bluuebunny/crossref_metadata_2025 huggingface dataset:
Separating mitogenic and metabolic activities of fibroblast growth factor 19 (FGF19)
Authors: Wu Xinle , Ge Hongfei , Lemon Bryan , Vonderfecht Steven , Baribault Helene , Weiszmann Jennifer , Gupte Jamila , Gardner Jonitha , Lindberg Richard , Wang Zhulun , Li Yang
Published: July 2010

FGF19 and FGF21 are distinctive members of the FGF family that function as endocrine hormones. Their potent effects on normalizing glucose, lipid, and energy homeostasis in disease models have made them an interesting focus of research for combating the growing epidemics of diabetes and obesity. Despite overlapping functions, FGF19 and FGF21 have many discrete effects, the most important being that FGF19 has both metabolic and proliferative effects, whereas FGF21 has only metabolic effects. Here we identify the structural determinants dictating differential receptor interactions that explain and distinguish these two physiological functions. We also have generated FGF19 variants that have lost the ability to induce hepatocyte proliferation but that still are effective in lowering plasma glucose levels and improving insulin sensitivity in mice. Our results add valuable insight into the structure–function relationship of FGF19/FGF21 and identify the structural basis underpinning the distinct proliferative feature of FGF19 compared with FGF21. In addition, these studies provide a road map for engineering FGF19 as a potential therapeutic candidate for treating diabetes and obesity.
Generation of genetically modified rats from embryonic stem cells
Authors: Kawamata Masaki , Ochiya Takahiro
Published: July 2010

At present, genetically modified rats have not been generated from ES cells because stable ES cells and a suitable injection method are not available. To monitor the pluripotency of rat ES cells, we generatedOct4-Venus transgenic (Tg) rats via a conventional method, in which Venus is expressed by theOct4promoter/enhancer. This monitoring system enabled us to define a significant condition of culture to establish authentic rat ES cells based on a combination of 20% FBS and cell signaling inhibitors for Rho-associated kinase, mitogen-activated protein kinase, TGF-β, and glycogen synthase kinase-3. The rat ES cells expressed ES cell markers such asOct4,Nanog,Sox2, andRex1and retained a normal karyotype. Embryoid bodies and teratomas were also produced from the rat ES cells. All six ES cell lines derived from three different rat strains successfully achieved germline transmission, which strongly depended on the presence of the inhibitors during the injection process. Most importantly, high-quality Tg rats possessing a correct transgene expression pattern were successfully generated via the selection of gene-manipulated ES cell clones through germline transmission. Our rat ES cells should be sufficiently able to receive gene targeting as well as Tg manipulation, thus providing valuable animal models for the study of human diseases.
Antigen-specific clonal expansion and cytolytic effector function of CD8+ T lymphocytes depend on the transcription factor Bcl11b
Authors: Zhang Shuning , Rozell Mike , Verma Raj K. , Albu Diana I. , Califano Danielle , VanValkenburgh Jeffrey , Merchant Akeel , Rangel-Moreno Javier , Randall Troy D. , Jenkins Nancy A. , Copeland Neal G. , Liu Pentao , Avram Dorina
Published: July 2010

CD8+ T lymphocytes mediate the immune response to viruses, intracellular bacteria, protozoan parasites, and tumors. We provide evidence that the transcription factor Bcl11b/Ctip2 controls hallmark features of CD8+ T cell immunity, specifically antigen (Ag)-dependent clonal expansion and cytolytic activity. The reduced clonal expansion in the absence of Bcl11b was caused by altered proliferation during the expansion phase, with survival remaining unaffected. Two genes with critical roles in TCR signaling were deregulated in Bcl11b-deficient CD8+ T cells, CD8 coreceptor and Plcγ1, both of which may contribute to the impaired responsiveness. Bcl11b was found to bind the E8I, E8IV, and E8V, but not E8II or E8III, enhancers. Thus, Bcl11b is one of the transcription factors implicated in the maintenance of optimal CD8 coreceptor expression in peripheral CD8+ T cells through association with specific enhancers. Short-lived Klrg1hiCD127lo effector CD8+ T cells were formed during the course of infection in the absence of Bcl11b, albeit in smaller numbers, and their Ag-specific cytolytic activity on a per-cell basis was altered, which was associated with reduced granzyme B and perforin.
Theoretical Study of Interaction Between S2 and SiHx(x= 1, 2, 3) in Porous Silicon
Authors: Li Zuo , Cheng Xin-lu , Wang Jiang , Chen Hai-hua
Published: July 2010

The interaction between S2 molecule and SiHx (x = 1, 2, 3) in porous silicon is investigated using the B3LYP method of density functional theory with the Ianl2dz basis set. The model of porous silicon doped with CH3, Si–O–Si and OH species is built. By analyzing the binding energy and electronic transfer, we conclude that the interaction of S2 molecule with SiHx (x = 1, 2, 3) is much stronger than the interaction of S2 molecule with CH3 and OH, as S2 molecule is located in different sites of the model. Using the transition state theory, we study the Si2H6+S2→H3SiH2SiS+HS reaction, and the reaction energy barrier is 50.2 kJ/mol, which indicates that the reaction is easy to occur.
Effect of Pressure on Electronic Structures and Optical Properties of Rocksalt InN
Authors: Xu Ming-yao , Xu Ming , Duan Man-yi , Hu Qing-ping
Published: July 2010

