scholarly journals STUDIES ON CARTILAGE

1960 ◽  
Vol 8 (1) ◽  
pp. 151-163 ◽  
Author(s):  
Huntington Sheldon ◽  
Robert A. Robinson
Keyword(s):  
Amorphous Material ◽  
Surface Membrane ◽  
Electrophoretic Pattern ◽  
Elastic Component ◽  
Elastic Tissue ◽  
Cell Cytoplasm ◽  
Elastic Cartilage ◽  
Rabbit Ear ◽  
The Matrix ◽  
Ear Cartilage

Electron microscope observations on rabbit ear cartilage following the administration of papain show that both the elastic component of the matrix and the amorphous material disappear leaving a matrix which consists of delicate fibrils which are presumed to be collagen. This unmasking of fibrils coincides with the appearance of an abnormal component in the electrophoretic pattern of the rabbit's serum. The chondrocytes show vacuoles in their cytoplasm which appear at the same time that the cells appear crenated in the light microscope. A ruffly appearance of the cell surface membrane coincides with this vacuolization, and vacuoles often appear open and in continuity with the extracellular space. The resurgence of the rabbit ear is accompanied by a reconstitution of both the amorphous material and the elastic component of the matrix. During this period numerous dilated cisternae of the endoplasmic reticulum which contain a moderately dense material are present in the chondrocyte cytoplasm. We have been unable to demonstrate a direct relationship between the elastic component of the matrix and a particular component of the chondrocyte cytoplasm, but it is clear that changes occur in the cartilage cell cytoplasm during both the depletion and reconstitution of the matrix. Previous studies on the effect of papain on elastic tissue are noted and the possible relationships between changes in the cells and matrix of this elastic cartilage are discussed.

scholarly journals Studies on the cathepsins in elastic cartilage

1969 ◽  
Vol 112 (4) ◽  
pp. 427-433 ◽  
Author(s):  
S. Y. Ali ◽  
Lois Evans
Keyword(s):  
Acid Phosphatase ◽  
Dna Content ◽  
Quantitative Method ◽  
Cathepsin C ◽  
Elastic Cartilage ◽  
Fixed Weight ◽  
Cathepsin Activity ◽  
Rabbit Ear ◽  
Ear Cartilage ◽  
Hydrolysis Of

1. The presence of several enzymes in rabbit ear cartilage was examined by a quantitative method that permits the incubation of a fixed weight of cartilage sections (18μm.) with an appropriate exogeneous substrate. 2. As the presence of cathepsins B and D in cartilage has already been established, evidence is now provided to show that cathepsins A and C are also present and are maximally active at pH5. 3. Cathepsin A was recognized by its hydrolysis of benzyloxycarbonyl-glutamyl-tyrosine and cathepsin C by its hydrolysis of glycyl-tyrosine amide; the cartilage also hydrolysed benzyloxycarbonyl-glutamyl-phenylalanine and benzoyl-dl-phenylalanine 2-naphthyl ester at pH5. 4. The acid phosphatase activity and the DNA content of cartilage have also been measured to provide a basis for comparison with the cathepsin activity of cartilage obtained from other sites and species.

scholarly journals Studies on Cartilage: Electron Microscope Observations on Normal Rabbit Ear Cartilage

1958 ◽  
Vol 4 (4) ◽  
pp. 401-406 ◽  
Author(s):  
Huntington Sheldon ◽  
Robert A. Robinson
Keyword(s):  
Electron Microscope ◽  
Three Dimensional ◽  
Elastic Fibers ◽  
Acid Fuchsin ◽  
Cartilage Cell ◽  
Cell Border ◽  
Rabbit Ear ◽  
The Matrix ◽  
Dense Substance ◽  
Ear Cartilage

Normal rabbit ear cartilage studied with the light and electron microscope shows chondrocytes in which large lipide spherules, and an abundance of glycogen, a few small mitochondria, and relatively few elements of the endoplasmic reticulum can be identified. The chondrocytes contain, in addition, a material which stains strongly with acid fuchsin and appears in the electron microscope as a relatively dense felt-work. In electron micrographs, the matrix of normal rabbit ear cartilage consists of two components: a uniformly distributed moderately dense substance which appears as a fine meshwork without any particular pattern extending from cartilage cell border to cartilage cell border; and a three-dimensional anastomotic network of more dense material, which is best described as "felt-like" lying between the cells. The similarity between the felt-like material of the matrix and the elastic fibers described in previous electron microscope observations is discussed.

