Reduced masticatory function is related to lower satellite cell numbers in masseter muscle

The physiology of masseter muscles is known to change in response to functional demands, but the effect on the satellite cell (SC) population is not known. In this study, the hypothesis is tested that a decreased functional demand of the masseter muscle causes a reduction of SCs. To this end, twelve 5-week-old male Sprague-Dawley rats were put on a soft diet (SD, n = 6) or a hard diet (HD, n = 6) and sacrificed after 14 days. Paraffin sections of the superficial masseter and the m. digastricus (control muscle) were stained with haematoxylin and eosin for tissue survey and with anti-myosin heavy chain (MHC) for slow and fast fibres. Frozen sections of both muscles were double-stained for collagen type IV and Pax7. Slow MHC fibres were equally distributed in the m. digastricus but only localized in a small area of the m. masseter. No differences between HD or SD for the m. digastricus were found. The m. masseter had more SCs per fibre in HD than in SD (0.093 ± 0.007 and 0.081 ± 0.008, respectively; P = 0.027). The m. masseter had more fibres per surface area than the m. digastricus in rats with an SD group (758.1 ± 101.6 and 568.4±85.6, P = 0.047) and a HD group (737.7 ± 32.6 and 592.2 ± 82.2; P = 0.007). The m. digastricus had more SCs per fibre than the m. masseter in the SD group (0.094 ± 0.01 and 0.081 ± 0.008; P = 0.039). These results suggest that reduced masseter muscle function is related to a lower number of SCs. Reduced muscle function might decrease microdamage and hence the requirement of SCs in the muscle fibre

Demographic, clinical and antibody characteristics of patients with digital ulcers in systemic sclerosis: data from the DUO Registry

OBJECTIVES: The Digital Ulcers Outcome (DUO) Registry was designed to describe the clinical and antibody characteristics, disease course and outcomes of patients with digital ulcers associated with systemic sclerosis (SSc). METHODS: The DUO Registry is a European, prospective, multicentre, observational, registry of SSc patients with ongoing digital ulcer disease, irrespective of treatment regimen. Data collected included demographics, SSc duration, SSc subset, internal organ manifestations, autoantibodies, previous and ongoing interventions and complications related to digital ulcers. RESULTS: Up to 19 November 2010 a total of 2439 patients had enrolled into the registry. Most were classified as either limited cutaneous SSc (lcSSc; 52.2%) or diffuse cutaneous SSc (dcSSc; 36.9%). Digital ulcers developed earlier in patients with dcSSc compared with lcSSc. Almost all patients (95.7%) tested positive for antinuclear antibodies, 45.2% for anti-scleroderma-70 and 43.6% for anticentromere antibodies (ACA). The first digital ulcer in the anti-scleroderma-70-positive patient cohort occurred approximately 5 years earlier than the ACA-positive patient group. CONCLUSIONS: This study provides data from a large cohort of SSc patients with a history of digital ulcers. The early occurrence and high frequency of digital ulcer complications are especially seen in patients with dcSSc and/or anti-scleroderma-70 antibodies

Tissue inhibitors of metalloproteinases (TIMPs): their biological functions and involvement in oral disease.

Contains fulltext : 51068.pdf (publisher's version ) (Closed access)Several families of enzymes are responsible for the degradation of extracellular matrix (ECM) proteins during the remodeling of tissues. An important family of such enzymes is that of the matrix metalloproteinases (MMPs). To control MMP-mediated ECM breakdown, tissue inhibitors of metalloproteinases (TIMPs) are able to inhibit MMP activity. A disturbed balance of MMPs and TIMPs is found in various pathologic conditions, such as cancer, rheumatoid arthritis, and periodontitis. The role of MMPs in pathology has been extensively described in the literature. The main focus of this review lies in the biological functions of TIMPs and their occurrence in disease, especially in the head and neck area. Their biological functions and their role in diseases like oral cancers and periodontitis, and in the development of cleft palate, will be discussed. Finally, the diagnostic and therapeutical opportunities of TIMPs will be evaluated

Hydrolysis and reduction of factor 390 by cell extracts of Methanobacterium thermoautotrophicum (strain delta H).

Cell extracts of Methanobacterium thermoautotrophicum (strain delta H) were found to perform a hydrogen-dependent reduction of factor 390 (F390), the 8-adenylyl derivative of coenzyme F420. Upon resolution of cell extracts, F390-reducing activity copurified with the coenzyme F420-dependent hydrogenase. This indicates that F390 serves as a substrate of that enzyme. Activity towards F390 was approximately 40-fold lower than that towards coenzyme F420 (0.12 and 5.2 mumol.min-1.mg of protein-1, respectively). In addition, cell extracts catalyzed the hydrolysis of F390 to AMP and coenzyme F420. This hydrolysis required the presence of thiols (6 mM) and much ionic strength (1 M KCl) and was reversibly inhibited by oxygen. The reaction proceeded optimally at pH 8.2 and was Mn dependent. Conditions for F390 hydrolysis in cell extracts are in many respects opposite to those previously described for F390 synthesis

Fgf8a mutation affects craniofacial development and skeletal gene expression in zebrafish larvae

Contains fulltext : 208498.pdf (publisher's version ) (Open Access

Visualisation of newly synthesised collagen in vitro and in vivo

Identifying collagen produced de novo by cells in a background of purified collagenous biomaterials poses a major problem in for example the evaluation of tissue-engineered constructs and cell biological studies to tumor dissemination. We have developed a universal strategy to detect and localize newly deposited collagen based on its inherent association with dermatan sulfate. The method is applicable irrespective of host species and collagen source