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Several morphogenetic sequences occur during esophageal development and birth defects occur due to defects in foregut morphogenesis. This work aimed to record the cellular events in the morphogenesis of rabbits' esophageal epithelium. On the 16th day of gestation, the esophageal epithelium varied from stratified ciliated columnar to stratified squamous type. The surface epithelium presented mucous cells with mucigen granules of various sizes occupying their supranuclear cytoplasm. Cytoplasmic vacuolation was evident in all layers of the esophageal epithelium at this age. On the 18th gestational day, some light cells could be detected in the middle portion of the epithelium, while others occupied the whole epithelial length. On the 21st day, mucous cells are more frequently observed at the apical esophageal part as well as at the surface epithelium. Numerous elongated dark cells could be distinguished embedded between the basal cells. On the 24th gestational day the number of the mucous cells reached its peak. Reaching the 30th gestational day, several lamellar bodies, a keratinized layer and mitotic divisions could be demonstrated, and the number of both mucous and dark cells was greatly decreased. Collectively, detection of surface mucous and dark cells together with the non‐cornified surface in some regions of the rabbit esophageal epithelium at the end of gestation ensure a postnatal development to reach the adult epithelium essential to sustain the passage of the harsh raw food. Future immunohistochemical studies are recommended to investigate the components of secretions in mucous cells and functional studies to highlight the dark cells significance. Research Highlights: Esophageal epithelium of fetal rabbit was analyzed by light and transmission microscopy.Surface epithelium presented mucous cells with mucigen granules of various sizes. They reached their maximum number on 24th day then decreased.On the 16th day, cytoplasmic vacuolation was evident in all epithelial layers.On the 21st day, numerous elongated dark cells could be distinguished embedded between the basal cells.Before birth, several lamellar bodies, a keratinized layer and mitotic divisions could be demonstrated, and the number of both mucous and dark cells was greatly decreased. [ABSTRACT FROM AUTHOR]

Pulmonary surfactant (PS), a complex mixture of lipids and proteins, is essential for maintaining proper lung function. It reduces surface tension in the alveoli, preventing collapse during expiration and facilitating re-expansion during inspiration. Additionally, PS has crucial roles in the respiratory system's innate defense and immune regulation. Dysfunction of PS contributes to various respiratory diseases, including neonatal respiratory distress syndrome (NRDS), adult respiratory distress syndrome (ARDS), COVID-19-associated ARDS, and ventilator-induced lung injury (VILI), among others. Furthermore, PS alterations play a significant role in chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). The intracellular stage involves storing and releasing a specialized subcellular organelle known as lamellar bodies (LB). The maturation of these organelles requires coordinated signaling to organize their intracellular organization in time and space. LB's intracellular maturation involves the lipid composition and critical processing of surfactant proteins to achieve proper functionality. Over a decade ago, the supramolecular organization of lamellar bodies was studied using electron microscopy. In recent years, novel bioimaging tools combining spectroscopy and microscopy have been utilized to investigate the in cellulo intracellular organization of lamellar bodies temporally and spatially. This short review provides an up-to-date understanding of intracellular LBs. Hyperspectral imaging and phasor analysis have allowed identifying specific transitions in LB's hydration, providing insights into their membrane dynamics and structure. A discussion and overview of the latest approaches that have contributed to a new comprehension of the trafficking and structure of lamellar bodies is presented. [ABSTRACT FROM AUTHOR]

Introduction: In human and experimentally induced asthma, a dysfunction of the intra-alveolar-surface active agent (surfactant) has been demonstrated. Type II alveolar epithelial cells (AEII) synthesize, secrete and recycle surfactant. Prior to secretion, intracellular surfactant is stored in specific secretory organelles of AEII. The lamellar bodies (Lb) represent its ultrastructural correlate. The aim of this study was to investigate whether disturbances of the intra-alveolar surfactant are accompanied by alterations in the intracellular surfactant.Material and Methods: Brown-Norway rats were sensitized twice with ovalbumin (OVA) and heat killed Bordetella pertussis bacilli. During airway challenge, an aerosol of 5% ovalbumin/saline solution (0.25 l/min) was nebulized. 24 h after airway challenge, lungs were fixed by vascular perfusion. AEII and their Lb were characterized stereologically by light and electron microscopy.Results: In both groups, AEII were structurally intact. The number of AEII per lung and their number-weighted mean volume did not differ (controls: 49 × 106, 393 µm3; asthmatics: 44 × 106, 390 µm3). A mean of 90 Lb in AEII of asthmatics and of 93 Lb in AEII of controls were evaluated. The Lb mean total volume was 59 µm in asthmatics and 68 µm in controls. Values of both parameters did not reach significance. Also, the size distribution and mean volume of Lb was not influenced by asthma induction, because the volume weighted mean volume of Lb (2.18 µm in asthmatics compared to 1.87 µm in controls) and the numerical weighted mean volume (0.96 µm in asthmatics and 0.75 µm in controls) were comparable in both groups.Conclusion: The obtained results suggest that asthma-induced surfactant dysfunction is not related to disturbances in the intracellular surfactant´s ultrastructural correlates. [ABSTRACT FROM AUTHOR]

By coating the alveolar air-liquid interface, lung surfactant overwhelms surface tension forces that, otherwise, would hinder the lifetime effort of breathing. Years of research have provided a picture of how highly hydrophobic and specialized proteins in surfactant promote rapid and efficient formation of phospholipid-based complex three-dimensional films at the respiratory surface, highly stable under the demanding breathing mechanics. However, recent evidence suggests that the structure and performance of surfactant typically isolated from bronchoalveolar lung lavages may be far from that of nascent, still unused, surfactant as freshly secreted by type II pneumocytes into the alveolar airspaces. In the present work, we report the isolation of lung surfactant from human amniotic fluid (amniotic fluid surfactant, AFS) and a detailed description of its composition, structure, and surface activity in comparison to a natural surfactant (NS) purified from porcine bronchoalveolar lavages. We observe that the lipid/ protein complexes in AFS exhibit a substantially higher lipid packing and dehydration than in NS. AFS shows melting transitions at higher temperatures than NS and a conspicuous presence of nonlamellar phases. The surface activity of AFS is not only comparable with that of NS under physiologically meaningful conditions but displays significantly higher resistance to inhibition by serum or meconium, agents that inactivate surfactant in the context of severe respiratory pathologies. We propose that AFS may be the optimal model to study the molecular mechanisms sustaining pulmonary surfactant performance in health and disease, and the reference material to develop improved therapeutic surfactant preparations to treat yet unresolved respiratory pathologies. [ABSTRACT FROM AUTHOR]

The presence of myeloid bodies (MBs) is classically associated with Fabry disease (FD). However, MBs are also identified in patients without clinical evidence of FD. We attempt to further understand the clinicopathologic significance of incidental MBs in those without FD. Among the 4400 renal biopsies accessioned at the University of Rochester Medical Center from 2010 to 2021, we identified 32 cases showing MBs, 6 of which had FD. Medications were compared between a non-FG and a control-group of randomly selected cases without MBs (non-MBs). Both Fabry-group (FG) and non-Fabry-group (non-FG) were predominantly middle-aged (mean 48 years vs 56, respectively). Non-FG had slight female predominance (1:4), while all in FG were female. The majority of both non-FG and non-MBs cohort were on the same medications reported to cause phospholipidosis except sertraline and hydralazine (p =.04), which were more frequent in non-FG. Ultrastructurally, non-FG tended to show focal MBs in predominantly podocytes, while FG showed more extensive MBs in not only podocytes but also parietal, tubular, endothelial, and myocyte cells (p =.03). In addition, half of FG had another superimposed renal disease including kappa-light chain deposition disease, thin-basement membrane nephropathy, and lithium-related changes. MBs are encountered not only in FD but in other settings including CADs, toxins, and other inheritable diseases. Although secondary causes of MBs typically show less extensive involvement compared to FD, these features overlap. Given the challenges in diagnosing female carriers, the finding of MBs, though not specific to FD, may be the only clue that leads to further work-up and timely diagnosis, underscoring the importance of considering FD among other etiologies in differential diagnosis. [ABSTRACT FROM AUTHOR]