The electronic structures and optical properties of rocksalt indium nitride (InN) under pressure were studied using the first-principles calculation by considering the exchange and correlation potentials with the generalized gradient approximation. The calculated lattice constant shows good agreement with the experimental value. It is interestingly found that the band gap energy Eg at the Γ or X point remarkably increases with increasing pressure, but Eg at the L point does not increase obviously. The pressure coefficient of Eg is calculated to be 44 meV/GPa at the Γ point. Moreover, the optical properties of rocksalt InN were calculated and discussed based on the calculated band structures and electronic density of states.
Effect of Interaction upon Translocation of Confined Polymer Chain Through Nanopore
Authors: Wang Yao , Xie Yong-jun , Yang Hai-yang , Zhang Xing-yuan
Published: July 2010

The effect of the interaction between nanopore and chain monomer on the translocation of a single polymer chain confined in a finite size square through an interacting nanopore to a large space has been studied by two-dimensional bond fluctuation model with Monte Carlo simulation. Results indicate that the free energy barrier before the successful translocation of the chain depends linearly on the chain length as well as the nanopore length for different pore-polymer interaction, and the attractive interaction reduces the free energy barrier, leading to the reduction of the average trapping time.
Synthesis of Biomorphic ZrO2-CeO2 Nanostructures by Silkworm Silk Template
Authors: Zhang Zong-jian , Li Jia , Sun Fu-sheng , L. Ng Dickon H. , Luen Kwong Fung
Published: July 2010

A simple and green technique has been developed to prepare hierarchical biomorphic ZrO2-CeO2, using silkworm silk as the template. Different from traditional immersion technics, the whole synthesis process depends more on the restriction or direction functions of the silkworm silk template. The analytic results showed that ZrO2-CeO2 exhibited a well-crystallized hierarchically interwoven hollow fiber structure with 16–28 μm in diameter. The grain size of the sample calcined at 800 °C was about 14 nm. Consequently, the interwoven meshwork at three dimensions is formed due to the direction of biotemplate. The action mechanism is summarily discussed here. It may bring the biomorphic ZrO2-CeO2 nanomaterials with hierarchical interwoven structures to more applications, such as catalysts.
Synthesis and Characterization of TiO2 Doped ZnO Microtubes
Authors: Li Yan
Published: July 2010

The TiO2-doped ZnO microtubes have been successfully fabricated via a wet chemical method, using zinc chloride and titanium sulphate as the starting materials. The assynthesized products were characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The photocatalytic activity in degrading methyl orange was measured with a UV-Vis spectrophotometer. The pure ZnO microtubes exhibit an exact hexangular hollow structure with a diameter of about 700 nm, a length of 3 μm and a wall thickness of about 40 nm. The TiO2-doped ZnO microtubes with TiO2/ZnO ratio less than 5% have the same dimension with the pure ZnO microtubes, a smooth column shape, not a hexangular structure. The growth of ZnO may be inhibited by the more Ti4+ doped into ZnO structure to achieve a small dimension or a multiphase. The crystallinity of ZnO microtubes decreases with increasing TiO2 content, and then a multiphase containing ZnO, Ti3O5 and TiO occur when the TiO2/ZnO ratio is more than 5%. The UV emission intensity of the TiO2-doped ZnO obviously increases and then tends to decrease with TiO2/ZnO ratio increasing. The photocatalytic properties of the TiO2-doped ZnO microtubes are very efficient in degrading organic dyes of methyl orange and are well identical with its PL properties and the crystallinity.
Metal Precursor Influence on Performance of Culn1−xGaxSe2 Films
Authors: Wang Man , Zhang Zhong-wei , Jiang Guo-shun , Zhu Chang-fei
Published: July 2010

CuIn1−xGaxSe2 (CIGS) films were prepared by a two-stage method, in which Cu-In-Ga metallic precursors were firstly deposited on unheated Mo-coated soda lime glass substrates by direct current sputtering CuGa (20%Ga) and radio frequency sputtering In targets in an Ar atmosphere, followed by selenization at 520 °C for 40 min in Se vapor. By adjusting the sputtering thickness ratio of surface CuGa (20%Ga) and bottom CuGa (20%Ga) alloy layers in metal precursor, different CIGS thin films were fabricated. Through X-ray diffraction spectra, Raman spectra, local energy dispersive spectrometer, planar- and cross-sectional views of scanning electron microscopy measurements, it revealed that the CIGS thin films from selenization of metal precursor with CuGa:In:CuGa thickness ratio of 7:20:3 (sample-2-se) was of chalcopyrite structure with the preferred (112) orientation, and the grains sizes ranged from 0.5 μm to 2 μm, and sample-2-se had no binary compound phase of In-Se and order defect compound phase. Consequently, the results of illuminated current-voltage curve and quantum efficiency measurements showed that the CIGS film device made from sample-2-se had relative higher photo-electric conversion efficiency (3.59%) and good spectrum response.
Protons and Deuterons in Magnesium‐Doped Sapphire Crystals
Authors: Ramrez Rafael , Gonzlez Roberto , Colera Inmaculada , Vila Rafael
Published: July 2010

The OH‐ and OD‐ stretching frequencies in magnesium‐doped aluminum oxide crystals were determined by infrared absorption measurements. Two very broad bands centered at }3005 and 2228 cm‐1 were observed for OH‐ and OD‐, respectively. Polarization experiment results were compatible with OH‐ (OD‐) ions lying in the basal plane, as is the case in undoped crystals. The threshold temperature for the in‐diffusion of deuterons was obtained by annealing the samples in flowing D2O vapor; the resulting value was }1050 K. At 1223 K, the diffusion coefficient was }3× 10‐7 cm2/s, and the activation energy was 1.6 eV.
Sequence of Phase Formation in Chemically Derived Ferroelectric Lead Zirconate Titanate Pb(Zr0.4Ti0.6)O3 Thin Films
Authors: Liu Yimin , Phule Pradeep P.
Published: July 2010

