areas of thinning, particularly in the east. Above 2000 meters elevation the ice sheet is in balance but thinning predominates at lower elevations, with rates exceeding 1 meter per year on east coast outlet glaciers. These high thinning rates occur at different latitudes and at elevations up to 1500 meters, which suggests that they are caused by increased rates of creep thinning rather than by excessive melting. Taken as a whole, the surveyed region is in negative balance.

Journal Article↗
PubMed1999

Thrombopoietin concentration in umbilical cord blood of healthy term newborns is higher than in adult controls.

Thrombopoietin (TPO) concentrations were determined in umbilical cord plasma of 121 healthy term newborns. The lower detection limit of the enzyme immunoassay employed was 32.5 pg/ml. Median cord plasma TPO concentration was 78 (interquartile range 55-107) pg/ml. 95th percentile was 255 pg/ml. In only 8% (10/121), TPO was below the detection limit compared to 81% of healthy adults (25/31). In cord blood and adult controls, there were no significant correlations of TPO with platelet count or mass.

Adult↗
PubMed1999

Effect of C1-inhibitor in a rat model of necrotizing enterocolitis.

Our aim was to investigate the effect of C1-inhibitor (C1-INH) in a rat model of necrotizing enterocolitis (NEC). Twenty-four anesthetized and artificially ventilated rats received 0.1 mg/kg endotoxin. Fifteen minutes later, the animals in the study group (n = 12) were treated with 200 IU/kg C1-INH whereas the control animals (n = 12) received normal saline. In all animals, FiO(2) was reduced after 90 min from 0.21 to 0.05 and ventilation continued until 180 min or death. All animals developed shock symptoms. Drop in mean arterial blood pressure was more pronounced and survival time was shorter in the control group. Whereas the C1-INH activity increased in the study group, it decreased in the control group. The extent of macroscopic intestinal lesions did not differ between the groups. In conclusion, C1-INH did not prevent shock, but mitigated and delayed its course.

Animals↗
PubMed1999

Complement and contact activation related to surfactant response in respiratory distress syndrome.

The activation of inflammation and coagulation cascades is part of the pathogenesis of adult respiratory distress syndrome (RDS). Previous studies have demonstrated contact activation in preterm infants with RDS, whereas no concordant results have been found with complement activation. In this study, both systems were investigated in preterm infants with severe RDS and related to surfactant response. Thirty preterm newborns with severe respiratory distress (FiO2 > 0.5), but with no evidence of infection or fetal acidosis, were studied. Eighteen healthy preterm newborns of similar gestational age and birth weight served as controls. The study group was divided into two subgroups, according to their response to a porcine natural surfactant 6 h after administration: responders (FiO2 reduction > 50%) and poor responders (FiO2 reduction < or = 50%). C1q, C4, factor B, C3a, C5a, complement, and C1-inhibitor activity, as well as factor XIIa, were determined in blood samples, drawn 24 h after birth. Except for C1-inhibitor concentration and C1-inhibitor activity, all parameters for infants with severe RDS were different from controls. Complement precursor proteins were lower, and activated split products of the complement and contact system were higher. Infants with a poor response after application of surfactant showed higher amounts of C3a, C5a, and factor XIIa but lower C1q and C4 levels compared with infants with a good response to surfactant. Activation of the complement and the contact system was demonstrated in all respiratory distress patients. This activation was more pronounced in poor responders to exogenous surfactant.

Complement Activation↗
PubMed1998

Complement and contact activation during cardiovascular operations in infants.

BACKGROUND: By comparing the results of cardiac operations with or without cardiopulmonary bypass (CPB) in infants in a prospective study, we sought to determine which part of the postoperative systemic inflammatory response was caused by CPB. METHODS: Thirty-five patients were divided into two groups: 11 infants operated on without CPB and 24 infants operated on with CPB. Blood samples were drawn before, during, and after the operation. We assessed complement function and the concentrations or activities of C1q, C3, C4, C1 inhibitor, factor B, the activated split product C3a, and prekallikrein and factor XIIa of the contact system. RESULTS: All of the patients exhibited a decrease of complement proteins. This was greater in infants who underwent CPB. A increase in C3a and factor XIIa and changes in prekallikrein activity occurred only in infants during CPB. CONCLUSIONS: Complement activation occurs in all infants, but is significantly higher in the group with CPB. Contact activation only occurs in patients who undergo CPB. Thus, the inflammatory response is caused by the use of a CPB circuit and to a lesser degree by surgical procedures and anesthesia.

Cardiac Surgical Procedures↗
PubMed1998

Multisystem organ failure and capillary leak syndrome in severe necrotizing enterocolitis of very low birth weight infants.

