Isolation of lung lamellar bodies and their conversion to tubular myelin figures in vitro

Sanders, Ronald L.; Hassett, Robert J.; Vatter, A. E.

doi:10.1002/ar.1091980310

Cited by 71 publications

(39 citation statements)

References 45 publications

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“…The extended networks bear a morphological resemblance to the lattice networks of tubular myelin that are formed by lung surfactant in the alveolar fluid. Lung surfactant is uniquely rich in dipalmitoyl phosphatidylcholine and phosphatidylglycerol, whose chain melting occurs close to physiological temperatures (13)(14)(15). Both the reversibility of the material properties demonstrated here, and the possible connection with the pulmonary surfactant cycle offer possibilities for future exploitation, e.g., in liposomal drug delivery and the design of synthetic lung surfactant substitutes.…”

mentioning

confidence: 99%

Network formation of lipid membranes: Triggering structural transitions by chain melting

Schneider

Marsh

Jahn

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

120

130

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Phospholipids when dispersed in excess water generally form vesicular membrane structures. Cryo-transmission and freeze-fracture electron microscopy are combined here with calorimetry and viscometry to demonstrate the reversible conversion of phosphatidylglycerol aqueous vesicle suspensions to a three-dimensional structure that consists of extended bilayer networks. Thermodynamic analysis indicates that the structural transitions arise from two effects: (i) the enhanced membrane elasticity accompanying the lipid state fluctuations on chain melting and (ii) solventassociated interactions (including electrostatics) that favor a change in membrane curvature. The material properties of the hydrogels and their reversible formation offer the possibility of future applications, for example in drug delivery, the design of structural switches, or for understanding vesicle fusion or fission processes. Lipids may undergo a cooperative melting reaction linked to the loss in conformational order of the lipid chains (1). This transition is accompanied by a large change of the internal energy (or enthalpy) that can be studied by calorimetry. It has long been known that the melting profiles are influenced by secondary components, e.g., proteins (2), cholesterol, or anesthetics (3, 4). Phase diagrams of lipid mixtures usually are constructed as a function of the chemical potential of the components and the temperature (5). Another kind of possible transition involves changes in vesicular shape. These transitions have been studied in some detail by theoretical means, resulting in phase diagrams for vesicle structure as a function of the elastic constants (6, 7). Changes in these constants can explain theoretically the wealth of shapes of erythrocytes (8). There are therefore two kinds of phase diagrams found for lipid systems: one describing the calorimetric features of chain melting, mainly dependent on short-range cooperative events within the membrane plane, and the other describing transitions in shape and long-range order influenced by changes in the elastic constants.Although seemingly different features of a lipid system, the elastic constants and the heat capacity of the lipid membrane are related because they are coupled to thermodynamic fluctuations in the membrane properties (9). Maximum elasticity is achieved in the regime of ordered (gel)-fluid phase coexistence (10), which implies that close to the heat capacity maximum the elastic constants change markedly and as a consequence the membranes become more flexible. From this it is expected that changes in structural equilibria may be found close to the chain-melting transition.We demonstrate here thermodynamically how the structural changes couple to the chain melting. Large viscosity changes of dimyristoyl phosphatidylglycerol (DMPG) dispersions close to the calorimetric melting transition have been reported that are accompanied by marked changes in heat capacity, light scattering, and electrical conductance (11,12). The changes in viscosity suggest a change in the l...

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mentioning

confidence: 99%

Network formation of lipid membranes: Triggering structural transitions by chain melting

Schneider

Marsh

Jahn

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

120

130

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“…Bizim de üretici firma ile aynı bulduğumuz değer >55 olup, daha önceden bildirilen 30 ve 50 eşik değerlerinden daha yüksek olmakla birlikte; birçok çalışmada her laboratuvarın kendi sonuçlarına göre bir eşik değeri belirlemesi önerilmektedir. Amnion sıvısının elektron mikroskobik çalışmaları laminasyon gösteren çeşitli partiküllerin varlığını ve karakterlerini göstermiş olup, bunlar lamellar cisimler ya da tübüler myelin figürler olarak bilinmektedirler (12,13 İki özetin ROC eğrilerine bakılarak her iki test karşılaştırıldığında LBC'nin tanısal performansının L/S oranına göre hafifçe avantajlı olabileceği sonucuna ulaşmışlardır. Ancak eşik aralığındaki genişlik nedeniyle en iyi doğruluktaki eşik değerini saptamanın mümkün olmadığını belirtmişlerdir.…”

