Comparison of amounts of collagen and elastin in pleura and parenchyma of dog lung

1984 ◽  
Vol 56 (5) ◽  
pp. 1383-1388 ◽  
Author(s):  
E. H. Oldmixon ◽  
F. G. Hoppin
Keyword(s):  
Collagen Fibrils ◽  
Visceral Pleura ◽  
Structural Explanation ◽  
Structural Result ◽  
Substantial Role ◽  
Frictional Forces ◽  
Volume Characteristics ◽  
Alveolar Septa ◽  
Alveolar Parenchyma

Pressure-volume characteristics of the lung have been thought to be due primarily to the properties of the network of alveolar septa. However, Hajji et al. (J. Appl. Physiol.: Respirat . Environ. Exercise Physiol. 47: 175–181, 1979) attributed a substantial role to the visceral pleura. Seeking a structural explanation for this result, we compared the relative amounts of collagen fibrils and elastin fibers in the visceral pleura and alveolar parenchyma using stereological measurements in five canine lobes. We found about one-fifth as much collagen and one-tenth as much elastin in the pleura as in the alveolar parenchyma. This structural result confirms the functional conclusions of Hajji et al. We argue that such a substantial structure is not needed for protection against overinflation but may have to do with stabilization of lobe shape or handling of frictional forces.

Lengths and topology of alveolar septal borders

1989 ◽  
Vol 67 (5) ◽  
pp. 1930-1940 ◽  
Author(s):  
E. H. Oldmixon ◽  
J. P. Butler ◽  
F. G. Hoppin
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Free Standing ◽  
And Topology ◽  
Section Area ◽  
Dimensional Reconstruction ◽  
Alveolar Duct ◽  
Mechanical Linkage ◽  
Alveolar Septa ◽  
Alveolar Parenchyma

To clarify the mechanics of alveolar parenchyma, we undertook a stereological and topological study in perfusion-fixed canine lungs of the borders of alveolar septa. We defined the principal borders as those along which one septum 1) joins two others (J), 2) joins one other at a distinct angle (B), or 3) joins no other structure (E). E and B borders are invariably reinforced with heavy connective tissue cables; J borders are not. Relative net lengths, determined from the number of traces per section area, were J, 45%; E, 19%; and B, 25%. These were remarkably constant over 10 canine lobes (5 animals, 4 volumes). Parenchyma, then, departs from the simple models that comprise only Js and Es. Bs are important; their net length exceeds that of Es. With lobe deflation, E shortened somewhat more than required to maintain geometric similarity, suggesting that the alveolar duct contracted disproportionately. A three-dimensional reconstruction was made from serial sections, and individual border segments were followed through the reconstruction. Typical lengths of individual J, B, and E borders were nearly equal. To characterize how the network of borders were interconnected, we counted the nodes at which they meet by class, e.g., EBE for the meeting of one B, two Es. The most common are JJJJ, 26%; EEEJ, 10%; EBJ, 24%; EBE, 8%; BBJJ, 12%. If parenchyma were constructed only from free-standing entrance rings and septal junctions, only JJJJ and EEEJ would be anticipated. The presence of EBJ, EBE, and BBJJ underscores parenchymal complexity. Only 7% of septa examined were bordered entirely by Js. Connective tissue cables were not confined to the alveolar duct's lumen but often extended to the primary septa at the periphery of the ductal unit. They rarely linked adjacent alveolar ducts; only 1 in 200 cable segments crossed from one duct to another. These observations support the concept that the parenchyma is an elastic network, characterized in part by a serial mechanical linkage from connective tissue cable to septal membrane to cable again.

scholarly journals The potential protective role of coenzyme q10 on the cyclophosphamide-induced lung toxicity in adult male albino rats: a histological and ultrastructural study

2018 ◽  
Vol 4 (9) ◽  
pp. 225 ◽  
Author(s):  
Nouran K. Olama ◽  
Medhat Taha ◽  
Hagar Y. Rady
Keyword(s):  
Adult Male ◽  
Coenzyme Q10 ◽  
Histopathological Examination ◽  
Treated Group ◽  
Collagen Fibrils ◽  
Lung Toxicity ◽  
Albino Rats ◽  
Blood Capillaries ◽  
Ultrathin Sections ◽  
Alveolar Septa

