Comparative studies, carried out in 17 Holstein calves, indicated that an adherent, thin, collagenous lining developed on the fibroblast-seeded polyurethane pump chamber in nine animals. Similar implantations of eight non-cell-seeded (control) devices resulted in formation of a predominantly acellular, fibrinous membrane, varying in thickness from 1 to 8 mm. Pump chamber compliance was significantly reduced when the histologic surface exceeded 3 mm in thickness, resulting in impaired filling and an inadequate stroke volume. API of 14C-thymidine-labeled fibroblasts permitted later identification of the donor cells in the collagenous linings by radioautography. Serial immunologic studies undertaken to detect evidence of rejection in recipient Holstein calves were negative.10111/j751-10970090648. x. Epub 2009 Nov 18.Collagenous extracellular matrix of cartilage submitted to mechanical forces studied by second harmonic generation microscopy.Moléculaire et Thérapeutique FR CNRS-INSERM 3209, Faculté de Médecine, Osteoarthritis is a degenerative pathology leading to degradation of the extracellular matrix (ECM). Similar effects can be visualized when applying mechanical or biochemical constraints on cartilaginous tissue. Here, we characterized modification of the ECM appearing under mechanical compression and/or biochemical action (hypoxia environment, nitric oxide and collagenase action). In recent decades, multiphoton microscopy has proved its interest for observing living, thick and opaque biological tissues. Thus, the main components of the cartilaginous ECM can be observed without fluorescent labeling. In particular, the collagen network emits strong second harmonic generation (SHG) signal which could be collected at half of the excitation wavelength. Combining autofluorescence and SHG signal detection enables to obtain complementary structural information. Here, we proved that multiphoton microscopy represents an appropriate tool for ex vitro cartilage imaging. First, we showed that SHG signal specifically comes from collagen (collagenase digestion). Further, we verified that the use of an appropriate band-pass filter enables to reject the autofluorescence from the ECM. Once this specificity was shown, we followed modification of the cartilage ECM submitted to mechanical or biochemical constraints (compression, enzymatic digestion). By performing textural analysis of SHG images (Haralick's method), we showed the restructuration of the collagen Paediatric knee anterolateral capsule does not contain a distinct ligament: analysis of histology, immunohistochemistry and gene expression.Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.OBJECTIVES: The presence of a discrete ligament within the knee anterolateral capsule (ALC) is controversial. Tendons and ligaments have typical collagens, ultrastructure, transcription factors and proteins. However, these characteristics have not been investigated in paediatric ALC. The purpose of this study was to characterise the paediatric ALC in terms of tissue ultrastructure and cellular expression of ligament markers scleraxis (SCX)-a basic helix-loop-helix transcription factor-and the downstream transmembrane glycoprotein tenomodulin (TNMD), as compared with the paediatric lateral collateral ligament (LCL) and paediatric quadriceps tendon (QT). Dermatological medications hypothesised that, in comparison to the LCL and QT, the ALC would possess poor collagen orientation and reduced SCX and TNMD expression. METHODS: 15 paediatric ALCs (age 6±3 years), 5 paediatric LCLs (age 3±1 years) and 5 paediatric QTs (age 2±1 years) from fresh cadaveric knees were used in this study. Fresh-frozen samples from each region were cryosectioned and then stained with H&E to evaluate collagen alignment and cell morphology. Expression of SCX and TNMD was determined by gene expression analysis and RESULTS: The histological sections of the paediatric LCL and QT showed well-organised, dense collagenous tissue fibres with elongated fibroblasts, while the ALC showed more random collagen orientation without clear cellular directionality. The aspect ratio of cells in the ALC was significantly lower than that of the LCL and QT (p<0001 and p<0001, respectively). The normalised distribution curve of the inclination angles of the nuclei in the ALC was more broadly distributed than that of the LCL or QT, indicating random cell alignment in the ALC. SCX immunostaining was apparent in the paediatric LCL within regions of aligned fibres, while the comparatively disorganised structure of the ALC was negative for SCX. The paediatric LCL also stained positive for TNMD, while the ALC was only sparsely positive for this tendon/ligament cell-surface molecule. Relative gene expression of SCX and TNMD were higher in CONCLUSION: In this study, a distinct ligament could not be discerned in the ALC based on histology, immunohistochemistry and gene expression analysis.LEVEL OF EVIDENCE: Controlled laboratory study.Medicine 2021. Re-use permitted under CC BY-NC. No commercial re-use. Published Conflict of interest statement: Competing interests: None declared.
API|Dermatological medications