A qualitative model for the sequence of phase transforma‐tions leading to perovskite phase formation in sol–gel‐derived PZT thin films is presented. It is suggested that for sol–gel‐derived Pb(ZrxTi1–x)O3 (x = 0.4) thin films, prepared using the molecularly modified alkoxide precursors (MMAP) approach, complete (or partial) conversion of the originally amorphous film into a “pyrochlore” phase, although possible, may not be necessary. Differences between the sequence of phase formation encountered in the tradi‐tional (oxide‐mix) synthesis and that in chemically derived ceramics are discussed. The sequence of phase formation in these thin films also appears to be intertwined with the texture development in that a (111) PZT texture develop‐ment appears to be controlled by nucleation of the perovs‐kite phase, assisted by a solid‐phase epitaxial effect, and the (100)/(001) texture appears to be growth controlled.x
Crystal and Defect Structure of Nd1.9Ce0.1CuO4±y
Authors: Petrov Alexander N. , Zuev Andrey Yu. , Rodionova Tatjana P. , Voronin Vladimir I.
Published: July 2010

The crystal and defect structure of neodymium cerium cu‐prate (Nd1.9 Ce0.1 CuO4±y) has been studied as a function of temperature (1200–1500 K) and oxygen pressure (100–103 atm) via X‐ray diffractometry, powder neutron diffraction, and thermogravimetry methods. The oxygen nonstoichiom‐etry changes from oxygen‐excess (positive y values) to oxygen‐ deficient oxides (negative y values). The absolute values of oxygen nonstoichiometry y are calculated from the neu‐tron diffraction and thermogravimetry data. The materials adopt the tetragonal structure (space group I4/mmm). A defect model is proposed for Nd2‐x Cex CuO4±y. It is con‐cluded that oxygen vacancies VÖ (which occupy O(1) crys‐tallographic positions (in planes)) and interstitial oxygen O(i (which occupy O(3) “apical” positions) are present simultaneously. Gaseous oxygen intercalates into the Nd1.9 Ce0.1 CuO4±y crystals and replaces oxygen vacancies in the O(1) position and interstitial oxygen atoms in the O(3) positions. The theoretical model and the experimental data are in good agreement with each other, and the equilibrium constants of defect formation have been calculated.
New Method to Fabricate Limiting‐Current‐Type Oxygen Sensors
Authors: Kim Do‐Hyeong , Miyayama Masaru
Published: July 2010

A cofiring process with the addition of carbon fiber was demonstrated successfully to be a new method to fabricate limiting‐current‐type oxygen sensors. Reproducible, limiting‐current behavior was realized in sensors that were made via cofiring. The limiting current was directly proportional to –ln (1 –XO2) over an oxygen concentration XO2 range of 0%–25%, and gas diffusion through the hole made by the burnout of the carbon fiber in the sensor was believed to be in the normal diffusion region.
Crystal Structure and Related Properties of Manganese‐Doped Barium Titanate Ceramics
Authors: Langhammer Hans Theo , Müller Thomas , Felgner Karl‐Heinz , Abicht Hans‐Peter
Published: July 2010

The influence of manganese on the crystallographic phase and the microstructure of BaTi1−xMnxO3 ceramics (0 ≤x≤ 0.05) is investigated. The crystal structure at room temperature changes from tetragonal to hexagonal between x= 0.005 and 0.017, which causes a drastic change in the microstructure. The Jahn_Teller distortion caused by the MnTi3+ ions is proposed as the driving force for the phase transition. Annealing of the as‐fired samples in both a reducing and oxidizing atmosphere restores the tetragonal phase, which is accompanied by a change in the microstructure based on the percentage of tetragonal phase.
High‐Temperature Flow Behavior of Ceramic Suspensions
Authors: Chu T.‐M. Gabriel , Halloran John W.
Published: July 2010

The objective of this study was to investigate the effects of temperature and solids loading on the viscosity of two nonaqueous ceramic suspensions. In this article, the viscosity of Al2O3 suspensions with 5%–50% solids loading and hydroxyapatite suspensions with a solids loading of 5%–40% were measured at temperatures of 25°, 45°, 65°, and 75°C. The high‐shear Newtonian viscosity at various temperatures was reduced to a single curve by the reduced viscosity and the temperature‐adjusted solids volume fraction of the suspensions. The Krieger–Dougherty model, with the intrinsic viscosity corrected for particle geometry, was fitted to the data and was observed to provide a satisfactory description to the solids‐loading–viscosity data for both suspensions.
Densification Behavior in Microwave‐Sintered Silicon Nitride at 28 GHz
Authors: Jones Mark I. , Valecillos Maria‐Cecilia , Hirao Kiyoshi , Toriyama Motohiro
Published: July 2010

Si3N4 powders were sintered using a 28 GHz gyrotron source, with Y2O3, Al2O3, and MgO as sintering aids, in an attempt to investigate the effect of microwave radiation on densification behavior. The microwave‐sintered samples were compared with identical samples produced by conventional pressureless sintering. The effect of sintering on the microstructural development and grain growth of the samples was assessed using scanning electron microscopy. Phase transformation behavior was assessed using X‐ray diffractometry. In the microwave‐sintered samples, densification and α→β transformation occurred at temperatures ∼200°C lower than those of the conventionally sintered samples. More importantly, at comparable stages of densification, the microstructures of the microwave‐sintered and conventionally sintered samples were significantly different, with the microwave‐sintered samples showing the development of elongated β grains at a much earlier stage of the α→β transformation. It was concluded that the effect of microwave radiation on sintering was not simply a decrease in sintering temperatures, but in possibly a different sintering mechanism, clearly related to localized heating within the grain‐boundary phase.
Symmetric Structures of Ultrahard Materials
Authors: Lowther John E.
Published: July 2010

