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Bone grafts are used for bone augmentation to ensure optimal implant placement. However, this procedure may sometimes cause sinusitis. The case of a 44-year-old woman with the diagnosis of recurrent and chronic sinusitis of her right maxillary sinus with a history of dental implant surgery is presented. After several attempts with normal standard sinusitis therapy, unrecognized bone substitute was removed from the sinus cavity, which finally led to resolution of the sinusitis. This case reiterates the importance of a careful examination, consultation, and second opinion for the selection of optimal treatment. [ABSTRACT FROM AUTHOR]

It was hypothesized that peri-implant tissue around loosening dental implants may contain cytokines with a potential to regulate osteoclasts. Peri-implant and/or gingival samples from loosened implants, chronic periodontitis (CP), and normal controls (n = 10 samples in each group) were analyzed using immunohistochemical staining to observe tumor necrosis factor alpha (TNF-alpha), interleukin 1-alpha (IL-1alpha), IL-6, platelet-derived growth factor A (PDGF-A), and transforming growth factor alpha (TGF-alpha). These cytokines were found in foreign-body giant cells, macrophages, fibroblasts, and epithelial cells. TNF-alpha, IL-1alpha, and IL-6 were increased (P < .05; unpaired t test) in peri-implantitis and CP, whereas PDGF-A and TGF-alpha were not. In conclusion, cytokines with a potential to activate osteoclasts were found in both peri-implantitis and CP, but the cytokine profiles differed in that IL-1alpha was the most prevalent cytokine in the former and TNF-alpha was the most common in the latter. These cytokines may contribute to peri-implant bone loss/loosening by stimulating formation and activity of osteoclasts and might be an amenable target for local therapies with cytokine modulators. [ABSTRACT FROM AUTHOR]

PURPOSE: Attachment of bacteria to titanium may differ not only between bacterial species but also between strains within a species. The aim of the present in vitro study was to examine differences in bacterial attachment using 4 gram-negative anaerobic species of bacteria that are considered potential periodontal pathogens. MATERIALS AND METHODS: The attachment of clinical and laboratory strains (n = 23) representing 2 Fusobacterium nucleatum subspecies, Porphyromonas gingivalis, and Prevotella intermedia to smooth, commercially pure titanium was examined using scanning electron microscopy. RESULTS: All bacterial strains were attached to the smooth titanium surface by their outer membrane. F nucleatum cells were poorly attached to the titanium, unlike P gingivalis or P intermedia cells, but only slight differences were observed in the quantity of attached cells between the strains within each bacterial group. DISCUSSION: In favorable conditions, some anaerobes can attach directly to an inert titanium surface. Microbial adhesion and subsequent colonization on the dental implant surface can lead to infection of the peri-implant tissue. CONCLUSION: The results indicated that the avidity of bacterial attachment to a smooth titanium surface varies between species of oral gram-negative anaerobes but not between strains. [ABSTRACT FROM AUTHOR]

AIMS: To investigate whether involvement of the temporomandibular joint (TMJ) can occur in men with Reiter's disease (RD). METHODS: Forty-nine men with RD and 49 individually matched (gender, age and dentition type) controls with no known general joint disease were screened for findings in the TMJ by panoramic tomography. RESULTS: Duration of subjective symptoms (e.g., pain) in the masticatory system correlated with duration of RD (P = .05). In the RD group, severity of clinical signs of symptoms correlated with the progressive form of RD (P = .01), number of affected joints (P = .0001), and involvement of the cervical (P = .0001) and lumbar spine (P = .05). Patients with RD more frequently had radiographic findings (33%) in the condyle of the TMJ than did controls (10%) (P = .002). The most characteristic radiographic sign in the condyle in the RD group was unilateral erosion (12%). CONCLUSION: Patients with RD often have erosion causing pain and dysfunction in the TMJ. Potential masticatory system problems for such patients should be brought to the attention of dentists and physicians. [ABSTRACT FROM AUTHOR]

