Shared decision making: a model for clinical practice.

The principles of shared decision making are well documented but there is a lack of guidance about how to accomplish the approach in routine clinical practice. Our aim here is to translate existing conceptual descriptions into a three-step model that is practical, easy to remember, and can act as a guide to skill development. Achieving shared decision making depends on building a good relationship in the clinical encounter so that information is shared and patients are supported to deliberate and express their preferences and views during the decision making process. To accomplish these tasks, we propose a model of how to do shared decision making that is based on choice, option and decision talk. The model has three steps: a) introducing choice, b) describing options, often by integrating the use of patient decision support, and c) helping patients explore preferences and make decisions. This model rests on supporting a process of deliberation, and on understanding that decisions should be influenced by exploring and respecting "what matters most" to patients as individuals, and that this exploration in turn depends on them developing informed preferences.

De novo synthesis of human dermis in vitro in the absence of a three-dimensional scaffold.

Neonatal human dermal fibroblasts cultured in vitro synthesize an organized and physically substantial three-dimensional extracellular matrix, without the addition of exogenous matrix components or synthetic scaffolds. De novo matrix synthesis proceeds in an orderly manner over a 21-d culture period and beyond. Analysis of the fibroblast phenotype, i.e., matrix synthesis by the fibroblasts, suggests that both serum and serum-free conditions are conducive to the production of a human tissue-engineered "dermal equivalent". We report that given the appropriate permissive environment, the fibroblasts establish and grow a tissue in vitro, which bears striking biochemical and physical resemblance to normal human dermis.

Deep dermal fibroblasts contribute to hypertrophic scarring.

Hypertrophic scar (HTS) following thermal injury is a dermal fibroproliferative disorder that leads to considerable morbidity. The development of HTS involves numerous cell types and cytokines with dermal fibroblasts being a key cell. We have previously reported that the phenotype of fibroblasts isolated from HTS was altered compared to fibroblasts from normal skin. In this study, normal skin was horizontally sectioned into five layers using a dermatome from which fibroblasts were isolated and cultured. Cells from the deeper layers were observed to proliferate at a slow rate, but were morphologically larger. In ELISA and FACS assays, cells from the deeper layers produced more TGF-beta1 and TGF-beta1 producing cells were higher. In quantitative RT-PCR, the cells from the deeper layers had higher CTGF and HSP47 mRNA levels compared to those from superficial layers. In western blot, FACS and collagen gel assays, fibroblasts from the deeper layers produced more alpha-smooth muscle actin (alpha-SMA), had higher alpha-SMA positive cells and contracted collagen gels more. Fibroblasts from the deeper layers were also found to produce more collagen, but less collagenase by mass spectrometry and collagenase assay. Interestingly, cells from the deeper layers also produced more of the proteoglycan, versican, but less decorin. Taken together, these data strongly demonstrate that fibroblasts from the deeper layers of the dermis resemble HTS fibroblasts, suggesting that the deeper layer fibroblasts may be critical in the formation of HTS.

Crystal structure of the biglycan dimer and evidence that dimerization is essential for folding and stability of class I small leucine-rich repeat proteoglycans.

Biglycan and decorin are two closely related proteoglycans whose protein cores contain leucine-rich repeats flanked by disulfides. We have previously shown that decorin is dimeric both in solution and in crystal structures. In this study we determined whether biglycan dimerizes and investigated the role of dimerization in the folding and stability of these proteoglycans. We used light scattering to show that biglycan is dimeric in solution and solved the crystal structure of the glycoprotein core of biglycan at 3.40-angstroms resolution. This structure reveals that biglycan dimerizes in the same way as decorin, i.e. by apposition of the concave inner surfaces of the leucine-rich repeat domains. We demonstrate that low concentrations of guanidinium chloride denature biglycan and decorin but that the denaturation is completely reversible following removal of the guanidinium chloride, as assessed by circular dichroism spectroscopy. Furthermore, the rate of refolding is dependent on protein concentration, demonstrating that it is not a unimolecular process. Upon heating, decorin shows a single structural transition at a T(m) of 45-46 degrees C but refolds completely upon cooling to 25 degrees C. This property of decorin enabled us to show both by calorimetry and light scattering that dimer to monomer transition coincided with unfolding and monomer to dimer transition coincided with refolding; thus these processes are inextricably linked. We further conclude that folded monomeric biglycan or decorin cannot exist in solution. This implies novel interrelated functions for the parallel beta sheet faces of these leucine-rich repeat proteoglycans, including dimerization and stabilization of protein folding.

Identification of fibrocytes in postburn hypertrophic scar.