Diamond and BN have common relatively soft precursor structures that are hexagonal. Electronic structure calculations have now revealed subtle energy differences between the two materials. Another hard material, stishovite, also has a relatively soft precursor phase, quartz, and here again electronic structure calculations have given insight into the nature of the phase transformation. On the other hand, with boron‐related materials, the main focus is to connect basic icosahedra structures to produce a hard material. The structural aspects of these materials are examined and possible consequences for low‐ and high‐coordination ultrahard nitrides considered.
Effect of Seeding on the Microstructure and Mechanical Properties of α‐SiAlON: I, Y‐SiAlON
Authors: Zenotchkine Misha , Shuba Roman , Kim Joo‐Sun , Chen I‐Wei
Published: July 2010

The effect of seeding on the microstructure and mechanical properties of single‐phase Y‐α‐SiAlON ceramics with elongated grains has been studied. Seeds of the intended α‐SiAlON compositions but with different size, shape, and number of grains have been compared for their effects. The microstructure, resistance (R‐curve) behavior, and Weibull modulus are strongly correlated to the number density of the seeds. The highest fracture toughness reached is ∼12 MPa·m1/2 and can be obtained with as little as 1% seeding. The thermodynamic stability of seeds has been examined and is attributed to their chemical composition.
Crystal Structure and Thermal Expansion of La1−xSrxFeO3−δ Materials
Authors: Fossdal Anita , Menon Mohan , Wærnhus Ivar , Wiik Kjell , Einarsrud Mari‐Ann , Grande Tor
Published: July 2010

Crystal structure and thermal properties of La1−xSrxFeO3−δ (x= 0, 0.1, 0.3, 0.4, 0.5, and 0.75) have been studied by high‐temperature X‐ray diffraction and thermal analysis in air and nitrogen (p(O2) ∼ 10−3 atm) atmosphere. The first‐order phase transition from orthorhombic‐to‐rhombohedral La1−xSrxFeO3−δ (x= 0, 0.1) was strongly shifted to lower temperatures with increasing Sr content. The phase‐transition temperature was observed significantly lower in polycrystalline ceramics compared with fine powders. The temperature depression of the phase transition in the ceramics was qualitatively explained by stresses induced both by the anisotropic thermal expansion of LaFeO3 and the observed volume contraction of the phase transition. Rhombohedral La1−xSrxFeO3−δ (x= 0.3, 0.4, 0.5) were observed to transform to the cubic perovskite structure during heating. The second‐order phase‐transition temperature decreased with increasing Sr content and decreasing partial pressure of oxygen. On the basis of the present findings, a pseudobinary phase diagram of the LaFeO3–SrFeO3−δ system is presented. Finally, a severely nonlinear thermal expansion was observed for the Sr‐rich materials at high temperature. The high thermal expansion in this region is due to a chemical expansion resulting from a reduction of the valence state of Fe.
Membrane Characteristics and Metabolic Properties of Glucose‐6‐Phosphate Dehydrogenase Deficient Red Cells
Authors: Jansson Sten‐Erik , Hekali Riitta , Gripenberg Johan , Härkönen Matti , Vuopio3 Pekka
Published: July 2010

Summary. Two Finnish variants of reduced erythrocyte glucose‐dehydrogenase (G‐6‐PD) activity were studied. The G‐6‐PD Espoo variant is characterized by severe enzyme deficiency which is normally non‐haemolytic although primaquine sensitive. The other variant, G‐6‐PD Helsinki, in which the enzyme activity is moderately reduced, is associated with chronic haemolytic anaemia.

The activity of the pentose phosphate pathway was not stimulated by methylene blue in G‐6‐PD Espoo cells, whereas in normal and G‐6‐PD Helsinki cells there were increases in shunt activity of 64.5‐ and 5.3‐fold, respectively. As judged by the accumulation of 6‐phosphogluconate after incubation with 6‐aminonicotinamide, the activity of the pentosc phosphate pathway was similar in normal and G‐6‐PD Helsinki cells, whereas in G‐6‐PD Espoo cells the metabolic flux through this pathway was decreased. Quantities of sulphydryl groups in intact cells and isolated membranes were similar in normal and G‐6‐PD deficient cells, as revealed by spin label experiments. In contrast to the situation in normal cells, sulphydryl groups in G‐6‐PD Espoo cells, and to a lesser extent in G‐6‐PD Helsinki cells, were sensitive to oxidation by acetylphenylhydrazine. In the G‐6‐PD Helsinki cells, but not in the G‐6‐PD Espoo cells, membrane fluidity was increased, as judged from the increased mobility of the stearic acid spin label.

Mechanisms are discussed by which G‐6‐PD deficient cells retain adequate levels of NADPH during resting conditions, and it is suggested that the chronic haemolysis associated with G‐6‐PD Helsinki could be due to a defect in the lipid region of the cell membrane.
Studies on Platelet Glycoproteins in Glanzmann's Thrombasthenia using 125I‐labelled Lectins
Authors: McGregor J. L. , Clemetson K. J. , James E. , Greenland T. , Lüscher E. F. , Dechavanne M.
Published: July 2010

Summary. Glycoproteins ((2) of Glanzmann's thrombasthenia (GT) and normal platelets were separated on sodium dodecyl sulphate (SDS) polyacrylamide slab gels and identified by their binding of 125I‐labelled lectins having different sugar specificities. This highly sensitive techniquc showed that in thrombasthenic platelets, glycoproteins in the positions of IIb and III (IIIa) were greatly reduced when compared to normal platelets. After incubation with neuraminidase, IIb became undectable. GT platelet glycoproteins I, IV (IIIb), and high molecular weight GPs bound 125I‐lectins more strongly than those in normal platelets, showing that there are drastic changes in the carbohydrate moieties of thcse major GPs.
MYELOFIBROSIS AND PROSTAGLANDINS: EFFECT OF PROSTAGLANDIN E1 ON COLONY‐FORMING CELLS (CFU‐GM)
Authors: Aglietta Massimo , Piacibello Wanda , Gavosto Felice
Published: July 2010

