In vivo induction of pyrimidine dimers in human skin by UVA radiation: initiation of cell damage and/or intercellular communication?

Pyrimidine dimers participate as important factors in ultraviolet-induced lethality, mutagenicity and tumorgenicity. Substantial efforts have been made in recent years to understand the induction of pyrimidine photodimers and their repair in human skin cells exposed to low physiological fluences of UV-light. Dimers are known to be efficiently induced after UVC and UVB irradiation, but these photoproducts are also highly induced in DNA isolated from human skin irradiated with UVA. By using a sensitive immunohistochemistry dimer detection assay, we confirm that in vivo UVA radiation induces substantial amounts of these DNA changes in the epidermis; in addition, this technique detects them far into the reticular dermis. A considerable number of these photodimers were also seen in non-irradiated control skin up to two centimeters from the irradiation site. All the lesions persist for at least two days post-irradiation. These results sustain the hypothesis that pyrimidine dimer formation and excision could be a modality of epidermal communication.     

Epstein-Barr virus (EBV) DNA levels in palatine tonsils and autologous serum from EBV carriers

A real-time polymerase chain reaction was employed to detect and quantitate Epstein-Barr virus (EBV) DNA in tonsils and autologous sera from EBV-seropositive children. EBV DNA was found in 95% of tonsils from 21 children and in 50% from 18 children with serum IgG titers to the virus capsid antigen (VCA) of > or =1:160 and 1:10 to 1:80, respectively (P = 0.002). Tonsils from children with titers > or =1:160 harbored more EBV DNA copies per mg tissue (mean, 1,237; range, < 2-13,998) than from children with titers 1:10 to 1:80 (mean, 23; range, < 2-226; P < 0.0001). By contrast, EBV DNA was detected only in serum from 25% of 20 children with titers > or = 1:160. Thus, ample differences in tonsillar EBV replication are mirrored inconstantly by detectable EBV in autologous serum suggesting that EBV DNA quantitation in tonsils may serve for refined monitoring of individuals at risk of EBV-associated lymphoproliferation.     

伴近视的鞍区肿瘤眼部病变特点

目的：探讨近视患者的鞍区肿瘤眼部病变的临床特点。方法：回顾分析了18例伴近视的鞍区肿瘤的视力、视野及眼底等情况。结果：18例初诊时,19眼（占52.8%）视力低下4.0,仅5例（占27.8%）视野缺损呈典型的视交性单、双颞侧偏盲,10例（占55.6%）双眼视神经不同程度萎缩,4例（占22.2%）单眼视神经萎缩。结论：伴近视的鞍区肿瘤眼部病变常很严重,容易被误诊为青光眼性视神经萎缩,视乳头炎、缺血性视神经病变。     

Non‐anaplastic peripheral T‐cell lymphoma in children and adolescents – a retrospective analysis of the NHL‐BFM study group

Mature (peripheral) T‐cell lymphoma (PTCL) other than anaplastic large cell lymphoma is a heterogeneous group of diseases and exceedingly rare in children and adolescents. Survival rates range between 46% and 85%. This study reports the disease characteristics, treatment and outcome of all patients with the diagnosis of mature TCL registered in the Berlin‐Frankfurt‐Munster non‐Hodgkin lymphoma database between 1986 and 2012. All diagnoses were centrally reviewed and revised by clinico‐pathological correlation according to the criteria of the current World Health Organization classification. Of the 69 patients originally registered as having PTCL, the diagnosis was confirmed in 38 of them. Most patients were treated with an anaplastic large cell lymphoma (ALCL)‐like therapy regimen. Patients with PTCL‐not otherwise specified comprised the largest group and showed a 5‐year event‐free survival rate of 61 ± 11%. Patients suffering from Natural Killer/T‐cell‐ and hepatosplenic TCL had the poorest outcome. Our results suggest that the outcomes of children with mature TCL other than ALCL depend on the subtype and are worse than in all other paediatric lymphomas. The clinical experience presented in this largest study on paediatric mature TCL may serve as basis for future collaborative international prospective clinical trials.     

