Influence of dental materials on dental MRI

Objectives:

To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI.

Methods:

A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures.

Results:

The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus^® (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold–ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient’s mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr.

Conclusions:

A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research.     

Recurrence of unexpected infant death

Families which had experienced two or more unexpected infant deaths were the subject of detailed confidential enquiries, including necropsy examination. Cases were derived from two main sources: first, deaths occurring during a nationwide programme of support for families with a subsequent baby (8 families) plus 2 families from a scries of confidential enquiries in Sheffield, and second, direct referrals from paediatricians (17 families). Fifty-seven deaths were studied. Twenty-four families had experienced 2 and three had experienced 3 deaths: 11 deaths (19%) were found to be adequately explained by history or post-mortem findings; 7 (12%) were probably accidental; 31 (55%) were most probably due to an action by one of the parents (filicide); only 5 (9%) were considered to be true or idiopathic sudden infant death syndrome; in 3 (5%) cases there was insufficient information to draw a conclusion. Five (18%) of the families lived in circumstances of serious social deprivation. A history of psychiatric illness was present in one or both parents in 18 (67%) of the families.     

Psoralen–ultraviolet A vs. narrow-band ultraviolet B phototherapy for the treatment of vitiligo

BACKGROUND: Although many treatment modalities have been tried for the treatment of vitiligo, none is uniformly effective. Psoralen phototherapy (psoralen ultraviolet A (PUVA)) is established as efficacious treatment for vitiligo. Recently, narrow-band UVB (NBUVB) has been reported to be an effective and safe therapeutic option in patients with vitiligo. OBJECTIVE: To compare the efficacy of PUVA and NBUVB in the treatment of vitiligo. DESIGN AND SETTING: Retrospective analysis of 69 patients with vitiligo who were treated either with PUVA or NBUVB at the pigmentary clinic of the Dermatology Department of the Postgraduate Institute of Medical Education and Research, Chandigarh, India. OUTCOME MEASURES: The following variables were compared between the two groups of patients: repigmentation status, number of treatments for marked to complete repigmentation in existing lesions, appearance of new lesions or increase in size of existing lesions, adverse effect of therapy, stability of repigmentation and colour match. RESULTS: In PUVA-treated group, 9 patients showed marked to complete repigmentation (23.6%) and 14 patients showed moderate improvement (36.8%), whereas in NBUVB-treated group, 13 patients showed marked to complete repigmentation (41.9%) and 10 patients showed moderate improvement (32.2%). A statistically significantly better stability and colour match of repigmentation with surrounding skin was seen in NBUVB-treated patients. CONCLUSION: We showed that NBUVB is more effective than PUVA and repigmentation induced with NBUVB is statistically significantly more stable.     

TGF-β1、dNCPs及TGF-β1/dNCPs复合物对组织工程牙髓形成促进作用的研究

目的研究转化生长因子(TGF-β1)、牙本质非胶原蛋白(dNCPs)及TGF-β1/ dNCPs复合物对组织工程牙髓形成的促进作用. 方法使用Ⅰ型胶原及牙本质粉构建牙髓细胞的三维培养模型,按不同分组分别在组织工程牙髓中加入TGF-β1、dNCPs及TGF-β1/ dNCPs复合物;对照组中不加入以上物质.培养3、6和14天,在不同时间点行HE染色,观察细胞的形态变化.牙本质涎蛋白(DSP)免疫组织化学观察牙髓细胞向成牙本质细胞的诱导. 结果胶原可形成凝胶网状结构,牙髓细胞的生长状况与体内牙髓细胞相似.加入TGF-β1和dNCPs后,培养第6天部分牙髓细胞开始出现成牙本质样细胞的一些特性,出现单侧细胞突起;培养第14天,牙本质粉区域附近细胞呈高柱状平行排列,形成类似体内的牙本质牙髓复合物.免疫组织化学染色可见部分细胞出现DSP的表达,其中TGF-β1组阳性细胞最多,复合物组次之,dNCPs组最少;而对照组未发现DSP的表达. 结论 TGF-β1和dNCPs可不同程度地刺激牙髓细胞向成牙本质样细胞转化,促进组织工程牙髓的形成.     

Superficial granulomatous pyoderma: an idiopathic granulomatous cutaneous ulceration

A 70-year-old male with a superficial granulomatous ulcer is reported. Histopathological findings were the same as those described for superficial granulomatous pyoderma, a recognized variant of classic pyoderma gangrenosum. The differences between pyoderma gangrenosum and its variant superficial granulomatous pyoderma are highlighted.     

Increased Pyridinoline Cross‐Link Levels in Fibrosis is Accomplished by TGFβ Induced Lysyl Hydroxylases 2B Expression

Differentiation of fibroblasts into contractile, α‐smooth muscle actin (α‐SMA) expressing myofibroblasts depends on the action of the cytokine TGFβ in conjunction with mechanical tension. The goal of this study was to assess whether mechanical stress may play a role in activating TGFβ. Previous studies have shown that myofibroblasts secrete TGFβ1 as a large latent complex, consisting of the latency associated protein (LAP), the latent TGFβ1 binding protein (LTBP‐1) and TGFβ1. LTBP‐1 targets the small latent complex of LAP and TGFβ1 to the extracellular matrix (ECM), providing a stock of latent TGFβ1. To reveal the mechanisms triggering the release of active TGFβ1 from LAP and LTBP‐1, myofibroblasts were cultured on flexible silicone membranes for 3d before being subjected to unique 5% uniaxial stretch. After stress application we observed the course of TGFβ1 activation over 24 h by quantifying luciferase synthesis under the control of the TGFβ‐inducible PAI‐1 promoter. TGFβ activation showed two distinct peaks 1 h and 6 h after stretch. TGFβ1 mRNA levels were increased after 6 h as assessed by semi‐quantitative RT‐PCR. To further determine if rapidly activated TGFβ1 was released from ECM stores, we stretched myofibroblast‐derived ECM after cells have been removed by desoxycholate or EDTA treatment. Finally, we assessed the importance of the actin cytoskeleton in TGFβ1 activation by stretching Triton‐X‐100‐ and cytochalasin‐D‐treated myofibroblasts. Our results suggest that mechanical activation of TGFβ in myofibroblast culture requires cell activity and a functional cytoskeleton.