<p class="abstract"><strong>Background:</strong> Cyclophosphamide is anticancer and immunosuppressant agent used to treat malignant and autoimmune diseases. Its long-term use causes side effects, as infertility and pulmonary toxicity. Coenzyme Q10; the only synthesized antioxidant in human body, acts as powerful antioxidant, scavenging free radicals, and inhibiting lipid peroxidation. Aim of present study was to examine effect of coenzyme Q10 on blood biochemical profiles, histopathological changes in lungs of adult rats exposed to cyclophosphamide-induced toxicity.</p><p class="abstract"><strong>Methods:</strong> 36 adult male albino rats divided into four groups; control and three experimental each having 9 rats. First experimental group received coenzyme Q10, second received cyclophosphamide while third group received coenzyme Q10 along with cyclophosphamide. Experiment lasted for 7 days. On 8th day, animals were sacrificed by decapitation. Lung tissue samples were collected for histopathological examination. SOD (superoxide dismutase) and MDA (malondialdehyde) levels were determined and used for statistical analysis.  </p><p class="abstract"><strong>Results:</strong> In coenzyme Q10 treated group, H&amp;E stained sections revealed normal respiratory alveoli. Ultrathin sections revealed normal alveolar septa, pneumocyte and blood capillaries contain erythrocytes. In cyclophosphamide treated group, H&amp;E stained sections revealed peribronchial and interstitial fibrosis. Ultrathin sections revealed alveoli having apparent free lumen with extravasated erythrocytes. Alveolar septa revealed collagen fibrils deposits, and proliferated fibroblasts. In combined coenzyme Q10 and cyclophosphamide treated group, H&amp;E stained sections revealed marked decrease of inter-alveolar tissue thickening. Ultrathin sections revealed destructed alveolar septa with dissociated remnants of collagen fibrils. Blood capillaries appeared wide, containing monocytes and erythrocytes.</p><p class="abstract"><strong>Conclusions:</strong> Administration of coenzyme Q10 with cyclophosphamide is advised to alleviate cyclophosphamide-induced lung toxicity.</p>

Dihedral angles of septal “bend” structures in lung parenchyma

1996 ◽  
Vol 81 (4) ◽  
pp. 1800-1806 ◽  
Author(s):  
J. P. Butler ◽  
E. H. Oldmixon ◽  
F. G. Hoppin
Keyword(s):  
Membrane System ◽  
Lung Parenchyma ◽  
Physical Principle ◽  
Dihedral Angles ◽  
Cable System ◽  
System A ◽  
Area Minimization ◽  
The Common ◽  
Alveolar Septa ◽  
Alveolar Parenchyma

Butler, J. P., E. H. Oldmixon, and F. G. Hoppin, Jr.Dihedral angles of septal “bend” structures in lung parenchyma. J. Appl. Physiol. 81: 1800–1806, 1996.—Alveolar parenchyma comprises two interacting tensile systems: the cable system (a network of linear condensations of connective tissue) and the membrane system (a network of quasiplanar alveolar septa). Inferences can be drawn about the mechanics of this structure from its configuration. We reported earlier (E. H. Oldmixon, J. P. Butler, and F. G. Hoppin, Jr. J. Appl. Physiol. 64: 299–307, 1988) that the angles between alveolar septa at the common three-way junctions (J) are nearly uniform, indicating that septal tensions are also nearly uniform. We now report on the interseptal angles at the next most common class of septal junction (B), a structure where two septa meet along a segment of the cable system. We find, first, that the distributions of interseptal angles at B junctions have means >120°, are narrow, and have few, if any, angles <120°. The findings of uniform 120° angles at J junctions and a cutoff below 120° at B junctions are also characteristic of soap films supported on a frame, which follows the physical principle of surface area minimization. We suggest that this principle may be operative in parenchymal development and remodeling.

Effects of Hyperoxia on Lung Utrastructure

1970 ◽  
Vol 28 ◽  
pp. 26-27
Author(s):  
Gladys Harrison
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Light Microscopy ◽  
Oxygen Effects ◽  
Age Dependent ◽  
The Central Nervous System ◽  
The Subject ◽  
Space Age ◽  
Alveolar Septa ◽  
Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

Quantitative analysis of in situ straining experiments in the case of strong frictional forces

1978 ◽  
Vol 36 (1) ◽  
pp. 570-571
Author(s):  
F. Louchet ◽  
L.P. Kubin
Keyword(s):  
Strain Rate ◽  
Radiation Effects ◽  
Dislocation Line ◽  
Critical Length ◽  
Local Strain ◽  
Local Flow ◽  
Double Kink ◽  
Dislocation Densities ◽  
Frictional Forces ◽  
Local Strain Rate

Investigation of frictional forces -Experimental techniques and working conditions in the high voltage electron microscope have already been described (1). Care has been taken in order to minimize both surface and radiation effects under deformation conditions.Dislocation densities and velocities are measured on the records of the deformation. It can be noticed that mobile dislocation densities can be far below the total dislocation density in the operative system. The local strain-rate can be deduced from these measurements. The local flow stresses are deduced from the curvature radii of the dislocations when the local strain-rate reaches the values of ∿ 10-4 s-1.For a straight screw segment of length L moving by double-kink nucleation between two pinning points, the velocity is :where ΔG(τ) is the activation energy and lc the critical length for double-kink nucleation. The term L/lc takes into account the number of simultaneous attempts for double-kink nucleation on the dislocation line.