Section: Discussionunclassified

FETAL AKCİĞER MATÜRASYONUNUN DEĞERLENDİRİLMESİNDE LAMELLER CİSİMCİK SAYIMI İLE TDxFLM TESTLERİNİN BİRBİRLERİNE ÜSTÜNLÜKLERİNİN İNCELENMESİ

Kars¹,

Sakin²,

Büyükbayrak³

et al. 2016

İst Tıp Fak D

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Material and Method: Amnion fluids that were taken into 2 separate tubes from 56 patients within a year were evaluated with both of the tests. Newborns were evaluated and monitored for respiratory distress syndrome of newborns by a neonatologist who was blinded to the results of the amnion fluids. Clinical findings such as grunting, tachypnea, retractions and cyanosis beginning within 6-8 hours after birth, oxygen need over 24 hours, arterial blood gas analyses

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“…Calcium ion appears to be involved in at least two, probably separate, processes in surfactant function. First, millimolar calcium is required for the formation of tubular myelin (7,8), a transformation probably also requiring the presence of a surfactant-associated protein (SP-A), which has recently been shown to undergo a calciumdependent aggregation (Kd = 1 mM) (9, 10). Tubular myelin is thought to be a form of surfactant that is intermediate between the lamellar bodies and the presumably functional form, the interfacial monolayer (6,8,14).…”

Section: Discussionmentioning

confidence: 99%

“…For example, surfactant material is stored in secretory granules known as lamellar bodies, which, when exocytosed into the alveolar lumen, undergo a transformation from the multilamellar form to a square lattice form known as tubular myelin (TM) (6). In vitro, this transformation is calcium dependent, requiring at least 1-2 mM (7,8). The calcium dependency of TM may be based on one of the major surfactant-associated proteins, SP-A, which is a calcium-binding protein (Kd = 1-2 mM) and which has been shown to aggregate into a multimolecular form in the presence of calcium (9,10).…”

Section: Introductionmentioning

confidence: 99%

“…The calcium dependency of TM may be based on one of the major surfactant-associated proteins, SP-A, which is a calcium-binding protein (Kd = 1-2 mM) and which has been shown to aggregate into a multimolecular form in the presence of calcium (9,10). Further, adsorption of the surfactant material in vitro also has a calcium dependency (1 [1][2][3][4][5][6][7][8][9][10][11][12][13], and thus the lipid-protein complex in the form ofTM has been proposed to be an important intermediate between the secreted material and the functional interfacial form of surfactant (7,14).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Perinatal changes in lung surfactant calcium measured in situ.

Eckenhoff¹

1989

J. Clin. Invest.

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Calcium ion is thought to play a role in the structure and function of pulmonary surfactant after secretion into the alveolar space. Since fetal lung liquid calcium concentration is inadequate for this hypothesized role, at a time when optimal surfactant function is necessary for survival, we speculated that the necessary calcium is secreted with the surfactant material, i.e., in the lamellar body. Lungs from rat fetuses at 20, 21, and 22 d gestation, and also from newborn rats at 3-5 h, 1 and 3 d, were rapidly frozen, sectioned, freeze-dried, and examined cold (-100°C) in a transmission electron microscope equipped with a fully quantitative energy-dispersive x-ray detector and analyzer. X-ray spectra were collected from the lamellar bodies and cytoplasm of type II cells at each time point. Lamellar body calcium concentration in the fetus was approximately twice that of the adult (70±4 vs. 37±2 mmol/kg dry wt±SEM, P < 0.01), and it decreased rapidly after birth to adult levels. Apically located lamellar bodies in the fetus have a significantly higher calcium concentration than those in a perinuclear position (76±4 vs. 52±3, P < 0.01). There is a significant correlation of calcium and chloride concentrations in lamellar bodies, suggesting that factors responsible for the distribution of chloride, i.e., pH, may also be responsible for the accumulation of calcium by these organelles. These results show that mature calcium transport in lamellar bodies is achieved prenatally in the rat, and suggest that the calcium required for normal surfactant function at birth is secreted with the lamellar body.

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Isolation of lung lamellar bodies and their conversion to tubular myelin figures in vitro

Cited by 71 publications

References 45 publications

Network formation of lipid membranes: Triggering structural transitions by chain melting

Network formation of lipid membranes: Triggering structural transitions by chain melting

FETAL AKCİĞER MATÜRASYONUNUN DEĞERLENDİRİLMESİNDE LAMELLER CİSİMCİK SAYIMI İLE TDxFLM TESTLERİNİN BİRBİRLERİNE ÜSTÜNLÜKLERİNİN İNCELENMESİ

Perinatal changes in lung surfactant calcium measured in situ.

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