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Biomedical subjects

M Obladen

Publications and source records attributed to M Obladen.

At least 127 records · Page 7Linked to original sources
PubMed1983

Studies on lung surfactant replacement in respiratory distress syndrome. Rapid film formation from binary mixed liposomes.

Binary mixed liposomes were prepared from dipalmitoylphosphatidylcholine (DPPC) and a minor compound, e.g., egg phosphatidylglycerol (PG) at a ratio of 9:1. Using different preparative techniques, large unilamellar vesicles (LUV), small unilamellar vesicles (SUV) or multilamellar vesicles (MLV) were obtained and were studied with an electron microscope for morphology, with a Wilhelmy balance for spreading and surface tension lowering potential, and in the surfactant-depleted isolated rat lung for their ability to restore expiratory lung capacity. Only the simultaneous investigation of phospholipids by negative staining and thin sectioning allows unequivocal classification of liposomes. The surface-active structures prepared with the technique of Bangham et al. (Bangham, A.D., Hill, M.W. and Miller, N.G.A. (1974) in Methods in Membrane Biology (Korn, E., ed.), Vol. 1, pp. 1-68, Plenum Press, New York) at room temperature are LUV. LUV containing DPPC:PG at a ratio of 9:1 rapidly spread to a film with high surface tension lowering potential. Within 5 min after injection into the subphase they rise to the surface and form a film at the air/liquid interface able to lower the surface tension to less than 1 mN/m at compression. SUV of the same chemical composition, however, are immediately surface-active only when spread directly onto the surface. MLV exhibit poor surface activity. LUV or pure DPPC, applied onto the surface, are weakly surface active within 5 min. DPPC vesicles injected into the subphase at 37 degrees C do not adsorb to any film with surface tension lowering potential in this time. The minor compounds PE, PI, PS, PA, lysoPC enable DPPC to form surface-active films after application on saline at 37 degrees C. Removal of surfactant decreases the expiratory lung capacity of the isolated rat lung from 49.7 to 12.4% at 4 cmH2O. After substitution with natural surfactant, the expiratory lung capacity is twice that of the washed lung (25.9%), but the original distensibility of the native lung is not restituted. The effect of LUV containing DPPC:PG at a ratio of 9:1 is also remarkable (21.2%).

Animals↗
PubMed1979

Acceleration of pulmonary surfactant maturation in stresses pregnancies: a study of neonatal lung effluent.

To determine the maturation of pulmonary surfactant at birth, phospholipid patterns in tracheal or pharyngeal aspirates of 54 newborn infants were analyzed by two-dimensional thin-layer chromatography. The compositions of phospholipids and their surface tension-lowering abilities were assessed after gestations with various complications. Preterm infants with respiratory distress syndrome (RDS) lacked phosphatidylglycerol and had lower lecithin/sphingomyelin ratios than infants without RDS. An acceleration of both phosphatidylcholine (lecithin) and phosphatidylglycerol concentrations was observed in 21 preterm infants born after prolonged rupture of the membranes and treatment with isoxuprine. In these infants, the phospholipid pattern of lung effluent was similar to that of term infants even at gestational ages less than or equal to 30 weeks. Biochemical lung maturation was delayed in aneccephalic infants, infants of diabetic mothers, and one infant of a mother with hypothyroidism.

Birth Weight↗
PubMed1979

Systemic air embolism in the respiratory distress syndrome of the newborn.

Details of 25 cases of neonatal systemic air embolism, including three of our patients, are reviewed. This rare complication of respiratory distress syndrome (RDS) was observed in 21 premature infants and 4 fullterm newborns, of whom 23 required intermittent positive pressure ventilation (IPPV). In 21 of these patients air embolism was preceded by pulmonary interstitial emphysema, pneumomediastinum, pneumothorax and/or pneumopericardium. Air embolism occurred between 3 and 288 hours after delivery. The outcome was lethal in 24 cases, only one patient survived. Two main pathogenic mechanisms are discussed; entrance of air from ruptured alveoli into the lung capillaries and introduction of air via catheters in umbilical vessels.

Embolism, Air↗
PubMed1979

[Tracheal phospholipid composition and respiratory distress syndrome of the newborn].

