Collagen Research Papers - Academia.edu (original) (raw)

Collagen pattern in healing anastomosis of intestinal wall was compared with its normal pattern in the submucosal layer. Polarization colours were recorded for thin (0.8 micron or less) and thick (1.6-2.4 micron) collagen fibres. The... more

Collagen pattern in healing anastomosis of intestinal wall was compared with its normal pattern in the submucosal layer. Polarization colours were recorded for thin (0.8 micron or less) and thick (1.6-2.4 micron) collagen fibres. The polarization colours of thick collagen fibres in the anastomotic site were more greenish-yellow and yellow than those in normal intestine which were more yellowish-orange and orange. These findings indicate that the collagen in the anastomotic site 4 days after operation is less packed than the collagen of normal rat intestine. Examination of the polarization colours of Picrosirius red-stained sections is a useful procedure to follow healing of anastomotic sites or diagnosis of collagen pathology in different pathologic conditions in the intestinal wall.

Cells in culture from a woman with a variety of the Marfan syndrome produce two species of the alpha 2 chains of type I collagen. One alpha 2 chain appears normal; the abnormal chain has a higher apparent molecular weight than normal and... more

Cells in culture from a woman with a variety of the Marfan syndrome produce two species of the alpha 2 chains of type I collagen. One alpha 2 chain appears normal; the abnormal chain has a higher apparent molecular weight than normal and migrates more slowly during electrophoresis in sodium dodecyl sulfate/polyacrylamide gels. A similar change in electrophoretic behavior is seen in the prepro alpha 2 chain and the pN alpha 2 chain (which contains the amino-terminal extension). Asymmetric cleavage of the pepsin-treated procollagens with a fibroblast collagenase locates the abnormal segment amino terminal to the cleavage site, and analysis of cyanogen bromide peptides of collagenase cleavage peptides and of whole collagens indicates that the abnormal segment is in either the alpha 2CB3 peptide or the short segment of alpha 2CB5 amino terminal to the collagenase site of the altered alpha 2 chain. The higher apparent molecular weight is consistent with the insertion of a small peptide f...

Congenital Hepatic Fibrosis (CHF) is a disease of the biliary epithelium characterized by bile duct changes resembling ductal plate malformations and by progressive peribiliary fibrosis, in the absence of overt necroinflammation.... more

Congenital Hepatic Fibrosis (CHF) is a disease of the biliary epithelium characterized by bile duct changes resembling ductal plate malformations and by progressive peribiliary fibrosis, in the absence of overt necroinflammation. Progressive liver fibrosis leads to portal hypertension and liver failure, however the mechanisms leading to fibrosis in CHF remain elusive. CHF is caused by mutations in PKHD1, a gene encoding for fibrocystin, a ciliary protein expressed in cholangiocytes. Using a fibrocystin-defective (Pkhd1(del4/del4) ) mouse, which is orthologous of CHF, we show that Pkhd1(del4/del4) cholangiocytes are characterized by a β-catenin-dependent secretion of a range of chemokines, including CXCL1, CXCL10 and CXCL12, which stimulate bone marrow-derived macrophage recruitment. We also show that Pkhd1(del4/del4) cholangiocytes, in turn, respond to proinflammatory cytokines released by macrophages by up-regulating αvβ6 integrin, an activator of latent local TGFβ1. While the macr...

Collagens and elastin form the fundamental framework of all tissues and organs, and their expression and post-translational processing are tightly regulated in disease and health. Because of their unique structural composition and... more

Collagens and elastin form the fundamental framework of all tissues and organs, and their expression and post-translational processing are tightly regulated in disease and health. Because of their unique structural composition and properties, it is a recognized challenge to access these protein structures within the complex tissue microenvironment to understand how localized changes modulate tissue health. We describe a new workflow using a combination of matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) with matrix metalloproteinase (MMP) enzymes to access and report on spatial localization of collagen and elastin sequences in formalin-fixed, paraffin-embedded (FFPE) tissues. The developed technology provides new access to collagens and elastin sequences localized to tissue features that were previously unattainable. This high-throughput technological advance should be applicable to any tissue regardless of disease type, tissue origin, or disease sta...