Semisolid agar cultures of committed granulocyte monocyte precursors (CFU‐GM) make it possible to study the regulation of normal and abnormal stem cells. In vitro growth of CFU‐GM is dependent on the presence of specific stimulators, called CSA (colony stimulating activity) (Metcalf, 1977; Broxmeyer & Moore, 1978). The influence of CSA on CFU‐GM may be inhibited by prostaglandins of the E series (Broxmeyer & Moore, 1978; Kurland et al, 1978). Recently it has been demonstrated that chronic granulocytic leukaemia (CGL) CFU‐GM are insensitive to prostaglandin E1 (PGE1) over a wide range of concentrations that are inhibitory to normal CFU‐GM development (Aglietta et al, 1980; Pelus et al, 1980; Taetle & Koessler, 1980). We report the effect of PGE1 on CFU‐GM from patients with idiopathic myelofibrosis (MF).
Thrombopoiesis‐ and Megakaryocyte Colony‐stimulating Factors in the Urine of Patients with Idiopathic Thrombocytopenic Purpura
Authors: Kawakita Makoto , Enomoto Katsuto , Katayama Noritaka , Kishimoto Susumu , Miyake Takaji
Published: July 2010

Summary.

The urinary extract from patients with severe, chronic idiopathic thrombocytopenic purpura (ITP) was capable of inducing significant thrombocytosis in rats in vivo and enhancing megakaryocyte colony formation in culture of mouse bone marrow cells. The apparent specific activity of megakaryocyte colony stimulating factor (MEG‐CSF) in the ITP extract was approximately one‐half of that of the urinary extract from patients with aplastic anaemia (AA). Daily injections of ITP extract did not cause an increase in Hb concentration, while rats receiving AA urinary extract revealed profound erythropoiesis 3 weeks later. In vitro assay of erythropoietin (EPO) failed to show significant EPO activity in the extract from patients with ITP. These findings excluded the possibility that the observed activities of thrombopoiesis‐stimulating factor (TSF) and MEG‐CSF in the ITP urinary extract are due to contaminating EPO. Urine of patients with severe ITP appears to be a good source of TSF and MEG‐CSF.
Overproduction of structurally normal enzyme in man: hereditary haemolytic anaemia with increased red cell adenosine deaminase activity
Authors: Fujii Hisaichi , Miwa Shiro , Tani Kenzaburo , Fujinami Noboru , Asano Hiroyuki
Published: July 2010

Summary.

The mechanism of red cell adenosine deaminase (ADA) accumulation in a case of hereditary haemolytic anaemia due to increased red cell ADA activity was investigated. ADA activity of the younger cells was twice that of the older cells. Rate of ADA synthesis in erythroid colony cells cultured from the patient's bone marrow cells was 11‐fold greater than that from the normal. The accumulation of ADA in the patient seems to be due to the increased synthesis in precursors of red cells in spite of the increased degradation in peripheral blood.
Normal activities of glycolytic enzymes in the fetal erythrocytes
Authors: Lestas A. N. , Rodeck C. H. , White J. M.
Published: July 2010

Pure fetal blood was obtained by direct‐vision fetoscopy from 24 fetuses at 17‐24 weeks’gestation. The activities of 14 glycolytic enzymes† in the erythrocytes were analysed by established techniques to find the normal ranges of activity for this gestational age. The results were compared with those obtained from 24 normal adults and with published values on neonatal blood. The activities of most enzymes in fetal erythrocytes were found to be higher and the relative pattern of activity different from those of adult or neonatal blood. The ranges were relatively narrow and can serve as reference values for the prenatal diagnosis of erythrocytic enzymopathies. Also, the activities of the glycolytic enzymes will provide a basis for the understanding of erythrocyte metabolism in the fetus.
Adverse effects of aneuploidy on the outcome of remission induction therapy for acute nonlymphocytic leukaemia: analysis of types of treatment failure
Authors: Preisler H. D. , Reese Peter A. , Marinello SMichelle J. , Pothier Lillian
Published: July 2010

Summary. Cytogenetic studies were carried out on bone marrow specimens obtained from 98 patients with acute nonlymphocytic leukaemia. Patients were treated with cytosine arabinoside and an anthracycline antibiotic. The remission rate for patients in whom only normal metaphases were detected (NN patients) was 69% while the remission rates were 50% and 40% respectively for patients in whom both normal and abnormal metaphases were seen (NA patients) and for those in whom only abnormal metaphases were noted (AA patients). Analysis of remission induction failure types suggests that the differences in outcome were related to a tendency for patients with aneuploid leukaemia to be more likely to have drug resistant disease and to the lesser ability of NA and A A patients to survive and receive a second course of therapy if the first course failed to induce a complete remission.
Rates of cholesterol biosynthesis are related to early differentiation in acute non‐lymphocytic leukaemia cells
Authors: Yachnin Stanley , Larson Richard A. , West E. Jayne
Published: July 2010

Summary. Cholesterol synthesis from acetate was studied in leukaemic cells from 20 patients with acute nonlymphocytic leukaemia. Marked differences in the rates of cholesterol biosynthesis were noted among three morphologically distinct types of leukaemia. As leukaemic cells differentiated along myeloid (acute promyelocytic) or monocytoid (acute myelomonocytic) pathways, their cholesterol‐synthetic rates diverged and approached those of their respective mature cellular counterparts, the neutrophil or the peripheral blood monocyte. Enhanced sterol synthesis in leukaemic cells could not be explained by more rapid efflux of membrane cholesterol to the environment. In addition, the different rates of cholesterol biosynthesis in leukaemic‐cell subgroups did not correlate with differences in their rates of cellular DNA synthesis. The normal divergence of sterol‐synthesizing capacity found between mature neutrophils and monocytes develops at an early stage of differentiation and is detectable even in leukaemic cells.
Evidence against enhanced platelet activity in sickle cell anaemia
Authors: Buchanan George R. , Holtkamp Christine A.
Published: July 2010