Development and testing of multi-phase glazes for adhesive bonding to zirconia substrates

Objectives

The aims of the study were to develop and test multi-phase glaze coatings for zirconia restorations, so that the surface could be etched and adhesively bonded.

Methods

Zirconia disc specimens (n = 125, 16 mm × 1 mm) were cut from cylinders of Y-TZP (yttria-stabilized tetragonal zirconia polycrystals) ZS-Blanks (Kavo, Everest) and sintered overnight. Specimens were subjected to the recommended firing cycles, and next sandblasted. The specimens were divided into 5 groups of 25, with Group 1 as the sandblasted control. Groups 2–5 were coated with overglaze materials (P25 and IPS e.max Ceram glazes) containing secondary phases. Group 2 was (wt%): 10% hydroxyapatite (HA)/P25 glaze, Group 3: 20% IPS Empress 2 glass–ceramic/glaze, Group 4: 20% IPS Empress 2 glass/glaze and Group 5: 30% IPS Empress 2 glass/glaze. After sintering and etching, Monobond-S and composite resin cylinders (Variolink II, Ivoclar-Vivadent) were applied and light cured on the test surfaces. Specimens were water stored for 7 days. Groups were tested using the shear bond strength (SBS) test at a crosshead speed of 0.5 mm/min. Overglazed and the fractured specimen surfaces were viewed using secondary electron microscopy. Room and high temperature XRD and DSC were carried out to characterize the materials.

Results

The mean (SD) SBS (MPa) of the test groups were: Group 1: 7.7 (3.2); Group 2: 5.6 (1.7); Group 3: 11.0 (3.0); Group 4: 8.8 (2.6) and Group 5: 9.1 (2.6). Group 3 was significantly different to the control Group 1 (p < 0.05). There was no significant difference in the mean SBS values between Group 1 and Groups 2, 4 and 5 (p > 0.05). Group 2 showed statistically lower SBS than Groups 3–5 (p < 0.05). Lithium disilicate fibres were present in Groups 3–5 and fine scale fibres were grown in the glaze following a porcelain firing cycle (Groups 4 and 5). XRD indicated a lithium disilicate/minor lithium orthophosphate phase (Group 3), and a tetragonal zirconia phase for the sintered Y-TZP ZS-Blanks. DSC and high temperature XRD confirmed the crystallization temperatures and phases for the IPS Empress 2 glass.

Conclusions

The application of a novel glass–ceramic/glaze material containing a major lithium disilicate phase might be a step in improving the bond strength of a zirconia substrate to a resin cement.     

Ig VH gene mutational patterns indicate different tumor cell status in human myeloma and monoclonal gammopathy of undetermined significance

Plasma cell tumors display a wide spectrum of clinical progression, ranging from aggressive multiple myeloma to a benign form known as monoclonal gammopathy of undetermined significance (MGUS), which requires no treatment. Because both diseases involve mature Ig- secreting plasma cells, the reason for this variation in malignant behavior is unclear. However, assessment of malignant potential is desirable for choice of treatment protocols. Ig variable (VH) gene sequences analysis has previously shown the tumor cell of multiple myeloma to be postfollicular, with mutated homogeneous clonal sequences indicating no continuing exposure to the somatic hypermutation mechanism, and this was confirmed in 7 of 7 patients. Comparison of the VH gene sequences in the monoclonal cells in MGUS yielded a different result, with 3 of 7 patients demonstrating mutated heterogeneous sequences consistent with the tumor cells remaining under the influence of the mutator. In 1 of 3 of these patients, an IgM-positive precursor cell was identified that expressed heterogeneous VH sequences similar to those of the isotype-switched plasma cell. These results indicate that the clonal cells in MGUS differ from those in myeloma and suggest that the difference may reflect malignant potential.