First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ

We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ^{0} final state (230-842 MeV for the nπ^{+} final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ^{0} final state.

Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton.

A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-t dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: α_{E1}=10.99±0.16±0.47±0.17±0.34, ß_{M1}=3.14±0.21±0.24±0.20±0.35; in units of 10^{-4} fm^{3} where the errors are statistical, systematic, spin polarizability dependent, and model dependent.

Single π 0 production off neutrons bound in deuteron with linearly polarized photons.

The quasifree γ → d → π 0 n ( p ) photon beam asymmetry, Σ , has been measured at photon energies, E γ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 ∘ to 148 ∘ . In this kinematic region, polarization observables are sensitive to contributions from the Δ ( 1232 ) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new Σ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict π 0 n photoproduction observables, based on fits to published data in the channels π 0 p , π + n and π - p .

Signatures of the d

We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570 MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d^{*}(2380) hexaquark.

Osteocyte differentiation and the formation of an interconnected cellular network in vitro.

Extracellular matrix (ECM) stiffness and cell density can regulate osteoblast differentiation in two dimensional environments. However, it is not yet known how osteoblast-osteocyte differentiation is regulated within a 3D ECM environment, akin to that existing in vivo. In this study we test the hypothesis that osteocyte differentiation is regulated by a 3D cell environment, ECM stiffness and cell density. We encapsulated MC3T3-E1 pre-osteoblastic cells at varied cell densities (0.25, 1 and 2 × 106 cells/mL) within microbial transglutaminase (mtgase) gelatin hydrogels of low (0.58 kPa) and high (1.47 kPa) matrix stiffnesses. Cellular morphology was characterised from phalloidin-FITC and 4',6-diamidino-2-phenylindole (DAPI) dilactate staining. In particular, the expression of cell dendrites, which are phenotypic of osteocyte differentiation, were identified. Immunofluorescent staining for the osteocytes specific protein DMP-1 was conducted. Biochemical analyses were performed to determine cell number, alkaline phosphatase activity and mineralisation at 2.5 hours, 3, 21 and 56 days. We found that osteocyte differentiation and the formation of an interconnected network between dendritic cells was significantly increased within low stiffness 3D matrices, compared to cells within high stiffness matrices, at high cell densities. Moreover we saw that this network was interconnected, expressed DMP-1 and also connected with osteoblast-like cells at the matrix surface. This study shows for the first time the role of the 3D physical nature of the ECM and cell density for regulating osteocyte differentiation and the formation of the osteocyte network in vitro. Future studies could apply this method to develop 3D tissue engineered constructs with an osteocyte network in place.

Rare-earth manganese copper phosphides REMnCu4P3 (RE = Gd-Ho): the first quaternary ordered variants of the YCo5P3-type structure.

The quaternary rare-earth phosphides REMnCu(4)P(3) (RE = Gd-Ho) were obtained from direct reactions of the elements at 800 °C. They are the first examples in which ordering of two different transition-metal atoms takes place within the orthorhombic YCo(5)P(3)-type structure [Pearson symbol oP36, space group Pnma, Z = 4; a = 12.667(2)-12.6489(4) Å, b = 3.8119(7)-3.7755(1) Å, and c = 10.895(2)-10.8632(4) Å for RE = Gd-Ho]. Columns of trigonal prisms centered by P atoms are connected in propellor-shaped units in zigzag arrangements to generate square-pyramidal (CN5) sites that are occupied by Mn atoms and tetrahedral sites (CN4) that are occupied by Cu atoms. Spin-polarized band-structure calculations predict that the hypothetical compound YMnCu(4)P(3) will exhibit magnetic ordering. Electrical resistivity measurements on TbMnCu(4)P(3) indicate a poor metal.

GAP JUNCTION FUNCTION IS ESSENTIAL FOR SURVIVAL OF ACUTE LYMPHOBLASTIC LEUKEMIA CELLS.