Objectives: Healthy human labial salivary glands produce epidermal growth factor (EGF). In Sjögren's syndrome (SS), EGF staining is diminished. SS is also associated with chronic autoimmune corpus gastritis. We therefore hypothesized that EGF secretion would be diminished in SS and that this could affect gastric target cells.Methods: Salivary EGF secretion in SS was compared to that in healthy controls using an enzyme-linked immunosorbent assay (ELISA). EGF receptor (EGFR) immunoreactive cells in the gastric corpus of healthy human subjects were analysed using immunostaining.Results: Salivary secretion of EGF was diminished in SS patients (232.4, range 52.6-618.4, vs. 756.6, range 105.3-1631.6 pg/min, p = 0.002). Proton-pump positive parietal cells were mostly EGFR immunoreactive whereas very few pepsinogen I (PGI)-positive cells were EGFR positive.Conclusions: As EGF is relatively acid resistant, salivary gland-derived EGF might participate in an exo/endocrine mode of parietal cell maintenance in the gastric corpus. Deficiency of salivary gland-derived EGF in SS patients may cause impairment of gastric parietal cells resulting in exposure of immunogenic cryptic antigens and loss of immunological self-tolerance. [ABSTRACT FROM AUTHOR]

Objectives Oral lichen planus ( OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. Materials and Methods Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. Results H4R immunoreactivity was weak in OLP and characterized by mast cell ( MC) hyperplasia and degranulation. In contrast to controls, H4R immunostaining and MC counts were negatively correlated in OLP ( P = 0.003). H4R agonist at nanomolar levels led to a rapid internalization of H4Rs, whereas high histamine concentration and interferon- γ decreased HRH4-gene transcripts. Conclusion Healthy oral epithelial cells are equipped with H4R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4R. Cell culture experiments suggest a rapid H4R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4R synthesis. H4R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines. [ABSTRACT FROM AUTHOR]

Objectives It was hypothesized that beta 2 defensin ( BD-2) is increased in RAU lesions compared with healthy controls to promote anti-microbial host defence. Methods RAU and control mucosa samples were subjected to quantitative real-time PCR and immunostained for BD-2, CD68, mast cell tryptase and 4-hydroxynonenal (4 HNE). The effect of tumour necrosis factor- α ( TNF- α) ± interleukin-17C ( IL-17C), without and with vitamin K3, was studied on BD-2 expression in epithelial SCC-25 cells. Results Although BD-2 mRNA did not differ between healthy and RAU mucosa, BD-2 stained strongly in acute-phase RAU epithelium ( P = 0.001). In controls, subepithelial BD-2+ cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD-2+ ( P = 0.004). In cell culture, BD-2 was increased 124-fold by TNF- α ( P < 0.0001) and 208-fold synergistically together with IL-17C ( P < 0.0001). 4HNE staining of RAU epithelium was not significantly increased, and vitamin K3-induced reactive oxygen species (ROS) did not affect BD-2. Conclusions Anti-microbial BD-2 was not affected by oxidative stress but was highly increased in the epithelial and immigrant cells in the acute-phase RAU lesions, probably in part synergistically by TNF- α and epithelial IL-17C, which are known to be induced by activation of danger-signal receptors by pathogen- and/or damage-associated molecular patterns. [ABSTRACT FROM AUTHOR]

Objective To study non-osteoclastic sources of cathepsin K in periodontitis. Materials and Methods Tissue samples were obtained from 10 otherwise healthy periodontitis pati-ents during routine periodontal flap operations and 10 systemically and periodontally healthy individuals who underwent extraction operations for retained third molars. Methods used were immunohistochemistry, image analysis, immunofluorescence double-staining, gingival fibroblast culture, tumour necrosis factor- α ( TNF- α) stimulation and Western blotting. Results Macrophage-like cells, fibroblast-like cells, vascular endothelial cells and gingival epithelial cells were more intensively stained for cathepsin K and also more frequent in periodontitis than in controls (665 ± 104 vs 258 ± 40 cells mm−2, P < 0.01). Some cathepsin K+ cells in periodontal tissues were CD68+, but some were CD68− and probably fibroblasts. Indeed, in gingival fibroblast culture, resting fibroblasts released cathepsin K, more 43 kD procathepsin K than 29 kD active cathepsin K. TNF- α increased the release of the activated cathepsin K 4- to 5-fold. Conclusions Results suggest that GCF-cathepsin K is not only osteoclast-derived, but in periodontitis, also other cells contribute to it. GCF-cathepsin K, perhaps together with intracellular, lysosomal collagenolytically active cathepsin K in fibroblasts, macrophages and gingival epithelial cells, can contribute to the loss of attachment and destruction of the periodontal ligament. [ABSTRACT FROM AUTHOR]

