Oral carcinoma after hematopoietic stem cell transplantation – a new classification based on a literature review over 30 years

BACKGROUND: Patients undergoing hematopoietic stem cell transplantation (HSCT) have a higher risk of developing secondary solid tumors, in particular squamous cell carcinoma, because of several risk factors, including full-body irradiation (TBI), chemotherapy, and chronic graft versus host disease (GVHD). Based on the review presented here, a classification of oral changes is suggested in order to provide a tool to detect high-risk patients. Methods and Results The literature over the last 30 years was reviewed for development of malignoma of the oral cavity after HSCT. Overall, 64 cases were found. In 16 out of 30 cases, the tongue was the primary location, followed by the salivary gland (10 out of 30); 56.4% appeared in a latency time of 5 to 9 years after HSCT. In 76.6%, GVHD was noticed before the occurrence of oral malignancy. Premalignant changes of the oral mucosa were mucositis, xerostomia, and lichenoid changes, developing into erosive form. CONCLUSION: All physicians involved in the treatment of post-HSCT patients should be aware of the increased risk, even after 5 years from the development of oral malignancy, in particular when oral graft versus host changes are visible. In order to develop evidence management and to detect and offer adequate therapy as early as possible in this patient group, multicenter studies, involving oncologists and head and neck surgeons, should be established

Chronic prenatal exposure to the 900 megahertz electromagnetic field induces pyramidal cell loss in the hippocampus of newborn rats

PubMed: 19671630Widespread use of mobile phones which are a major source of electromagnetic fields might affect living organisms. However, there has been no investigation concerning prenatal exposure to electromagnetic fields or their roles in the development of the pyramidal cells of the cornu ammonis in postnatal life. Two groups of pregnant rats, a control group and an experimental group, that were exposed to an electromagnetic field were used. For obtaining electromagnetic field offspring, the pregnant rats were exposed to 900 megahertz electromagnetic fields during the 1–19th gestation days. There were no actions performed on the control group during the same period. The offspring rats were spontaneously delivered—control group (n = 6) and electromagnetic field group (n = 6). Offspring were sacrificed for stereological analyses at the end of the 4th week. Pyramidal cell number in rat cornu ammonis was estimated using the optical fractionator technique. It was found that 900 megahertz of electromagnetic field significantly reduced the total pyramidal cell number in the cornu ammonis of the electromagnetic field group (P < 0.001). Therefore, although its exact mechanism is not clear, it is suggested that pyramidal cell loss in the cornu ammonis could be due to the 900 megahertz electromagnetic field exposure in the prenatal period. © 2009, SAGE Publications. All rights reserved

Brazing Ti-47Al-2Cr-2Nb to Inconel 718 with different filler alloys: microstructural characterization of the interfaces

Vacuum brazing of γ-TiAl alloy (Ti-47Al-2Cr-2Nb, at.%) to Inconel 718 (53Ni-19Fe-19Cr-5Nb-3Mo-1Ti wt.%) using Incusil-ABA (Ag-27.25Cu-12.5In-l.25Ti, wt.%), Nicusil-3 (Ag-28.lCu-0.75Ni, wt.%) and Tini 67 (Ti-33Ni, wt.%) as filler alloys was investigated. The lowest temperatures at which joining was successfully accomplished were 730, 810 and 1200°C for brazing with Incusil-ABA, Nicusil-3 and Tini 67, respectively. The interfaces were examined by scanning electron microscopy (SEM) and chemically analysed by energy dispersive X-ray spectroscopy (EDS). Series of microhardness tests were performed across the brazed joints to assess the interfacial hardness profiles. All filler alloys induced the formation of multilayered interfaces. For joining with either Incusil-ABA or Nicusil-3 most of the interface was softer than both base materials. AlCu 2 Ti was formed at the γ-TiAl alloy side, while near the superalloy (Cu) and Cr-Fe-Ni rich phases were detected. The centre of the interface consisted of a mixture of (Ag), (Cu) and Al(Cu,Ni) 2 Ti. For joining with Tini 67 the interface was harder than both base materials. Reaction layers formed in vicinity of the γ-TiAl alloy were composed of α 2 -Ti 3 Al and TiNiAl, while near the superalloy, TiNi 2 Al and several phases rich in Cr, Fe and Ni were observed. The experiments performed in this investigation showed that brazing with Incusil-ABA allows lowering the brazing temperature of at least 50°C in comparison with Ag-Cu eutectic filler, while brazing with Tini 67 produces harder interfaces and may enhance the temperature capability of the joints in comparison with filler alloys that contain Ag. However, joining using Tini 67 as brazing filler has to be performed at substantially higher temperatures.(undefined)info:eu-repo/semantics/publishedVersio