scholarly journals Diverse effects of Perlecan-HS on cell and matrix regulation: Tendon destabilization in Hspg2 Exon 3 null HS deficient mice reveals essential homeostatic roles for HS in cellular regulation and tendon functionality

2018 ◽  
Author(s):  
Cindy C Shu ◽  
Margaret M Smith ◽  
Richard C Appleyard ◽  
Christopher B Little ◽  
James Melrose
Keyword(s):  
Material Properties ◽  
Tensile Modulus ◽  
Ultimate Tensile Stress ◽  
Cellular Regulation ◽  
Achilles Tenotomy ◽  
Transmission Electron ◽  
Tail Tendon ◽  
Fibril Diameter ◽  
Deficient Mice

The aim of this study was to determine the regulatory role of the perlecan HS side chains on cell and matrix homeostasis in tail and Achilles tendons in 3 and 12 week old Hspg2 exon 3 null HS deficient (Hspg2∆3-/∆3- ) and C57 BL/6 Wild Type (WT) mice. Tendons were biomechanically tested (ultimate tensile stress [UTS], tensile modulus [TM]) and glycosaminoglycan (GAG) and collagen (hydroxyproline) compositional analyses undertaken. Monolayer cultures of Hspg2∆3-/∆3- tenocytes stimulated with FGF-2 showed elevated Adamts4, Mmp2, 3, 13 gene expression compared to WT mice. Col1A1, Vcan, Bgn, Dcn, Lum, Hspg2, Ltbp1, Ltbp2, Eln and Fbn1 showed no major differences between genotypes. Type VI collagen and perlecan were immunolocalised in tail tendon and collagen fibrils imaged using transmission electron microscopy (TEM). The amplified catabolic phenotype of Hspg2∆3-/∆3- mice may account for the age-dependent decline in GAG observed in tail tendon and changes in UTS/TM biomechanics. Collagen fibril diameter increased in WT but decreased in Hspg2∆3-/∆3- tail tendons over 3 to 12 weeks. Achilles tenotomy resulted in changes in tendon material properties in both genotypes but, Hspg2∆3-/∆3- mice had a slower recovery of UTS after tenotomy. HS deficiency in Hspg2∆3-/∆3- tendon impaired tenocyte repair responses to FGF-2 and led to deleterious changes in tendon organization which was reflected in changes in their material properties. .

scholarly journals Diverse effects of Perlecan-HS on cell and matrix regulation: Tendon destabilization in Hspg2 Exon 3 null HS deficient mice reveals essential homeostatic roles for HS in cellular regulation and tendon functionality

2018 ◽  
Author(s):  
Cindy C Shu ◽  
Margaret M Smith ◽  
Richard C Appleyard ◽  
Christopher B Little ◽  
James Melrose
Keyword(s):  
Material Properties ◽  
Tensile Modulus ◽  
Ultimate Tensile Stress ◽  
Cellular Regulation ◽  
Achilles Tenotomy ◽  
Transmission Electron ◽  
Tail Tendon ◽  
Fibril Diameter ◽  
Deficient Mice

The aim of this study was to determine the regulatory role of the perlecan HS side chains on cell and matrix homeostasis in tail and Achilles tendons in 3 and 12 week old Hspg2 exon 3 null HS deficient (Hspg2∆3-/∆3- ) and C57 BL/6 Wild Type (WT) mice. Tendons were biomechanically tested (ultimate tensile stress [UTS], tensile modulus [TM]) and glycosaminoglycan (GAG) and collagen (hydroxyproline) compositional analyses undertaken. Monolayer cultures of Hspg2∆3-/∆3- tenocytes stimulated with FGF-2 showed elevated Adamts4, Mmp2, 3, 13 gene expression compared to WT mice. Col1A1, Vcan, Bgn, Dcn, Lum, Hspg2, Ltbp1, Ltbp2, Eln and Fbn1 showed no major differences between genotypes. Type VI collagen and perlecan were immunolocalised in tail tendon and collagen fibrils imaged using transmission electron microscopy (TEM). The amplified catabolic phenotype of Hspg2∆3-/∆3- mice may account for the age-dependent decline in GAG observed in tail tendon and changes in UTS/TM biomechanics. Collagen fibril diameter increased in WT but decreased in Hspg2∆3-/∆3- tail tendons over 3 to 12 weeks. Achilles tenotomy resulted in changes in tendon material properties in both genotypes but, Hspg2∆3-/∆3- mice had a slower recovery of UTS after tenotomy. HS deficiency in Hspg2∆3-/∆3- tendon impaired tenocyte repair responses to FGF-2 and led to deleterious changes in tendon organization which was reflected in changes in their material properties. .

scholarly journals Bimodal collagen fibril diameter distributions direct age-related variations in tendon resilience and resistance to rupture

2012 ◽  
Vol 113 (6) ◽  
pp. 878-888 ◽  
Author(s):  
K. L. Goh ◽  
D. F. Holmes ◽  
Y. Lu ◽  
P. P. Purslow ◽  
K. E. Kadler ◽  
...  
Keyword(s):  
Collagen Fibril ◽  
Strain Energy ◽  
Age Groups ◽  
Bimodal Distribution ◽  
Tensile Tests ◽  
Age Related ◽  
Transmission Electron ◽  
Rupture Energy ◽  
Tail Tendon ◽  
Fibril Diameter