Oral Diseases (2012) 19, 46-58 Sjögren's syndrome (SjS) is one of the most common autoimmune rheumatic diseases, clinically characterized by xerostomia and keratoconjunctivitis sicca. We investigated the following controversial topics: (i) Do we have reliable ways of assessing saliva production? (ii) How important are the quantity and quality of saliva? (iii) Are only anti-SSA/Ro and anti-SSB/La relevant for the diagnosis of SjS? (iv) Are the American-European Consensus criteria (AECC) the best way to diagnose SjS? Results from literature searches suggested the following: (i) Despite the fact that numerous tests are available to assess salivation rates, direct comparisons among them are scarce with little evidence to suggest one best test. (ii) Recent developments highlight the importance of investigating the composition of saliva. However, more research is needed to standardize the methods of analysis and collection and refine the quality of the accumulating data. (iii) In addition to anti-Ro/La autoantibodies, anti α-fodrin IgA and anti-MR3 autoantibodies seem to be promising diagnostic markers of SjS, but more studies are warranted to test their sensitivity and specificity. (iv) AECC are classification, not diagnostic criteria. Moreover, recent innovations have not been incorporated into these criteria. Consequently, treatment directed to patients diagnosed using the AECC might exclude a significant proportion of patients with SjS. [ABSTRACT FROM AUTHOR]

Oral Diseases (2012) 18, 255-259 Objectives: (i) To determine whether salivary cortisol and electrolyte levels differ between patients with Sjogren's syndrome (SjS) and healthy individuals. (ii) To assess correlations between whole-saliva cortisol and some clinical manifestations in patients with SjS. Methods: A total of 24 healthy women (mean age 49.3 ± 9.8) served as controls (C) vis-à-vis 17 patients with SjS (mean age 55.5 ± 15.7). Salivary cortisol concentration was determined, and sialochemistry analysis was performed. Results: Significantly lower saliva flow rates and higher salivary chloride (Cl−), potassium (K+), and Ca2+ levels were found in the SjS group. No significant differences or correlations were found in other parameters, including sodium (Na+), magnesium (Mg2+), phosphate (−), urea (U), and salivary cortisol levels. Conclusion: Increased whole-salivary output of Cl− and K+ in SjS may reflect release from apoptotic rests of acinar cells after secondary necrosis. Normal levels of salivary Na+, Mg2+, and − argue against concentration effect, deranged tubular function or cortisol (mineralocorticosteroid) effect as the cause for these findings. Increased salivary Ca2+ levels probably reflect leakage of plasma Ca2+ through the injured oral mucosa in SjS. In spite of disease-associated stress, salivary cortisol, a stress biomarker, was not increased, suggesting insufficient hypothalamus-pituitary-adrenal (HPA) axis response and/or local consumption of cortisol by lymphocyte infiltrates. [ABSTRACT FROM AUTHOR]

Usually no distinction is made between female and male salivary glands although cyclic changes of and / or differences in serum and salivary sex steroid concentrations characterize women and men. Moreover, sexual dimorphism is well recognized in salivary glands of rodents. Salivary glands contain estrogen and androgen receptors and are, according to modern high throughput technologies, subjected to gender differences not explainable by gene dose effects by the X chromosome alone. Because sex steroids are lipophilic, it is often thought that approximately 10% of them passively diffuse from plasma to saliva. Indeed, saliva can find use as sample material in sports medicine, pediatrics, veterinary medicine and behavioral sciences. Last but not least, humans and other primates are unique in that they have a reticular zone in their adrenal cortex, which produces dehydroepiandrosterone and androstendione pro-hormones. These are processed in peripheral tissues, not only in female breast and uterus and male prostate, but also in salivary glands by an intracrine enzymatic machinery to active 17 beta-estradiol, dihydrotestosterone and others, to satisfy and buffer against a constantly changing needs caused by circadian, menstrual, pregnancy and chronobiological hormonal changes in the systemic circulation. Female dominance of Sjogren's syndrome and certain forms of salivary gland cancer probably reflect these gender-based differences. [ABSTRACT FROM AUTHOR]

Oral Diseases (2010) 16, 577-585 Usually no distinction is made between female and male salivary glands although cyclic changes of and/or differences in serum and salivary sex steroid concentrations characterize women and men. Moreover, sexual dimorphism is well recognized in salivary glands of rodents. Salivary glands contain estrogen and androgen receptors and are, according to modern high throughput technologies, subjected to gender differences not explainable by gene dose effects by the X chromosome alone. Because sex steroids are lipophilic, it is often thought that approximately 10% of them passively diffuse from plasma to saliva. Indeed, saliva can find use as sample material in sports medicine, pediatrics, veterinary medicine and behavioral sciences. Last but not least, humans and other primates are unique in that they have a reticular zone in their adrenal cortex, which produces dehydroepiandrosterone and androstendione pro-hormones. These are processed in peripheral tissues, not only in female breast and uterus and male prostate, but also in salivary glands by an intracrine enzymatic machinery to active 17β-estradiol, dihydrotestosterone and others, to satisfy and buffer against a constantly changing needs caused by circadian, menstrual, pregnancy and chronobiological hormonal changes in the systemic circulation. Female dominance of Sjögren's syndrome and certain forms of salivary gland cancer probably reflect these gender-based differences. [ABSTRACT FROM AUTHOR]

