Search PubMed⌕ Search

Biomedical subjects

O Linderkamp

Publications and source records attributed to O Linderkamp.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of caffeine on oxygen consumption and metabolic rate in very low birth weight infants with idiopathic apnea.

OBJECTIVE: Methylxanthines are among the most commonly prescribed drugs in neonatal intensive care. This study evaluates the effect of caffeine on oxygen consumption and metabolic rate in premature infants with idiopathic apnea. METHODS: Eighteen preterm infants at gestational ages from 28 to 33 weeks and birth weights of 890 to 1680 g were enrolled in the study. Nine preterm infants received caffeine therapy, and 9 served as a control group. Oxygen consumption and energy expenditure were examined before, during, and after caffeine treatment. RESULTS: Oxygen consumption increased significantly from 7.0 +/- 0.9 before caffeine to 8.8 +/- 0.7 mL/kg/min after 48 hours of caffeine therapy, and energy expenditure increased from 2.1 +/- 0.3 to 3.0 +/- 0.2 kcal/kg/hour. During the observation period of 4 weeks of caffeine treatment, oxygen consumption increased significantly in the caffeine group compared with the control patients. In the caffeine group, a lower environmental temperature was sufficient to maintain a normal body temperature. With similar caloric intake in both groups during the study period, daily weight gain in the control group was significantly higher (21 +/- 4 vs 42 +/- 2 g/d). None of the other parameters recorded changed during caffeine therapy. CONCLUSION: Long-term administration of caffeine in preterm infants is associated with an increase in oxygen consumption and with a reduction of weight gain. This may have implications for clinical practice as nutritional regimens need to be adjusted during this therapy.

Apnea↗
PubMed2000

[Acute retinpathia praematurorum. Is plasma prorenin level of prognostic value?].

BACKGROUND: In patients with diabetes mellitus an elevated level of plasma prorenin (PP) may be associated with proliferative diabetic retinopathy. Although retinopathy of prematurity (ROP) is also characterized by retinal vasoproliferation, no study on PP in ROP appears to have been carried out. This study investigated PP prospectively in preterm infants with high risk of ROP. PATIENTS AND METHODS: In 304 preterm infants (gestational age 24-36 weeks, mean +/- SD 29.8 +/- 2.6 weeks; birth weight 570-1750 g, 1180 +/- 294 g) PP was examined prospectively between 3 and 14 weeks postnatally. Renin and total renin (after cryoactivation) were determined by radioimmunoassay. Total renin minus renin is the PP level; PP was correlated with the presence of ROP, stage of ROP, gestational age, birth weight, and postnatal age. RESULTS: There was no significant difference between mean PP in 112 preterm infants with ROP (682 +/- 666 ng/l) and that in 192 preterm infants without ROP (622 +/- 454 ng/l). There was no correlation between PP and the stage of ROP, gestational age, or birth weight. Mean PP decreased with increasing postnatal age (postnatal age 3-4 weeks: 906 +/- 587 ng/l; 7-8 weeks: 585 +/- 423 ng/l; 13-14 weeks: 326 +/- 205 ng/l). CONCLUSION: This study found no significant difference in PP between preterm infants with and those without ROP. Thus PP is not a valid predictor or indicator of ROP. However, the study showed a hitherto unknown correlation between PP and postnatal age in preterm infants.

Birth Weight↗
PubMed2000

Visual-motor function of very low birth weight and full-term children at 3 1/2 to 4 years of age.

Improvements in perinatal and neonatal management have not only led to a higher survival rate of very low birth weight infants (VLBW; < or = 1,500 g or < 32 weeks gestational age), but also to a better outcome of these children. However the percentage of VLBW children who need special education because of later school problems remains high even in children considered neurologically normal during infancy. We assessed 40 VLBW children and 83 healthy full-term children at age 3 to 4 years by means of a simple and short test for visual-motor deficits. The test included the copying and cutting-out of geometric shapes, the building of models, the recognition of colours and the observation of the concentration and cooperation during the test. All VLBW children had had a good perinatal outcome and had been considered neurologically normal at one year of age. Most VLBW children scored within 1 standard deviation (S.D.) of the test mean, but on average the VLBW children scored significantly lower than the full-term infants in the copying of figures, the cutting-out of geometric forms, the building of models and in the overall concentration and cooperation during the test. Children who attended a nursery school achieved significantly better test results. Girls tended to have better results, but this was not statistically significant. Social factors and age had a significantly greater impact on results than perinatal factors. In summary, VLBW children scored significantly less in almost every test item compared to their term peers. Our test battery could serve as a short introductory test to screen for deficits in visual-motor skills, especially in VLBW children.