Summary. Although numerous studies have provided indirect evidence for enhanced platelet activity in sickle cell anaemia, little attention has been directed to examination of platelet alpha and dense granule release in the sickling disorders. We simultaneously measured by radioimmunoassay plasma levels of the alpha granule constituents β‐thromboglobulin (β‐TG) and platelet factor 4 (PF4) in 43 children with sickle cell anaemia in steady state and 24 patients during severe vaso‐occlusive crisis. β‐TG levels during steady state (50 ± 3.6 ng/ml, mean ± SEM) were greater (P<0.001) than in normal controls (36 ± 1.6), but there was no additional significant rise during crisis (55 ± 5.9). PF4 levels were similar (P= 0.12) in both steady state (10 ± 1.2 ng/ml) and crisis (9.3 ± 2.3) to those of normal controls (6.0 ± 0.8). The similarity of β‐TG/PF4 ratios in normal and sickle cell anaemia patients as well as the positive correlation (P<0.05) between platelet count and β‐TG and PF4 suggested that an artefactual in vitro platelet activation was responsible for some of the observed increased β‐TG and PF4 levels. Further evidence against enhanced platelet activity in these sickle cell patients included normal intraplatelet content of the dense granule constituent 5‐HT and a normal ATP/ADP ratio. From this data we conclude that platelet activation in children with sickle cell anaemia appears minimal.
A reappraisal of the effects of iron and desferrioxamine on the growth of Plasmodium falciparum‘in vitro’: the unimportance of serum iron
Authors: Peto T. E. A. , Thompson J. L.
Published: July 2010

Summary. It has been suggested that P. falciparum takes up iron from serum and that desferrioxamine, an iron chelating agent, inhibits parasite growth. We have now shown, however, that when all the iron is transferrin bound, P. falciparum, in culture, takes up less than 7 pmol Fe/109 parasites/24 h and that incorporation is increased only in the presence of a high molecular weight iron complex not naturally found in serum. Furthermore, removal of iron serum did not reduce parasite growth, and addition of excess iron was inhibitory. Desferrioxamine inhibited growth, but this inhibition was reduced under conditions in which the transfer of iron from transferrin to desferrioxamine was accelerated. We conclude that P. falciparum does not directly utilize serum iron and that desferrioxamine does not inhibit the parasite by interfering with the supply of iron from the incubation medium. The results are relevant to clinical data which suggest that added nutritional iron enhances the host susceptibility to malaria.
Antibodies against glycosphingolipids in sera of patients with idiopathic thrombocytopenic purpura
Authors: van Vliet H. H. D. M. , Kappers‐Klunne M. C. , van der Hel J. W. B. , Abels J.
Published: July 2010

Summary. Evidence is presented for the existence of antibodies against platelet glycosphingolipids in sera of patients with chronic idiopathic thrombocytopenic purpura and antiplatelet antibodies. Increased binding of IgG/IgM to neutral glycosphingolipids or gangliosides extracted from donor platelets was measured by an ELISA in 17 sera of 30 patients. Thirteen sera, five with anticardiolipin antibodies, demonstrated an increased binding to sulphatides confirmed by immuno HPTLC. Four sera showed reactivity with the platelet minor gangliosides established by immuno‐HPTLC.
Interleukin 1 or endotoxin increases the release of von Willebrand factor from human endothelial cells
Authors: Schorer Anna E. , Moldow Charles F. , Rick Margaret E.
Published: July 2010

von Willebrand factor (vWF), a large adhesive glycoprotein, is synthesized by vascular endothelial cells (EC). Plasma levels of vWF manifest a broad normal range, and are elevated during sepsis and in inflammatory states. Since the inflammatory mediator, interleukin 1 (IL1) and bacterial endotoxin (LPS) both initiate procoagulant changes in vascular endothelium, we investigated the effect of these substances on endothelial cell release and residual endothelial cell content of vWF‐antigen (vWFAg). Cultured human EC exposed to either IL1 or LPS released greater amounts of vWFAg compared to control EC. The augmented release could be detected within 1–2 h after exposure to IL1 or LPS and was not inhibited by cycloheximide, suggesting that de novo protein synthesis was not required for release to occur. Residual cellular vWFAg was reciprocally lower in IL1‐ or LPS‐treated EC at 24 and 48 h, indicating that compensatory increase in synthesis of vWFAg did not occur during this time interval. Released vWF contained the higher molecular weight multimers observed in normal endothelial cells, and it possessed ristocetin cofactor activity. We propose that release of functional vWF from EC exposed to inflammatory mediators may be at a mechanism for localization of platelets and enhanced thrombogenicity at inflammatory foci.
High levels of anti‐cytoskeleton autoantibodies are frequently associated with chronic GVHD
Authors: Dighiero Guillaume , Intrator Liliane , Cordonnier Catherine , Tortevoye Patricia , Vernant Jean‐Paul
Published: July 2010

