Singlet-triplet dispersion reveals additional frustration in the triangular-lattice dimer compound Ba3Mn2O8

We present single crystal inelastic neutron scattering measurements of the S=1 dimerized quasi-two-dimensional antiferromagnet Ba(3)Mn(2)O(8). The singlet-triplet dispersion reveals nearest-neighbor and next-nearest-neighbor ferromagnetic interactions between adjacent bilayers that compete against each other. Although the interbilayer exchange is comparable to the intrabilayer exchange, this additional frustration reduces the effective coupling along the c axis and leads to a quasi-two-dimensional behavior. In addition, the obtained exchange values are able to reproduce the four critical fields in the phase diagram.

Evaluation of a classroom-based physical activity promoting programme

The purpose of the present study was to evaluate the effect of the Happy 10 programme on the promotion of physical activity, physical growth and development of primary school students, and on obesity control and prevention. Two similar primary schools from one district of Beijing, China were selected, one as an intervention school and the other as a control school. A Happy 10 programme was implemented at least once every school day in the intervention school for two semesters, whereas no intervention was adopted in the control school. The information on energy expenditure and duration of physical activity was collected by a validated 7-day physical activity questionnaire. Height and weight were measured by the trained investigators following standardized procedure. Energy expenditure and intensity of each Happy 10 session were measured by a physical activity monitor. The average energy expenditure and duration of total physical activity per day among students in the intervention school increased significantly from 15.0 to 18.2 kcal kg(-1) and 2.8 to 3.3 h, respectively, whereas the figures significantly decreased in the control school. There was a significant difference in change of weight and body mass index between girls in the intervention and control school (2.4 kg vs. 4.6 kg; 0.47 kg m(-2) vs. 0.66 kg m(-2)). The prevalence of overweight and obesity in the intervention school decreased by 0.4-5.6%, as compared with the increase by 0.6-4.5% in the control school. The average energy expenditure and intensity per 10-min session ranged from 25.0 to 35.1 kcal and from 4.8 to 6.2 kcal kg(-1) h(-1), respectively, in grades 1-5. The Happy 10 programme provides a useful strategy to promote physical activity among school children, and also plays a positive role in building up physical growth and development of girls.

Adenovirus-mediated heme oxygenase transfer inhibits graft arteriosclerosis in rat aortic transplants

PURPOSE

Heme oxygenase-1 (HO-1) has been implicated in graft protection because its induction is associated with long-surviving allografts. The aim of this study was to analyze the efficacy of adenovirus-mediated HO-1 overexpression to inhibit graft arteriosclerosis and estimate whether the protective role correlated with nuclear factor kappaB (NF=kappaB) expression and grafts apoptosis.

METHODS

Aortic transplantation was performed using inbred Brown-Norway (BN) rats (RT1n male) as donors and Lewis rats (RT1l male) as recipients. The experiments were divided into four groups: group A, Lewis-Lewis (n=6), no treatment; group B, BN-Lewis (n=6), no treatment; group C, BN-Lewis (n=6), donor aorta perfused with buffer containing 4x10(10) pfu Ad-Null (the noncoding adenoviral vector); and group D, BN-Lewis (n=6), donor aorta perfused with buffer containing 4x10(10) pfu Ad-HO-1 (adenoviral vector coding for HO-1). All grafts were harvested at 60 days after transplantation. Reverse transcriptase polymerase chain reaction was performed to detect the expression of HO-1 gene. Hematoxylin and eosin staining was used to detect the morphology and cytology of the transplanted vessels. Intimal thickening was detected by Masson staining. Immunohistochemistry was used to detect the localization and expression of HO-1 and NF-kappaB and TUNEL assays to detect the apoptosis of the grafts.

RESULTS

Gene transfer of HO-1 grafts using an adenoviral vector resulted in the expression of HO-1 protein in endothelium and adventitia. We observed that the intimal thickness in Ad-HO-1-treated aortas (11.11+/-0.92 microm) was significantly thinner compared with untreated (85.20+/-6.90 microm) or Ad-null treated (87.20+/-6.20 microm) aortas (P<.01). Immunohistology showed that treatment with Ad-HO-1 resulted in a significant reduction in leukocyte infiltration and a decreased number of vascular smooth muscle cells in the intima, compared with Ad-null-treated aortas. The levels of NF-kappaB and the number of apoptotic cells in Ad-HO-1-treated aortas showed significantly lower compared with Ad-null-treated arotas (P<.05).

CONCLUSION

HO-1 prevented the development of graft arteriosclerosis in the rat aortic transplant model. The protective role of HO-1 in chronic rejection lesions seemed to correlate with downregulation of the expression of NF-kappaB and inhibition of apoptosis in the grafts.

Heme oxygenase-1 protects INF-gamma primed endothelial cells from Jurkat T-cell adhesion

PURPOSE

The heme oxygenase-1 (HO-1) system is associated with the rate-limiting step of conversion of heme, one of the most critical roles in cytoprotective mechanisms. Our study investigated its potential role in protection of endothelial cells from T cells.