BACKGROUND: Classification systems for necrotizing enterocolitis (NEC) in preterm infants have been developed to define severity grades relevant for treatment and prognosis. Multisystem organ failure (MSOF) and capillary leak syndrome (CLS) also have prognostic value in these patients. The aim of this retrospective study was to investigate the incidence and predictive value of MSOF and CLS according to the classification criteria. METHODS: The records of 1,022 very low birth weight infants admitted from 1982 to 1996 were reviewed for diagnosis of NEC stage IIA or higher (classification of Walsh and Kliegman). Among those patients (n = 50) the incidence of MSOF and CLS was determined, separately for surgical or conservative treatment. RESULTS: Twelve patients were assigned to stage II, 22 to stage IIIa, and 16 to stage IIIb; 31 infants underwent operation. Mortality rate was not influenced by the grade. In eight patients only gastrointestinal symptoms were found, whereas in 23 patients, up to three organ systems and in 19 patients, four or more organ systems were affected. Mortality depended on the number of involved organ systems. CLS occurred postoperatively in 10 of the 31 infants; eight of them died. CONCLUSION: The prognostic values of MSOF and CLS are higher than that of classification criteria in NEC of VLBW infants.

Capillary Leak Syndrome↗
PubMed1998

Complement activation during plasma production depends on the apheresis technique.

Elevated anaphylatoxin concentrations have been found in fresh frozen plasma packs produced by apheresis. The aim of this study was to investigate anaphylatoxin generation during apheresis production in relation to two frequently used techniques: employing either centrifugation alone or centrifugation with simultaneous filtration. The concentrations of C3a. C5a and sC5b-9 were measured in 50 plasmas after apheresis and before freezing generated by combined centrifugation and filtration and in 50 plasmas generated solely by centrifugation and in the corresponding 100 donors before apheresis. The median C3a concentration increased during apheresis by centrifugation alone from 62 (donor) to 380 micrograms L-1 (FFP pack) and during apheresis by combined centrifugation and filtration from 70 to 992 micrograms L-1. The median C5a concentration increased during apheresis by centrifugation alone from 0.38 to 0.83 microgram L-1 and during apheresis by combined centrifugation and filtration from 0.29 to 4.9 micrograms L-1. The soluble terminal complement complex increased only by combined centrifugation and filtration apheresis from 162 to 426 micrograms L-1. Complement activation during apheresis by combined centrifugation and filtration is more pronounced than that obtained by the centrifugation method alone. Changes in the construction or the materials used in the membrane-type separation units may reveal possibilities of prevention.

Adolescent↗
PubMed1998

In vitro activation of complement and contact system by lactic acidosis.

The activation of complement and contact systems occurs in reperfusion injuries with initial tissue hypoxia, and lactic acidosis such as mycardial infarction and birth asphyxia. The aim of our experiment was the formal proof of activation by sole lactic acidosis. Lactic acid was added to blood and plasma samples from 10 healthy volunteers. C5a and factor XIIa were measured by EIA after incubation at 37 degrees C for 1 h. Both concentrations increased (P < 0.0001 by Friedman analysis) in blood and plasma samples with increasing amount of added lactic acid. Lactic acidosis can activate C5 from the complement system and factor XII from the contact system directly, even in the absence of cellular components.

Acidosis, Lactic↗
PubMed1998

Acidosis activates complement system in vitro.

We investigated the in vitro effect of different forms of acidosis (pH 7.0) on the formation of anaphylatoxins C3a and C5a. Metabolic acidosis due to addition of hydrochloric acid (10 micromol/ml blood) or lactic acid (5.5 micromol/ml) to heparin blood (N=12) caused significant activation of C3a and C5a compared to control (both p=0.002). Respiratory acidosis activated C3a (p=0.007) and C5a (p=0.003) compared to normocapnic controls. Making blood samples with lactic acidosis hypocapnic resulted in a median pH of 7.37. In this respiratory compensated metabolic acidosis, C3a and C5a were not increased. These experiments show that acidosis itself and not lactate trigger for activation of complement components C3 and C5.

Acidosis↗
PubMed1998

Complement and contact activation in term neonates after fetal acidosis.

AIMS: To evaluate complement and contact activation after fetal acidosis. METHODS: Fifteen term neonates with hypoxic-ischaemic encephalopathy after umbilical arterial pH < 7.10 were compared with 15 healthy neonates with umbilical arterial pH > 7.20. Determinations of the complement function and C1-inhibitor activity were performed as kinetic tests 22-28 hours after birth. C1q, C1-inhibitor, and factor B concentrations were determined by radial immunodiffusion and those of C3a, C5a, and factor XIIa by enzyme immunoabsorbent assay. RESULTS: Median complement function (46 vs 73%), C1q (4.3 vs 9.1 mg/dl), and factor B (5.2 vs 7.7 mg/dl) decreased after fetal acidosis. The activated split products C3a (260 vs 185 micrograms/l), C5a (5.0 vs 0.6 micrograms/l), and factor XIIa (3.2 vs 1.3 micrograms/l) increased in the neonates after fetal acidosis. No differences were found in the concentration and activity of C1-inhibitor. CONCLUSIONS: Complement and contact activation occurred in the newborns with hypoxic-ischaemic encephalopathy. Activation of these systems generates mediators which can trigger inflammation and tissue injury.

Acidosis↗