Many-body Theory vs Simulations for the pseudogap in the Hubbard model

The opening of a critical-fluctuation induced pseudogap (or precursor pseudogap) in the one-particle spectral weight of the half-filled two-dimensional Hubbard model is discussed. This pseudogap, appearing in our Monte Carlo simulations, may be obtained from many-body techniques that use Green functions and vertex corrections that are at the same level of approximation. Self-consistent theories of the Eliashberg type (such as the Fluctuation Exchange Approximation) use renormalized Green functions and bare vertices in a context where there is no Migdal theorem. They do not find the pseudogap, in quantitative and qualitative disagreement with simulations, suggesting these methods are inadequate for this problem. Differences between precursor pseudogaps and strong-coupling pseudogaps are also discussed.Comment: Accepted, Phys. Rev. B15 15Mar00. Expanded version of original submission, Latex, 8 pages, epsfig, 5 eps figures (Last one new). Discussion on fluctuation and strong coupling induced pseudogaps expande

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Prevention of Radiation-enhancement Dermatitis and Breast Cancer Cell Invasion by an Anti-Inflammatory Agent

For women with early stage breast cancer, the primary tumour is removed by conservative surgery. However, malignant microfoci are often scattered in the breast. To eliminate these cells radiotherapy is designed to irradiate the whole breast. But the dose is not calculated to eliminate all residual cancer cells but rather to optimize long-term results with minimal complications to normal tissues such as fibrosis. These complications are mainly caused by the induction of an inflammation, associated with the upregulation of the cyclooxygenase-2 (COX-2). Furthermore the inhibition of COX-2 decreases matrix metalloproteinases (MMPs) expression, such as MMP-2 and MMP-9, both playing a central role in breast cancer cell invasion. The aim of this study is to further improve radiotherapy of breast cancer by preventing radiation-enhancement dermatitis and breast cancer cell invasion with the administration of NS-398, a COX-2 specific inhibitor. Female Balb/c mice were irradiated on a healthy thigh followed by the s.c. injection of MC7-L1 mammary cancer cells. NS-398 was injected i.p. before and after irradiation. Controls without irradiation and without cancer cells were also performed. For 3 and 6 weeks the degree of skin inflammation was scored and cancer cell invasion was monitored by contrast-enhanced magnetic resonance imaging. Tumors and surrounding tissues were subsequently removed and processed for histological analysis and zymography. We have shown that radiation actually enhances the invasiveness of breast cancer cells. MC7-L1 cells grown mainly under the skin in non irradiated thighs but invaded into the muscle fibers in irradiated thighs. These patterns were distinct 4 weeks after irradiation, but more pronounced on the 6th week. The calculated apparent invasion tumor volume was significantly greater in irradiated thighs. The activity of MMP-2 and -9 were enhanced in muscle and skin after irradiation. Our preliminary results with the COX-2 inhibitor NS-398 demonstrated an improvement of skin tolerance and a decrease of the invasion marker MMP-2 in the irradiated area. The NS-398 seemed also to reduce cancer cells proliferation and invasion. Our promising preliminary data showed that the NS-398, a specific COX-2 inhibitor, might improve the efficacy of radiotherapy for breast cancer by preventing radiation-induced dermatitis and radiation-enhancement of cancer cell invasion

Elevated concentration and biologic activity of monocyte chemotactic protein-1 levels in the peritoneal fluid of patients with endometriosis

ObjectiveTo estimate the concentration and the biologic activity of monocyte chemotactic protein-1 (MCP-1) in the peritoneal fluid (PF) of women with and without endometriosis.DesignA case control study was conducted.SettingGynecology clinic and Laboratories of endocrinology of reproduction and immunology.PatientsWomen presenting for infertility, pelvic pain, or tubal ligation in which endometriosis was diagnosed at laparoscopy (n = 36) and normal fertile controls presenting for tubal ligation (n = 21).InterventionsCollection of PF via laparoscopy.Main outcome measuresDetermination of PF concentrations of MCP-1 by an ELISA and evaluation of its monocyte chemotactic activity using a human hystiocytic cell line (U937). RESULTS. The concentration of MCP-1 (median, range of values) was increased in the PF of endometriosis patients (283, 0 to 1,930 pg/mL; conversion factor to SI unit, 0.155) compared with the control group (140, 0 to 435 pg/mL). The most significant elevation of MCP-1 levels was found in the stage II of the disease (371, 200 to 1,930 pg/mL). An increased chemotactic activity for monocytes (mean number of migrating cells/mm2 +/- SD) also was found in stages I (1,460 +/- 312) and II (1,541 +/- 336) of the disease when compared with fertile controls (393 +/- 56). Forty percent to 53% of this activity was inhibited in the presence of an antibody specific to MCP-1.ConclusionsThese observations are consistent with previous data indicating increased leukocyte chemotaxis in the PF of patients with endometriosis and suggest that MCP-1 may play a relevant role in the peritoneal inflammatory reaction associated with the disease

High-level heterologous expression and secretion in Streptomyces lividans of two major antigenic proteins from Mycobacterium tuberculosis.: Can.J.Microbiol.

NRC publication: Ye