Background Modern metal-on-metal hip resurfacing implants are being increasingly used for young and active patients, although the long-term outcome and failure mechanisms of these implants are still unknown. In this consecutive revision case series, early failures of femoral implants (at < 4 years) were studied. Methods 3 revisions were done due to a fracture of the femoral neck and 1 due to loosening and varus position of the femoral component. Femoral heads were removed en bloc 2-46 months after the primary operation, embedded in methylmethacrylate, sectioned, stained, and analyzed as whole-mount specimens in 4 55-62-year-old patients with osteoarthritis. Results Histopathology was characterized by new but also partly healed trabecular microfractures, bone demineralization, cysts, metallosis, and abnormal formation of new woven bone. All samples displayed signs of notching, osteoporosis, and aseptic necrosis, which seemed to have been the main reason for the subsequent development and symptoms of the patients and revision operations of the hips. Interpretation Based on these early revision cases, it appears that aseptic necrosis is a common cause of early loosening of resurfacing hip implants. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To describe the clinical presentation, diagnosis, classification, grading, evaluation of prognosis, and treatment of amyloidosis against the background of its pathomechanisms. METHODS: PubMed and MEDLINE databases (1990 to October 2007) and internet were searched for the key word amyloidosis and evaluated on the basis of the authors' own clinical experience and work on the topic. RESULTS: A clinical suspicion of amyloidosis arises when a patient with a chronic inflammatory disease, plasma cell dyscrasia, or a family history of hereditary amyloidosis develops 'an amyloid syndrome' or more rare but specific signs. Microscopy of Congo red stained tissue specimens under polarized light shows birefringent amyloid, which is typed by identification of the amyloid precursor by immunohistochemistry, amino acid sequencing, or proteomics. The diagnosis can be supported by genetic tests. Amyloidosis now covers biochemically and clinically 27 distinct types in man and 9 in animals. Grading to mild, moderate, and severe disease based on laboratory tests and radiology is introduced. Prognosis is affected by the rate of synthesis and the concentration of the circulating precursor. Accurate diagnosis of the underlying disease is mandatory as the treatment is based on disease control and inhibition of amyloid precursor production. Organ-specific treatment, such as transplantation, hemodialysis, treatment of heart failure, pacemakers, and substitution to prevent nutritional deficiencies, is often needed. CONCLUSIONS: As our knowledge of the pathogenesis of amyloidosis and the structure-function relationship of amyloid proteins increases, new therapies will be developed to prevent protein misfolding and aggregation, inhibit fibrillogenesis, and enhance clearance of amyloid. Copyright © 2010 by Elsevier Inc. [ABSTRACT FROM AUTHOR]