Fibrocytes are a unique leukocyte subpopulation implicated in wound healing. They are derived from peripheral blood mononuclear cells, display fibroblast-like properties, and synthesize extracellular matrix macromolecules. This study investigated whether fibrocytes are present in healing burn wounds and whether the number of fibrocytes in tissue correlates with the degree of burn injury and the development of hypertrophic scar. Proteins extracted from cultured fibrocytes and nonadherent lymphocytes were found to be similar using two-dimensional gel electrophoresis and quite distinct from those obtained from fibroblasts. However, one protein, identified as leukocyte-specific protein 1 using mass spectrometric peptide mapping, was found in significantly larger amounts in fibrocytes than in lymphocytes but was undetectable in fibroblasts. Double immunostaining with antibodies to leukocyte-specific protein-1 and to the N-terminal propeptide of type I collagen was performed on cryosections of hypertrophic scar, mature scar, and normal skin. Fibrocytes were seen in scar tissue as dual-labeled spindle-shaped cells but were absent from normal skin. Moreover, the number of fibrocytes was higher in hypertrophic than in mature scar tissue. We conclude that fibrocytes, which have been reported to be antigen-presenting cells, are recruited to wounds following extensive burn injury and could potentially upregulate the inflammatory response and synthesize collagen and other matrix macromolecules, thus contributing to the development of hypertrophic scarring.

Crystal structure of the dimeric protein core of decorin, the archetypal small leucine-rich repeat proteoglycan.

Decorin is a ubiquitous extracellular matrix proteoglycan with a variety of important biological functions that are mediated by its interactions with extracellular matrix proteins, cytokines, and cell surface receptors. Decorin is the prototype of the family of small leucine-rich repeat proteoglycans and proteins (SLRPs), characterized by a protein core composed of leucine-rich repeats (LRRs), flanked by two cysteine-rich regions. We report here the crystal structure of the dimeric protein core of decorin, the best characterized member of the SLRP family. Each monomer adopts the curved solenoid fold characteristic of LRR domains, with a parallel beta-sheet on the inside interwoven with loops containing short segments of beta-strands, 3(10) helices, and polyproline II helices on the outside. Two main features are unique to this structure. First, decorin dimerizes through the concave surfaces of the LRR domains, which have been implicated previously in protein-ligand interactions. The amount of surface buried in this dimer rivals the buried surfaces of some of the highest-affinity macromolecular complexes reported to date. Second, the C-terminal region adopts an unusual capping motif that involves a laterally extended LRR and a disulfide bond. This motif seems to be unique to SLRPs and has not been observed in any other LRR protein structure to date. Possible implications of these features for decorin ligand binding and SLRP function are discussed.

Assessing the safety and effectiveness of hip protectors.

Hip protectors are used in the preventive management of older people who are at risk of fracturing their hip after a fall. However, nurses have little guidance about which type is the most appropriate for particular patients. This article highlights the different designs available and their mechanical performance was assessed by the authors using a purpose-built impact rig. Problems with compliance and issues about tissue viability are discussed and the article also contains a risk assessment tool to help nurses decide on which is the most suitable type of hip protector to use.

Light and X-ray scattering show decorin to be a dimer in solution.

Decorin is a widely distributed member of the extracellular matrix small leucine-rich repeat glycoprotein/proteoglycan family. For investigation of its physical properties, decorin from two sources (young steer skin and a recombinant adenovirus) was used. The first sample was extracted into 7 m urea and purified, while the second was isolated from medium conditioned by 293A cells infected with adenovirus and purified without chaotropes. The only chemical differences detected between these materials were a slightly shorter glycosaminoglycan chain and the retention of the propeptide on the latter. Circular dichroism spectra of the two samples were virtually identical, showing a high proportion of beta-sheet and beta-turn and little alpha-helix. The protein cores were completely denatured in 2.25 m guanidine HCl (GdnHCl) but recovered their secondary structure on removal of chaotrope. Light scattering of material eluted from gel-filtration columns in Tris-buffered saline, pH 7.0, gave molecular mass values of 165 +/- 1 kDa and 84.6 +/- 4 kDa for intact decorin and the glycoprotein core produced by digestion with chondroitin ABC lyase, respectively. Intact recombinant prodecorin had a mass of 148 +/- 18 kDa. These values, which are double those estimated from SDS gel electrophoresis or from the known sequences and compositions, were halved in 2.5 m GdnHCl. Data from solution x-ray scattering of intact decorin and its core in Tris-buffered saline are consistent with a dimeric particle whose protein component has a radius of gyration of 31.6 +/- 0.4 A, a maximum diameter of 98 +/- 5 A, and approximates two intertwined C shapes.

Biochemical and immunohistochemical studies of the protein expression and localization of decorin and biglycan in the temporomandibular joint disc of growing rats.

To analyze the growth-related changes in extracellular matrix components, biochemical/immunohistochemical techniques were used to examine the protein expression and localization of two small leucine-rich proteoglycans, biglycan and decorin, in the temporomandibular joint discs of growing rats. Western blotting showed that the protein expression of decorin increased with age, but that of biglycan gradually decreased. An immunohistochemical study showed that staining for decorin was weak and homogeneously distributed in the discs from birth to 2 weeks. Regional differences in staining for decorin became prominent at 4, 8 and 16 weeks; decorin was more abundant in the peripheral area (the periphery of the band and the attachment) than in the central area (the intermediate zone and central area of the posterior band). In contrast, staining for biglycan was evenly distributed throughout the disc until 4 weeks, and after that became rather intense in the anterior and posterior bands. These results demonstrate that there are growth-related changes and regional differences in the expression of biglycan and decorin in the temporomandibular joint discs of growing rats, which probably reflect changes in the biomechanical environment caused by the development of orofacial functions.