Showing papers by "Peter Möller published in 2008"

First Demonstration of Leukemia Imaging with the Proliferation Marker 18F-Fluorodeoxythymidine

Abstract: Acute myeloid leukemia (AML) is a neoplasm of hematopoietic stem cells with partial or complete loss of the ability to differentiate but with preserved proliferation capacity. The aim of our study was to evaluate if the in vivo proliferation marker 3'-deoxy-3'-18F-fluorothymidine (FLT) is suitable for visualizing leukemia manifestation sites and if 18F-FLT is a surrogate marker for disease activity. METHODS: In this pilot study, 10 patients with AML underwent pretherapeutic imaging with 18F-FLT PET or 18F-FLT PET/CT. The biodistribution of 18F-FLT was assessed 60 min after intravenous injection of the radiotracer. Standardized uptake values were calculated for reference segments of bone marrow, spleen, and normal organs. 18F-FLT PET in 10 patients with benign pulmonary nodules and the absence of malignant or inflammatory disease served as controls. RESULTS: Retention of 18F-FLT was observed predominantly in bone marrow and spleen and was significantly higher in AML patients than in controls (mean 18F-FLT SUV in bone marrow, 11.5 and 6.6, P< 0.05; mean 18F-FLT SUV in spleen, 6.1 and 1.8, P< 0.05). Outside bone marrow, focal 18F-FLT uptake showed extramedullary manifestation sites of leukemia in 4 patients (meningeal disease, pericardial, abdominal, testicular, and lymph node), proven by other diagnostic procedures. CONCLUSION: This pilot study indicated that PET using 18F-FLT is able to visualize extramedullary manifestation sites of AML and reflects disease activity. Because 18F-FLT uptake in bone marrow is caused by a combination of both neoplastic and normal hematopoietic cells, the correlation of 18F-FLT uptake in bone marrow and leukemic blast infiltration did not reach statistical significance.

Calculation of delayed-neutron energy spectra in a quasiparticle random-phase approximation-Hauser-Feshbach model

Abstract: Theoretical {beta}-delayed-neutron spectra are calculated based on the Quasiparticle Random-Phase Approximation (QRPA) and the Hauser-Feshbach statistical model. Neutron emissions from an excited daughter nucleus after {beta} decay to the granddaughter residual are more accurately calculated than in previous evaluations, including all the microscopic nuclear structure information, such as a Gamow-Teller strength distribution and discrete states in the granddaughter. The calculated delayed-neutron spectra agree reasonably well with those evaluations in the ENDF decay library, which are based on experimental data. The model was adopted to generate the delayed-neutron spectra for all 271 precursors.

Neutron reactions in accreting neutron stars: a new pathway to efficient crust heating

Abstract: In our calculation of neutron star crust heating we include several key new model features. In earlier work electron capture (EC) only allowed neutron emission from the daughter ground state; here we calculate, in a deformed quasi-random-phase approximation (QRPA) model, EC decay rates to all states in the daughter that are allowed by Gamow-Teller selection rules and energetics. The subsequent branching ratios between the 1n,...,xn channels and the competing {gamma} decay are calculated in a Hauser-Feshbach model. In our multicomponent plasma model a single (EC, xn) reaction step can produce several neutron-deficient nuclei, each of which can further decay by (EC, xn). Hence, the neutron emission occurs more continuously with increasing depth as compared to that in a one-component plasma model.

Review of the Dinematichthyini (Teleostei: Bythitidae) of the Indo-west Pacific.Part IV. 'Dinematichthys' and two new genera with descriptions of nine new species

Abstract: A revision of the dinematichthyine fishes (Ophidiiformes: Bythitidae: Brosmophycinae) of the Indo-West Pacific based on more than 6500 specimens is published in several parts. Part IV is the last part and includes 4719 identified specimens in the genera 'Alionematichthys' (new genus with three described and eight new species), 'Dinematichthys' Bleeker, 1855 (with one described and one new species) and Porocephalichthys (new genus with one described species). A neotype of 'Dinematichthys iluocoeteoides' Bleeker, 1855 is here designated. The genera reviewed here have in common a high anterior nostril and are considered to be related to each other. When previously described, they were all included in the genus 'Dinematichthys'. The separating characters of the species are the pseudoclasper morphology, morphometric characters, vertebrae and fin ray counts, otolith morphology, head squamation, presence or absence of the upper preopercular pore and development of cirri on the snout.