Scaling relationships have been formulated to investigate the influence of collagen fibril diameter ( D) on age-related variations in the strain energy density of tendon. Transmission electron microscopy was used to quantify D in tail tendon from 1.7- to 35.3-mo-old (C57BL/6) male mice. Frequency histograms of D for all age groups were modeled as two normally distributed subpopulations with smaller ( DD1) and larger ( DD2) mean Ds, respectively. Both DD1 and DD2 increase from 1.6 to 4.0 mo but decrease thereafter. From tensile tests to rupture, two strain energy densities were calculated: 1) uE [from initial loading until the yield stress (σ Y)], which contributes primarily to tendon resilience, and 2) uF [from σ Y through the maximum stress (σ U) until rupture], which relates primarily to resistance of the tendons to rupture. As measured by the normalized strain energy densities uE/σ Y and uF/σ U, both the resilience and resistance to rupture increase with increasing age and peak at 23.0 and 4.0 mo, respectively, before decreasing thereafter. Multiple regression analysis reveals that increases in uE/σ Y (resilience energy) are associated with decreases in DD1 and increases in DD2, whereas uF/σ U (rupture energy) is associated with increases in DD1 alone. These findings support a model where age-related variations in tendon resilience and resistance to rupture can be directed by subtle changes in the bimodal distribution of Ds.

scholarly journals Role of Complement Receptors in Uptake ofMycobacterium avium by Macrophages In Vivo: Evidence from Studies Using CD18-Deficient Mice

1999 ◽  
Vol 67 (9) ◽  
pp. 4912-4916 ◽  
Author(s):  
Luiz E. Bermudez ◽  
Joseph Goodman ◽  
Mary Petrofsky
Keyword(s):  
Mouse Strains ◽  
Histopathological Study ◽  
Intracellular Pathogen ◽  
Complement Receptors ◽  
Transmission Electron ◽  
Granulomatous Lesions ◽  
Deficient Mice

ABSTRACT Mycobacterium avium is an intracellular pathogen that has been shown to invade macrophages by using complement receptors in vitro, but mycobacteria released from one cell can enter a second macrophage by using receptors different from complement receptors. Infection of CD18 (β2 integrin) knockout mice and the C57 BL/6 control mice led to comparable levels of tissue infection at 1 day, 2 days, 1 week, and 3 weeks following administration of bacteria. A histopathological study revealed similar granulomatous lesions in the two mouse strains, with comparable numbers of organisms. In addition, transmission electron microscopy of spleen tissues from both strains of mice showed bacteria inside macrophages. Our in vivo findings support the hypothesis that M. avium in the host is likely to use receptors other than CR3 and CR4 receptors to enter macrophages with increased efficiency.

scholarly journals Achilles and tail tendons of perlecan exon 3 null heparan sulphate deficient mice display surprising improvement in tendon tensile properties and altered collagen fibril organisation compared to C57BL/6 wild type mice

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5120 ◽  
Author(s):  
Cindy C. Shu ◽  
Margaret M. Smith ◽  
Richard C. Appleyard ◽  
Christopher B. Little ◽  
James Melrose
Keyword(s):  
Electron Microscopy ◽  
Heparan Sulphate ◽  
Tendon Repair ◽  
Collagen Fibrils ◽  
Mrna Levels ◽  
Wild Type ◽  
Normal Tendon ◽  
Transmission Electron ◽  
Tail Tendon

The aim of this study was to determine the role of the perlecan (Hspg2) heparan sulphate (HS) side chains on cell and matrix homeostasis in tail and Achilles tendons in 3 and 12 week old Hspg2 exon 3 null HS deficient (Hspg2Δ3 − ∕Δ3 −) and C57 BL/6 Wild Type (WT) mice. Perlecan has important cell regulatory and matrix organizational properties through HS mediated interactions with a range of growth factors and morphogens and with structural extracellular matrix glycoproteins which define tissue function and allow the resident cells to regulate tissue homeostasis. It was expected that ablation of the HS chains on perlecan would severely disrupt normal tendon organization and functional properties and it was envisaged that this study would better define the role of HS in normal tendon function and in tendon repair processes. Tail and Achilles tendons from each genotype were biomechanically tested (ultimate tensile stress (UTS), tensile modulus (TM)) and glycosaminoglycan (GAG) and collagen (hydroxyproline) compositional analyses were undertaken. Tenocytes were isolated from tail tendons from each mouse genotype and grown in monolayer culture. These cultures were undertaken in the presence of FGF-2 to assess the cell signaling properties of each genotype. Total RNA was isolated from 3–12 week old tail and Achilles tendons and qRT-PCR was undertaken to assess the expression of the following genes Vcan, Bgn, Dcn, Lum, Hspg2, Ltbp1, Ltbp2, Eln and Fbn1. Type VI collagen and perlecan were immunolocalised in tail tendon and collagen fibrils were imaged using transmission electron microscopy (TEM). FGF-2 stimulated tenocyte monolayers displayed elevated Adamts4, Mmp2, 3, 13 mRNA levels compared to WT mice. Non-stimulated tendon Col1A1, Vcan, Bgn, Dcn, Lum, Hspg2, Ltbp1, Ltbp2, Eln and Fbn1 mRNA levels showed no major differences between the two genotypes other than a decline with ageing while LTBP2 expression increased. Eln expression also declined to a greater extent in the perlecan exon 3 null mice (P < 0.05). Type VI collagen and perlecan were immunolocalised in tail tendon and collagen fibrils imaged using transmission electron microscopy (TEM). This indicated a more compact form of collagen localization in the perlecan exon 3 null mice. Collagen fibrils were also smaller by TEM, which may facilitate a more condensed fibril packing accounting for the superior UTS displayed by the perlecan exon 3 null mice. The amplified catabolic phenotype of Hspg2Δ3 − ∕Δ3 − mice may account for the age-dependent decline in GAG observed in tail tendon over 3 to 12 weeks. After Achilles tenotomy Hspg2Δ3 − ∕Δ3 − and WT mice had similar rates of recovery of UTS and TM over 12 weeks post operatively indicating that a deficiency of HS was not detrimental to tendon repair.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

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