BACKGROUND: Acute lymphoblastic leukemia has an intimate physical relationship with nonmalignant bone marrow stromal cells. We have recently demonstrated that stromal cells contribute to the survival of leukemia cells and that there is a bidirectional transfer of intracellular material between them. Understanding the mechanisms of stromal support of leukemia may provide insights into new therapies. AIM: To test the hypothesis that gap junctions are formed between acute lymphoblastic leukemia cells and nonmalignant stromal cells, and that gap junction function is essential for the survival of leukemia cells. MATERIALS AND METHODS: We employed a well-characterized in vitro model of human bone marrow stromal cells and primary human B lymphoblastic leukemia cells and measured leukemia cell survival in coculture using flow cytometry. We measured the effects of gap junction antagonist peptides, carbenoxolone (a drug known to interfere with the gap junction function), and several leukemia chemotherapy drugs including methotrexate upon leukemia cell survival. RESULTS: We demonstrated that stromal cells need to be alive and metabolically active to keep leukemia cells alive. Physical contact between stromal and leukemia cells leads to an increase in gap junction proteins in leukemia cells. Gap junction inhibitory peptides impaired leukemia cell survival as did carbenoxolone, a nonpeptide inhibitor of the gap junction function. Stromal cell survival was not affected. We observed a very modest enhancement of methotrexate antileukemia activity by low-dose carbenoxolone but no significant interactions with dexamethasone, vincristine, mercaptopurine, or doxorubicin. CONCLUSION: These studies demonstrate that acute lymphoblastic cell survival is impaired by interference with the gap junction function. The development of drugs targeting gap junctions may provide a novel approach to the therapy of acute lymphoblastic leukemia.

Rare-earth manganese copper pnictides RE2Mn3Cu9Pn7 (Pn = P, As): quaternary ordered variants of the Zr2Fe12P7-type structure.

The pnictides RE(2)Mn(3)Cu(9)Pn(7) (Pn = P, As) have been prepared by stoichiometric reaction of the elements at 800 °C. They are quaternary ordered variants of the hexagonal Zr(2)Fe(12)P(7)-type structure (Pearson symbol hP21, space group P6, Z = 1; a = 9.6444(3)-9.5970(7) Å, c = 3.9027(1)-3.7761(3) Å for RE(2)Mn(3)Cu(9)P(7) (RE = La-Nd, Sm, Gd-Dy); a = 9.9376(6)-9.9130(3) Å, c = 4.0194(2)-3.9611(1) Å for RE(2)Mn(3)Cu(9)As(7) (RE = La-Nd)). Of the four possible sites available for the transition metal, the square pyramidal site (CN5) is occupied preferentially by Mn atoms, whereas the three tetrahedral sites (CN4) are occupied by Cu atoms. On proceeding to smaller RE members in the RE(2)Mn(3)Cu(9)Pn(7) series, one of the transition-metal-centered polyhedra (Cu1) tends to become less distorted, while the remaining three (Cu2, Cu3, Mn4) become more distorted. Band structure calculations on La(2)Mn(3)Cu(9)P(7) confirm that Mn-P and Cu-P contacts provide the strongest bonding interactions. Electrical resistivity measurements on Ce(2)Mn(3)Cu(9)P(7) reveal metallic behavior with transitions at 165 and 18 K, probably of magnetic origin.

Myeloid sarcoma of uterine cervix: A case report with review of the literature.

Myeloid sarcoma is a rare clinical entity, characterised by the extramedullary presence of myeloblasts. It can occur de novo or signify disease recurrence. Involvement of the female reproductive tract is uncommon, with most cases involving the uterine corpus or ovary. Patients with non-leukaemic myeloid sarcoma are treated with acute myeloid leukaemia (AML) regimens, but the optimal therapy is unclear due to the relative rarity of the condition and lack of clinical trial data. We present an unusual case of myeloid sarcoma of the uterine cervix diagnosed incidentally in a patient with cervical-intraepithelial neoplasia grade 2 (CIN2), followed by a literature review.