Alveolar epithelial type II (AT2) cells secrete pulmonary surfactant via lamellar bodies (LBs). Abnormalities in LBs are associated with pulmonary disorders, including fibrosis. However, high-content screening (HCS) for LB abnormalities is limited by the lack of understanding of AT2 cell functions. In the present study, we have developed LB cells harboring LB-like organelles that secrete surfactant proteins. These cells were more similar to AT2 cells than to parental A549 cells. LB cells recapitulated amiodarone (AMD)-induced LB enlargement, similar to AT2 cells of patients exposed to AMD. To reverse AMD-induced LB abnormalities, we performed HCS of approved drugs and identified 2-hydroxypropyl-β-cyclodextrin (HPβCD), a cyclic oligosaccharide, as a potential therapeutic agent. A transcriptome analysis revealed that HPβCD modulates lipid homeostasis. In addition, HPβCD inhibited AMD-induced LB abnormalities in human induced pluripotent stem cell–derived AT2 cells. Our results demonstrate that LB cells are useful for HCS and suggest that HPβCD is a candidate therapeutic agent for AMD-induced interstitial pneumonia. [ABSTRACT FROM AUTHOR]

Mechanical ventilation triggers the manifestation of lung injury and pre-injured lungs are more susceptible. Ventilation-induced abnormalities of alveolar surfactant are involved in injury progression. The effects of mechanical ventilation on the surfactant system might be different in healthy compared to pre-injured lungs. In the present study, we investigated the effects of different positive end-expiratory pressure (PEEP) ventilations on the structure of the blood–gas barrier, the ultrastructure of alveolar epithelial type II (AE2) cells and the intracellular surfactant pool (= lamellar bodies, LB). Rats were randomized into bleomycin-pre-injured or healthy control groups. One day later, rats were either not ventilated, or ventilated with PEEP = 1 or 5 cmH2O and a tidal volume of 10 ml/kg bodyweight for 3 h. Left lungs were subjected to design-based stereology, right lungs to measurements of surfactant proteins (SP−) B and C expression. In pre-injured lungs without ventilation, the expression of SP-C was reduced by bleomycin; while, there were fewer and larger LB compared to healthy lungs. PEEP = 1 cmH2O ventilation of bleomycin-injured lungs was linked with the thickest blood–gas barrier due to increased septal interstitial volumes. In healthy lungs, increasing PEEP levels reduced mean AE2 cell size and volume of LB per AE2 cell; while in pre-injured lungs, volumes of AE2 cells and LB per cell remained stable across PEEPs. Instead, in pre-injured lungs, increasing PEEP levels increased the number and decreased the mean size of LB. In conclusion, mechanical ventilation-induced alterations in LB ultrastructure differ between healthy and pre-injured lungs. PEEP = 1 cmH2O but not PEEP = 5 cmH2O ventilation aggravated septal interstitial abnormalities after bleomycin challenge. [ABSTRACT FROM AUTHOR]

ABCA3 transports phospholipids across lamellar body membranes in pulmonary alveolar type II cells and is required for surfactant assembly. Rare, biallelic, pathogenic ABCA3 variants result in lethal neonatal respiratory distress syndrome and childhood interstitial lung disease. Qualitative functional characterization of ABCA3 missense variants suggests two pathogenic classes: disrupted intracellular trafficking (type I mutant) or impaired ATPase‐mediated phospholipid transport into the lamellar bodies (type II mutant). We qualitatively compared wild‐type (WT‐ABCA3) with four uncharacterized ABCA3 variants (c.418A>C;p.Asn140His, c.3609_3611delCTT;p.Phe1203del, c.3784A>G;p.Ser1262Gly, and c.4195G>A;p.Val1399Met) in A549 cells using protein processing, colocalization with intracellular organelles, lamellar body ultrastructure, and ATPase activity. We quantitatively measured lamellar body‐like vesicle diameter and intracellular ABCA3 trafficking using fluorescence‐based colocalization. Three ABCA3 variants (p.Asn140His, p.Ser1262Gly, and p.Val1399Met) were processed and trafficked normally and demonstrated well‐organized lamellar body‐like vesicles, but had reduced ATPase activity consistent with type II mutants. P.Phe1203del was processed normally, had reduced ATPase activity, and well‐organized lamellar body‐like vesicles, but quantitatively colocalized with both endoplasmic reticulum and lysosomal markers, an intermediate phenotype suggesting disruption of both intracellular trafficking and phospholipid transport. All ABCA3 mutants demonstrated mean vesicle diameters smaller than WT‐ABCA3. Qualitative and quantitative functional characterization of ABCA3 variants informs mechanisms of pathogenicity. [ABSTRACT FROM AUTHOR]

Aim: To develop a fast bedside lung maturity test.Methods: Gastric aspirates obtained from premature infants contain lamellar bodies, carrying lung surfactant. To estimate lung maturity, we isolated lamellar bodies from fresh gastric aspirates by centrifugation. Erythrocytes and other cells were lysed by adding water and discarded subsequently with the supernatant. Mid-infrared spectroscopy was then performed to measure the lung maturity as lecithin-sphingomyelin ratio. Lecithin was determined as dipalmitoylphosphatidylcholine, the most surface-active phospholipid. Algorithms to measure lecithin and sphingomyelin concentrations in fresh gastric aspirates were developed on aspirates from 140 premature infants. Each gastric aspirate sample was divided into two samples: one for mass spectrometry as reference and one for spectroscopy. Development of the algorithm is described in detail in Appendix S1.Results: Gastric aspirates stored at 4-5°C avoid flocculation of proteins and phospholipids in contrast to when the aspirates were frozen and thawed. Omission of freezing and concentration of the lung surfactant by centrifugation combined with diminished influence of proteins improves the spectroscopic measurement of lecithin-sphingomyelin ratio. Measurement of lecithin-sphingomyelin ratio by the new method was performed within 10-15 minutes.Conclusion: We present a new fast bedside lung maturity test on fresh gastric aspirate for early targeted surfactant treatment. [ABSTRACT FROM AUTHOR]

Abstract: Based upon the efficacy of recently developed biologics, the pathogenesis of atopic dermatitis (AD) is being attributed once again to the prominent inflammation that occurs in this disorder. Yet, molecular genetics has clearly shown that the aetiology of AD can be attributed to mutations in stratum corneum structural proteins that impact epidermal barrier function, while inflammation instead emerges as a downstream consequence of a sustained, barrier‐driven cytokine cascade. Although several different mutations that compromise barrier function are associated with AD, all of these mutations compromise either the contents or secretion of epidermal lamellar bodies. Therapies directed at specific immune participants, though effective temporarily, inevitably are followed by “rebound flares,” just as occur following glucocorticoid therapy. While occlusive moisturizers dampen inflammation, they do not address the underlying lipid biochemical abnormality in AD, which can be corrected more specifically with topical, physiologic lipid‐based forms of barrier repair therapy (BRT). Accordingly, BRT has been shown to be as effective as topical, mid‐potency steroids for the treatment of moderate‐to‐severe paediatric AD. [ABSTRACT FROM AUTHOR]