Twenty‐two patients (acute myeloid leukaemia 13, acute lymphoid leukaemia 5, chronic myeloid leukaemia 4) with an average age of 25 years (range 8–36 years), had received allogeneic bone marrow transplantation (BMT) from an HLA identical sibling. The BMT recipients were followed up for a period of 4–65 months. All patients were given cyclophosphamide, total body irradiation and methotrexate in order to prevent graft‐versus‐host disease (GvHD). Eleven of 22 patients exhibited chronic graft versus host disease (cGvHD) (extensive in five, limited in six at the time of the study) assessed by clinical and histological parameters. Serum samples were collected from these patients, before BMT (except in one case) and then every 2 or 3 months. Sequential studies to determine the presence of autoantibodies against cytoskeletal proteins (actin, tubulin, myosin), dsDNA and dDNA in these sera were performed by an ELISA method. Simultaneously, immunoelectrophoresis and measurement of complement fractions C3, C4 were performed on each sample. High levels of autoantibodies against cytoskeletal proteins were found in 10/11 patients with cGvHD and were absent in 11/11 patients without cGvHD; none of them exhibited anti‐DNA activity. At the same time, C4 levels were decreased in seven of these patients with cGvHD. Monoclonal immunoglobulins IgG and IgM (2–15 g/1) were found in 8/11, but the antibody activity was never found to be located within the M component. These results show a direct relationship between the presence of these autoantibodies and occurrence of cGvHD and indicate that they may constitute an immunological marker related to this complication. However, their predictive value is not clearly evident in this retrospective series as in some patients they preceded clinical signs of cGvHD, whereas in others they were associated with the onset of cGvHD.
Platelet reactions after interaction with cultured Plasmodium falciparum infected erythrocytes
Authors: Inyang A. L. , Sodeinde O. , Okpako D. T. , Essien E. M.
Published: July 2010

An in vitro model for studying the interaction between normal human platelets and Plasmodium falciparum infected erythrocytes in culture is described. After the interaction, changes in platelet function such as enhanced aggregation response to exogenous ADP and increased secretion of dense granule contents were reproduced. Some of these responses represented manifestations of platelet hypersensitivity described earlier in acute malaria infections in man and mice. Preliminary investigations of the mechanisms involved in such reactions revealed that ADP and thromboxane A2 mechanisms contributed about 79% and 18.5% of the enhanced aggregation response to exogenous stimuli in the system.
Transient reduction in erythrocyte membrane sialoglycoprotein β associated with the presence of elliptocytes
Authors: Daniels G. L. , Reid M. E. , Anstee D. J. , Beattie K. M. , Judd W. J.
Published: July 2010

Erythrocyte membranes from an anaemic patient receiving gold therapy for rheumatoid arthritis had reduced β‐sialoglycoprotein (β‐SGP) content but normal expression of sialoglycoproteins α, δ and γ. Elliptocytes were present in the peripheral blood. The serum of the patient contained anti‐β‐SGP which did not appear to bind to her own cells. It reacted with all erythrocytes apart from β‐SGP deficient Leach phenotype cells. The antibody was inhibited by purified β‐SGP from normal red cells, bound to β‐SGP on immunoblots and also reacted with the abnormal β‐related‐SGP in erythrocyte membranes of both the Gerbich type and Yus type of Gerbich negative. Two years later the patient was no longer anaemic, no elliptocytes were seen in her peripheral blood film and her erythrocyte membranes had normal β‐SGP content. Antibody was no longer present in her serum and antibody from the earlier sample now reacted with the patient's erythrocytes.

Erythrocyte membrane β‐SGP is known to be important in the maintenance of normal cell shape. It is likely that the transient occurrence of elliptocytes in the patient resulted from the concurrent temporary reduction in β‐SGP content of her erythrocyte membranes.
In‐vitro differentiation of cells of patients with acute undifferentiated leukaemia
Authors: Schoot C. Ellen van der , Visser Frans J. , Tetteroo Pedro A. T. , Kr. von dem Borne Albert E. G.
Published: July 2010

Summary The diagnosis of acute undifferentiated leukaemia (AUL) is made when the cells of patients with acute leukaemias cannot be classified as myeloid or lymphoid by means of morphological, cytochemical and immunological criteria. The mononuclear cells of eight different AUL patients were cultured in suspension for 3 d with or without TPA. After culture, especially in the presence of TPA, the cells of all patients expressed at least one myeloid membrane antigen. It was shown that this antigen expression was dependent on de novo protein synthesis and not influenced by inhibition of proliferation.
Maturation of human acute myeloid leukaemia in vitro; the response to five recombinant haematopoietic factors in a serum‐free system
Authors: Salem Mohammad , Delwel Ruud , Mahmoud Lotfy A. , Clark Steven , Elbasousy Elmahdy M. , Louwenberg Bob
Published: July 2010

Summary The abilities of human recombinant IL‐3, GMCSF, G‐CSF, M‐CSF and Epo to induce maturation in human AML cells in vitro were investigated using cell specimens from 25 AML patients. The experiments were carried out under exactly defined serum‐free culture conditions. In the absence of CSFs, monocytic and/or granulocytic maturation was detected in 14/25 cases. IL‐3, GM‐CSF, G‐CSF and M‐CSF elevated the proportions of monocyte/macrophages in 3/25, 2/25, 1/25 and 6/25 cases respectively, and increased the percentages of mature granulocytes in 2/25, 1/25, 1/25 and 0/25 cases, and if so only to a limited extent (values below 50%). The 3H‐thymidine (3H‐TdR) uptake studies revealed that IL‐3, GM‐CSF, G‐CSF and M‐CSF were efficient stimulators of DNA synthesis of AML cells in 19, 15, 13 and four of those cases, respectively. Thus, although the cells in most cases responded to CSFs by activation of DNA synthesis, they were unable to give rise to terminally differentiated stages. Provision of CSFs in combination was more frequently effective in enhancing maturation and also increased the magnitude of maturation response. Monocytic versus granulocytic maturation of AML cells after culture did not correlate with the FAB cytology nor with the type of CSF presented; but generally granulocytic maturation was an infrequent phenomenon. Epo stimulated erythroid differentiation and DNA synthesis only in the case of erythroleukaemia, but it had no effect on the cells of 10 other AML cases. Extrapolation of these in vitro findings would suggest that CSFs would have a limited therapeutic utility to induce AML cell maturation in vivo and that hazards of stimulating blast cell proliferation with these factors may be anticipated.
Familial hypofibrinolysis and venous thrombosis
Authors: Petäjä Jari , Rasi Vesa , Myllyla Gunnar , Vahtera Elina , Hallman Heikki
Published: July 2010