Peripheral expansion of pre-existing mature T cells is an important means of CD4+ T-cell regeneration HIV-infected adults.

The CD4+ T-cell pool in HIV-infected patients is in a constant state of flux as CD4+ T cells are infected and destroyed by HIV and new cells take their place. To study T-cell survival, we adoptively transferred peripheral blood lymphocytes transduced with the neomycin phosphotransferase gene between syngeneic twin pairs discordant for HIV infection. A stable fraction of marked CD4+ T cells persisted in the circulation for four to eighteen weeks after transfer in all patients. After this time there was a precipitous decline in marked cells in three of the patients. At approximately six months, marked cells were in lymphoid tissues in proportions comparable to those found in peripheral blood. In two patients, the proportion of total signal for the transgene (found by PCR analysis) in the CD4/CD45RA+ T-cell population relative to the CD4/CD45RO+ population increased in the weeks after cell infusion. These findings indicate that genetically-marked CD4+ T cells persist in vivo for weeks to months and that the CD4+ T-cell pool in adults is maintained mostly by the division of mature T cells rather than by differentiation of prethymic stem cells. Thus, after elements of the T-cell repertoire are lost through HIV infection, they may be difficult to replace.

Multiple cancers. Tumor burden permits the outgrowth of other cancers.

We demonstrate that tumor-bearing hosts permit the outgrowth of "potentially malignant" cells that are located at a different site. These second cancers continued to grow and kill their hosts even though they retain the "premalignant" phenotype, even after removal of the original malignancy. The potentially malignant cells used in these experiments were ultraviolet light- or methylcholanthrene-induced regressor tumor cells that are rejected regularly by normal mice at any testable dose, and only form progressive tumors in immunosuppressed individuals. The immunological rejection of these highly immunogenic, potentially malignant cells was suppressed by Thy-1+, Ly-2-, nonadherent, radio-sensitive suppressor cells in the tumor-bearing mice. These suppressor cells were absent in nude tumor-bearing mice. Unlike helper and cytolytic T cell-mediated responses, which are exquisitely tumor specific, the suppression caused by a progressively growing tumor was crossreactive among many syngeneic, independently derived tumors induced by different carcinogens. However, T cell-mediated immune responses to alloantigens, allogeneic tumors, certain syngeneic tumors, and humoral responses to xenogeneic red blood cells were normal in these mice. The immune suppression in the tumor-bearing animals closely simulated that induced by ultraviolet light irradiation, and both types of suppression might therefore share common mechanisms. Our findings may contribute to understanding the growth, development, and possible control of multicentric malignancies and add a precaution to the potential use of strongly immunogenic tumor variants for active immunotherapy in hosts bearing less immunogenic tumors.

A soluble form of B cell maturation antigen, a receptor for the tumor necrosis factor family member APRIL, inhibits tumor cell growth.

A proliferation-inducing ligand (APRIL) is a ligand of the tumor necrosis factor (TNF) family that stimulates tumor cell growth in vitro and in vivo. Expression of APRIL is highly upregulated in many tumors including colon and prostate carcinomas. Here we identify B cell maturation antigen (BCMA) and transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI), two predicted members of the TNF receptor family, as receptors for APRIL. APRIL binds BCMA with higher affinity than TACI. A soluble form of BCMA, which inhibits the proliferative activity of APRIL in vitro, decreases tumor cell proliferation in nude mice. Growth of HT29 colon carcinoma cells is blocked when mice are treated once per week with the soluble receptor. These results suggest an important role for APRIL in tumorigenesis and point towards a novel anticancer strategy.

BAFF-R, a newly identified TNF receptor that specifically interacts with BAFF.