Effects of EDTA, Hyaluronidase and Collagenase on Epiphyseal Cartilage Matrix

1968 ◽  
Vol 26 ◽  
pp. 56-57
Author(s):  
H. Clarke Anderson ◽  
Priscilla R. Coulter
Keyword(s):  
Light And Electron Microscopy ◽  
Matrix Vesicles ◽  
Cartilage Matrix ◽  
Collagen Fibrils ◽  
Epiphyseal Cartilage ◽  
Dense Matrix ◽  
Type Iv ◽  
Bovine Testicular Hyaluronidase ◽  
The Matrix ◽  
Testicular Hyaluronidase

Epiphyseal cartilage matrix contains fibrils and particles of at least 5 different types: 1. Banded collagen fibrils, present throughout the matrix, but not seen in the lacunae. 2. Non-periodic fine fibrils <100Å in diameter (Fig. 1), which are most notable in the lacunae, and may represent immature collagen. 3. Electron dense matrix granules (Fig. 1) which are often attached to fine fibrils and collagen fibrils, and probably contain protein-polysaccharide although the possibility of a mineral content has not been excluded. 4. Matrix vesicles (Fig. 2) which show a selective distribution throughout the epiphysis, and may play a role in calcification. 5. Needle-like apatite crystals (Fig. 2).Blocks of formalin-fixed epiphysis from weanling mice were digested with the following agents in 0.1M phosphate buffer: a) 5% ethylenediaminetetraacetate (EDTA) at pH 8.3, b) 0.015% bovine testicular hyaluronidase (Sigma, type IV, 750 units/mg) at pH 5.5, and c) 0.1% collagenase (Worthington, chromatograhically pure, 200 units/mg) at pH 7.4. All digestions were carried out at 37°C overnight. Following digestion tissues were examined by light and electron microscopy to determine changes in the various fibrils and particles of the matrix.

Banded Structures in the Connective Tissue of Meningioma

1976 ◽  
Vol 34 ◽  
pp. 234-235
Author(s):  
C. N. Sun ◽  
H. J. White
Keyword(s):  
Connective Tissue ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Collagen Fibrils ◽  
Lead Citrate ◽  
Connective Tissues ◽  
Native Collagen ◽  
Routine Procedures

Previously, we have reported on extracellular cross-striated banded structures in human connective tissues of a variety of organs (1). Since then, more material has been examined and other techniques applied. Recently, we studied a fibrocytic meningioma of the falx. After the specimen was fixed in 4% buffered glutaraldehyde and post-fixed in 1% buffered osmium tetroxide, other routine procedures were followed for embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate. There were numerous cross striated banded structures in aggregated bundle forms found in the connecfive tissue of the tumor. The banded material has a periodicity of about 450 Å and where it assumes a filamentous arrangement, appears to be about 800 Å in diameter. In comparison with the vicinal native collagen fibrils, the banded material Is sometimes about twice the diameter of native collagen.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Platelet Adhesion to Native Collagens Involves Proteoglycans and May Be a Two-Step Process

1987 ◽  
Vol 58 (02) ◽  
pp. 786-789 ◽  
Author(s):  
O Behnke
Keyword(s):  
Electron Microscope ◽  
Platelet Adhesion ◽  
Close Contact ◽  
Blood Platelets ◽  
Collagen Fibrils ◽  
Platelet Membrane ◽  
Step Process ◽  
Rat Blood ◽  
Wide Gap ◽  
Rat Tail

SummaryAdhesion of rat blood platelets to native rat tail collagen fibrils was studied in the electron microscope under conditions that preserved collagen-associated proteoglycans (CAPG). The CAPG molecules were aligned in chain-like configurations that encircled the fibrils with a 65 nm period; they appeared to coat the fibrils completely and extended 60-100 nm away from the fibril. The initial platelet-fibril contact occurred between the platelet glycocalyx and the CAPG of the fibrils i.e. between two surfaces with net-negative charges. When close contact was established between the fibril surface proper and the platelet membrane, CAPG were not identified in the area of contact, and the collagen-platelet distance was reduced to a ~10-12 nm wide gap traversed by delicate links in register with fibril periodicities.

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