Splitting sensitivity of the ground and 7.6 eV isomeric states of Th 229

Abstract: The lowest-known excited state in nuclei is the 7.6 eV isomer of $^{229}\mathrm{Th}$. This energy is within the range of laser-based investigations that could allow accurate measurements of possible temporal variation of this energy splitting. This in turn could probe temporal variation of the fine-structure constant or other parameters in the nuclear Hamiltonian. We investigate the sensitivity of this transition energy to these quantities. We find that the two states are predicted to have identical deformations and thus the same Coulomb energies within the accuracy of the model (viz., within roughly 30 keV). We therefore find no enhanced sensitivity to variation of the fine-structure constant. In the case of the strong interaction the energy splitting is found to have a complicated dependence on several parameters of the interaction, which makes an accurate prediction of sensitivity to temporal changes of fundamental constants problematical. Neither the strong- nor Coulomb-interaction contributions to the energy splitting of this doublet can be constrained within an accuracy better than a few tens of keV, so that only upper limits can be set on the possible sensitivity to temporal variations of the fundamental constants.

Different rates of telomere attrition in peripheral lymphocytes in a pair of dizygotic twins with hematopoietic chimerism.

Abstract: Hematopoietic chimerism in dizygotic twins is due to placental vascular anastomoses and arises when hematopoietic stem cells from one twin home to the bone marrow of the other. We report a case of hematopoietic chimerism in a pair of 27-year-old dizygotic twins who each had a mixture of 46,XX and 46,XY blood lymphocytes, both with 98% male (XY) lymphocytes and 2% female (XX) lymphocytes. Analysis of telomere length by T/C FISH revealed that the female twin generally had longer telomeres than the male twin. Moreover, in the male sibling, the telomeres within the female lymphocytes were shortened to 87% of their original length, while the telomeres within the male lymphocytes were 33% longer in the female sibling. Thus, telomere length attrition in peripheral lymphocytes is determined mainly by the environment of the cell and less by intracellular factors.

New Global Calculation of Nuclear Masses and Fission Barriers for Astrophysical Applications

Abstract: The FRDM(1992) mass model [1] has an accuracy of 0.669 MeV in the region where its parameters were determined. For the 529 masses that have been measured since, its accuracy is 0.46 MeV, which is encouraging for applications far from stability in astrophysics. We are developing an improved mass model, the FRDM(2008). The improvements in the calculations with respect to the FRDM(1992) are in two main areas. (1) The macroscopic model parameters are better optimized. By simulation (adjusting to a limited set of now known nuclei) we can show that this actually makes the results more reliable in new regions of nuclei. (2) The ground‐state deformation parameters are more accurately calculated. We minimize the energy in a four‐dimensional deformation space (e2, e3, e4, e6,) using a grid interval of 0.01 in all 4 deformation variables. The (non‐finalized) FRDM (2008‐a) has an accuracy of 0.596 MeV with respect to the 2003 Audi mass evaluation before triaxial shape degrees of freedom are included (in progress). Wh...

Rare abyssal, ophidiid fishes from off the Crozet Islands, Southern Ocean, with a new species of Apagesoma Carter, 1983

Abstract: Sept specimens d'Ophidiidae ont ete recoltes au cours de la campagne d'exploration benthique D300 du N.O. "Discovery" autour des iles Crozet, dans le secteur indien de l'ocean Austral, en decembre 2005 et janvier 2006. Deux specimens representent une nouvelle espece, Apagesoma australis sp. nov., qui se distingue des deux autres especes decrites dans ce genre par le nombre de vertebres precaudales (15 vs 13), la hauteur du corps au niveau de l'anale (9,0-10,65 vs 17,0-21,0% LS) et la forme des sagitta. Quatre specimens appartiennent a l'espece rare Holcomycteronus brucei (Dollo, 1906) qui n'etait connue que par trois specimens. Le dernier specimen est assigne a Bathyonus Goode et Bean, 1885, un genre dont la revision est necessaire. La nouvelle espece est decrite, et des caracteres diagnostiques complementaires sont donnes pour H. brucei. Avec ce nouveau materiel, 13 specimens d'Ophidiidae ont maintenant ete recoltes dans les eaux antarctiques et subantarctiques.