Adolescent↗
PubMed2000

Decrease of cholestasis under "continuous extracorporeal stool transport (CEST)" in prematures and neonates with stomas.

According to recent studies, the percentage of neonates suffering a combination of very low birth weight (VLBW) and intestinal malformation or diseases that require surgery has increased. As opposed to mature newborn, split stoma is the therapy of choice in VLBW infants. These neonates and patients with other causes for a congenital or acquired short-bowel syndrome usually require parenteral nutrition and have a high risk of a cholestasis. Until 1993, stoma patients were treated with a special diet in our department, but depending of the stoma site often required parenteral nutrition, while the non-used distal bowel was irrigated with an isotonic electrolyte solution. With this regime, up to 38.5% of the treated patients (10126) were found to have a hyperbilirubinemia (> 3 mg/dl) after the 21st day of life. 1994, we started to use a device that continuously transfers the intestinal chylus from the proximal into the aboral bowel via a pump like a continuous extracorporeal stool transport (CEST). In this study, we evaluated the risk of cholestasis by comparison of the prospectively investigated group (CEST-group 1994-1998) of 33 infants with the results of the retrospectively studied group of 26 patients operated on between 1987 and 1993. We found a significantly lower risk of cholestasis in the CEST-Group (12.9% versus 38.5%; p<0.04). Only 3% of our patients with CEST (one patient) required permanent parenteral nutrition, compared to 50% of the conventionally treated patients.

Bilirubin↗
PubMed2000

Influence of the endothelial glycocalyx on cerebral blood flow in mice.

The endothelial surface layer (glycocalyx) of cerebral capillaries may increase resistance to blood flow. This hypothesis was investigated in mice by intravenous administration of heparinase (2500 IU/kg body weight in saline), which cleaves proteoglycan junctions of the glycocalyx. Morphology was investigated by transmission electron microscopy. Cerebral perfusion velocity was recorded before and during heparinase or saline treatment using laser-Doppler flowmetry. In addition, cerebral blood flow (CBF) was measured 10 minutes after heparinase or saline treatment using the iodo[14C]antipyrine method. Laser-Doppler flowmetry and CBF measurements were performed during normocapnia and severe hypercapnia (PCO2: 120 mm Hg). After heparinase, morphology showed a reduced thickness of the glycocalyx in cortical microvessels by 43% (P < 0.05) compared with saline-treated controls. Under normocapnic conditions, a 15% (P < 0.05) transient increase of cerebral flow velocity occurred 2.5 to 5 minutes after heparinase injection. Laser-Doppler flow and CBF returned to control values ten minutes after the injection. However, during severe hypercapnia, heparinase treatment resulted in a persisting increase in laser-Doppler flow (6%, P < 0.05) and CBF (30%, P < 0.05). These observations indicate the existence of a flow resistance in cerebral capillaries exerted by the glycocalyx. The transient nature of the CBF increase during normocapnia may be explained by a vascular compensation that is exhausted during severe hypercapnia.

Adaptation, Physiological↗
PubMed2000

Risk factors in retinopathy of prematurity. a multivariate statistical analysis.

OBJECTIVE: To analyze risk factors in retinopathy of prematurity (ROP). PATIENTS AND METHODS: Four hundred forty-seven surviving very-low-birth-weight infants (birth weight </=1,500 g) were enrolled in a retrospective study. Clinical data underwent multivariate analysis using stepwise logistic forward regression. RESULTS: For 402 of the babies a complete dataset of 38 possible risk factors was available. Multivariate analysis showed 10 factors to be independently significant variables. Low birth weight, low gestational age, artificial ventilation for more than 7 days, high volume of blood transfusion and surfactant therapy were risk factors associated with higher rates of ROP. Necrotizing enterocolitis, maternal pre-eclampsia, lung maturation by antepartum betamethasone application, vitamin E and phototherapy were accompanied by a lower incidence of ROP. CONCLUSIONS: This study confirms several risk factors recognized by previous statistical analysis. In addition, this study reveals maternal pre-eclampsia, which is associated with chronic intrauterine stress, as a statistically independent factor and as having an influence on the incidence of ROP.

Female↗
PubMed2000

Surfactant modulates intracellular signaling of the adhesion receptor L-selectin.