Mitochondria: the birth place, battle ground and the site of melatonin metabolism in cells

2019 ◽  
Vol 2 (1) ◽  
pp. 44-66 ◽  
Author(s):  
Dun-Xian Tan ◽  
Russel. J. Reiter
Keyword(s):  
Ischemia Reperfusion ◽  
Surface Membrane ◽  
Strong Association ◽  
Membrane Receptors ◽  
Melatonin Receptors ◽  
Metabolic Enzyme ◽  
Intermembrane Space ◽  
Antitumor Effects ◽  
The Matrix ◽  
Surprising Discovery

     It was a surprising discovery when mitochondria, as the power houses of cells, were also found to synthesize the potent mitochondrial targeted antioxidant, melatonin. The melatonin synthetic enzyme serotonin N-acetyltransferase (SNAT) was found in matrix and also in the intermembrane space of mitochondria. We hypothesize that the melatonin synthesis occurs in the matrix due to substrate (N-acetyl co-enzyme A) availability while the intermembrane space may serve as the recycling pool of SNAT to regulate the melatonin circadian rhythm. Another surprise was that the melatonin membrane receptors, including MT1 and MT2, were also present in mitochondria. The protective effects of melatonin against neuronal injury induced by brain ischemia/reperfusion were proven to be mainly mediated by mitochondrial melatonin receptors rather than the cell surface membrane receptors which is contrary to the classical principle. In addition, melatonin metabolic enzyme has also been identified in the mitochondria. This enzyme can convert melatonin to N-acetylserotonin to strengthen the antitumor effects of melatonin. Thus, mitochondria are the generator, battle ground and metabolic sites of melatonin. The biological significance of the strong association between mitochondria and melatonin should be intensively investigated. 

Mitochondria: the birth place, battle ground and the site of melatonin metabolism in cells

2019 ◽  
Vol 2 (1) ◽  
pp. 44-66 ◽  
Author(s):  
Dun-Xian Tan ◽  
Russel. J. Reiter
Keyword(s):  
Ischemia Reperfusion ◽  
Surface Membrane ◽  
Strong Association ◽  
Membrane Receptors ◽  
Melatonin Receptors ◽  
Metabolic Enzyme ◽  
Intermembrane Space ◽  
Antitumor Effects ◽  
The Matrix ◽  
Surprising Discovery

     It was a surprising discovery when mitochondria, as the power houses of cells, were also found to synthesize the potent mitochondrial targeted antioxidant, melatonin. The melatonin synthetic enzyme serotonin N-acetyltransferase (SNAT) was found in matrix and also in the intermembrane space of mitochondria. We hypothesize that the melatonin synthesis occurs in the matrix due to substrate (N-acetyl co-enzyme A) availability while the intermembrane space may serve as the recycling pool of SNAT to regulate the melatonin circadian rhythm. Another surprise was that the melatonin membrane receptors, including MT1 and MT2, were also present in mitochondria. The protective effects of melatonin against neuronal injury induced by brain ischemia/reperfusion were proven to be mainly mediated by mitochondrial melatonin receptors rather than the cell surface membrane receptors which is contrary to the classical principle. In addition, melatonin metabolic enzyme has also been identified in the mitochondria. This enzyme can convert melatonin to N-acetylserotonin to strengthen the antitumor effects of melatonin. Thus, mitochondria are the generator, battle ground and metabolic sites of melatonin. The biological significance of the strong association between mitochondria and melatonin should be intensively investigated. 

Schistosoma mansoni: a comparative study of artificially transformed schistosomula and schistomula recoverd after cercarial penetration of isolated skin

Parasitology ◽  
1977 ◽  
Vol 74 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Linda H. Brink ◽  
Diane J. McLaren ◽  
S. R. Smithers
Keyword(s):  
Comparative Study ◽  
Schistosoma Mansoni ◽  
Amorphous Material ◽  
Surface Membrane ◽  
Antigenic Determinants ◽  
Agglutination Reaction ◽  
Rat Serum ◽  
Mechanical Separation ◽  
B Blood Group

A comparison was made of the ultrastructure, development and antigenic nature of the surfaces and of the viability of three types of schistosomula of Schistosoma mansoni: schistosomula formed afrer cercariae had penetrated isolated skin (SS), schistosomula produced after mechanical separation of cercarial tails from bodies (MS), and schistosomula transformed from cercariae after incubation in fresh rat serum (RS).Within 2 h of transformation, the surface membrane of all three types of schistosomula had changed from trilaminate to heptalaminate structures and SS and MS had lost their cercarial glycocalyx. Initially a dense amorphous material was demonstrated on the surfaces of RS, which was thought to be the result of an interaction between a factor in rat serum and the glycocalyx: this material was greatly reduced within 2 h of transformation. The pre-acetabular glands of SS were emptied while those of MS and RS retained their contents. Immunofluorescent studies showed that all schistosomula bound serum from mice immune to S. mansoni, but the binding was stronger with MS and RS. The mixed agglutination reaction demonstrated the presence of human A and B blood group-like antigenic determinants on approximately 30% of 3 h old SS; these determinants were not detected on MS or RS. In vitro, the development of MS and RS was similar to SS; the first schistosomula reached the ‘gut-closed’ stage by day 10; 50–70% of SS reached this stage by day 12, in contrast to only 25–50% of MS and RS. Between 28 and 45% of all schistosomula developed to maturity when injected intravenously into mice.It was concluded that the two types of artificially prepared schistosomula fultil the main criteria of transformation from cercaria to schistosomulum. Further, it is suggested that MS are the most appropriate source of material for immunochemical and physiological studies.