Electron Capture‐delayed neutron‐emissions in neutron star crust simulations using a Hauser‐Feshbach model

Abstract: Recently, Electron Captures (henceforth EC) into excited states of neutron‐rich nuclei were shown by the LANL‐Michigan State‐Mainz collaboration to result in Neutron Star (henceforth NS) Crust heating which was 4–5 times that of previous calculations. That result also highlighted the importance of a spread in X‐ray burst abundances over several mass chains which could contribute to substantial heating through large shell and sub‐shell gaps showing up in the excitation energy spectrum of the EC daughter. Such effects did not dominate when a single beta‐stable species was evolved in an accreted parcel of matter in earlier calculations. We are now exploring the nucleosynthesis and heating from neutron processes deeper in the NS Crust around 1011 gcm−3. Electron captures into excited states of neutron‐rich nuclei above neutron separation energies requires a Hauser‐Feshbach code to calculate the branchings between 1‐, 2‐, 3‐,…neutron emission rates in the stellar environment. Since the evolving composition has...

Prognostic Relevance of hTERT mRNA Expression in Ductal Adenocarcinoma

Abstract: Telomerase is thought to play an essential role in tumorigenesis and progression. Its activity is directly correlated with the expression of its catalytic subunit, human telomerase reverse transcriptase (hTERT). A correlation of transcript expression with a poor prognosis has been detected in different human malignancies. However, data on hTERT in pancreatic ductal adenocarcinoma (PDAC) are purely descriptive so far. Therefore, we evaluated the impact of hTERT expression on patients’ prognosis. Human telomerase reverse transcriptase mRNA isolates from 56 human microdissected PDAC tissues were analyzed by quantitative reverse transcription–polymerase chain reaction and multivariate Cox regression hazard test. Elevated hTERT transcript levels were measured in 23 of 56 PDAC tissues, 33 patients showed no detectable transcripts. Unexpectedly, a low expression of hTERT mRNA levels was associated with a worse prognosis for overall survival (relative risk = 5.33; P = .013) when compared to high levels, whereas undetectable expression showed an intermediate risk of tumor-related death. These data challenge previous findings outlining hTERT’s negative impact on overall survival. The risk pattern obtained in PDAC suggests a more complex regulation of hTERT.

Combinatorial nuclear level-density model

Abstract: A microscopic nuclear level-density model is presented. The model is a completely combinatorial (micro-canonical) model based on the folded-Yukawa single-particle potential and includes explicit treatment of pairing, rotational and vibrational states. The microscopic character of all states enables extraction of level distribution functions with respect to pairing gaps, parity and angular momentum. The results of the model are compared to available experimental data: neutron separation energy level spacings, data on total level-density functions from the Oslo method and data on parity ratios.

[U-HO1. A new cell line derived from a primary refractory classical Hodgkin lymphoma].

Abstract: The Hodgkin cell line U-HO1 was established from a malignant pleural effusion of a 23-yr-old male patient during the end stage of refractory nodular sclerosing classical Hodgkin lymphoma (cHL). Since its establishment in 2005, U-HO1 has maintained stable characteristics in vitro and has a doubling time of about 4 days under standard culture conditions. U-HO1 forms typical Reed/Sternberg cells in suspension, is EBV negative, lacks HLA-ABC- but expresses HLA-D- proteins/CD74 and surface exposes CD15 together with CD30 in the absence of CD19 and CD20. Karyotype analysis of U-HO1 revealed a hyperdiploid karyotype with multiple clonal aberrations. Most significant is an elongated chromosome 2, der(2)t(2;10)(q35;q16.1)add(2)(p13). CGH analysis revealed the following imbalances: ish cgh dim(1)(p13p31)(p12q21), enh(2)(p13p23), dim(4)(q31.3qter), enh(6)(q22q27), enh(12), enh(18),enh(20)(q13.1pter). FISH analysis showed about six-fold amplification of REL and BCL-11A, thus, U-HO1 is prototypical for cHL in every aspect tested so far. Compared to other HL cell lines, U-HO1 proved far less genetically aberrant suggesting that U-HO1’s imbalances suffice to cause the full-blown phenotype of primary refractory cHL.