METHODS

The recombinant plasmid pcDNA3-HO-1 was transfected into endothelial cells. Indirect fluorescent staining was used to examine the expression of HO-1 protein. Then endothelial cells primed by INF-gamma were mixed in culture with Jurkat T cells labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE). The number of adhesive Jurkat T cells was determined using FACS to evaluate the adhesion effect. After being cultured with endothelial cells, the cell cycle of Jurkat T cells was detected using FACS.

RESULTS

Expression of HO-1 on endothelial cells conferred significant protection against Jurkat T-cell-mediated adhesion. The rate of Jurkat T-cell adhesions was reduced to 19.06%, in contrast with 31.42% in the control group (P<.05). After using ZnPP, an inhibitor of HO-1, the rate of Jurkat T-cell adhesion recovered to 29.08%. The binding activities between endothelial cells and Jurkat T cells was blocked by HO-1 expression. The proliferation of Jurkat T cells was inhibited after culture with endothelial cells, which had been transfected with HO-1, which blocked cell cycle entry of T cells. More than 60% of Jurkat T cells remained in G0/G1 compared with 40% among the control group.

CONCLUSION

HO-1 directly protected endothelial cells primed by INF-gamma from Jurkat T cells and down-regulated the expression of HLA-DR on the surface of endothelial cells. These results indicated that transgenic expression of HO-1 may be useful to prevent lymphocytes from responding to endothelial cells.

Zener double exchange from local valence fluctuations in magnetite

Magnetite (Fe3O4) is a mixed valent system where electronic conductivity occurs on the B site (octahedral) iron sublattice of the spinel structure. Below T(V)=123 K, a metal-insulator transition occurs which is argued to arise from the charge ordering of 2+ and 3+ iron valences on the B sites (Verwey transition). Inelastic neutron scattering measurements show that optical spin waves propagating on the B site sublattice (approximately 80 meV) are shifted upwards in energy above T_{V} due to the occurrence of B-B ferromagnetic double exchange in the mixed valent phase. The double exchange interaction affects only spin waves of Delta(5) symmetry, not all modes, indicating that valence fluctuations are slow and the double exchange is constrained by short-range electron correlations above T(V).

Orbital fluctuations and orbital flipping in RVO3 perovskites

The effect of the average R-site ionic radius IR and variance on the orbital and magnetic order in R3+-doped YVO3 was studied in Y1-xLaxVO3 and Y1-x(La0.2337Lu0.7663)xVO3 with fixed IR. The orbital flipping temperature T{CG} increases nonlinearly with increasing R-site variance, indicating that the V-O-V bond angle is not the primary driving force stabilizing the C-type orbitally ordered phase. The suppressed thermal conductivity in the G-type orbitally ordered phase signals some remaining orbital randomness that is enhanced by t{2} and et hybridization in {3}T{1g} site symmetry.

Damping of antiferromagnetic spin waves by valence fluctuations in the double layer perovskite YBaFe2O5

Inelastic neutron scattering experiments show that spin dynamics in the charge-ordered insulating ground state of the double layer perovskite YBaFe(2)O(5) is well described in terms of e(g) superexchange interactions. Above the Verwey transition at T(V)=308 K, t(2g) double exchange-type conduction proceeds within antiferromagnetic FeO(2)-BaO-FeO(2) double layers by an electron hopping process that requires a spin flip of the five-coordinated Fe ions, costing an energy of 5<J>S(2) approximately 0.1 eV. The hopping process disrupts near-neighbor spin correlations, leading to massive damping of zone-boundary spin waves.

Phase I/II study of enzastaurin plus temozolomide during and following radiation therapy in patients with newly diagnosed glioblastoma multiforme (GBM) or gliosarcoma

12511

Background: Enzastaurin is a potent, selective, oral serine/threonine kinase inhibitor of PKCβ, an enzyme activated by vascular endothelial growth factor (VEGF). VEGF is upregulated in most cases of GBM, producing significant angiogenesis. This study combines the anti-angiogenic properties of enzastaurin with the current standard treatment of radiation therapy (RT) and cytotoxic chemotherapy (temozolomide; TMZ). Methods: A Phase 1/2 study of enzastaurin with TMZ during and following RT is ongoing in patients with newly diagnosed GBM. Two doses of enzastaurin will be evaluated during Phase 1. The first 6 patients will received 250 mg of enzastaurin daily. If no more than one patient experiences a dose-limiting toxicity (DLT) during RT and the first adjuvant cycle, an additional 6 patients will receive an escalated dose of 500 mg daily. The dose established in Phase 1 will be administered to 60 patients in Phase 2. The primary objective of Phase 2 is to determine the efficacy of enzastaurin as measured by overall survival. Multiple pharmacokinetic (PK) and pharmacodynamic (PD) endpoints will be evaluated using perfusion imaging and plasma biomarkers. Relevant growth factors and pathways will be analyzed in primary tumor tissue from each patient. Results: Since September 06, 6 patients have completed RT with concurrent enzastaurin (250 mg) and TMZ. None of these patients has experienced a DLT to date. It is expected that an additional 6 patients will be enrolled in January 07 and Phase 2 will start in May 2007. Conclusions: Enzastaurin with concurrent RT and TMZ appears safe. Final Phase 1 safety results and preliminary PK and PD data will be presented.

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