Objective: A correlation exists between the absence of α5-laminin and transit checkpoint fenestrations in vascular basement membranes. We hypothesized that similar laminin α5 low expression regions might exist in synovial lining, which, although lacking basement membrane, contains all basement membrane components in its interstitial matrix. Methods: Laminin α4 and α5 chains and lactoferrin were stained using immunofluorescence and cathepsin G and neutrophil elastase using immunoperoxidase. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure laminin α4 and α5 mRNA copy numbers in cultured synovial fibroblasts, without/with tumour necrosis factor-α (TNFα) and interleukin-1β (IL-1β). Results: Laminin α4 and α5 chains were found in the intercellular matrix in synovial lining samples of trauma and revision total hip replacements. Laminin α5 was weaker in osteoarthritis (OA) and rheumatoid arthritis (RA), and RA synovial lining also contained local low expression areas. Double staining disclosed convergence of lactoferrin-degranulating neutrophils towards these laminin α5 low expression regions. In cultured OA synovial fibroblasts, laminin α5 mRNA decreased (p < 0.05) at 1 ng/mL TNFα and was not found at all in cultured resting or cytokine-stimulated RA fibroblasts. Degranulation of cathepsin G and neutrophil elastase was seen in neutrophils passing through blood vessels or synovial lining. Conclusions: Migrating neutrophils in RA seem to use laminin α5 chain low expression regions to exit synovial tissue to enter synovial fluid. Transmigrating neutrophils remodel the intercellular matrix by releasing their proteolytic granular contents to enhance these low expression checkpoints and/or to produce chemotactic stimuli. In RA fibroblasts this is facilitated by cytokine-mediated down-regulation or lack of laminin α5 synthesis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Sjögren's syndrome (SS) is characterized by atrophy and malfunction of the acinar cells. The aim of this study was to investigate whether type IV collagen alpha-chain composition of acinar cell compartments could be abnormal in diseased glands. METHODS: Messenger RNA (mRNA) from human submandibular gland (HSG) cells, cultured with or without growth factor-depleted Matrigel, was analyzed using quantitative reverse transcription-polymerase chain reaction (RT-PCR). Labial salivary glands were analyzed using quantitative RT-PCR and immunohistochemistry. RESULTS: HSG cells of both the ductal and acinar phenotypes synthesized all alpha-chain mRNA, in particular those of the alpha1 and alpha2 chains. Labial salivary glands (LSGs) contained alpha1/2 chains but also contained mRNA of all the other alpha-chains, although the mRNA copy numbers for the alpha3 and alpha4 chains were low, and the corresponding proteins were absent. Type IV collagen alpha1/2-chains were observed in all tubuloalveolar basement membranes. In healthy glands, alpha5 and alpha6 chains were continuous around ducts but discontinuous around acini. In SS glands, these chains were absent or patchy around the ducts and absent around the acini. CONCLUSION: Ductal and acinar epithelial cells are able to locally produce mRNA for all 6 different alpha-chains. Type IV collagen alpha1/2-chains seem to form the backbone in the tubuloalveolar basement membrane in salivary glands. Type IV collagen alpha3 and alpha4 chain mRNA were found in cultured salivary epithelial cells and LSG explants but were not translated to the corresponding alpha-chains in LSGs. Both alpha5 and alpha6 mRNA were observed in salivary epithelial cells and glands. In healthy glands, immunolabeling always disclosed corresponding alpha-chains around ducts, but their synthesis and/or degradation seemed to be locally regulated around acinar cells. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Specialist hospitals have reported an incidence of early deep infections of < 1% following primary knee replacement. The purpose of this study was to estimate the infection rate in a nationwide series using register-based data. METHODS: The Finnish Arthroplasty Register (FAR) was searched for primary unicompartmental, total, and revision knee arthroplasties performed in 1997 through 2003 and eventual revision arthroplasties. The FAR data on revision arthroplasties was supplemented by a search of the national Hospital Discharge Register (HDR) for debridements, partial and total revision knee replacements, resection arthroplasties, arthrodeses, and amputations. RESULTS: During the first postoperative year, 0.33% (95% CI: 0.13-0.84), 0.52% (0.45-0.60) and 1.91% (1.40-2.61) of the primary UKAs, primary TKAs, and revision TKAs, respectively, were reoperated due to infection. The 1-year rate of reoperations due to infection remained constant in all arthroplasty groups over the observation period. The overall infection rate calculated using FAR data only was 0.77% (95% CI: 0.69-0.86), which was lower, but was not, however, statistically significantly different from the overall infection rate calculated using endpoint data combined from FAR and HDR records (0.89%; 95% CI: 0.80-0.99). FAR registered revision arthroplasties and patellar resurfacing arthroplasties reliably but missed a considerable proportion of other reoperations. INTERPRETATION: More reoperations performed due to infection can be expected as the numbers of knee arthroplasties increase, since there has been no improvement in the early infection rate. Finnish Arthroplasty Register data appear to underestimate the incidence of reoperations performed due to infection. [ABSTRACT FROM AUTHOR]