Matrix remodeling of cells is highly regulated by proteases and their inhibitors. Nevertheless, how would the chondrogenesis of mesenchymal stem cells (MSCs) be affected, when the balance of the matrix remodeling is disturbed by... more

Matrix remodeling of cells is highly regulated by proteases and their inhibitors. Nevertheless, how would the chondrogenesis of mesenchymal stem cells (MSCs) be affected, when the balance of the matrix remodeling is disturbed by inhibiting matrix proteases, is incompletely known. Using a previously developed collagen microencapsulation platform, we investigated whether exposing chondrogenically differentiating MSCs to intracellular and extracellular protease inhibitors will affect the extracellular matrix remodeling and hence the outcomes of chondrogenesis. Results showed that inhibition of matrix proteases particularly the extracellular ones favors the phenotype of fibrocartilage rather than hyaline cartilage in chondrogenically differentiating hMSCs by upregulating type I collagen protein deposition and type II collagen gene expression without significantly altering the hypertrophic markers at gene level. This study suggests the potential of manipulating extracellular proteases to...

This study evaluates the effect of subgingival irrigation with a 1% chlorhexidine collagen gel in periodontal pockets as an adjunct procedure to scaling and root planing (SRP). Thirty-seven sites with probing depth (PD) of 5-7 mm and BANA... more

This study evaluates the effect of subgingival irrigation with a 1% chlorhexidine collagen gel in periodontal pockets as an adjunct procedure to scaling and root planing (SRP). Thirty-seven sites with probing depth (PD) of 5-7 mm and BANA positive in 6 patients with chronic periodontal disease were selected. Sites were assigned to different treatment groups consisting of SRP only (group 1), SRP + irrigation with collagen gel (group 2), or SRP + irrigation with collagen gel containing 1% chlorhexidine (group 3). Subgingival irrigation was performed after initial SRP and at 7, 14 and 21 days. Clinical measurements including PD, plaque index (PI), gingival index (GI), gingival recession (GI), bleeding on probing (BOP) and clinical attachment level (CAL) were performed at the selected sites at baseline, 60 and 90 days and the BANA test was performed on plaque samples from the same sites at baseline and 90 days. There was an improvement in clinical parameters in all groups with a signifi...

This clinical case report describes and demonstrates successful use of recombinant human platelet-derived growth factor (rhPDGF-BB) in conjunction with autogenous bone, anorganic bone mineral, and barrier membranes to reconstruct severe... more

This clinical case report describes and demonstrates successful use of recombinant human platelet-derived growth factor (rhPDGF-BB) in conjunction with autogenous bone, anorganic bone mineral, and barrier membranes to reconstruct severe alveolar bone defects. A combined sinus augmentation and vertical alveolar ridge augmentation was successfully performed. In addition, a significant amount of periodontal bone gain was achieved in close apposition to a previously denuded root surface, which is significant from a periodontal standpoint, given the possibility of vertical periodontal regeneration.

Comparisons of 2D and 3D cell culture models in literature have indicated differences in cellular morphology and metabolism, commonly attributed the better representation of in vivo conditions of the latter cell culture environment. Thus,... more

Comparisons of 2D and 3D cell culture models in literature have indicated differences in cellular morphology and metabolism, commonly attributed the better representation of in vivo conditions of the latter cell culture environment. Thus, interest in the use of 3D collagen gels for in vitro analysis has been growing. Although comparative studies to date have indicated an enhanced resistance of cells on collagen matrices against different toxicants, in the present study it is demonstrated that non-adapted protocols can lead to misinterpretation of results obtained from classical colorimetric dye-based cytotoxic assays. Using the well established Alamar blue assay, the study demonstrates how the transfer from 2D substrates to 3D collagen matrices can affect the uptake of the resazurin itself, affecting the outcome of the assay. Using flow cytometry, it is demonstrated that the cell viability is unaffected when cells are grown on collagen matrices, thus the difference seen in the fluor...