In the present work, ultrastructural changes of rat liver mitochondria in hyperthyroidism were studied. Hyperthyroidism was induced in male Wistar rats by daily administration of 100 μg thyroxin per 100 g body weight for 5 days. The level of triiodothyronine and thyroxine increased 3- and 4-fold, respectively, in comparison with the same parameters in the control group, indicating the development of hyperthyroidism in experimental animals. It was found that under this experimental pathology 58% of the mitochondria are swollen, with their matrix enlightened, as compared to the control. In 40% of the profiles, the swollen mitochondria in the liver under hyperthyroidism exhibited rounded mono- or multilayer membrane structures, called lamellar bodies (LBs), presumably at different stages of their development: from the formation to the release from the organelles. Most LBs were located in the mitochondria near the nuclear zone (27%), while their number was reduced in the part of the cell adjacent to the plasma membrane. In a number of swollen mitochondria the cristae were shown to change their orientation, being directed radially toward the center of the mitochondria. We suggested that it is the first stage of formation of LBs. The second stage can be attributed to the formation of monomembrane structures in the center of the organelles. The third stage is characterized by the fact that the membrane of the lamellar bodies consists of several layers, and in this case the bodies were located closer to the outer mitochondrial membrane. The evagination of the outer mitochondrial membrane and its connection with lamellar structure can be recognized as the fourth stage of formation of LBs. At the fifth stage the developed lamellar formations exited the mitochondria. At the same time, following the exit of LBs from the mitochondria, no damage to the mitochondrial membrane was registered, and the structure of the remaining part of the mitochondria was similar to the control. The nucleus of the hepatocyte also underwent structural changes in hyperthyroidism, exhibiting changes in the membrane configuration, and chromatin condensation. The nature and structure of the LBs, as well as their functional role in the liver mitochondria in hyperthyroidism, require further investigation. [ABSTRACT FROM AUTHOR]

Premise of the Study: Ultraviolet (UV) radiation influences the viability of algal spores and seed‐plant pollen depending on the species, the dose, and the wavelength. In bryophytes, one of the dominant groups of plants in many habitats, UV radiation could determine their spore dispersal strategy, and such data are critical for reconstructing the ancestral state in plants and for determining the distribution range and persistence of bryophyte species. Methods: Spores of four bryophyte species of the moss genus Orthotrichum that were either hygrochastic or xerochastic (spores dispersed under wet or dry conditions, respectively) were exposed to realistic doses of UV radiation under laboratory conditions. Spore viability was evaluated through germination experiments and, for the first time in bryophytes, ultrastructural observations. Given that the UV‐B doses used were relatively higher than the UV‐A doses, the UV effect was probably due more to UV‐B than UV‐A wavelengths. Key Results: All four species reduced their spore germination capacity in a UV dose‐dependent manner, concomitantly increasing spore ultrastructural damage (cytoplasmic and plastid alterations). Most spores eventually died when exposed to the highest UV dose. Interestingly, spores of hygrochastic species were much more UV‐sensitive than those of xerochastic species. Conclusions: UV tolerance determines moss spore viability, as indicated by germination capacity and ultrastructural damage, and differs between spores of species with different dispersal strategies. Specifically, the higher UV tolerance of xerochastic spores may enable them to be dispersed to longer distances than hygrochastic spores, thus extending more efficiently the distribution range of the corresponding species. [ABSTRACT FROM AUTHOR]

Alterations to the pulmonary surfactant system have been observed consistently in ventilation-induced lung injury (VILI) including composition changes and impairments in the surface tension reducing ability of the isolated extracellular surfactant. However, there is limited information about the effects of VILI on the intracellular form of surfactant, the lamellar body. It is hypothesized that VILI leads to alterations of lamellar body numbers and function. To test this hypothesis, rats were randomized to one of three groups, nonventilated controls, control ventilation, and high tidal volume ventilation (VILI). Following physiological assessment to confirm lung injury, isolated lamellar bodies were tested for surfactant function on a constrained sessile drop surfactometer. A separate cohort of animals was used to fix the lungs followed by examination of lamellar body numbers and morphology using transmission electron microscopy. The results showed an impaired ability of reducing surface tension for the lamellar bodies isolated from the VILI group as compared with the two other groups. The morphological assessment revealed that the number, and the relative area covered by, lamellar bodies were significantly decreased in animals with VILI animals as compared with the other groups. It is concluded that VILI causes significant alterations to lamellar bodies. It is speculated that increased secretion causes a depletion of lamellar bodies that cannot be compensated by de novo synthesis of surfactant in these injured lungs. [ABSTRACT FROM AUTHOR]

The article offers information on topics related to joint and spinal pain and dysbaric osteonecrosis. Topics mentioned include the causes of pain, the symptoms of decompression illness (DCI), and the analysis of phospolipids. Also mentioned are the osteonecrosis that occurs in areas with large areas of fatty marrow and the analaysis of synovial fluid.

Abstract: Amiodarone (AD) is an iodinated benzofuran derivative, especially known for its antiarrhythmic properties. It exerts serious side‐effects even in patients receiving low doses. AD is well‐known to induce apoptosis of type II alveolar epithelial cells (AECII), a mechanism that has been suggested to play an important role in AD‐induced lung fibrosis. The precise molecular mechanisms underlying this disease are, however, still unclear. Because of its amphiphilic nature, AD becomes enriched in the lysosomal compartments, affecting the general functions of these organelles. Hence, in this study, we aimed to assess the role of autophagy, a lysosome‐dependent homeostasis mechanism, in driving AECII apoptosis in response to AD. In vitro, AD‐treated MLE12 and primary AECII cells showed increased proSP‐C and LC3B positive vacuolar structures and underwent LC3B‐dependent apoptosis. In addition, AD‐induced autophagosome‐lysosome fusion and increased autophagy flux were observed. In vivo, in C57BL/6 mice, LC3B was localised at the limiting membrane of lamellar bodies, which were closely connected to the autophagosomal structures in AECIIs. Our data suggest that AD causes activation of macroautophagy in AECIIs and extensive autophagy‐dependent apoptosis of alveolar epithelial cells. Targeting the autophagy pathway may therefore represent an attractive treatment modality in AD‐induced lung fibrosis. [ABSTRACT FROM AUTHOR]

Alveolar epithelial type II ( AEII) cells are a key structure and defender in the lung but also are the targets in many lung diseases, including acute respiratory distress syndrome, ventilator-induced lung injury, and pulmonary fibrosis. We sought to establish an optimized method for high yielding and long maintenance of characteristics of primary human AEII cells to facilitate the investigation of the mechanisms of lung diseases at the cellular and molecular levels. Adult human peripheral normal lung tissues of oncologic patients undergoing lung resection were collected. The AEII cells were isolated and identified by the expression of pro-surfactant protein ( SP)C, epithelial sodium channel ( α ENaC) and cytokeratin ( CK)-8, the lamellar bodies specific for AEII cells, and confirmed by the histology using electron microscopy. The phenotype of AEII cells was characterized by the expression of surfactant proteins ( SP-A, SP-B, SP-C, SP-D), CK-8, KL-6, α ENaC, and aquaporin ( AQP)-3, which was maintained over 20 days. The biological activity of the primary human AEII cells producing SP-C, cytokines, and intercellular adhesion molecule-1 was vigorous in response to stimulation with tumor necrosis factor- α. We have modified previous methods and optimized a method for isolation of high purity and long maintenance of the human AEII cell phenotype in primary culture. This method provides an important tool for studies aiming at elucidating the molecular mechanisms of lung diseases exclusively in AEII cells. [ABSTRACT FROM AUTHOR]