Background and purpose Two-stage revision remains the gold standard in the treatment of infected knee arthroplasty. Lately, good long-term results of direct exchange arthroplasty have been reported. The purpose of this literature review is to compare the clinical outcome achieved with one-stage revision and two-stage revision with different types of spacers. Methods A thorough systematic review of literature was undertaken to idenepsy reports on the treatment alternatives. Papers written in English or including an English abstract, published from 1980 through 2005, and reporting either the success rate in eradication of infection or the clinical status achieved were reviewed. 31 original articles describing the results of 154 one-stage exchange arthoplasties and of 926 two-stage exchange arthoplasties were included. The depth of detail in the description of materials and methods varied markedly, making it impossible to perform a meta-analysis. Instead, a descriptive review of the results is presented. Results With a follow-up of 12-122 months, the overall success rate in eradication of infection was 73-100% after one-stage revisions and 82-100% after two-stage revisions. Reinfection rates were the lowest in series where articulating cement spacers were used, though the follow-up was relatively short. Studies using articulating spacers reported the highest average postoperative ranges of motion. Otherwise, no correlations were observed between the clinical outcome and the length of follow-up, the type of revision, or the type of spacer. The clinical outcome (knee scores and range of motion) of the one-stage revisions was no different from that of the two-stage revisions. Interpretation Two-stage exchange is an effective treatment. Mobile spacers may further improve the range of motion. More experience in one-stage revision is required in order to define its role in the management of infected knee arthroplasties. [ABSTRACT FROM AUTHOR]

Unlabelled: Local attempts to repair a cartilage lesion could cause increased levels of anabolic and catabolic factors in the synovial fluid. After repair with regenerated cartilage, the homeostasis of the cartilage ideally would return to normal. In this pilot study, we first hypothesized levels of synovial fluid markers would be higher in patients with cartilage lesions than in patients with no cartilage lesions, and then we hypothesized the levels of synovial fluid markers would decrease after cartilage repair. We collected synovial fluid samples from 10 patients before autologous chondrocyte transplantation of the knee. One year later, a second set of samples was collected and arthroscopic evaluation of the repair site was performed. Fifteen patients undergoing knee arthroscopy for various symptoms but with no apparent cartilage lesions served as control subjects. We measured synovial fluid matrix metalloproteinase-3 (MMP-3) and insulinlike growth factor-I (IGF-I) concentrations with specific activity and enzyme-linked immunosorbent assays, respectively. The levels of MMP-3 and IGF-I were higher in patients having cartilage lesions than in control subjects with no cartilage lesions. One year after cartilage repair, the lesions were filled with repair tissue, but the levels of MMP-3 and IGF-I remained elevated, indicating either graft remodeling or early degeneration.Level Of Evidence: Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) is the key material for achieving excellent long-term results in total joint arthroplasties. Despite the fact that there has been a substantial amount of research and development over the years, new aspects of this material are still controversial and the most recent innovations have had a variable reception regarding clinical use. Advancements in conventional UHMWPE in the 1990s (nitrogen atmosphere irradiation, barrier package) were further improved by introduction of first-generation crosslinked polyethylene, as seen both from laboratory findings and clinical results. However, while clinical data on first-generation highly crosslinked polyethylene (HXLPE) showed reduced wear in the medium-term, academic and industrial research have helped to refine the material further, to overcome criticisms regarding residual oxidation and potential material fracture. Present concerns, although less nowadays, relate to the post-irradiation techniques used to stabilize the crosslinked polyethylene, namely annealing and remelting. Current topics of research interest include in vivo oxidation, second-generation highly crosslinked polyethylene, vitamin E doped or blended polyethylene, fracture mechanics, and consequences of wear. Some of these improvements derived from recent research are already available to the orthopedic community, and others will appear in the next few years. This review gives an overview of these topics, and the latest advancements are described in detail with a view to help the orthopedic surgeon make scientifically sound decisions when selecting material for total-joint implants. We conclude the review by affirming that today's state-of-the-art material is no longer conventional UHMWPE, but HXLPE.1 [ABSTRACT FROM AUTHOR]