Tracheal or pharyngeal aspirates were collected in 50 newborn infants with and without respiratory distress syndrome (RDS). After lipid extraction the phospholipids were analyzed with 2-dimensional thin layer chromatography. Surface-active are lecithin (PC), phosphatidylglycerol (PG), and phosphatidylinositol (PI). Newborn infants with RDS always have a complete lack of PG, which makes up to 11% of phospholipid-phosphors in mature newborns. In all infants with and without RDS, a sharp increase of PC occurs in the lung effluent after birth. The recovery from RDS is characterized by marked changes of PI: this phospholipid rises up to twice its initial value if the infants survive. The PI-increase parallels the clinical improvement and reaches its maximum usually on the 5th day of life. At the time of the PI-peak, the infants' surfactant function is sufficient to maintain alveolar stability with spontaneous breathing. In infants dying from RDS the PI-increase was not observed.

Humans↗
PubMed1979

Surfactant substitution.

A mixture of synthetic phospholipids containing 90% Dipalmitoylphosphatidylcholine and 10% Dipalmitoylphosphatidylglycerol was tested for its suitability as surfactant substitute. Different methods of preparation were employed. The substance was studied by chromatography, Wilhelmy balance, and in rabbits after tracheal instillation during mechanical ventilation. When prepared as suspension of multilamellar liposomes in NaCl, the phospholipid samples displayed the essential surfactant features of adsorption from the subphase, spreading to a monolayer and lowering the surface tension to 3.7 dyn/cm at compression. For a dose of 2.55 microgram/cm2, the stability index was 1.83 +/- 0.29. Samples prepared with ultrasound were not surface-active. Sonication also destroyed the surface-tension-lowering ability of previously active samples. No signs of local toxicity were found in the treated animals. When radioactive DPPC/DPPG was instillated into the trachea of the ventilated rabbit, autohistoradiography demonstrated radioactive material in the alveoli covering the alveolar wall with a thin layer. Provided that proper techniques of preparation and administration are employed, the phospholipids tested are a promising surfactant substitute worthy of clinical study.

Adsorption↗
PubMed1978

Factors influencing surfactant composition in the newborn infant.

In order to evaluate the surfactant maturation of the neonate, tracheal aspirates were analyzed in 84 newborn infants with 12h of birth. Using 2-dimensional thin-layer chromatography, 9 different phospholipids were identified. Dynamic surface tension measurements were performed with a modified Wilhelmy balance. Five different groups of infants with typical phospholipid patterns were characterized: i.e., 1. Normal term newborn. 2. RDS in the preterm infant. 3. Acceleration of lung maturity in preterm infants without RDS. 4. Retardation in term infants with RDS. 5. Therapeutic induction of pulmonary maturity in preterm infants following maternal glucocorticoid administration. Mature lung effluent contains high concentrations of phosphatidylcholine (PC) and phsophatidylglycerol (PG). In infants with RDS, PC is low and PG absent. Accelerated lung maturity was observed after chronic prenatal stress, such as prolonged rupture of the membranes, chronic vaginal bleeding, and maternal hepatitis or drug addiction. Retardation of pulmonary maturity was seen in infants with alpha-1-AT-deficiency, maternal diabetes and maternal hypothyroidism. Administration of methylprednisolone to the mother 24 h to 72h before birth induced both the synthesis of PC and PG in the preterm infants, resulting in an almost full-term phospholipid pattern as early as 31 weeks of gestation. The significance of these factors on the pathogenesis of RDS is discussed.

Female↗
PubMed1977

Bronchopulmonary dysplasia in premature infants. A radiological and pathological correlation.

In a group of 70 premature and newborn infants, treated with artificial ventilation, 24.3% developed bronchopulmonary dysplasia (BPD). Only in a very few cases did the typical radiological stages, as described by Northway, succeed each other in a chronological order. It is impossible to differentiate BPD stage I or II from RDS stage III and IV without a knowledge of the clinical course and of the duration of artificial ventilation. The lower the gestational age, the more severe and earlier do the radiological and histological changes occur. The radiological differential diagnosis of BPD includes Wilson-Mikity-syndrome, congenital pulmonary lymphangiectasia, neonatal tuberculosis, cystic fibrosis and Hamman-Rich-syndrome.

Bronchial Diseases↗
PubMed1977

RDS and tracheal phospholipid composition in twins: independent of gestational age.

