Classification of large circulating tumor cells isolated with ultra-high throughput microfluidic Vortex technology.

Circulating tumor cells (CTCs) are emerging as rare but clinically significant non-invasive cellular biomarkers for cancer patient prognosis, treatment selection, and treatment monitoring. Current CTC isolation approaches, such as immunoaffinity, filtration, or size-based techniques, are often limited by throughput, purity, large output volumes, or inability to obtain viable cells for downstream analysis. For all technologies, traditional immunofluorescent staining alone has been employed to distinguish and confirm the presence of isolated CTCs among contaminating blood cells, although cells isolated by size may express vastly different phenotypes. Consequently, CTC definitions have been non-trivial, researcher-dependent, and evolving. Here we describe a complete set of objective criteria, leveraging well-established cytomorphological features of malignancy, by which we identify large CTCs. We apply the criteria to CTCs enriched from stage IV lung and breast cancer patient blood samples using the High Throughput Vortex Chip (Vortex HT), an improved microfluidic technology for the label-free, size-based enrichment and concentration of rare cells. We achieve improved capture efficiency (up to 83%), high speed of processing (8 mL/min of 10x diluted blood, or 800 μL/min of whole blood), and high purity (avg. background of 28.8±23.6 white blood cells per mL of whole blood). We show markedly improved performance of CTC capture (84% positive test rate) in comparison to previous Vortex designs and the current FDA-approved gold standard CellSearch assay. The results demonstrate the ability to quickly collect viable and pure populations of abnormal large circulating cells unbiased by molecular characteristics, which helps uncover further heterogeneity in these cells

Studies on the performance of a rocket propelled orbiting missile

NOTE: Text of symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. This report is a study of the performance requirements necessary to launch a rocket propelled missile into a circular orbit about the earth. Various trajectories by which a missile can be launched into such an orbit are investigated and an estimation is made of the minimum propellant-gross weight ratio required to reach stable orbital conditions at various altitudes. The velocity of a projectile traveling about the earth in a circular orbit must be such that its weight is exactly balanced by the centrifugal force acting upon it. The expression for the required velocity, relative to a non-rotating earth, can be derived from the following figure. [...]. By the law of Conservation of Energy, such an orbit, once obtained, must remain circular unless influenced by additional forces. The action of atmospheric drag would be to cause a continual loss of energy; this loss would be made up at the expense of potential energy, causing the projectile to move in toward the earth in a contracting spiral. It can be shown (of. ref. 2) that, for altitudes greater than one hundred and twenty miles, the rate of this contraction is negligible. The practical applications of an orbiting missile are numerous. A few are as follows: a) A radio relay station for television and other high frequency communication. b) To carry instruments for continuous measurement of upper atmospheric phenomena. c) A military weapon of unlimited range, provided it can be brought back to earth at will. The possibility of launching a vehicle into a circular orbit by means of rocket propulsion depends primarily upon the conditions of propellant consumption which are required to reach a stable orbital velocity. These conditions are: a) Propellant characteristics (in particular, specific impulse). b) Rate of propellant consumption. c) Propellant-gross weight ratio. The velocity necessary for a circular orbit is in the neighborhood of 26,000 ft/sec. For an unboosted rocket with an uniform burning rate the terminal velocity (neglecting drag and gravity forces) is given by [...] where [...] is assumed constant. If we take [...] to be equal to 400 sec., a representative value for a rocket fuel consisting of oxygen and hydrogen, the value of [...], the propellant-gross weight ratio, corresponding to [...] =26,000 ft/sec., is [...]=. 0.867. Thus, even with the most powerful rocket fuel, the required propellant gross weight ratio is very high, and the importance of a more careful estimation of this ratio is evident. A comprehensive analysis of the important factors which influence the performance of an orbiting rocket has been made by W. Z. Chien of GALCIT. In this analysis, Dr. Chien considered a vertical trajectory as a first approximation in obtaining estimates of the altitude of the circular orbit and of the propellant-gross weight ratio required (cf. ref. 2). This report extends the considerations of Chien's work to oblique trajectories of various types, all of which terminate at the end of burning with the proper velocity conditions for a circular orbit. The first part of the report is a recapitulation of Chien's analysis. The second part deals with the characteristics of various oblique trajectories by which a rocket may be launched directly into a circular orbit; and the third part analyses a procedure whereby the rocket is launched into an elliptical orbit near its perihelion, is allowed to travel as a free body around the earth to the aphelion of the ellipse and then, by an additional boost of velocity, is projected into a circular orbit