Odland bodies (lamellar) bodies are small sub-cellular structures of size 200-300 nm that are present in the upper spinous and granular cell layers of the epidermis. These act as processing and repository areas for lipids that contribute to the epidermal permeability barrier. They also contain proteases, cathepsin D, kallikrein and other proteins including corneo-desmosins. Recent information also credits them with a role in the local innate immune response as they contain beta 2 defensins, which are anti-microbial peptides with potent activity against Gram-negative bacteria and candida. Odland bodies are important for maintaining homeostasis of the epidermis and are involved in epidermal permeability barrier function, desquamation of keratinocytes, formation of the cornified envelope and in local anti-microbial immunity. This article reviews the structure and functions of these bodies with a brief biography of George F. Odland who first described these bodies in 1960 and whose name is eponymically associated with them. [ABSTRACT FROM AUTHOR]

We investigated the role of flow-induced shear stress on the mechanisms regulating surfactant secretion in type II alveolar epithelial cells (ATII) using microfluidic models. Following flow stimulation spanning a range of wall shear stress (WSS) magnitudes, monolayers of ATII (MLE-12 and A549) cells were examined for surfactant secretion by evaluating essential steps of the process, including relative changes in the number of fusion events of lamellar bodies (LBs) with the plasma membrane (PM) and intracellular redistribution of LBs. F-actin cytoskeleton and calcium levels were analyzed in A549 cells subjected to WSS spanning 4-20 dyn/cm². Results reveal an enhancement in LB fusion events with the PM in MLE-12 cells upon flow stimulation, whereas A549 cells exhibit no foreseeable changes in the monitored number of fusion events for WSS levels ranging up to a threshold of ~8 dyn/cm2; above this threshold, we witness instead a decrease in LB fusion events in A549 cells. However, patterns of LB redistribution suggest that WSS can potentially serve as a stimulus for A549 cells to trigger the intracellular transport of LBs toward the cell periphery. This observation is accompanied by a fragmentation of F-actin, indicating that disorganization of the F-actin cytoskeleton might act as a limiting factor for LB fusion events. Moreover, we note a rise in cytosolic calcium ([Ca2+]c) levels following stimulation of A549 cells with WSS magnitudes ranging near or above the experimental threshold. Overall, WSS stimulation can influence key components of molecular machinery for regulated surfactant secretion in ATII cells in vitro. [ABSTRACT FROM AUTHOR]

Background: We have developed a rapid method, based on lamellar body counts (LBC) on gastric aspirate, for identifying newborns who will develop respiratory distress syndrome with a need for surfactant supplementation. Objective: We set out to test whether it was possible to improve the outcome when used in a clinical trial. Methods: We randomly assigned 380 infants born at 24-29 weeks' gestation and supported with nasal continuous positive airway pressure (nCPAP) to receive surfactant guided either by LBC (intervention group) or increasing need for oxygen (control group). The primary outcome was mechanical ventilation or death within 5 days. Secondary outcomes included need for oxygen expressed by arterial to alveolar oxygen tension ratio (a/APO2) at the age of 6 h and need for oxygen at day 28. Results: The primary outcomes were equal (25%) in the two groups. The intervention group had higher a/APO2 than the control group at 6 h, median 0.64 versus 0.52 (p < 0.01), and the subgroup with gestational age 26-29 weeks needed fewer days of oxygen supplementation than the controls, median 2 vs. 9 days (p = 0.01), and fewer infants needed oxygen at day 28 (p = 0.04). Furthermore, there was a tendency in the intervention group towards a shorter duration of nCPAP. Too little or viscose aspirate in 23% of the cases was a limitation of the method. Conclusion: Using LBC test as indicator of lung maturity and early surfactant therapy in very preterm newborns, it is possible to reduce the need for oxygen supplementation. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

To develop a rapid method for diagnosing lung maturity at birth with the purpose of administering surfactant early to infants with immature lungs and to spare infants with mature lungs from this treatment. Lamellar body counts (LBC) on gastric aspirates from 191 newborns were counted in the platelet window in automatic blood cell counters. A preliminary study was performed on 108 aspirates from 2000 in infants with <32 weeks' gestation. Furthermore, 83 aspirates from 2004 to 2005 in infants with <30 weeks' gestation were analysed. Lamellar bodies in gastric aspirate were identified by electron microscopy. Seventy of the aspirates from 2004 to 2005 were analysed with a Sysmex XE-2100 (Sysmex, Holbæk, Næstved, Odense and Rigshospitalet, Denmark) counter. Twenty-four of these infants developed moderate to severe respiratory distress syndrome (RDS). The best cut-off value was 8000/μL with a sensitivity of 75% and a specificity of 72%. Forty-four of the 70 aspirates from 2004 to 2005 were analysed by Sysmex, Advia 120 and Cell-Dyn 4000. Thirteen other aspirates from 2004 to 05 were analysed by Sysmex and Coulter Counter LH755. Using Advia and Coulter the results were similar to Sysmex, but LBC obtained with Cell-Dyn were not correlated with the development of RDS. Lamellar body counts on gastric aspirate is a promising tool for prediction of development of RDS in infants of <30 weeks` gestation. [ABSTRACT FROM AUTHOR]

Alveolar epithelial (AE) surface area is closely correlated with body mass (BM) in mammals. The AE is covered by a surfactant layer produced by alveolar epithelial type II (AE2) cells. We hypothesized that the total number of AE2 cells and the volume of intracellular surfactant-storing lamellar bodies (Lb) are correlated with BM with a similar slope as AE surface area. We used light and electron microscopic stereology to estimate the number and mean volume of AE2 cells and the total volume of Lb in 12 mammalian species ranging from 2 to 3 g (Etruscan shrew) to 400-500 kg (horse) BM. The mean size of Lb was evaluated using the volume-weighted mean volume and the volume-to-surface ratio of Lb. The mean volume of AE2 cells was 500-600 µm³ in most species, but was higher in Etruscan shrew, guinea pig, and human lung. The mean volume of Lb per AE2 cell was 80-100 µm³ in most species, with the same exceptions as above. However, the total number of AE2 cells and the total volume of Lb were closely correlated with BM and exhibited an allometric relationship similar to the slope of AE surface area. The mean size of Lb was similar in all investigated species. In conclusion, the mean volume of AE2 cells and their Lb are independent of BM but show some interspecific variations. The adaptation of the intracellular surfactant pool size to BM is obtained by the variation of the number of AE2 cells in the lung. [ABSTRACT FROM AUTHOR]

Objective. The detection of amniotic lamellar bodies (LB) has been shown to be a rapid and simple way to assess fetal lung maturity (FLM). The maturity thresholds for LB vary due to different factors, one being the type of particle-count analyser used. Material and methods. The SysmexR XE-2100 hematological analyser was evaluated in determination of amniotic LB counts and compared with lecithin/sphingomyelin (L/S) and phosphatidylglycerol (PG) determination. We analysed 132 amniotic samples from a total of 109 mothers (71 diabetic) with 112 infants. Results. The correlation between the LB counts obtained with the SysmexR XE-2100 and our reference thin layer chromatography (TLC) phospholipid method was good. Samples with low L/S ratio (≤2.0) and no PG (i.e. premature fetal lung status), had low LB counts ( n = 18, mean 8500/uL, range 1000–26000), whereas 51 samples with mature fetal lung status had high LB counts (mean 63600/uL, range 20,000–139,000). In all our four cases of respiratory distress syndrome the LB counts were low (range 1000 – 28000/uL). The reference values for FLM determination were established: ≤6000/uL for immature, values between 7000 and 35,000/uL for borderline results and >35,000/uL for mature. Conclusions. The amniotic LB count analysis with SysmexR XE-2100 has many advantages being a repeatable, inexpensive and quantitative method with a very short turn-around time. Consequently, our routine is to perform LB counts initially from all amniotic samples and only borderline LB results are analysed with TLC. [ABSTRACT FROM AUTHOR]