Intraalveolar leukocyte accumulation is one of the hallmarks during respiratory distress. In the intraalveolar space, leukocyte activation is mediated by pathogens, cytokines, and different ligands binding to adhesion molecules. Leukocyte stimulation via the adhesion molecule L-selectin is specifically induced by ligands expressed on leukocytes, platelets, endothelial cells, or lipopolysaccharide. Recently, we have demonstrated that leukocyte activation by L-selectin transmits several intracellular signaling cascades resulting in capping and cytoskeletal changes, the activation of kinases and neutral sphingomyelinase, the recruitment of adaptor proteins to the cell membrane, the activation of the small G-proteins Ras and Rac, and the release of oxygen. In the present study, we examined the effects of surfactant on L-selectin-induced signal transduction in leukocytes. Using fluorescence microscopy, we provide evidence that preincubation of leukocytes with surfactant significantly inhibits receptor capping; 28+/-7% of cells show capping after L-selectin stimulation versus 8+/-5% and 3+/-1% of cells after preincubation with Exosurf and Curosurf, respectively (p < 0.05). The activity of the neutral sphingomyelinase in cell lysates is also modulated by surfactant. In addition, we show that the activation of the tyrosine kinase p56lck is diminished by approximately 50% after surfactant treatment. This results in inhibition in tyrosine phosphorylation of certain intracellular proteins. The interaction of the L-selectin molecule with its antibody was not influenced by surfactant as shown by flow cytometry. Surfactant inhibits intracellular signaling events of the L-selectin receptor in leukocytes and might therefore contribute to the modulatory effects of surfactant on immune function.

Humans↗
PubMed2000

Decreased mechanical stability of neonatal red cell membrane quantified by measurement of the elastic area compressibility modulus.

Previous studies suggest that early loss of membrane might account for the shortened life-span of neonatal red blood cells (RBC). The elastic area compressibility modulus describes the force required to achieve a defined expansion of the membrane and is thus a suitable intrinsic material property to describe mechanical stability of the RBC membrane. We studied RBC in eight cord blood samples (representing fetal blood), ten 5-day old full-term neonates and seven healthy adults. The RBC were suspended in hypotonic buffer solution and investigated using a modification of the micropipet technique by Evans et al. Cord blood RBC (204+/-33 dyn/cm) and neonatal RBC (209+/-11 dyn/cm) showed a 25% lower elastic area compressibility modulus than adult cells (278+/-26 dyn/cm; p < 0.05). Thus, less force was necessary for expansion of neonatal RBC membrane. We conclude that neonatal RBC are more susceptible to mechanical damage of their membrane than adult cells.

Adult↗
PubMed2000

[Results of a survey on the use of guidelines in neonatology].

To assess the use of guidelines in neonatology we conducted a survey on hyperbilirubinemia in 185 German pediatric hospitals from June to September 1999. Of these 136 hospitals (73%) treating infants with hyperbilirubinemia responded. Specific standards or guidelines were used by 99% of participating hospitals. 49% of those used a hospital-based guideline, 54% the recommendations of the Gesellschaft für Neonatologie und pädiatrische Intensivmedizin, 24% another not further specified guideline. In 98% of the hospitals paper copies were used. In 21% of the hospitals the implemented guidelines were also electronically available. A coordinator for their guidelines was available in 51% of the hospitals, whereas 49% did not coordinate locally the use of their guidelines. In conclusion, guidelines should be well maintained and regularly updated in order that they do not lose their impact and significance. In addition, the potential of these concise summaries of medical expertise do not seem to be fully exploited.

Germany↗
PubMed1999

Impaired deformability of erythrocytes and neutrophils in children with newly diagnosed insulin-dependent diabetes mellitus.

