Effective temperature in relaxation of Coulomb glasses

We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.

Circulating tumor cells expressing the insulin growth factor-1 receptor (IGF-1R): Method of detection, incidence and potential applications

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Purpose: To detect IGF-1R on circulating tumor cells (CTCs) as a biomarker in the clinical development of a monoclonal human antibody, CP-751,871, targeting IGF-1R. Experimental Design: An automated sample preparation and analysis system for enumerating CTCs (Celltracks) was adapted for detecting IGF-1R positive CTCs with a diagnostic antibody targeting a different IGF-1R epitope to CP-751,871. This assay was utilized in three phase I trials of CP-751,871 as a single agent or with chemotherapy and was validated using cell lines and blood samples from healthy volunteers and patients with metastatic carcinoma. Results: There was no interference between the analytical and therapeutic antibodies. CP-751,871 was well tolerated as a single agent, and in combination with docetaxel or carboplatin and paclitaxel, at doses ranging from 0.05 mg/kg to 20 mg/kg. Eighty patients were enrolled on phase 1 studies of CP-751,871, with 47 (59%) patients having CTCs detected during the study. Prior to treatment 26 patients (33%) had CTCs, with 23 having detectable IGF-1R positive CTCs. CP-751,871 alone, and CP-751,871 with cytotoxic chemotherapy, decreased CTCs and IGF-1R positive CTCs; these increased towards the end of the 21-day cycle in some patients, falling again with retreatment. CTCs were commonest in advanced hormone refractory prostate cancer (11/20). Detectable IGF-1R expression on CTCs before treatment with CP-751,871 and docetaxel was associated with a higher frequency of PSA decline by more than 50% (6/10 vs 2/8 patients). A relationship was observed between sustained falls in CTCs counts and PSA declines by more than 50%. Conclusions: IGF-1R expression is detectable by immunofluorescence on CTCs. These data support the further evaluation of CTCs in pharmacodynamic studies and patient selection, particularly in advanced prostate cancer.

No significant financial relationships to disclose.

An integrated assessment of options for rural wastewater management in Austria

This paper reports a recently finished, interdisciplinary project on rural wastewater management in Austria. The objective of the project was to study alternative wastewater management options based on separation of the wastewater into its constituent parts, and to compare them with conventional ones. Thereby, a feasibility study of both conventional and alternative options for wastewater management in six model regions was carried out. Life cycle costs and social acceptance were analysed by using a case study-based assessment approach. However, hygienic and environmental risks were evaluated on a more general level. In order to complement the findings, a survey on urine separation system users in the Solar City of Linz was conducted. Based on these assessments and empirical findings, the paper concludes that options using a full separation of all wastewater fractions should be considered with care. Options based on a separation of only grey water and black water or in the liquid/solid phase can offer ecological and financial advantages over conventional options. Further, options combining wastewater management and regional biogas plants were identified as an interesting solution. However, legal constraints restrict this option currently.

Insulin-like growth factor-binding protein-3 inhibition of prostate cancer growth involves suppression of angiogenesis

Insulin-like growth factor-binding protein-3 (IGFBP-3) is a multifunctional protein that induces apoptosis utilizing both insulin-like growth factor receptor (IGF)-dependent and -independent mechanisms. We investigated the effects of IGFBP-3 on tumor growth and angiogenesis utilizing a human CaP xenograft model in severe-combined immunodeficiency mice. A 16-day course of IGFBP-3 injections reduced tumor size and increased apoptosis and also led to a reduction in the number of vessels stained with CD31. In vitro, IGFBP-3 inhibited both vascular endothelial growth factor- and IGF-stimulated human umbilical vein endothelial cells vascular network formation in a matrigel assay. This action is primarily IGF independent as shown by studies utilizing the non-IGFBP-binding IGF-1 analog Long-R3. Additionally, we used a fibroblast growth factor-enriched matrigel-plug assay and chick allantoic membrane assays to show that IGFBP-3 has potent antiangiogenic actions in vivo. Finally, overexpression of IGFBP-3 or the non-IGF-binding GGG-IGFBP-3 mutant in Zebrafish embryos confirmed that both IGFBP-3 and the non-IGF-binding mutant inhibited vessel formation in vivo, indicating that the antiangiogenic effect of IGFBP-3 is an IGF-independent phenomenon. Together, these studies provide the first evidence that IGFBP-3 has direct, IGF-independent inhibitory effects on angiogenesis providing an additional mechanism by which it exerts its tumor suppressive effects and further supporting its development for clinical use in the therapy of patients with prostate cancer.

Randomized phase II study of two doses of gefitinib in hormone-refractory prostate cancer: a trial of the National Cancer Institute of Canada-Clinical Trials Group

PURPOSE

Overexpression of the epidermal growth factor receptor has been demonstrated in advanced prostate cancer and is associated with a poor outcome. A multi-institutional, randomized, phase II study was undertaken by the National Cancer Institute of Canada-Clinical Trials Group to evaluate the efficacy and toxicity of two doses of oral gefitinib in patients with minimally symptomatic, hormone-refractory prostate cancer (HRPC).

PATIENTS AND METHODS

Between July and November 2001, 40 patients with HRPC and increasing prostate-specific antigen (PSA) or progression in measurable disease who had not received prior chemotherapy were randomly assigned to 250 mg (n = 19) or 500 mg (n = 21) oral gefitinib daily continuously. The primary end points were PSA response rate and objective measurable response. Functional Assessment of Cancer Therapy Prostate Cancer Subscale (FACT-P) quality-of-life questionnaires were completed at baseline and during treatment.

RESULTS

None of the patients demonstrated a PSA or objective measurable response. Five (14.3%) of 35 assessable patients had stable PSA (one patient at 250 mg and four patients at 500 mg), and five patients (14.3%) had a best response of stable disease (duration, 2.5 to 16.8 months). No significant effect on the rate of increase in PSA was seen. The most common drug-related nonhematologic toxicities observed were grade 1 to 2 diarrhea (250 mg, 65%; 500 mg, 56%), fatigue (250 mg, 29%; 500 mg, 33%), and grade 1 to 2 skin rash (250 mg, 24%; 500 mg, 39%). FACT-P scores decreased during treatment, indicating worsening of symptoms compared with baseline.

CONCLUSION

Gefitinib did not result in any responses in PSA or objective measurable disease at either dose level. Gefitinib has minimal single-agent activity in HRPC.

Co-targeting IGF-1R and c-kit: synergistic inhibition of proliferation and induction of apoptosis in H 209 small cell lung cancer cells

Most small cell lung cancers (SCLC) coexpress the c-kit protein tyrosine receptor kinase and its ligand stem cell factor, resulting in an autocrine loop. As SCLC growth is also driven by insulin-like growth factor-1 receptor (IGF-1R) signalling, tyrphostins AG 1024 and 1296 (inhibitors of IGF-1R and c-kit activity, respectively) were used to co-target these receptors in H 209 SCLC cells. Combination treatment caused synergy in proliferation inhibition and in apoptosis induction, and also enhanced reduction in phosphorylation of Erk1/Erk2, suggesting that co-targeting IGF-1R and c-kit in SCLC may be more effective than single-agent therapies.