Lack of estrogen receptor (ER) and presence of vimentin (VIM) associate with poor prognosis in human breast cancer. We have explored the relationships between ER, VIM, and invasiveness in human breast cancer cell lines. In the matrigel... more

Lack of estrogen receptor (ER) and presence of vimentin (VIM) associate with poor prognosis in human breast cancer. We have explored the relationships between ER, VIM, and invasiveness in human breast cancer cell lines. In the matrigel outgrowth assay, ER+/VIM‐ (MCF‐7, T47D, ZR‐75‐1), and ER‐/VIM‐ (MDA‐MB‐468, SK‐Br‐3) cell lines were uninvasive, while ER‐/VIM+ (BT549, MDA‐MB‐231, MDA‐MB‐435, MDA‐MB‐436, Hs578T) lines formed invasive, penetrating colonies. Similarly, ER‐/VIM+ cell lines were significantly more invasive than either the ER+/VIM‐ or ER‐/VIM‐ cell lines in the Boyden chamber chemoinvasion assay. Invasive activity in nude mice was only seen with ER‐/VIM+ cell lines MDA‐MB‐231, MDA‐MB‐435 and MDA‐MB‐436. Hs578T cells (ER‐/VIM +) showed hematogenous dissemination to the lungs in one of five mice, but lacked local invasion. The ER‐/VIM+ MCF‐7ADR subline was significantly more active than the MCF‐7 cells in vitro, but resembled the wild‐type MCF‐7 parent in in vivo activity....

A cylindrical post dipping (CPD) method to fabricate the PDMS microlens arrays is presented in this paper. The proposed CPD method is based on the surface tension effect. 2 ㎜ gap and gapless lenses with 2 ㎜ diameter are fabricated and... more

A cylindrical post dipping (CPD) method to fabricate the PDMS microlens arrays is presented in this paper. The proposed CPD method is based on the surface tension effect. 2 ㎜ gap and gapless lenses with 2 ㎜ diameter are fabricated and characterized geometically. Both profiles of the fabricated microlens are well-fitted with ideal lens profile. The surface roughness average of the fabricated lens is measured to be 1.953 ㎚. The focal length of 2㎜ gap lenses and the gapless lenses is calculated to be 17.00 ㎜ with 0.65 ㎜ standard deviation and 29.88 ㎜ with 2.58 ㎜ standard deviation, respectively. The proposed CPD method can be applied to wafer level lens fabrication due to its simplicity and versatility.

An in vitro study using human degenerated nucleus pulposus cells. To determine the effect of osmolality and different osmolytes on the regeneration by human nucleus pulposus cells through gene expression and extracellular matrix... more

An in vitro study using human degenerated nucleus pulposus cells. To determine the effect of osmolality and different osmolytes on the regeneration by human nucleus pulposus cells through gene expression and extracellular matrix production. Intervertebral disc (IVD) degeneration is a major problem in developed countries. Regeneration of the IVD can prevent pain and costs due to diminished work absence and health care, and improve quality of life. The osmotic value of a disc decreases during degeneration due to loss of proteoglycans and might increase degeneration. It is known that gene expression of matrix genes of nucleus pulposus (NP) cells increases when cultured in hyperosmotic medium. Thus, increasing the osmolality of the disc might be beneficial for disc regeneration. In the current study, isolated degenerated human NP cells were used in regeneration culture with medium of different osmolalities, adjusted with different osmolytes. NaCl, urea and sucrose. The cells were cultur...

Chondrocytes respond to glucose deprivation with a decreased collagen synthesis due to disruption of a proper functioning of the endoplasmic reticulum (ER): ER stress. Since the mechanisms involved in the decreased synthesis are unknown,... more

Chondrocytes respond to glucose deprivation with a decreased collagen synthesis due to disruption of a proper functioning of the endoplasmic reticulum (ER): ER stress. Since the mechanisms involved in the decreased synthesis are unknown, we have investigated whether chaperones and collagen-modifying enzymes are affected by glucose deprivation. Chondrocytes obtained from nucleus pulposus, annulus fibrosus, articular cartilage, and meniscus and dermal fibroblasts were cultured under control conditions or exposed to the ER stress-inducing treatments of tunicamycin addition or glucose withdrawal. Both treatments resulted in an up-regulation of the gene expression of the ER stress markers in all cell types, but dermal fibroblasts showed a delayed response to glucose deprivation. Collagen gene expression was down-regulated, and less collagen protein was present in the cells under both ER stress-inducing conditions. The expression levels of the prolyl 4-hydroxylases were either not affecte...