scholarly journals Characterization of cathepsins in cartilage

1967 ◽  
Vol 105 (2) ◽  
pp. 549-557 ◽  
Author(s):  
S. Y. Ali ◽  
L. Evans ◽  
E. Stainthorpe ◽  
C. H. Lack
Keyword(s):  
Cathepsin B ◽  
Cartilage Matrix ◽  
Heat Inactivation ◽  
Ph Values ◽  
Fixed Weight ◽  
Exogenous Substrate ◽  
Nitrophenyl Phosphate ◽  
Rabbit Ear ◽  
Ear Cartilage

The presence of a cathepsin B-like enzyme in rabbit ear cartilage was established by the use of the synthetic substrates benzoyl-l-arginine amide and benzoyl-dl-arginine 2-naphthylamide. This was facilitated by using a technique that permits the incubation of a fixed weight of thin (18μ) cartilage sections with an appropriate exogenous substrate. The enzymic properties of cathepsin B in cartilage have been compared with an endogenous enzyme that liberates chondromucopeptide by degrading the cartilage matrix autocatalytically at pH5. Besides being maximally active at pH4·7, these cartilage enzymes are enhanced in activity by cysteine and inhibited by arginine analogues, iodoacetamide, chloroquine and mercuric chloride. They are not inhibited by EDTA, di-isopropyl phosphorofluoridate and diethyl p-nitrophenyl phosphate. When inhibiting the release of chondromucopeptide from cartilage at pH5, the arginine-containing synthetic substrates are hydrolysed simultaneously. These enzymes also share the same heat-inactivation characteristics at various pH values, being stable at acid pH and unstable at neutral and alkaline pH. The experimental evidence indicates that a cathepsin B-like enzyme may be partly responsible for the autolytic degradation of cartilage matrix at pH5.

scholarly journals The Significant Impact of Carbon Nanotubes on the Electrochemical Reactivity of Mg-Bearing Metallic Glasses with High Compressive Strength

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2989 ◽  
Author(s):  
Lou ◽  
Cheng ◽  
Zhao ◽  
Misra ◽  
Feng
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Metallic Glasses ◽  
Fracture Strain ◽  
Amorphous Material ◽  
Shear Bands ◽  
The Matrix ◽  
Superior Mechanical Properties ◽  
Pressure Die Casting

Here, we elucidate the significant impact of carbon nanotubes (CNTs) on the electrochemical behavior of Mg-based amorphous composite materials that were reinforced with CNTs while using pressure die casting. The addition of 3 vol % CNTs led to an increase in the compressive strength of Mg-based amorphous material from 812 MPa to 1007 MPa, and the fracture strain from 1.91% to 2.67% in the composite. Interestingly, the addition of CNTs significantly contributed to the enhancement of corrosion resistance of Mg-based glass by ~30%. The superior mechanical properties are primarily related to the fact that the addition of CNTs hindered the growth of shear bands (cracks), while the high corrosion resistance is related to inferior wettability and the bridging effect between adherent corrosive oxide film and the matrix that provided enhanced corrosion resistance.

Intracellular Lipids in Rabbit Ear Cartilage during Tissue Regeneration

1986 ◽  
Vol 127 (4) ◽  
pp. 249-254 ◽  
Author(s):  
J. Labandeira-Garcia ◽  
M. Guerra -Seijas
Keyword(s):  
Tissue Regeneration ◽  
Intracellular Lipids ◽  
Rabbit Ear ◽  
Ear Cartilage

scholarly journals The synthesis of low-molecular weight proteoglycans in rabbit-ear cartilage

FEBS Letters ◽  
1972 ◽  
Vol 26 (1-2) ◽  
pp. 336-340 ◽  
Author(s):  
A. Serafini-Fracassini ◽  
W.H. Stimson
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Rabbit Ear ◽  
Ear Cartilage

Thermochondroplasty of rabbit ear cartilage using the carbon dioxide laser

1994 ◽  
Vol 9 (4) ◽  
pp. 265-272 ◽  
Author(s):  
George Velegrakis ◽  
Miltos Volitakis ◽  
Irene Naumidi ◽  
John Bizakis ◽  
Panos Christodoulou ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Laser ◽  
Rabbit Ear ◽  
Ear Cartilage
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