The surfactant phospholipids in the tracheal effluent of eight pairs of preterm twins were followed, serially. In four pairs only one of the twins had RDS; in the other four pairs both twins had RDS. Twins with and without RDS had markedly different surfactant phospholipids. Phosphatidylglycerol was absent in all twins with RDS. L/S ratios in tracheal effluent increased after birth in infants with and without RDS. With recovery from RDS, phosphatidylinositol increased. The study helps confirm previous studies of the necessity of the acidic phospholipids, PI and PG, in stabilizing lecithin, as well as that surfactant composition can be independent of gestational age.

Body Composition↗
PubMed1976

[Extrahepatic stenosis of the portal vein after infection or catheterization of the umbilical vein during the neonatal period (author's transl)].

147 children with high risk of developing a prehepatic portal vein obstruction were reexamined. The children had survived during their neonatal period:--Serious umbilical infection and sepsis (n=33)--Multiple exchange transfusion (n=55)--Long-term umbilical vein catheter treatment for at least 24 hrs (n=59). The reexamination at the age of 2--4 years revealed one case of total occlusion of the vena lienalis with partial obstruction of the vena portae in a child with former umbilical sepsis. Even though the etiologic relation of neonatal umbilical disorders and prehepatic portal obstruction is evident, the risk for the individual case seems to be low.

Catheterization↗
PubMed1975

Portal hypertension in children following neonatal umbilical disorders.

10 children presented pre-hepatic portal vein obstruction during their first 6 years of life. 8 of them had massive esophageal varices, 1 died from acute esophageal hemorrhage. The perinatal history of these childre was studied: All of them had an abnormal birth history and all had been hospitalized during their neonatal period. In 5 of them an umbilical infection had been diagnosed, one had an injection of THAM and one other an exchange transfusion through an umbilical vein catheter. Pre-hepatic portal vein occlusion in children is presumed to be mainly an acquired disease resulting from neonatal umbilical disorders.

Child↗
PubMed1975

[Mobile intensive-care-unit for transportation of premature and newborn babies at risc (author's transl)].

This is a technical report on a specially equipped ambulance for transportation of high-risk, seriously ill neonates. A mobile neonatal intensive-care-unit operating independently of the car utilized an Ohio-transport-incubator with 12V-DC portable power pak and collapsible stand, battery-operated ECG-monitor with optical and acoustical signal, a ECG-monitor with optical and acoustical signal, a battery-operated infusion pump, a Bird-respirator mark 8 with oxygen-blender, nebulizer and infant circuit with modification for PEEP as well as additional accessories. Ambulance-duty service is guaranteed by the German Red Cross (DRK) to facilitate transfer at any time, while skilled personal (physician, nurse) of the intensive care ward in on 24 hs call.

Electrocardiography↗
PubMed1975

[Neonatal information system I: computer-adapted pregnancy and birth record (author's transl)].

A computerized documentation system for the main perinatal data of the newborn is presented. The information about pregnancy and birth are recorded on two optic mark reader forms. They can be used as a part of the conventional patient's history and as a transport document. The forms are recorded by simple pencil marking without further clerical effort for the staff. A direct data processing of the marked informations is possible with a computer. After two years' use of the new documentation system our information about the admitted newborns had markedly improved. An early regstration of pre- and pernatal risk factors is possible.

Electronic Data Processing↗
PubMed1975

[Diagnostic and Therapeutical problems of extrahepatic portal vein stenosis].

In seven children the clinical course of extrahepatic portal vein stenosis was studied angiographically. In all children with splenomegaly it was deemed necessary to perform an X-ray barium examination of the oesophagus. Transsplenic portal venography was performed when oesophageal varices were detected to set up the best scheme for emergency treatment. In our patients with hypersplenism there were no specific bone marrow alterations. In contrast to the literature most of our cases had fibrosis of the liver.

Adolescent↗
PubMed1975

[Neonatal information system II: computer-adapted examination form for the newborn (author's transl)].

For the documentation of the neonatal status we use computer-adapted optic mark reader forms since 1972. All important symptoms and signs are scheduled on two sheets and are assigned by pencil marking. The forms can be read automatically and are suitable for data processing. A copy remains in the patients clinical file and can be used like a conventionally written status. The mark reader forms improved singificantly our knowledge about the newborn's status. The problems of introducing the new documentation into the hospital routine are reported.

Computers↗