scholarly journals Reduction of type V collagen using a dominant-negative strategy alters the regulation of fibrillogenesis and results in the loss of corneal-specific fibril morphology.

1996 ◽  
Vol 135 (5) ◽  
pp. 1415-1426 ◽  
Author(s):  
J K Marchant ◽  
R A Hahn ◽  
T F Linsenmayer ◽  
D E Birk
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Dominant Negative ◽  
Northern Analysis ◽  
Type V Collagen ◽  
V Protein ◽  
Amino Terminal ◽  
Fibril Morphology ◽  
Type V ◽  
Fibril Diameter

A number of factors have been implicated in the regulation of tissue-specific collagen fibril diameter. Previous data suggest that assembly of heterotypic fibrils composed of two different fibrillar collagens represents a general mechanism regulating fibril diameter. Specifically, we hypothesize that type V collagen is required for the assembly of the small diameter fibrils observed in the cornea. To test this, we used a dominant-negative retroviral strategy to decrease the levels of type V collagen secreted by chicken corneal fibroblasts. The chicken alpha 1(V) collagen gene was cloned, and retroviral vectors that expressed a polycistronic mRNA encoding a truncated alpha 1(V) minigene and the reporter gene LacZ were constructed. The efficiency of viral infection was 30-40%, as determined by assaying beta-galactosidase activity. To assess the expression from the recombinant provirus, Northern analysis was performed and indicated that infected fibroblasts expressed high steady-state levels of retroviral mRNA. Infected cells synthesized the truncated alpha 1(V) protein, and this was detectable only intracellularly, in a distribution that colocalized with lysosomes. To assess endogenous alpha 1(V) protein levels, infected cell cultures were assayed, and these consistently demonstrated reductions relative to control virus-infected or uninfected cultures. Analyses of corneal fibril morphology demonstrated that the reduction in type V collagen resulted in the assembly of large-diameter fibrils with a broad size distribution, characteristics similar to fibrils produced in connective tissues with low type V concentrations. Immunoelectron microscopy demonstrated the amino-terminal domain of type V collagen was associated with the small-diameter fibrils, but not the large fibrils. These data indicate that type V collagen levels regulate corneal fibril diameter and that the reduction of type V collagen is sufficient to alter fibril assembly so that abnormally large-diameter fibrils are deposited into the matrix.

Collagen fibrillogenesis in vitro: interaction of types I and V collagen regulates fibril diameter

1990 ◽  
Vol 95 (4) ◽  
pp. 649-657 ◽  
Author(s):  
D.E. Birk ◽  
J.M. Fitch ◽  
J.P. Babiarz ◽  
K.J. Doane ◽  
T.F. Linsenmayer
Keyword(s):  
Type I Collagen ◽  
Small Diameter ◽  
Collagen Molecule ◽  
Type I ◽  
Collagen Types ◽  
Type V Collagen ◽  
Amino Terminal ◽  
Type V ◽  
Fibril Diameter

The small-diameter fibrils of the chick corneal stroma are heterotypic, composed of both collagen types I and V. This tissue has a high concentration of type V collagen relative to other type I-containing tissues with larger-diameter fibrils, suggesting that heterotypic interactions may have a regulatory role in the control of fibril diameter. The interactions of collagen types I and V were studied using an in vitro self-assembly system. Collagens were purified from lathyritic chick embryos in the presence of protease inhibitors. The type V collagen preparations contained higher molecular weight forms of the alpha 1(V) and alpha 2(V) chains constituting 60–70% of the total. Rotary-shadow electron micrographs showed a persistence of a small, pepsin-sensitive terminal region in an amount consistent with that seen by electrophoresis. In vitro, this purified type V collagen formed thin fibrils with no apparent periodicity, while type I collagen fibrils had a broad distribution of large diameters. However, when type I collagen was mixed with increasing amounts of type V collagen a progressive and significant decrease in both the mean fibril diameter and the variance was observed for D periodic fibrils. The amino-terminal domain of the type V collagen molecule was required for this regulatory effect and in its absence little diameter reducing activity was observed. Electron microscopy using collagen type-specific monoclonal antibodies demonstrated that the fibrils formed were heterotypic, containing both collagen types I and V. These data indicate that the interaction of type V with type I collagen is one mechanism modulating fibril diameter and is at least partially responsible for the regulation of collagen fibril formation.

Collagen fibrillogenesis in vitro: interaction of types I and V collagen

1986 ◽  
Vol 44 ◽  
pp. 210-211
Author(s):  
Arthur J. Wasserman ◽  
Kathy C. Kloos ◽  
David E. Birk
Keyword(s):  
Type I Collagen ◽  
Corneal Stroma ◽  
Minor Component ◽  
Homogeneous Distribution ◽  
Type I ◽  
Type V Collagen ◽  
Fibril Morphology ◽  
Type V ◽  
In Vitro Interaction

Type I collagen is the predominant collagen in the cornea with type V collagen being a quantitatively minor component. However, the content of type V collagen (10-20%) in the cornea is high when compared to other tissues containing predominantly type I collagen. The corneal stroma has a homogeneous distribution of these two collagens, however, immunochemical localization of type V collagen requires the disruption of type I collagen structure. This indicates that these collagens may be arranged as heterpolymeric fibrils. This arrangement may be responsible for the control of fibril diameter necessary for corneal transparency. The purpose of this work is to study the in vitro assembly of collagen type V and to determine whether the interactions of these collagens influence fibril morphology.

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

scholarly journals Binding of heparan sulfate to type V collagen

1989 ◽  
Vol 264 (14) ◽  
pp. 7950-7956 ◽  
Author(s):  
R G LeBaron ◽  
A Höök ◽  
J D Esko ◽  
S Gay ◽  
M Höök
Keyword(s):  
Heparan Sulfate ◽  
Type V Collagen ◽  
Type V

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

scholarly journals A single chain 19-kDa fragment from bovine thrombospondin binds to type V collagen and heparin

1993 ◽  
Vol 268 (21) ◽  
pp. 15544-15549
Author(s):  
J. Takagi ◽  
T. Fujisawa ◽  
T. Usui ◽  
T. Aoyama ◽  
Y. Saito
Keyword(s):  
Single Chain ◽  
Type V Collagen ◽  
Type V

Localization of Type V Collagen with Monoclonal Antibodies in Developing Dental and Peridental Tissues of the Rat and Hamster

1986 ◽  
Vol 6 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Antonius L.J.J. Bronckers ◽  
Steffen Gay ◽  
Donacian M. Lyaruu ◽  
Renate E. Gay ◽  
Edward J. Miller
Keyword(s):  
Monoclonal Antibodies ◽  
Type V Collagen ◽  
Type V

Analysis Influence of Pile Embedded Depth and Diameter on Pile Tip Resistance

2013 ◽  
Vol 353-356 ◽  
pp. 459-462
Author(s):  
Ying Jie Zheng ◽  
Bin Fang ◽  
Lian Xiang Li
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Stiffness Ratio ◽  
Initial Stiffness ◽  
Tip Resistance

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.

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