OBJECTIVE: The excellent poster painter Henri de Toulouse-Lautrec is the most famous patient with cathepsin K-deficient pycnodysostosis. Cathepsin K is believed to play a major role in osteoclast-driven bone resorption. In this study we explored the role of cathepsin K in bone resorption in a patient with a cathepsin K mutation causing pycnodysostosis in whom psoriatic arthritis also developed. We hypothesized that the patient would develop only inflammatory synovitis but would not develop bone erosions or other osteolytic changes. METHODS: Monocytes from the patient with pycnodysostosis and normal control monocytes were isolated and stimulated to fuse and form multinuclear osteoclast-like cells, which were identified by evaluating messenger RNA expression of osteoclast markers. The ability to resorb bone was assessed by determining the extent of pit formation and levels of collagen degradation products generated by cathepsin K (C-terminal crosslinking telopeptide of type I collagen [CTX]) and matrix metalloproteinases (pyridinoline crosslinked C-terminal telopeptide of type I collagen). These experiments were also done in normal control cells after incubation with the cathepsin K inhibitor E64 during bone resorption. RESULTS: In contrast to our a priori hypothesis, the patient developed a mutilating disease with extensive bony erosions associated with lysis of some of the distal phalanges of her hands and feet. After stimulation of monocytes from this patient, the cells formed multinuclear tartrate-resistant acid phosphatase-positive and calcitonin receptor-positive multikaryons, which, however, totally lacked cathepsin K. These multinuclear cells were able to resorb bone but, in contrast to normal control osteoclasts, did not produce CTX. The resorption pattern was abnormal in that, unlike normal control osteoclasts, both osteoclasts from the patient and E64-inhibited osteoclasts did not leave extensive osteoclast trails, but were relatively sessile. CONCLUSION: In this 'experiment of nature' we observed that cathepsin K is not necessary for bone degradation. These findings may be pertinent to our understanding of the functions of cathepsin K inhibitors, which are currently being developed as drugs to treat metabolic bone diseases. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Normal synovial lining is composed of macrophage-like type A and fibroblast-like type B lining cells. This sheet-like structure lacks a basement membrane, but its intercellular substance contains some basement membrane components, including type IV collagen. We undertook this study to determine the alpha-chain composition of type IV collagen in normal and arthritic synovial lining, using monoclonal alpha-chain antibodies. METHODS: Samples were analyzed using avidin-biotin-peroxidase complex staining for the presence of collagen alpha1/2(IV), alpha3(IV), alpha4(IV), alpha5(IV), alpha6(IV), matrix metalloproteinase 2 (MMP-2), and MMP-9, and the enzyme activity was detected using gelatin zymography. Double immunofluorescence was performed for type IV collagen/MMP-9 and type IV collagen/CD68. Synovial fibroblasts were studied using quantitative reverse transcriptase-polymerase chain reaction. RESULTS: In mildly inflamed synovium from 5 trauma patients, alpha1/2(IV) chains were strongly stained, but alpha5(IV) and alpha6(IV) chains were weakly stained. Coding messenger RNA was shown in cultured synovial fibroblasts. Basement membranes of blood vessels contained all alpha(IV) chains and served as useful positive sample controls. In the synovial lining from 5 patients with rheumatoid arthritis (RA), all alpha-chains were absent/very weakly stained. This was coupled with numerous type A lining cells containing MMP-9 (type IV collagenase), also found in synovial fluid. CONCLUSION: Synovial lining has a unique and very limited alpha-chain composition, different from that of the vascular basement membrane, which contains all alpha-chains. This special composition and lack of nidogen are probably of relevance for the bidirectional translining diffusion. Such tentative alpha-chain-dependent adhesive and transport-regulating properties seem to be deranged in RA, probably in part due to type IV collagenases produced in the lining and/or released by transmigrating or synovial fluid neutrophils. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess collagen degradation and its relationship to some of the key collagenolytic proteinases in the aggressive synovial membrane-like interface tissue around aseptically loosened hip replacement implants. METHODS: The medical indication for the primary total hip replacement was osteoarthritis in all study patients. Samples from the study patients were compared with control synovial membranes obtained from trauma (hip fracture) patients. Proteoglycans were extracted with 4M guanidinium chloride. Denatured collagen in the remaining matrix was solubilized with alpha-chymotrypsin. Nonsoluble matrix and supernatant fractions were acid hydrolyzed before measurement of hydroxyproline. The proportion of soluble (in vivo-degraded) collagen of the total sample collagen content was calculated. Proteinases were stained using the avidin-biotin-peroxidase complex method. RESULTS: Collagen in the interface membrane from the implants was highly degraded (mean +/- SEM 20 +/- 3%) compared with that in the control synovial membranes (12 +/- 1%; P = 0.007). In controls, the degree of collagen degradation did not correlate with levels of matrix metalloproteinase 1 (MMP-1), MMP-13, or cathepsin K, although MMP-1 approached statistical significance. In interface membranes, the correlations were r = 0.88 (P = 0.002), r = 0.92 (P = 0.001), and r = 0.98 (P < 0.0001) for MMP-1, MMP-13, and cathepsin K, respectively. CONCLUSION: In normal synovial membrane, collagen matrix remodeling may be mainly an intracellular process. In contrast, pathologic tissue destruction in the interface membrane from prosthetic hip joints is associated with a shift toward MMP-13 and cathepsin K, which become activated and overcome their endogenous inhibitors (tissue inhibitors of metalloproteinases and cystatin C). The highly significant correlation between collagen degradation and cathepsin K indicates an extracellular role of this acidic endoproteinase, consistent with previous observations concerning the acidity of the interface membrane. [ABSTRACT FROM AUTHOR]