AIMS/HYPOTHESIS: Abnormal rheological properties of erythrocytes, leucocytes and plasma may have a role in the development of diabetic microangiopathy. We hypothesized that changed haemorrheological variables may already be found in children with onset diabetes. METHODS: Erythrocyte deformation (rheoscope), neutrophil deformation (micropipette), erythrocyte aggregation, blood and plasma viscosity were measured in 15 children with insulin-dependent diabetes mellitus before initiation of insulin treatment and 4 to 6 weeks later, 15 diabetic children treated with insulin for 5 to 8 years, 15 healthy children and 15 healthy adults. RESULTS: At a low shear stress of 0.6 Pa, erythrocyte deformation was decreased in the diabetic children before (-28%), after 4 to 6 weeks (-22%) and after 5 to 8 years (-17%) of insulin treatment compared with healthy children. More active neutrophils were counted in the untreated diabetic children (9 +/- 6%) than in healthy children (3 +/- 2%). Deformability of passive neutrophils was greatly decreased in the children with onset diabetes and moderately reduced in the diabetic children who were treated with insulin. Neutrophil deformation (r = -0.52) and erythrocyte deformation at 0.6 Pa (r = -0.62) were inversely related to haemoglobin A1c. Haematocrit and blood viscosity were increased in the untreated children and in the children treated with insulin for 5 to 8 years. Plasma viscosity and erythrocyte aggregation were similar in the three groups of children. CONCLUSION/INTERPRETATION: Decreased erythrocyte deformation at low shear force, increased count of active neutrophils and impaired deformability of passive neutrophils may increase the risk for acute cerebro-vascular complications in children with uncontrolled insulin-dependent diabetes mellitus.

Adolescent↗
PubMed1999

Clinical symptoms, biochemical studies and therapeutic approaches in a sibship with a new congenital tubulopathy.

UNLABELLED: We report on two siblings suffering from a new congenital tubulopathy. Following normal pregnancies not complicated by polyhydramnios, severe renal losses of potassium, chloride, sodium and magnesium occurred in the first weeks after birth. Calcium metabolism was not affected. The distal tubular chloride reabsorption was considerably decreased in the two siblings (0.25 and 0.28, respectively). Secondary hyperaldosteronism, activation of the kallikrein-kinin system and elevated urinary prostaglandin excretion were observed. The effects of indomethacin, spironolactone and captopril on symptoms, electrolyte wasting, activation of renin-angiotensin-aldosterone and kallikrein-kinin system and prostaglandin synthesis were studied. In spite of persisting elevation of prostaglandin synthesis, captopril decreased electrolyte wasting, polyuria and hyperaldosteronism most effectively. CONCLUSION: We delineate an apparently new disorder characterized by a postnatal onset, an extremely decreased chloride reabsorption with extensive hyperchloriduria and hypermagnesiuria in the presence of normal calcium metabolism. The disorder can be distinguished from other tubulopathies with hypokalaemic alkalosis.

Absorption↗
PubMed1999

Effects of dietary supplementation of saturated fatty acids and of n-6 or n-3 polyunsaturated fatty acids on plasma and red blood cell membrane phospholipids and deformability in weanling guinea pigs.

The fatty acid composition of plasma cholesteryl esters, plasma phospholipids, red blood cell (RBC) membrane phosphatidylcholine (corresponding to the outer membrane leaflet), and phosphatidylethanolamine (corresponding to the inner membrane leaflet) was investigated in weanling guinea pigs fed with diets of cacao (saturated fatty acids), sunflower oil [n-6 polyunsaturated fatty acids (PUFA)] or fish oil (n-3 PUFA) for 20 wk. RBC deformation was measured by means of a cell-transit analyzer (filtration) and a cone-plate rheoscope. The contents of saturated fatty acids in plasma phospholipids and RBC membrane leaflets were similar in all three groups. Diets with sunflower oil resulted in a high content of linoleic acid in plasma cholesteryl esters and in the outer leaflet of RBC membranes. Fatty acids of fish oil were mainly incorporated in plasma phospholipids and in the inner leaflet of RBC membranes. The arachidonic acid content was high in all groups in the plasma phospholipids and in the inner leaflet. The n-6 and n-3 PUFA were mainly incorporated in the inner leaflet. In all groups the polyunsaturated/saturated fatty acid ratio and the total PUFA content were similar in the inner RBC membrane. The RBC filtration times and the RBC deformation indices were not affected by the dietary treatment.

Animals↗
PubMed1999

Fatal course of veno-occlusive disease of the liver (endophlebitis hepatica obliterans) in a preterm infant.

We describe the fatal course of a preterm infant of 34 weeks' gestation with veno-occlusive disease of the liver and refractory ascites. Despite aggressive medical management, the baby died twenty-two hours post partum because of cerebral haemorrhage before potentially life-saving organ transplantation could take place. At autopsy, paucity of lymphoid tissue in lymph nodes, thymus, spleen, and gastrointestinal tract were also seen. To our knowledge, this is the youngest infant with veno-occlusive disease of the liver reported in the literature.