Summary Nine patients with, and 11 without, venous thromboses (DVT) from two families were studied. In family 1, four members with, and one without. DVT had t‐PA activity below the lower limit of the controls (21.3 IU/ml, n= 19) after 20 min venous occlusion (VO). After VO t‐PA antigen (t‐PA:Ag) was below the lowest value of the controls (22.8 ng/ml) in all five cases with low t‐PA activity. All the family members, both with and without thrombosis, had normal t‐PA inhibitor activities (PAI). In family 2 t‐PA activity after VO was low in three symptomatic and four asymptomatic family members. t‐PA : Ag was also low in four of these. PAI level was normal in all but one family member. Mild type I von Willebrand's disease was discovered in four members of family 2. Deficient t‐PA : Ag response was found in two of these. Antithrombin III, protein C and protein S were normal in both families. It is concluded that low fibrinolytic capacity, independent of PAI, is associated with familial DVT. Our data suggests autosomal dominant inheritance.
Interferon‐alpha‐induced morphological changes of megakaryocytes: a histomorphometrical study on bone marrow biopsies in chronic myeloproliferative disorders with excessive thrombocytosis
Authors: Chott Andreas , Gisslinger Heinz , Thiele Juergen , Fritz Elke , Linkesch Werner , Radaszkiewicz Thaddaeus , Ludwig Heinz
Published: July 2010

Interferon(rIFN)‐alpha, a successful therapeutic agent in the control of thrombocytosis, has been shown to suppress human megakaryopoiesis. We investigated bone marrow biopsies from 12 patients with thrombocytosis due to chronic myeloproliferative disorders. Prior to treatment as well as during rIFN‐alpha‐2c therapy, several morphometric parameters of megakaryopoiesis were evaluated. Megakaryocyte density decreased significantly in all patients, megakaryocyte size decreased in polycythaemia vera, agnogenic myeloid metaplasia, and essential thrombocythaemia, but increased in chronic myeloid leukaemia. The various changes observed during therapy indicate an inhibitory effect of rIFN‐alpha‐2c on megakaryopoiesis and suggest a selective influence on megakaryocytes at various stages of maturation. Increased numbers of pyknotic (bare) nuclei may reflect a shortening of megakaryocyte life‐span. No remarkable changes were found in the fibre content of the bone marrow.
A novel dysfunctional protein C (Protein C Padua 2) associated with a thrombotic tendency: substitution of Cys for Arg‐1 results in a strongly reduced affinity for binding of Ca++
Authors: Girolami A. , Simioni P. , Girolami B. , Marchiori A. , Millar D. S. , Bignell P. , Kakkar V. V. , Cooper D. N.
Published: July 2010

Summary. A dysfunctional protein C (PC) molecule (Protein C Padua 2) was found in a 40‐year‐old man presenting with recurrent deep vein thrombosis/pulmonary embolism and a family history of thrombotic disease. The patient exhibited a normal PC antigen level, normal chromogenic activity (using Protac as PC activator) but markedly reduced coagulometric activity. After adsorption of patient plasma onto AI(OH), between 30% and 45% PC antigen/chromogenic activity but no coagulometric activity was detectable in the supernatant. The dysfunctional molecule exhibited reduced affinity for a Ca++ dependent anti‐protein C monoclonal antibody as detected by specific ELISA assay. Immunoblotting experiments showed that PC Padua 2 had an increased MW (95 kD v 65 kD for normal PC).

The lesion responsible was determined by PCR/direct sequencing to be a heterozygous CGT/TGT transition in exon 3 of the protein C gene resulting in the substitution of Arg by Cys at residue — 1 in the pro‐peptide leader sequence.

The presence of a high MW PC was consistent with the fact that (part of) the propeptide (at least Cys‐1) still was attached to the protein C molecule. This finding could also explain the strongly reduced affinity of PC Padua 2 for the Ca++ dependent anti‐protein C monoclonals.
A point mutation in the protein 4.2 gene (allele 4.2 Tozeur) associated with hereditary haemolytic anaemia
Authors: Hayette S. , Morle L. , Bozon M. , Ghanem A. , Risinger M. , Korsgren C. , Tanner M. J. A. , Fattoum S. , Cohen C. M. , Delaunay J.
Published: July 2010

A recessively transmitted haemolytic anaemia associated with the lack of protein 4 2 was found in a Tunisian kindred. Trace amounts of this protein (72 kD component) became visible using high‐sensitivity Western blots. Band 3 and ankyrin genes were excluded as candidate genes by linkage studies, and nucleotide sequencing of band 3 cytoplasmic domain cDNA revealed no alteration. In contrast, protein 4.2 gene contained in the homozygous state a mutation at position 310: CGA → CAA (Arg → Gln). This mutation defining allele 4.2 Tozeur was co‐inherited with the disease. The mRNA encoding the variant protein was normal in size and approximately normal in amount. Recombinant protein 4.2 Tozeur bound normally to red cell IOVs but disclosed an increased susceptibility to proteolysis in vitro. We infer that the nearly total absence of protein 4.2 in the patients results from imbalance between destruction and synthesis of mutated protein 4.2 prior to its binding to the membrane.