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Biomedical subjects

L Gluck

Publications and source records attributed to L Gluck.

At least 55 records · Page 3Linked to original sources
PubMed1981

Premature labor. II. Bacterial sources of phospholipase.

Human term labor is thought to be initiated by amniotic and chorionic phospholipase A2, an enzyme that liberates arachidonic acid esters from the phospholipids of these membranes, leading to the synthesis of prostaglandins by the placental membranes. The striking association of premature labor with intrauterine infection or contamination, urinary tract infection, and early neonatal sepsis led us to study the microorganisms present in these infections for phospholipase A2 activity. Activity was found in Bacteroides fragilis, Peptostreptococcus, Fusobacterium necrophorum, Streptococcus viridans, Streptococcus fecalis, Streptococcus A and B, Escherichia coli, Klebsiella, Staphylococcus epidermidis, Pneumococcus, Lactobacillus, and Mycoplasma hominis. Bacteroides fragilis, Peptostreptococcus, Fusobacterium, and S viridans had the highest activities. The specific activities of phospholipase A2 from these organisms were several times higher than that of the membrane phospholipase A2 of the amnion and chorion. We postulate that premature labor may be initiated by microorganisms with phospholipase A2 activity from endocervical and/or intrauterine contamination or infection, producing deacylation of arachidonic acid from amniotic phospholipids with increased concentrations of free arachidonic acid and increased prostaglandin synthesis, which triggers labor.

Animals↗
PubMed1981

Tc-99m HIDA scintigraphy in segmental biliary obstruction.

Segmental biliary obstruction as a result of primary or secondary hepatic malignancy has been reported with increasing frequency. For two representative patients, the clinical and Tc-99m HIDA scintigraphic findings in segmental biliary obstruction are described. The presence of photon-deficient dilated bile ducts in one segment of the biliary tree is highly suggestive of localized biliary obstruction and should be considered in the patient with suspected or proven hepatic malignancy despite the absence of jaundice.

Adenocarcinoma↗
PubMed1981

Premature labor. I. Prostaglandin precursors in human placental membranes.

Amnion and chorion from premature and term placentas after both spontaneous labor and elective cesarean section were assayed for phospholipids and fatty acid composition by 2-dimensional thin-layer chromatography and gas-liquid chromatography. In preterm placental phospholipids, phosphorus concentrations were higher in amnion than in chorion, whereas at term the membranes were similar owing to an increase in phospholipid concentration in the chorion late in gestation. PHosphatidylcholine (PC) accounted for 47% of the total phospholipid phosphorus, followed by sphingomyelin at 20%, phosphatidylethanolamine (PE) at 15%, phosphatidylserine (PS) at 12%, and phosphatidylinositol (PI) at 5%. These percentages were similar for amnion and chorion and they did not change during gestation. The percentage of arachidonic acid (AA) was higher in PS (40 to 65%) than in PE (30 to 53%) and PC (10 to 13%). The percentage of AA was significantly higher in PC, PE, and PS from the amnion in premature pregnancies than in those of the premature chorion. At term, these amnionic and chorionic phospholipids had similar concentrations of AA owing to a significant increase in AA in the chorion late in gestation. Amnionic PE from term and preterm elective cesarean section had a significantly higher percentage of AA than that from preterm and term labor. These data suggest that AA is consumed during labor and that amnionic phospholipids, particularly PE, may be its principal source. The amnion seems to be more important for the storage of AA than the chorion, particularly in preterm pregnancies in which the concentrations of phospholipids and the percentages of AA in PC, PE, and PS were significantly higher than in the chorion.

Amnion↗
PubMed1981

Changes in the lecithin:sphingomyelin ratio during labor and the associated fetal heart rate patterns.

Serial samples of amniotic fluid were taken from 38 patients in spontaneous labor and the lecithin:sphingomyelin (L:S) ratios were estimated. The fetal heart rate (FHR) pattern for each patient was analyzed, and the baseline rate, long-term variability, and periodic changes wee determined. It was found that changes in the L:S ratios were significantly correlated with the duration of labor and FHR long-term variability. Very low L:S ratios were observed in some patients whose infants did not subsequently develop respiratory distress syndrome. This raises the possibility that during labor the amniotic fluid is no longer representative of lung fluid, perhaps because of reduced tracheal fluid efflux, a process which may operate when the fetus is under stress.