The surfactant system of the lung has essential biophysical and immunomodulatory functions. Only at the electron microscopic level does surfactant reveal its morphological complexity - and beauty. Therefore, morphological tools are indispensible to characterize the surfactant system in health and disease. Stereology provides the gold standard for obtaining quantitative (morphometric) data in microscopy. The combination of microscopy and stereology allows for qualitative and quantitative analysis of the intraalveolar as well as the intracellular surfactant pool, both in its preserved microorganization and localization within the lung. Surfactant-producing alveolar epithelial type II cells can be counted and sampled for size estimation with physical disectors at a high magnification light microscopic level. The number of their surfactant storing lamellar bodies can be estimated using physical disectors at the electron microscopic level. Electron tomography allows for high resolution 3D visualization of lamellar body fusion pores. Intraalveolar surfactant subtypes can be quantitated in situ, thus reflecting the functional state of the intraalveolar surfactant pool. By immunoelectron microscopy, surfactant protein distribution can be analyzed. These methods allow for a comprehensive quantitative analysis of surfactant (ultra-)structure. Here, we give an overview on the analysis of the normal and disordered surfactant system by electron microscopy and stereology. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Alveolar type II (ATII) cells produce surfactant and release it into the alveolar space via exocytosis of lamellar bodies (LBs). On the other hand, various forms of endocytosis take place, enabling the recycling of surfactant as well as of integral membrane proteins to the LB. Here we investigated the trafficking of protein and lipid components of plasma membrane between the plasma and limiting LB membrane by over-expressing lysosomal associated membrane protein 3 fused to green fluorescence protein (LAMP-3-GFP) and farnesylated DsRed (DsRed-Farn). LAMP-3-GFP was homogenously distributed over the entire limiting LB membrane, whereas DsRed-Farn predominantly accumulated at the plasma membrane. However, in a minor LB fraction, DsRed-Farn was also found in discrete domains at its limiting membrane. Upon stimulation of ATII cells with secretagogues, the area of DsRed-Farn domains on LB surfaces increased 2 to 4 fold within 20 minutes of stimulation. This increase remained unaffected by phenylarsine oxide, an inhibitor of clathrin-dependent endocytosis, but was almost abolished by filipin and indomethacin, blockers of clathrin-independent endocytosis. It was also blocked by bafilomycin A1, wortmannin and LY294002, inhibitors of intra-cellular vesicular transport. We conclude that secretagogues facilitate the transport of plasma membrane components to LBs via a clathrin-independent vesicular transport pathway. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

A flow cytometry method, to monitor peripheral lymphocytes phospholipidosis, has been set up using a single staining with Nile red and double staining with Nile red and anti-CD3 monoclonal antibody. Blood has been collected from rats treated with amiodarone (phospholipidogenic antiarrhythmic drug). By flow cytometer, it is possible to detect phospholipids, using Nile red, a probe for intracellular lipids staining, changing its fluorescence on the stained lipid basis. CD3 antigen has been selected to focus on T cells, to evaluate whether these cells are the target of phospholipidosis amiodarone-dependent. In the study A, Sprague–Dawley rats were treated with three different doses (75, 150, and 300 mg kg−1 day−1) of amiodarone or vehicle alone, for 14 days, followed by 14 days of recovery: Data obtained show that by flow cytometry, with Nile red alone, it is possible to detect a dose- and time-related response of phospholipidosis-positive lymphocytes; a partial recovery is also assessed. In the study B, Sprague–Dawley rats were treated with a single dose (300 mg kg−1 day−1) of amiodarone, for 14 days: Data obtained show that animals treated with amiodarone have a significant increase of phospholipidosis-positive lymphocytes ( p = 0.008), in particular of CD3+ cells ( p = 0.0056). Transmission electron microscopy analysis confirmed data obtained by flow cytometry. This work shows that flow cytometry with Nile red could be a good tool to monitor ex vivo phospholipidosis in lymphocyte cells of animals treated with amiodarone: The phospholipidogenic effect is more evident focusing on CD3+ T lymphocytes, thus suggesting that these cells are probably the target of phospholipidosis. [ABSTRACT FROM AUTHOR]

Background Maintenance of a competent permeability barrier in the face of external and internal stressors requires signals between the stratum corneum interface and the metabolic machinery in the underlying nucleated layers. For example, reductions in the ion gradients for Ca2+ after acute barrier disruption stimulate lamellar body (LB) secretion, a response required to restore barrier homeostasis. Although alterations in external K+ levels also regulate barrier recovery after acute insults, the mechanisms whereby K+ regulates barrier function remain unknown. Objectives To evaluate effects of regulators of K+ channels on barrier homeostasis in hairless mice. Methods We tested a number of chemically different drugs that alter intracellular K+ levels. Results Single applications of either K+ channel openers (i.e. 1-EBIO, minoxidil, diazoxide) or the K+ ionophore, valinomycin, accelerated barrier recovery after acute insults to murine skin, paralleled by a reduction in intracellular K+ levels in cultured human keratinocytes. In contrast, applications of K+ channel blockers (i.e. gilbenclamide, dequalinium) delayed barrier recovery. Alterations in intracellular K+ regulated barrier homeostasis by either stimulating (reduced K+) or inhibiting (elevated K+) LB secretion. Finally, development of epidermal hyperplasia, a downstream consequence of barrier disruption, was also inhibited by agents that reduce intracellular K+ levels. Conclusions These results demonstrate that changes in K+ levels that can be presumed to occur after barrier disruption signal metabolic responses, i.e. LB secretion, which accelerates normalization of barrier function. [ABSTRACT FROM AUTHOR]

Molecular mechanisms of surfactant delivery to the air/liquid interface in the lung, which is crucial to lower the surface tension, have been studied for more than two decades. Lung surfactant is synthesized in the alveolar type II cells. Its delivery to the cell surface is preceded by surfactant component synthesis, packaging into specialized organelles termed lamellar bodies, delivery to the apical plasma membrane and fusion. Secreted surfactant undergoes reuptake, intracellular processing, and finally resecretion of recycled material. This review focuses on the mechanisms of delivery of surfactant components to and their secretion from lamellar bodies. Lamellar bodies-independent secretion is also considered. Signal transduction pathways involved in regulation of these processes are discussed as well as disorders associated with their malfunction. [ABSTRACT FROM AUTHOR]

Objectives: To compare the morphological changes and quantitative distribution of lamellar bodies (Lb) (membrane coating granules) in the hamster cheek pouch epithelium with smokeless tobacco (ST). Materials and methods: Archives of experimental material from previously published studies [S. Ashrafi, A. Das, R. Worawongvasu, B. Mehdinejad and J. Waterhouse (1992) Scanning Microscopy 6: 183] were utilized. Animals in experimental group received most ST (snuff) in their right pouch, 5 days weekly, for 24 months, while no snuff was given to control group. After 24 months, the epithelial tissues were processed for electron microscopic study. Volume densities of Lb were assessed by morphometry. Main outcome measures: Densities of Lb in the two groups, experimental vs control. Results: In the control, Lb extruded their contents into the intercellular spaces of upper granular layers and in between the last granular cell layers and keratin layers to form a permeability barrier. Conversely, in the smokeless tobacco-treated epithelium, the majority of the Lb that were formed remained inside and accumulated within the granular cells, without extruding their contents into the intercellular spaces to form a lipid compound permeability barrier. Conclusions: Commercial alkaline ST may have contributed to the abnormal accumulation of Lb in the granular cell layer and affected the extrusion process of Lb to form an incomplete permeability barrier in the oral epithelium. [ABSTRACT FROM AUTHOR]