B cell homeostasis has been shown to critically depend on BAFF, the B cell activation factor from the tumor necrosis factor (TNF) family. Although BAFF is already known to bind two receptors, BCMA and TACI, we have identified a third receptor for BAFF that we have termed BAFF-R. BAFF-R binding appears to be highly specific for BAFF, suggesting a unique role for this ligand-receptor interaction. Consistent with this, the BAFF-R locus is disrupted in A/WySnJ mice, which display a B cell phenotype qualitatively similar to that of the BAFF-deficient mice. Thus, BAFF-R appears to be the principal receptor for BAFF-mediated mature B cell survival.

T lymphocyte-directed gene therapy for ADA- SCID: initial trial results after 4 years.

In 1990, a clinical trial was started using retroviral-mediated transfer of the adenosine deaminase (ADA) gene into the T cells of two children with severe combined immunodeficiency (ADA- SCID). The number of blood T cells normalized as did many cellular and humoral immune responses. Gene treatment ended after 2 years, but integrated vector and ADA gene expression in T cells persisted. Although many components remain to be perfected, it is concluded here that gene therapy can be a safe and effective addition to treatment for some patients with this severe immunodeficiency disease.

Diabetes, malignancy and age as predictors of Candida glabrata bloodstream infection: A re-evaluation of the risk factors.

OBJECTIVE: Echinocandins and azoles are widely used in the treatment of candidaemia. Guidelines of the Infectious Diseases Society of America recommend commencing treatment with an echinocandin in candidaemic patients with risk factors for Candida glabrata i.e. patients who are elderly, or who have diabetes or malignancy, or those with recent prescription of azoles. We attempted to validate whether age, diabetes and malignancy are associated with C. glabrata candidaemia. PATIENTS, MATERIALS AND METHODS: Information in relation to demographics, patient associated risk factors, and laboratory parameters were collected from the casenotes and the laboratory information system. We then analysed the distribution of the risk factors (age, diabetes, and malignancy) in candidaemic patients with C. glabrata and patients with species other than C. glabrata (excluding Candida krusei). RESULTS: Over a 42-month period (April 2011-September 2017), 124 patients had candidaemia. We analysed data for 119 patients of whom 33 (27.7%) had C. glabrata and the remaining 86 (72.2%) were infected with other species. Sixty-five patients were elderly (age≥65), 40 had some form of malignancy, 34 had diabetes, and 4 patients were prescribed azoles in the 30 days prior to candidaemia (many patients had multiple risk factors). Comparing patients with C. glabrata to patients infected with other species, we found no association with diabetes (39.3% vs. 24.4%, P=0.1), malignancy (36.3 vs. 32.5%, P=0.69), and age (54.5% vs. 54.6%, P=0.99). CONCLUSIONS: Diabetes, malignancy and age are not reliable predictors of candidaemia due to C. glabrata.

Background characterization of an ultra-low background liquid scintillation counter.

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3-3600keV can be realized. Initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Interferon-alpha after autologous stem cell transplantation in pediatric patients with advanced Hodgkin's lymphoma.

Thirteen children with refractory or recurrent Hodgkin's lymphoma (HL) received high-dose chemotherapy and autologous hematopoietic stem cell transplant (ASCT). After hematologic recovery, 10 patients were given interferon-alpha (IFN-alpha) as adjuvant therapy, starting at a dose of 0.5 x 10(6) U/m2 subcutaneously, three times a week. The dose was escalated as tolerated. Patients were treated for a median of 12 (4-24) months. Transient myelosuppression was the most common toxicity and led to temporary treatment interruption in five patients. The IFN-alpha dose was increased in nine patients, to a median final dose of 3.5 x 10(6) U/m2/week. With a median follow-up of 67 (range 25-114) months, nine of the 10 patients are alive and in continuous remission. One patient relapsed. Three patients were not treated with IFN-alpha initially, two because of rapidly progressive disease. One patient received IFN-alpha for treatment of relapse after transplant, and is alive in remission 10 years later. IFN-alpha has activity in children with advanced HL, and prolonged, low-dose treatment given after ASCT can be tolerated. Its therapeutic effect as a post-transplant adjuvant warrants further investigation.

