Analysis of Adverse Events in Drug Safety: A Multivariate Approach Using Stratified Quasi-least Squares

Safety assessment in drug development involves numerous statistical challenges, and yet statistical methodologies and their applications to safety data have not been fully developed, despite a recent increase of interest in this area. In practice, a conventional univariate approach for analysis of safety data involves application of the Fisher\u27s exact test to compare the proportion of subjects who experience adverse events (AEs) between treatment groups; This approach ignores several common features of safety data, including the presence of multiple endpoints, longitudinal follow-up, and a possible relationship between the AEs within body systems. In this article, we propose various regression modeling strategies to model multiple longitudinal AEs that are biologically classified into different body systems via the stratified quasi-least squares (SQLS) method. We then analyze safety data from a clinical drug development program at Wyeth Research that compared an experimental drug with a standard treatment using SQLS, which could be a superior alternative to application of the Fisher\u27s exact test

精神看護実習における構造判別図作成に対する学生の評価

本研究では，精神看護実習で用いた「構造判別図自己評価表」および「実習自己評価表」について，統計的に記述し，実習指導における示唆を得ることを目的とした．記述統計量を検討した結果，学生は構造判別図を用いることにより，対象者の【過去】【現在】の状態理解と対象者の問題・強みの【把握】が進み，根拠を捉えた【思考】能力を実感し，看護現象診断の候補の【立案】へつなげていることが考えられた．また実習の自己評価【自評】と中程度の相関が認められた2 項目（【未来】【投影】）において，学生の自己評価が低かったことから，【未来】の情報の展開を強化すること，対象者に対する自分自身のありようをうまく【投影】できるように，指導者を交えて探求し，自己理解を促すことという精神看護実習指導上の課題が示唆された

Curved Tails in Polymerization-Based Bacterial Motility

The curved actin ``comet-tail'' of the bacterium Listeria monocytogenes is a visually striking signature of actin polymerization-based motility. Similar actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae, the Vaccinia virus, and vesicles and microspheres in related in vitro systems. We show that the torque required to produce the curvature in the tail can arise from randomly placed actin filaments pushing the bacterium or particle. We find that the curvature magnitude determines the number of actively pushing filaments, independent of viscosity and of the molecular details of force generation. The variation of the curvature with time can be used to infer the dynamics of actin filaments at the bacterial surface.Comment: 8 pages, 2 figures, Latex2

In silico evolution of diauxic growth

The glucose effect is a well known phenomenon whereby cells, when presented with two different nutrients, show a diauxic growth pattern, i.e. an episode of exponential growth followed by a lag phase of reduced growth followed by a second phase of exponential growth. Diauxic growth is usually thought of as a an adaptation to maximise biomass production in an environment offering two or more carbon sources. While diauxic growth has been studied widely both experimentally and theoretically, the hypothesis that diauxic growth is a strategy to increase overall growth has remained an unconfirmed conjecture. Here, we present a minimal mathematical model of a bacterial nutrient uptake system and metabolism. We subject this model to artificial evolution to test under which conditions diauxic growth evolves. As a result, we find that, indeed, sequential uptake of nutrients emerges if there is competition for nutrients and the metabolism/uptake system is capacity limited. However, we also find that diauxic growth is a secondary effect of this system and that the speed-up of nutrient uptake is a much larger effect. Notably, this speed-up of nutrient uptake coincides with an overall reduction of efficiency. Our two main conclusions are: (i) Cells competing for the same nutrients evolve rapid but inefficient growth dynamics. (ii) In the deterministic models we use here no substantial lag-phase evolves. This suggests that the lag-phase is a consequence of stochastic gene expression

The formin FHOD1 and the small GTPase Rac1 promote vaccinia virus actin-based motility

Vaccinia virus dissemination relies on the N-WASP– ARP2/3 pathway, which mediates actin tail formation underneath cell-associated extracellular viruses (CEVs). Here, we uncover a previously unappreciated role for the formin FHOD1 and the small GTPase Rac1 in vaccinia actin tail formation. FHOD1 depletion decreased the number of CEVs forming actin tails and impaired the elongation rate of the formed actin tails. Recruitment of FHOD1 to actin tails relied on its GTPase binding domain in addition to its FH2 domain. In agreement with previous studies showing that FHOD1 is activated by the small GTPase Rac1, Rac1 was enriched and activated at the membrane surrounding actin tails. Rac1 depletion or expression of dominant-negative Rac1 phenocopied the effects of FHOD1 depletion and impaired the recruitment of FHOD1 to actin tails. FHOD1 overexpression rescued the actin tail formation defects observed in cells overexpressing dominant-negative Rac1. Altogether, our results indicate that, to display robust actin-based motility, vaccinia virus integrates the activity of the N-WASP– ARP2/3 and Rac1–FHOD1 pathways.Fil: Alvarez, Diego Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Yale. School of Medicine; Estados UnidosFil: Agaisse, Herve. University of Yale. School of Medicine; Estados Unido

A Phase II Study of Cetuximab (Erbitux®) plus FOLFIRI for Irinotecan and Oxaliplatin-refractory Metastatic Colorectal Cancer

We have evaluated the efficacy and safety of cetuximab plus FOLFIRI for irinotecan and oxaliplatin-refractory colorectal cancers. From September 2004 to February 2006, 31 patients with metastatic colorectal cancer were treated with cetuximab (400 mg/m2 intravenously [IV] over 2 hr on day 1 followed by weekly 1-hr infusions of 250 mg/m2) plus bi-weekly FOLFIRI (irinotecan 150 mg/m2 IV over 90 min, and leucovorin 100 mg/m2 IV over 2 hr, followed by 5-FU 400 mg/m2 IV bolus on day 1, and followed by 5-FU 2,400 mg/m2 by continuous IV over 46 hrs). Patients received a median of four cycles (range: 1-23). Eight (25.8%) patients had confirmed partial responses and 10 (32.2%) had stable disease. After a median follow-up of 13.2 months for surviving patients, the median time to progression was 2.9 months, the median duration of response was 5.4 months, and the median overall survival was 10.9 months. Skin toxicity was observed in 25 patients (80.4%) including grade 3 in 6 patients (19.4%). Other common non-hematologic toxicities of all grades were mucositis (32.3%), asthenia (22.6%), diarrhea (12.9%), and paronychial cracking (12.9%). The combination of cetuximab with FOLFIRI was effective and tolerable in colorectal cancer patients heavily pretreated with a number of chemotherapy regimens

Long-Term Survivors of Metastatic Colorectal Cancer Treated with Systemic Chemotherapy Alone: A North Central Cancer Treatment Group Review of 3811 Patients, N0144

Although systemic chemotherapy in patients with unresectable metastatic colorectal cancer (mCRC) is palliative in nature, some patients experience long-term remission beyond 5 years consequent to treatment with chemotherapy alone

Treatment of Colorectal Peritoneal Carcinomatosis With Systemic Chemotherapy: A Pooled Analysis of North Central Cancer Treatment Group Phase III Trials N9741 and N9841

Symptoms and complications of metastatic colorectal cancer (mCRC) differ by metastatic sites. There is a paucity of prospective survival data for patients with peritoneal carcinomatosis colorectal cancer (pcCRC). We characterized outcomes of patients with pcCRC enrolled onto two prospective randomized trials of chemotherapy and contrasted that with other manifestations of mCRC (non-pcCRC)