Objective: To determine if lamellar body counts determined using light microscopy and a manual hemochromocytometer correlate with counts made on standard electronic cell counters. Methods: Aliquots of amniotic fluid samples obtained by amniocentesis to assess fetal lung maturity were divided into two sterile tubes. One tube was sent immediately to be counted in a cell counter by standard technique and the other tube was stored at –70°C until manual counting could be performed. Manual counts on the same samples were made on two different occasions. Intra-observer variability and correlation with the standard technique was determined. Pearson coefficient was calculated. Results: There were 11 specimen pairs. The intra-observer correlation was significant: intraclass correlation coefficient 0.95 (CI 0.84–0.99). There was significant correlation between the Coulter counter lamellar body counts and manual counts: intraclass correlation coefficients 0.88 (CI 0.62–0.97) and 0.92 (CI 0.73–0.98), respectively. Conclusion: Lamellar body counts determined by light microscopy correlate well with results obtained for lamellar body counts using standard Coulter counter techniques. Results of this pilot study show that this experimental method of evaluating fetal lung maturity deserves further evaluation. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

On immunohistochemical examination several morphological types of disease-specific prion protein (PrPd) accumulation are recognised in the brain of sheep suffering from scrapie. The present study examined the relationship between the type of PrPd deposits seen by light microscopy and ultrastructural changes in the olivary nuclei and the dorsal motor nucleus of the vagus (DMNV) in naturally infected sheep with clinical scrapie. The nature and magnitude of sub-cellular morphological changes found in the olivary nuclei differed from the patterns of degeneration previously described in the DMNV. In the olivary nuclei, lamellar bodies in the neuronal perikaryon were found to correlate with marked intraneuronal PrPd accumulation. Bizarre, coated, spiral invaginations of the plasmalemma were only found in A136 homozygous sheep in this nucleus, where few coated pits were usually observed. Neuropil vacuolation in the olivary nuclei was mild and correlated with sparse extracellular PrPd deposition. In the DMNV, the magnitude of extracellular immunolabelling in the neuropil was prominent. These extracellular PrPd aggregates coincided with intense neuropil vacuolation, increased numbers of coated pits, and with the presence of pre-amyloid changes and infrequent short fibrils in the extracellular space. Scrapie-infected neurons in the two neuroanatomic sites examined, therefore, appear to process and respond to the presence of PrPd differently. We hypothesise that vacuolation, coated pits and spiral invaginations of the plasmalemma may be responses to extracellular PrPd molecules, and that lamellar bodies are changes associated with the high levels of intraneuronal PrPd. [ABSTRACT FROM AUTHOR]

Objectives: To determine the number of lamellar bodies in the amniotic fluid indicating fetal lung maturity and to define the effectiveness of a diagnostic test in a healthy pregnant population. Methods: The study took place at the Hospital General de Zona #16 Centro Me´dico Nacional del Instituto Mexicano del Seguro Social. Torreo´n, Coahuila, Me´xico, where 264 pregnant women were followed-up from August 1997 to October 1998. The women presented in labor between 26 and 41 weeks of gestation. Amniotic fluid was obtained during cesarean section or from the vaginal pool and lamellar bodies were counted without prior centrifugation in Cell-Dyn 3000's channel for blood platelets. Results were masked for neonatologists. Results: The prevalence of respiratory distress syndrome (RDS) was found to be 14.9%. At the 8200/μl threshold, sensitivity was: 15.4% (95% CI=5.9–30.5%), specificity: 99.6% (95% CI=97.5–99.9%), positive predictive value (PPV): 85.7, negative predictive value (NPV): 87.1, likelihood ratio for a negative test (LR−): 0.85, and likelihood ratio for a positive test (LR+): 85.7. At the 57 000/μl level, sensitivity was: 92.3% (95% CI=79.1–98.3%), specificity: 70.9% (64.4–76.7%), PPV: 35.6, NPV: 98.1, LR−: 0.11, and LR+: 3.17. When the cut-off point was 79 000/μl, sensitivity was: 100.0%, specificity: 43.0% (95% CI=36.5–49.8%), PPV: 23.5, NPV: 100.0, LR+: 34.3, and LR−: less than 0.001. Conclusions: Counting lamellar bodies is a quick, readily available, and very effective test. [Copyright &y& Elsevier]

Aims Giant lamellar bodies (GLBs) are rare pulmonary inclusions, most frequently described in sclerosing haemangiomas. Following a recent report of their presence in a case of pulmonary lymphoma of MALT origin, our aims were to determine their frequency in pulmonary lymphoproliferative disorders, examine their structure and investigate their aetiology further. Methods and results We reviewed a series of 29 pulmonary lymphomas (23 low-grade, six high-grade) and 18 cases of reactive pulmonary lymphoid hyperplasia. Five of 23 (22%) low-grade lymphomas contained GLBs, 4/4 of which stained for surfactant apoprotein A but not for surfactant apoprotein B. No GLBs were seen in 18 cases of reactive pulmonary lymphoid hyperplasia or six high-grade primary pulmonary lymphomas. Ultrastructural examination revealed concentrically arranged extracellular material forming roughly spherical structures up to 25 μm in diameter. The GLBs were often surrounded by foamy cells and cholesterol clefts, supporting an origin, at least in part, from products of cell breakdown and surfactant degradation. Conclusion These findings support the idea that the presence of lamellar bodies is in part due to stasis of products arising from degradation of surfactant, in association with certain types of chronic pulmonary pathology. Given their absence in reactive pulmonary lymphoid hyperplasia, the presence of GLBs as an epiphenomenon in a pulmonary lymphoid infiltrate should warrant careful investigation with regard to the diagnosis of low-grade MALT lymphoma. [ABSTRACT FROM AUTHOR]

Structures identified as annulate lamellae, lamellar bodies and subsurface cisternae were found in neurons of the hyperstriatum accessorium of the avian forebrain. Annulate lamellar arrays with up to six lamellae were present in the larger somata. The lamellae were made up of fused smooth-surfaced cisternae forming pores or annuli and were surrounded by a dense filamentous to granular material. Stacks of nonfenestrated, parallel, regularly spaced cisternae, designated as lamellar bodies, also appeared in the cytoplasm. When flattened they were reminiscent of the electron dense subsurface cisternae. Continuity could be demonstrated between peripherally located subsurface cisternae and lamellar bodies. The dense filamentous to finely granular substance was also located between these structures. Annulate lamellae, lamellar bodies and subsurface cisternae were always observed in conjunction with the rough endoplasmic reticulum. The functional significance of these structural associations is considered. [ABSTRACT FROM AUTHOR]

The columnar epithelial cells of the gas gland in the swimbladder of the toadfish, Opsanus tau L., contain lamellar bodies that resemble the lamellar bodies found in epithelial cells of vertebrate lungs. Cytochemical assays indicate that swimbladder lamellar bodies are soluble in chloroform-methanol solution, react with tricomplex flocculation solution (indicating a phospholipid component), exhibit a positive reaction for cholesterol when exposed to digitonin, and contain acid phosphatase. The anterior chamber of the toadfish swimbladder is lined by an extracellular layer. Digitonin-cholesterol crystals are found in this layer when the swimbladder is treated with digitonin. A ruthenium red positive layer is also present in the anterior chamber of the toadfish swimbladder. The structure and cytochemistry of swimbladder lamellar bodies are compared with those of vertebrate lung lamellar bodies. Similarities between the extracellular layer in the swimbladder and the extracellular layer in lungs are also noted. [ABSTRACT FROM AUTHOR]