Adult↗
PubMed1999

Increased energy expenditure and fecal fat excretion do not impair weight gain in small-for-gestational-age preterm infants.

In order to optimize the nutrition of high-risk premature infants beyond the early postnatal period, a more precise knowledge of individual nutritional requirements is needed. We therefore studied the influence of intrauterine growth retardation on energy expenditure and nutrient utilization determined by indirect calorimetry and fecal fat excretion (steatocrit) in nineteen premature infants who were appropriate-for-gestational-age (AGA; mean gestational age 29.9+/-0.3 weeks, mean birth weight 1.30+/-0.05 kg) and thirteen small-for-gestational-age (SGA) premature infants [mean gestational age 32.4+/-0.5 weeks, mean birth weight 1.024+/-0.07 kg (i.e., below the 10th percentile)] during the first and second month of life. All infants were clinically stable during the study period. In nine SGA infants we observed a significantly higher steatocrit compared to twelve AGA infants (29+/-1 vs. 17+/-1% p = 0.0001). SGA infants (n = 12) also showed a slightly (albeit statistically not significantly) higher energy expenditure than AGA infants (n = 15) (58.7+/-1.9 vs. 53.6+/-1.5 kcal/kg per day, p = 0.054). Despite the increased fat excretion and higher energy expenditure, SGA infants gained weight more rapidly during the study period than AGA infants (20+/-1 vs. 17+/-1 g/kg per day, p = 0.026). We conclude that influences of intrauterine growth retardation on energy expenditure and nutrient utilization persist during the first weeks of extrauterine life. However, these metabolic changes do not impair the capability of SGA infants for extrauterine catch-up growth if adequate nutrition is provided.

Aging↗
PubMed1999

Intracellular mechanisms of L-selectin induced capping.

Leucocyte adhesion to endothelial cells is a tightly regulated process involving selectins, integrins and immunoglobulin-like proteins. Cell adhesion and communication are controlled by membrane dynamics like receptor capping. Capping of surface receptors is an ubiquitous mechanism but still not well understood. Employing immunofluorescence techniques, we demonstrate that L-selectin triggering results in receptor capping of the L-selectin molecules in lymphocytes. Using pharmacological inhibitors and genetic deficient cell lines we show that this process involves intracellular signalling molecules. L-Selectin capping seems to be independent on activation of p56lck-kinase, but requires the neutral sphingomyelinase, small G proteins and the cytoskeleton. Therefore, capping of L-selectin upon stimulation might play an important role in the very early phase of lymphocyte trafficking.

B-Lymphocytes↗
PubMed1999

Integration of generic indicators for quality management in hospital information systems.

Hospital information systems may contribute in different ways to quality management activities such as monitoring of quality indicators. Most existing quality management activities in hospitals are adjusted to a special medical field or particular disease. These activities often run simultaneously with other procedures and the documentation of patient care. To determine an interdisciplinary integrated quality management procedure, a pilot study was carried out at the Neurosurgery Department and Neonatology Division of the Medical Center of the University of Heidelberg. Predefined generic indicators that may be integrated in an existing information system and used in hospital routine were the basis of this project. The aim of the study was to support the quality management with periodic reports of these indicators. The pilot study showed that there were barriers along the path to an integrated generic quality management. To meet the requirements of routine monitoring, using predefined generic indicators of hospital care, much integration effort, directed at organizational aspects of information processing and information systems architecture, is still needed.

Germany↗
PubMed1999

Refractory congenital ascites as a manifestation of neonatal sialidosis: clinical, biochemical and morphological studies in a newborn Syrian male infant.

A Syrian newborn with coarse facies, hepato-splenomegaly, and refractory ascites is reported. Examination of the ascitic fluid showed vacuolated lymphocytes and thin-layer chromatography of urinary oligosaccharides revealed an abnormal pattern indicative of sialidosis. Despite intensive care, the baby died of respiratory insufficiency 28 days after birth. In cultured skin fibroblasts an increase of the incorporation of [14C]methylamine pointed to excessive lysosomal storage and the demonstration of an isolated deficiency of alpha-N-acetylneuraminidase (sialidase) led to the diagnosis of a sialidosis. At postmortem examination, foam cells were found mostly in bone marrow, liver, and brain. To date very few cases of neonatal sialidosis have been reported, and, to the best of our knowledge, this is the first child with neonatal sialidosis from Syria and the first case of neonatal sialidosis studied by the [14C]methylamine incorporation assay.

Ascites↗