Amniotic Fluid↗
PubMed1980

Effect of prolactin on phospholipid biosynthesis by alveolar cell carcinoma (A549) in monolayer tissue culture.

By means of an alveolar cell carcinoma (A549) model, the effect of prolactin on pulmonary surfactant phospholipid biosynthesis was investigated. Preliminary results suggest that phosphatidylcholine synthesis via the phosphatidic acid phosphohydrolase pathway in addition to phosphatidylglycerol may be stimulated by the presence of prolactin.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1980

The immature lung: radiographic appearance, course, and complications.

Thirty-six premature newborn infants of a very low birthweight (1,500 g or less) are described who did not have respiratory distress syndrome (RDS) by clinical criteria or by biochemical analysis of pulmonary effluent phospholipid (surfactant). Such patients seem to be protected against the development of RDS by intrauterine stress, which results in accelerated maturation of the surfactant system. Chest radiographs in these patients show a pattern of fine, diffuse granularity together with mild congestion suggesting excessive lung fluid, without significant air bronchograms, underaeration, or cardiomegaly. The most frequent complications are apnea with bradycardia and/or a significant left-to-right shunt through a patent ductus arteriosus. The serious complications of intraventricular hemorrhage, bronchopulmonary dysplasia, and death are more common in the smaller (1,000 g or less) infants; necrotizing enterocolitis, observed in 25% of patients, was not related to birthweight. The radiographic and clinical presentation of "immature lung" should be distinguished from that of RDS, because the prognosis in this birthweight range is considerably better (83% survival).

Apnea↗
PubMed1980

Diagnosis and follow-up of intraventricular and intracerebral hemorrhages by ultrasound studies of infant's brain through the fontanelles and sutures.

A technique to diagnose subependymal hemorrhage (SEH), intraventricular hemorrhage (IVH), intracerebral hemorrhage, and posthemorrhage hydrocephalus in tiny infants, using real time ultrasound studies of the brain ventricular system, is described. This is a bedside technique that visualizes the brain through the fontanelles and the sutures, in three planes: coronal, sagittal, and horizontal. Excellent visualization of the ventricular system, caudate nuclei, the thalamus, the choroid plexus, the corpus callosum, and the foramen of Monro is obtained. This method has good definition using high frequency transducers since there is no bone interference. The ultrasound diagnosis correlated well with computed tomography (CT) and with direct pathologic studies. This technique was more sensitive in diagnosing small IVH/SEH and organized clots than were CT studies. IVH/SEH were found in 90% of 113 infants less than or equal to 34 weeks of gestation; 49% of the hemorrhages were large and 41% were small. Most hemorrhages were found in the first scan, usually shortly after birth. Twenty-one premature infants who never had perinatal asphyxia or respiratory distress syndrome had IVH/SEH. The hemorrhages were followed until disappearance, usually in one to three months in cases of large hemorrhages.

Cerebral Hemorrhage↗
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

The lung profile. I. Normal pregnancy.

The lung profile run by two-dimensional thin-layer chromatography is described, including the L/S ratio and the percentages of disaturated acetone precipitated lecithin, PI, and PG. Results show that the accuracy of this profile increases that of the mature L/S ratio value even further, while decreasing the missed predictions with low L/S ratios to only about 7%.

Amniotic Fluid↗
PubMed1979

Significance of phosphatidylglycerol in amniotic fluid in complicated pregnancies.

In normal pregnancy lecithin/sphingomyelin ratios correlate with gestational age. In complicated pregnancies biochemical maturation of fetal lung may be accelerated or delayed, depending upon maternal, fetal, or placental conditions. Surfactant contains other phospholipids besides lecithin, including phosphatidylglycerol (PG), the second major component of mature surfactant. Ninety phospholipid patterns in amniotic fluid were studied by two-dimensional thin-layer chromatography. In uncomplicated pregnancies PG was absent until 37 weeks' gestation, then increased there after. In complicated pregnancies (pre-eclampsia, diabetes Classes D, F, and R, premature rupture of membranes) PG was identified before 35 (as early as 29 weeks' gestation. These results verify accelerated lung maturation in certain complicated pregnancies. No newborn infant developed respiratory distress syndrome in the presence of PG.

Amniocentesis↗