Background: National and regional arthroplasty registries have been used to study the results of primary total knee arthroplasties. The purpose of this paper was to present the results of revision total knee replacements and describe predictors of survival of those replacements, with repeat revision as the end point.Methods: The nationwide Finnish Arthroplasty Registry included 2637 revision total knee arthroplasties from 1990 through 2002. Survivorship of the revision total knee arthroplasties was analyzed, with repeat revision as the end point. The survivorship analyses comprised evaluations of the proportional hazards assumption followed by calculations of univariate and multivariate statistics and model diagnostics as appropriate.Results: The survival rate following the revision total knee arthroplasties was 95% (95% confidence interval, 94% to 96%) at two years (1874 knees), 89% (95% confidence interval, 88% to 90%) at five years (944 knees), and 79% (95% confidence interval, 78% to 81%) at ten years (141 knees). Multivariate regression analysis showed the most significant predictors of prosthetic survival to be the age of the patient and the life in service of the primary total knee replacement (that is, the time between the primary total knee replacement and the revision). Survivorship was also significantly predicted by the year of the first revision total knee arthroplasty and the reason for the revision.Conclusions: An age greater than seventy years, revision five years or more after the primary arthroplasty, and absence of patellar subluxation are positive indicators of survival of a revision total knee replacement. We believe that normal aging as well as the deconditioning effect of disease (osteoarthritis and rheumatoid arthritis) and its treatment (primary total knee replacement) may lead to a reduced activity level, which, together with a presumed reluctance to operate on elderly patients, protects against repeat revisions.Level Of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

The classic stimulus for cellular cytokine production is bacterial lipopolysaccharide (endotoxin). It was therefore hypothesized that tumor necrosis factor-alpha (TNF-alpha) may be responsible for pericoronitis. TNF-alpha and its receptors were detected by immunohistochemical staining in third molar pericoronitis in ten patients and ten healthy control samples. The percentage of TNF-alpha positive cells was high in pericoronitis (p = 0.0317). TNF receptors TNF-R1 and TNF-R2 were found in macrophage- and fibroblast-like cells, vascular endothelial cells in post-capillary venules, and basal epithelial cells in pericoronitis, but were only weakly expressed in controls. Increased expression of interleukin-1beta and vascular cell adhesion molecule-1 was found as a biological indicator of TNF-alpha ligand-receptor interaction. Explanted tissues acquired destructive potential upon TNF-alpha stimulation, whereas TNF-alpha blockers controlled it in inflamed tissues. These findings suggest that, in pericoronitis, inflammatory and resident cells produce and respond to potent pro-inflammatory cytokine TNF-alpha, with pathogenic and potential therapeutic relevance. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is no previous evidence that collagenases in chronic periodontitis excessively cleave collagen fibrils. OBJECTIVES: In this study the eventual presence of neoepitopes produced in such a cleavage were looked for. METHODS: A polyclonal antibody, which recognizes collagenase-cleaved collagen type I 3/4 carboxy-terminal neoepitope (COL1-3/4C), was used in avidin-biotin-peroxidase complex staining. RESULTS: In addition, moderate staining was seen in connective tissue bordering to the sulcular and junctional epithelium, surrounding some of the fibroblasts and in some areas infiltrated by inflammatory mononuclear cells. COL1-3/4C staining in chronic periodontitis was more extensive (6.3 +/- 1.2%, n = 10) and intense than that observed in controls (1.6 +/- 0.7%, n = 10, Unpaired Student's t-test, p < 0.01). CONCLUSIONS: It is concluded that collagenases produced by host cells contribute to periodontal tissue destruction and attachment loss. [ABSTRACT FROM AUTHOR]

Bone stress injuries can cause long-lasting damage, especially in young athletes and military conscripts, if not diagnosed and treated properly.Diagnosis has been traditionally based on clinical, radiographic and scintigraphic examinations, but MRI has become increasingly important. High resolution MRI is particularly valuable for the grading of bone stress injuries. The clinician should be aware of the wide range of bone stress injuries and available diagnostic methods. Early diagnosis is the prerequisite for avoiding long-lasting complications.Most bone stress injuries heal with closed treatment, but surgery is necessary in some cases. They heal well if the diagnosis is not delayed and the treatment adequate. [ABSTRACT FROM AUTHOR]