Gene-environment interactions: Neurodegeneration in non-mammals and mammals

El pdf del artículo es el manuscrito de autor: PMCID:PMC2912949.-- et al.The understanding of how environmental exposures interact with genetics in central nervous system dysfunction has gained great momentum in the last decade. Seminal findings have been uncovered in both mammalian and non-mammalian model in large result of the extraordinary conservation of both genetic elements and differentiation processes between mammals and non-mammalians. Emerging model organisms, such as the nematode and zebrafish have made it possible to assess the effects of small molecules rapidly, inexpensively, and on a miniaturized scale. By combining the scale and throughput of in vitro screens with the physiological complexity and traditional animal studies, these models are providing relevant information on molecular events in the etiology of neurodegenerative disorders. The utility of these models is largely driven by the functional conservation seen between them and higher organisms, including humans so that knowledge obtained using non-mammalian model systems can often provide a better understanding of equivalent processes, pathways, and mechanisms in man. Understanding the molecular events that trigger neurodegeneration has also greatly relied upon the use of tissue culture models. The purpose of this summary is to provide-state-of-the-art review of recent developments of non-mammalian experimental models and their utility in addressing issues pertinent to neurotoxicity (Caenorhabditis elegans and Danio rerio). The synopses by Aschner and Levin summarize how genetic mutants of these species can be used to complement the understanding of molecular and cellular mechanisms associated with neurobehavioral toxicity and neurodegeneration. Next, studies by Suñol and Olopade detail the predictive value of cultures in assessing neurotoxicity. Suñol and colleagues summarize present novel information strategies based on in vitro toxicity assays that are predictive of cellular effects that can be extrapolated to effects on individuals. Olopade and colleagues describe cellular changes caused by sodium metavanadate (SMV) and demonstrate how rat primary astrocyte cultures can be used as predicitive tools to assess the neuroprotective effects of antidotes on vanadium-induced astrogliosis and demyelination. © 2010 Elsevier Inc.This review was supported in part by PHS grant NIEHS R01 ES10563 and ES07331 (MA), the Duke University Superfund Basic Research Center NIEHS ES010356 (EDL). Partial support was also provided by IBRO Research Fellowship (JOO).Peer Reviewe

Textbook of rheumatology

XXVIII+1904hlm.;27c

Effects of HIV Protease Inhibitor Ritonavir on Akt-Regulated Cell Proliferation in Breast Cancer

Purpose These studies were designed to determine whether ritonavir inhibits breast cancer in vitro and in vitro and, if so, how. Experimental Design Ritonavir effects on breast cancer cell growth were studied in the estrogen receptor (ER)-positive lines MCF7 and T47D and in the ER-negative lines MDA-MB-436 and MDA-MB-231. Effects of ritonavir on Rb-regulated and Akt-mediated cell proliferation were studied. Ritonavir was tested for inhibition of a mammary carcinoma xenograft. Results ER-positive estradiol-dependent lines (IC50, 12–24 µmol/L) and ER-negative (IC50, 45 µmol/L) lines exhibit ritonavir sensitivity. Ritonavir depletes ER-α levels notably in ER-positive lines. Ritonavir causes G1 arrest, depletes cyclin-dependent kinases 2, 4, and 6 and cyclin D1 but not cyclin E, and depletes phosphorylated Rb and Ser473 Akt. Ritonavir induces apoptosis independent of G1 arrest, inhibiting growth of cells that have passed the G1 checkpoint. Myristoyl-Akt, but not activated K-Ras, rescues ritonavir inhibition. Ritonavir inhibited a MDA-MB-231 xenograft and intratumoral Akt activity at a clinically attainable serum Cmax of 22 ± 8 µmol/L. Because heat shock protein 90 (Hsp90) substrates are depleted by ritonavir, ritonavir effects on Hsp90 were tested. Ritonavir binds Hsp90 (KD, 7.8 µmol/L) and partially inhibits its chaperone function. Ritonavir blocks association of Hsp90 with Akt and, with sustained exposure, notably depletes Hsp90. Stably expressed Hsp90α short hairpin RNA also depletes Hsp90, inhibiting proliferation and sensitizing breast cancer cells to low ritonavir concentrations. Conclusions Ritonavir inhibits breast cancer growth in part by inhibiting Hsp90 substrates, including Akt. Ritonavir may be of interest for breast cancer therapeutics and its efficacy may be increased by sustained exposure or Hsp90 RNA interference