Total body irradiation, fludarabine, melphalan, and allogeneic hematopoietic stem cell transplantation for advanced pediatric hematologic malignancies.

We evaluated the efficacy and toxicity of adding 9 Gy of total body irradiation (TBI), in three single daily fractions of 3 Gy, to the reduced intensity regimen of fludarabine 30 mg/m2 i.v. x 4 days and melphalan 140 mg/m2 i.v. x 1 day in advanced pediatric hematologic malignancies. Twenty-two acute lymphoblastic leukemia (ALL), six acute myeloid leukemia (AML), and one non-Hodgkin lymphoma patients were transplanted. Of these, 13 were beyond second remission, and five had prior hematopoietic stem cell transplant (HSCT). Twenty-one donors were unrelated, of which 19 were from cord blood (CB) units. Three of the eight related donors were genotypically disparate. Oral mucositis and diarrhea were the most common toxicities. Twenty-seven patients achieved neutrophil engraftment (median 16 days), and 23 had platelet engraftment (median 42 days). One patient had primary graft failure. Seven patients died of non-relapse causes in the first 100 days. With a median follow-up of 52 months, seven of 22 ALL, five of six AML, and one of one lymphoma patients are alive and in remission. The regimen of TBI, fludarabine, and melphalan allows the engraftment of allogeneic hematopoietic stem cells (including mismatched CB). It was fairly well tolerated in pediatric patients, even for second transplants. Its efficacy requires further evaluation.

Treatment of microscopic pulmonary metastases with recombinant autologous tumor vaccine expressing interleukin 6 and Escherichia coli cytosine deaminase suicide genes.

Poorly immunogenic tumor cells genetically transduced to simultaneously express the cytokine interleukin 6 (IL-6) and the bacterial metabolic suicide gene cytosine deaminase (205-IL6-CD) become highly immunogenic. They are rejected by normal mice without 5-fluorocytosine prodrug treatment. Mice with preexisting wild-type pulmonary micrometastases exhibit prolonged survival and an increased rate of cure when treated with live 205-IL6-CD cells as a therapeutic vaccine. Treatment with these autologous tumor cells producing both the cytokine and the bacterial protein was more effective than treatment with exogenous IL-6 and/or irradiated wild-type tumor cells. Irradiation of the 205-IL6-CD cells significantly reduced their therapeutic efficacy. Therapeutic vaccination with 205-IL6-CD was more effective in animals with wild-type 205 tumor than in animals bearing an unrelated syngeneic tumor. Vaccine efficacy was significantly reduced in animals pretreated with high-dose cyclophosphamide. The results indicate that genetically engineered autologous tumor vaccines may be capable of inducing significant antitumor immunity in hosts of preexisting micrometastatic disease.

Tumors expressing the cytosine deaminase suicide gene can be eliminated in vivo with 5-fluorocytosine and induce protective immunity to wild type tumor.

Successful expression of the cytosine deaminase (CD) suicide gene in vivo is demonstrated in three weakly immunogenic murine tumor models: the 102 and 205 fibrosarcomas and the 38 adenocarcinoma. Normal mammalian cells do not contain cytosine deaminase, but tumor cells transduced with retroviral vectors containing the CD gene metabolize the relatively nontoxic prodrug 5-fluorocytosine to the highly toxic 5-fluorouracil. In vitro cells expressing the CD gene are killed by 5-fluorocytosine while unmodified cells are not. When injected into syngeneic mice, CD+ tumors can also be eliminated in vivo by systemic treatment with 5-fluorocytosine without significant toxicity to the host. Animals whose CD+ tumors were eliminated with prodrug treatment resist subsequent rechallenge with unmodified wild type tumor. This posttreatment immunity appears to be tumor specific. Applications of the CD system in gene therapy models are discussed.