Lamellar bodies in first cleavage Xenopus laevis embryos have been examined with the electron microscope. Based on the arrangement and relative thickness of the lamellae, three types of lamellar bodies have been identified. In the first type, a band of two to ten lamellae (spacing about 3.5 nm) was intertwined at random. This type of lamellar body was seen closely associated with the concave or the forming face of the Golgi body and may have been derived from this organelle. The frequent association of these lamellar bodies with the growing cleavage furrow may suggest a transfer of materials from the Golgi body to the furrow through the lamellar bodies or their precursors. In the second type, typical myelin-like figures with a repeating distance of about 10 nm were located close to the furrow tip. In the third type, membrane whorls containing tetrads of lamellae (approximately 16 nm thickness) were seen associated with lipid droplets. If the lamellar bodies observed in this study were formed during fixation then the appearance of three different types after the same fixation procedure would indicate the presence of a similar number of pools of precursor materials which differ in their chemical composition and distribution in the embryo. [ABSTRACT FROM AUTHOR]

Biochemical and ultrastructural analysis of epidermis from the porpoise, Phocena phocena, revealed certain similarities and differences between cetaceans and terrestrial mammals. The predominant cell of cetacean epidermis, not found in normal terrestrial mammals, is a lipoker-atinocyte, which elaborates not only keratin filaments, but also two types of lipid organelles: first, lamellar bodies, morphologically identical to those of terrestrial mammals, are elaborated in great abundance in all suprabasal epidermal layers, forming intercellular lipid bilayers in the stratum corneum interstices: and second, non-membrane-bounded droplets appear and persist in all epidermal layers. Although the porpoise lipokeratinocyte morpologically resembles the sebokeratocyte of avians in certain respects, nonmembrane-bounded lipid droplets are not released into the intercorneocyte space as they are in avian stratum corneum. Whereas phospholipid/neutral lipid gradients are similar in porpoise and terrestrial mammals, PAS-positive glycoconjugates, specifically glycosphingolipids, are retained in porpoise stratum corneum, but lost from these layers in terrestrials. The novel, non-polar acylglucosyl-ceramides, which also are lost during cornification in terrestrial mammals, are retained in porpoise stratum corneum. The lipid components of porpoise lipokeratinocytes appear to subserve not only barrier function in a hypertonic milieu, but also underlie the unique buoyancy, streamlining, insulatory, and caloric properties exhibited as adaptations to the cetacean habitat. [ABSTRACT FROM AUTHOR]

The fine structure of subsurface cisternae and lamellar bodies in the outer hair cells of the guinea-pig organ of Corti was studied with thin sections and freeze-fracture replicas. Subsurface cisternae in the outer hair cells consist of multilayers along the lateral plasma membrane of the cell. The outermost layer is a flattened cistern in the upper part of the supranuclear region, but comprises a series of tubules in the lower part. Deeper layers are fenesrated cisternae in which disc-like areas are found in the upper part of the supranuclear region. Lamellar bodies consist of concentric layers of fenestrated cisternae and are located in the apical cytoplasm beneath the cuticular plate. They are continuous with the subsurface cisternae. In the supranuclear cytoplasm, bulges of the subsurface cisternae and the lamellar bodies are found. Dilated cisternae are also present. Some dilated cisternae contain many small vesicles, which display acid phosphatase activity. The dilated cisternae are considered as forms of the bulges undergoing transformation into multivesicular bodies. The possible role of the lamellar bodies, and the origin and fate of the subsurface cisternae are discussed. [ABSTRACT FROM AUTHOR]

Subsurface cisterns (SSC's) and less frequent lamellar bodies (LB's) were identified in the granule cells of the guinea-pig fascia dentata. Both structures, composed of flattened or collapsed agranular cisterns, are continuous with the regular rough endoplasmic reticulum and occasionally connected with each other forming LB-SSC complexes. The SSC's are apposed to glia, synaptic boutons, and nerve cell processes as well as to neighboring granule cells appearing here singly and in confronting pairs. The quantitative analysis of the various cisternal appositions compared to the distribution of the tissue components on the granule cell soma shows that the overwhelming majority of SSC's are related to glial cells. [ABSTRACT FROM AUTHOR]

Lung tissue expiants from mid-trimester human abortuses were maintained for 8 days in organ culture in medium with or without serum. Before the start of culture the cells lining the pre-alveolar ducts were undifferentiated and contained no lamellar bodies, the intracellular organelle that contains surfactant. After 4 days in organ culture, the epithelium lining the pre-alveolar ducts was composed of differentiated type II cells containing numerous lamellar bodies. During the 8-day culture period there was increased incorporation of [H]choline into phosphatidylcholine and disaturated phosphatidylcholine. In addition, the specific activity of phosphatidate phosphohydrolase, a regulatory enzyme in lung phospholipid synthesis, increased 4-fold during the culture period. Lamellar bodies isolated by differential centrifugation from expiants maintained in culture for 7 days had the characteristic ultrastructure described for this organelle. Lamellar bodies were isolated from expiants which had been incubated with [C]glycerol. When the glycerophospholipid composition of lamellar bodies was analyzed it was found that the majority of the radiolabeled glycerol (74%) was incorporated into phosphatidylcholine and into the anionic phospholipids, phosphatidylglycerol (5%) and phosphatidylinositol (6%). Thus, human fetal lung expiants maintained in organ culture contain differentiated type II cells which synthesize surfactant characteristic of human fetal lung at 36 to 38 weeks of gestation. [ABSTRACT FROM AUTHOR]

Previous studies have shown that synovial surfactant could have beneficial roles in the joint, especially as a very effective boundary lubricant capable of high load bearing. This study is aimed at further characterization and identification of the source. Known to be an important minor component of pulmonary surfactant, proteolipid has now been detected in appreciable quantities in bovine synovial fluid and bound to the articular surface. Using standard procedures to separate it from the major component [surface-active phospholipid (SAPL)] by column chromatography, proteolipid :phospholipid ratios were found to be comparable to those in the lung or in lamellar bodies (LBs). LBs are the unequivocal source of surfactant in the lung and we have confirmed an earlier study demonstrating their presence in Type B synoviocytes. Using a fixation procedure specifically designed to preserve the graphite-like structure of SAPL deposited as oligolamellar layers, or coiled as lamellar bodies, we were able to demonstrate these structures in equine joints adjacent to the Golgj apparatus associated with the secretory mechanism of the cell. These results indicate that proteolipid could be facilitating the deposition of the graphite-like surface lining of SAPL providing efficient boundary lubrication just as it promotes surfactant adsorption in the lung and in the formation of myelin. Any deficiency in synovial surfactant, compromising its roles in the joint, is discussed in relation to osteoarthritis and the possible administration of exogenous SAPL to the degenerating joint. [ABSTRACT FROM PUBLISHER]

The intra- and extracellular distribution and relative density of lamellar bodies (LBs) were determined by electron microscopy in synovial biopsies from 20 non-rheumatoid arthritis (RA) patients. LBs were found on the synovial surface, in Lntimal cells, throughout intimal matrix, in blood vessel walls, in endothelial cytoplasm and within vascular lumena. Lamellar profiles were observed in type B synoviocytes within rough cndopLasmic reticulum (RER), in association with the Golgi apparatus, and embedded in electron dense matrix (projection cores) in multivesicular bodies. Exocytotic release of mature LBs into intimal matrix was observed. In type A synoviocytes the outer lamellae of LBs were frequently found in contiguity with the limiting membrane of lysosomes. An investigation of the ultrastructural features of LB formation in cultured type B synoviocytes (from 3 non-RA patients) gave results similar to those obtained in biopsies. These studies provide ultrastructural evidence of synoviocyte activity in secreting and degrading phospholipid lubricant in a sophisticated system whose function and pathological derangements are largely unknown. [ABSTRACT FROM PUBLISHER]

