85 research outputs found
hints to chromosomal instability after irradiation
Background Total body irradiation (TBI) has been part of standard conditioning
regimens before allogeneic stem cell transplantation for many years. Its
effect on normal tissue in these patients has not been studied extensively.
Method We studied the in vivo cytogenetic effects of TBI and high-dose
chemotherapy on skin fibroblasts from 35 allogeneic stem cell transplantation
(SCT) patients. Biopsies were obtained prospectively (n = 18 patients) before,
3 and 12 months after allogeneic SCT and retrospectively (n = 17 patients)
23–65 months after SCT for G-banded chromosome analysis. Results Chromosomal
aberrations were detected in 2/18 patients (11 %) before allogeneic SCT, in
12/13 patients (92 %) after 3 months, in all patients after 12 months and in
all patients in the retrospective group after allogeneic SCT. The percentage
of aberrant cells was significantly higher at all times after allogeneic SCT
compared to baseline analysis. Reciprocal translocations were the most common
aberrations, but all other types of stable, structural chromosomal aberrations
were also observed. Clonal aberrations were observed, but only in three cases
they were detected in independently cultured flasks. A tendency to non-random
clustering throughout the genome was observed. The percentage of aberrant
cells was not different between patients with and without secondary
malignancies in this study group. Conclusion High-dose chemotherapy and TBI
leads to severe chromosomal damage in skin fibroblasts of patients after SCT.
Our long-term data suggest that this damage increases with time, possibly due
to in vivo radiation-induced chromosomal instability
Frequent induction of chromosomal aberrations in in vivo skin fibroblasts after allogeneic stem cell transplantation: hints to chromosomal instability after irradiation
BACKGROUND: Total body irradiation (TBI) has been part of standard conditioning regimens before allogeneic stem cell transplantation for many years. Its effect on normal tissue in these patients has not been studied extensively. METHOD: We studied the in vivo cytogenetic effects of TBI and high-dose chemotherapy on skin fibroblasts from 35 allogeneic stem cell transplantation (SCT) patients. Biopsies were obtained prospectively (n = 18 patients) before, 3 and 12 months after allogeneic SCT and retrospectively (n = 17 patients) 23-65 months after SCT for G-banded chromosome analysis. RESULTS: Chromosomal aberrations were detected in 2/18 patients (11 %) before allogeneic SCT, in 12/13 patients (92 %) after 3 months, in all patients after 12 months and in all patients in the retrospective group after allogeneic SCT. The percentage of aberrant cells was significantly higher at all times after allogeneic SCT compared to baseline analysis. Reciprocal translocations were the most common aberrations, but all other types of stable, structural chromosomal aberrations were also observed. Clonal aberrations were observed, but only in three cases they were detected in independently cultured flasks. A tendency to non-random clustering throughout the genome was observed. The percentage of aberrant cells was not different between patients with and without secondary malignancies in this study group. CONCLUSION: High-dose chemotherapy and TBI leads to severe chromosomal damage in skin fibroblasts of patients after SCT. Our long-term data suggest that this damage increases with time, possibly due to in vivo radiation-induced chromosomal instability
Flexible and Transparent All-Graphene Circuits for Quaternary Digital Modulations
In modern communication system, modulation is a key function that embeds the
baseband signal (information) into a carrier wave so that it can be
successfully broadcasted through a medium such as air or cables. A flexible
signal modulation scheme is hence essential to wide range of applications based
on flexible electronics. Here we report a fully bendable all-graphene modulator
circuit with the capability to encode a carrier signal with quaternary digital
information for the first time. By exploiting the ambipolarity and the
nonlinearity in a graphene transistor, we demonstrated two types of quaternary
modulation schemes: 4-ary amplitude-shift keying (4-ASK) and quadrature
phase-shift keying (QPSK). Remarkably, 4-ASK and QPSK can be realized with just
1 and 2 all-graphene transistors, respectively, representing a drastic
reduction in circuit complexity when compared with conventional digital
modulators. In addition, the circuit is not only flexible but also highly
transparent (~95% transmittance) owing to their all-graphene design with every
component (channel, interconnects, load resistor, and source/drain/gate
electrodes) fabricated from graphene films. Taken together, these results
represent a significant step toward achieving a high speed communication system
that can be monolithically integrated on a flexible and transparent platform.Comment: 29 pages, 8 figures, 1 tabl
Modular Server - Client - Server (MSCS) Approach for Process Optimization in early R&D of Emerging Technologies by LCA.
Modular Server - Client - Server (MSCS) Approach for Process Optimization in early R&D of Emerging Technologies by LCA.
Process Optimisation through Dynamic Life Cycle Assessment - the Case of a Microreactor Plant for Gas to Liquid Application
PET-CT screening of a family with pheochromocytoma-paraganglioma inherited tumor syndrome
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