Intracytoplasmic lamellar organelles identical in ultrastructure to surfactant-containing lamellar bodies found in type II pneumocytes, have been demonstrated in other tissues, in synoviocytes and mesothelial cells, in a distribution pattern which reflects the systemic expression of rheumatoid disease. Antibodies raised against surfactant protein A (SP-A), exhibit a ranking of tissue reactivity in area, intensity and density of cells which also parallels the frequency and degree of pathological involvement characteristic of rheumatoid disease, showing in ascending order of immunopositivity, lachrymal and salivary epithelia, pulmonary parenchyma, mesothelium and synoviocytes. Maximal tissue reactivity to anti-SP-A antibodies was found in the synovium of 55 rheumatoid patients exhibiting classical histopathological appearances of RA, in a pattern of immunostaining identical to that obtained with ML30, an antibody to mycobacterial heat shock protein 65kDa which, in turn, cross-reacted with SP-A in dot blot testing. [ABSTRACT FROM PUBLISHER]

The fetal respiratory distress syndrome is due, in part, to the presence of abundant pre-type II alveolar epithelial cells that have not yet differentiated into mature type II cells. Studies of this syndrome have been limited somewhat by the lack of an adequate in vitro model. In the present study we immortalized pre-type II cells by infecting primary isolates obtained from fetal rat lung with a retroviral construct expressing the adenoviral 12S E1A gene product. The immortalized pre-type II cells retained many of the ultrastructural features typical of pre-type II cells in primary culture, most notably lamellar bodies were not detected and the cells contained abundant stores of glycogen, expressed cytokeratin filaments, and bound the lectin Maclura pomifera. Karyotyping revealed that the cells are diploid. Growth studies demonstrate log phase growth in the presence of serum with a markedly decreased growth rate shortly after the cells reach confluence. Exposure of the immortalized pre-type II cells to hydrocortisone and dibutryl cAMP resulted in the induction of lamellar bodylike organelles; however, these cells did not secrete surfactant or express surfactant protein A. These cells may serve as useful models for some in vitro studies of fetal type II cell maturation or the fetal respiratory distress syndrome, or both. [ABSTRACT FROM AUTHOR]

Amiodarone HCl (AD) is a very effective antiarrhythmic drug, but its use is often associated with serious pulmonary complications. It is shown to induce lung phospholipidosis. Nevertheless, the effects of this drug on pulmonary surfactant which is composed of about 75% phospholipids and which prevents alveolar collapse is not known. Therefore, we have examined the effect of AD on the intra- and extracellular surfactant pools and on the levels of phosphatidylcholine (PC), the primary constituent of pulmonary surfactant. Male Wistar rats were fed AD (175 mg/kg) by oral gavage for three weeks. At the end of the experimental period, the rats were killed, the lungs removed and perfused, and surfactant isolated. Some lungs were prepared for ultrastructural examination. Phospholipid was assayed in the intra- and extracellular surfactant. Amiodarone produced a significant increase in both the intra- and extracellular sufactant phospholipid along with an appreciable change in the phospholipid profile. Also, the drug seemed to increase the number of lamellar inclusions in the surfactant producing type II alveolar cells. These data suggest that administration of AD leads to an increase in the lung surfactant phospholipid levels and lamellar bodies in alveolar type II cells. [ABSTRACT FROM AUTHOR]

The behavior of fibroblast-populated collagen lattices under mechanical stress was studied. Lattice retraction was blocked to allow the application of mechanical stress by contraction of the fibroblasts against the fixed ends of the lattice. The forces were modulated by varying the collagen/fibroblast ratio and the amount of collagen fibrils produced, by which the forces were transmitted. Transmission electron microscopy showed several disturbances of fibroblast ultrastructure, with empty and full vacuoles, lamellar bodies and signs of cytolysis. It is suggested that the morphological alterations in the fibroblasts may constitute a feedback reaction to the mechanical stress. [ABSTRACT FROM AUTHOR]

Birds in the genus Pitohui and Ifrita carry potent neurotoxins that are most abundant in skin and feathers. It was unknown precisely how or where in the skin these chemicals are stored. Here, we report high-resolution electron microscopy using Os O4 staining to visualize the location of alkaloids. Our images suggest that toxic alkaloids accumulate in multigranular bodies of epidermal cells and are likely secreted as part of the avian epidermal barrier, where they are made available for chemical defense. [ABSTRACT FROM AUTHOR]

Structures identified as subsurface cisterns (SSC's) and lamellar bodies (LB's) have been observed in the neurons, but not in the glial cells, of the rat and cat substantia nigra. The SSC's are most often opposite what appears to be glial cells, but they are also subsynaptic in position. A single, large (0.4-1.5 μ), unfenestrated, usually flattened cistern closely underlies the inner aspect of the plasma membrane of the perikaryon and proximal parts of the neuronal processes at a regular interval ranging about 100-130 Å. They are sheet-like or discoid in configuration and consists of a pentalaminar structure which usually widens at its lateral edges where its membranes are continuous with each other or with rough ER profiles. Filaments, about 70 Å thick, bridge the cleft between the SSC and the overlying plasmalemma. One or more ER cisterns devoid of ribosomes except on their outermost membrane may be stacked up parallel to an SSC and immediately subjecent to it. A dense filamentous network intervenes between the SSC and its closely applied ER cisterns. At higher magnification, it is seen to consist of a finely textured material which is apparently composed of loosely packed tiny particles. These constituent subunits in turn may represent transverse sections of very fine filaments rather than granules. A mitochondrion frequently occurs in the immediate vicinity of an SSC and may be closely applied to its deep surface. Stacks of unfenestrated, parallel, regularly spaced (about 300-400 Å) cisterns, designated lamellar bodies, appear deeper in the karyoplasm. They are most often flattened and appear as pentalaminar structures. These cisterns, as well as the dense filamentous network intervening between them, are structurally similar to those closely applied to SSC's. They are also devoid of ribosomes except on their outermost surfaces. Whorls of similar cisterns are also occasionally observed. Another particular feature of the rough ER consists of the close apposition of two cisterns without any ribosome attached to the inner membranes of the latter structure. It evokes a simplified type of LB's. It is of particular interest to point out that all these cisterns, i.e. the SSC's, their closely applied cistern(s) and those forming the LB's, are connected to the RER membranes, so that a continuous channel occurs between the nuclear membrane and the SSC which closely underlies the plasma membrane. Our observations show that the SSC's and the LB's are structurally related forms of the ER. A parallel may be drawn between the SSC and the lateral element(s) of a dyad (triad). The structural complex consisting of an SSC, the overlying plasmalemma and the cross-bridges linking them, indeed, bears some resemblance to a dyad. It is suggested that membranes which are closely applied may interact, resulting in alterations in their respective properties. These patches of the neuronal plasma membrane associated with SSC's may, therefore, have special properties because of this relationship, resulting in a non-uniform spread of an action potential on the neuronal surface. The possible significance of SSC's in relation to neuronal electrophysiology, as well as of the latter structures and LB's in relation to cell metabolism, is to be discussed. [ABSTRACT FROM AUTHOR]

Lamellar bodies are described in the non-ciliated epithelial bronchiolar cells of the normal mouse lung. They are constituted of smooth concentric membranes, with a cytoplasmic center. They are related to mitochondria. They seem to belong to smooth endoplasmic reticulum. An origin from Golgi elements is discussed. [ABSTRACT FROM AUTHOR]