43055872
Modeling T Cell Proliferation and Death in Vitro Based on Labeling Data: Generalizations of the Smith–Martin Cell Cycle Model
Abstract
The fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE) classifies proliferating cell populations into groups according to the number of divisions each cell has undergone (i.e., its division class). The pulse labeling of cells with radioactive thymidine provides a means to determine the distribution of times of entry into the first cell division. We derive in analytic form the number of cells in each division class as a function of time based on the distribution of times to the first division. Choosing the distribution of time to the first division to fit thymidine labeling data for T cells stimulated in vitro under different concentrations of IL-2, we fit CFSE data to determine the dependence of T cell kinetic parameters on the concentration of IL-2. As the concentration of IL-2 increases, the average cell cycle time is shortened, the death rate of cells is decreased, and a higher fraction of cells is recruited into division. We also find that if the average cell cycle time increases with division class then the qualify of our fit to the data improves.

25911131
Modeling sequence evolution in acute HIV-1 infection.
We describe a mathematical model and Monte Carlo (MC) simulation of viral evolution during acute infection. We consider both synchronous and asynchronous processes of viral infection of new target cells. The model enables an assessment of the expected sequence diversity in new HIV-1 infections originating from a single transmitted viral strain, estimation of the most recent common ancestor (MRCA) of the transmitted viral lineage, and estimation of the time to coalesce back to the MRCA. We also calculate the probability of the MRCA being the transmitted virus or an evolved variant. Excluding insertions and deletions, we assume HIV-1 evolves by base substitution without selection pressure during the earliest phase of HIV-1 infection prior to the immune response. Unlike phylogenetic methods that follow a lineage backwards to coalescence, we compare the observed data to a model of the diversification of a viral population forward in time. To illustrate the application of these methods, we provide detailed comparisons of the model and simulations results to 306 envelope sequences obtained from eight newly infected subjects at a single time point. The data from 68 patients were in good agreement with model predictions, and hence compatible with a single-strain infection evolving under no selection pressure. The diversity of the samples from the other two patients was too great to be explained by the model, suggesting multiple HIV-1-strains were transmitted. The model can also be applied to longitudinal patient data to estimate within-host viral evolutionary parameters.
3798043
Simulation and prediction of the adaptive immune response to influenza A virus infection.
The cellular immune response to primary influenza virus infection is complex, involving multiple cell types and anatomical compartments, and is difficult to measure directly. Here we develop a two-compartment model that quantifies the interplay between viral replication and adaptive immunity. The fidelity of the model is demonstrated by accurately confirming the role of CD4 help for antibody persistence and the consequences of immune depletion experiments. The model predicts that drugs to limit viral infection and/or production must be administered within 2 days of infection, with a benefit of combination therapy when administered early, and cytotoxic CD8 T cells in the lung are as effective for viral clearance as neutralizing antibodies when present at the time of challenge. The model can be used to investigate explicit biological scenarios and generate experimentally testable hypotheses. For example, when the adaptive response depends on cellular immune cell priming, regulation of antigen presentation has greater influence on the kinetics of viral clearance than the efficiency of virus neutralization or cellular cytotoxicity. These findings suggest that the modulation of antigen presentation or the number of lung resident cytotoxic cells and the combination drug intervention are strategies to combat highly virulent influenza viruses. We further compared alternative model structures, for example, B-cell activation directly by the virus versus that through professional antigen-presenting cells or dendritic cell licensing of CD8 T cells.
13786750
Interpreting CFSE Obtained Division Histories of B Cells in Vitro with Smith–Martin and Cyton Type Models
The fluorescent dye carboxyfluorescin diacetate succinimidyl ester (CFSE) classifies proliferating cell populations into groups according to the number of divisions each cell has undergone (i.e., its division class). The pulse labeling of cells with radioactive thymidine provides a means to determine the distribution of times of entry into the first cell division. We derive in analytic form the number of cells in each division class as a function of time using the cyton approach that utilizes independent stochastic distributions for the time to divide and the time to die. We confirm that our analytic form for the number of cells in each division class is consistent with the numerical solution of a set of delay differential equations representing the generalized Smith–Martin model with cell death rates depending on the division class. Choosing the distribution of time to the first division to fit thymidine labeling data for B cells stimulated in vitro with lipopolysaccharide (LPS) and either with or without interleukin-4 (IL-4), we fit CFSE data to determine the dependence of B cell kinetic parameters on the presence of IL-4. We find when IL-4 is present, a greater proportion of cells are recruited into division with a longer average time to first division. The most profound effect of the presence of IL-4 was decreased death rates for smaller division classes, which supports a role of IL-4 in the protection of B cells from apoptosis.
22843758
Insulin-like growth factor binding protein-3 inhibits the growth of non-small cell lung cancer.
Insulin-like growth factors (IGFs) have mitogenic and antiapoptotic properties and have been implicated in the development of lung cancer. The effects of IGFs are modulated by insulin-like growth factor binding proteins (IGFBPs). This study explored the effects of IGFBP-3 on non-small cell lung cancer (NSCLC) cells after infection with an adenovirus constitutively expressing IGFBP-3 under the control of the cytomegalovirus promoter (Ad5CMV-BP3). We found that IGFs, especially IGF-I, stimulated the growth of NSCLC cells, and Ad5CMV-BP3 suppressed this IGF-I-induced NSCLC cell growth. We also found that the clonogenicity of H1299 cells in soft agar was markedly reduced by Ad5CMV-BP3. Furthermore, direct injection of Ad5CMV-BP3 into H1299 NSCLC xenografts s.c. established in athymic nude mice induced massive destruction of the tumors. Ad5CMV-BP3 did not induce detectable cytotoxicity on normal human bronchial epithelial cells, suggesting therapeutic efficacy of this virus. Ad5CMV-BP3 infection was accompanied by apoptotic cell death in vitro as detected by flow cytometry, DNA fragmentation analysis, and Western blot analysis on the expression of Bcl-2 and on the cleavage of poly(ADP-ribose) polymerase, a substrate of caspase 3. Immunofluorescence confocal microscopy was also used to show the apoptotic effect of Ad5CMV-BP3 in H1299 tumors established in nude mice. These findings indicated that IGFBP-3 was a potent inducer of apoptosis in NSCLC cells in vitro and in vivo. To delineate the underlying mechanism, we examined the effect of IGFBP-3 on Akt/protein kinase B and glycogen synthase kinase-3beta, downstream mediators of the phosphatidylinositol 3-kinase pathway, and on mitogen-activated protein kinase (MAPK), all three of which are activated by IGF-mediated signaling pathways and have important roles in cell survival. IGFBP-3 overexpression inhibited the phosphorylation of Akt and glycogen synthase kinase-3beta and the activity of MAPK. Furthermore, IGF-I rescued the NSCLC cells from serum depletion-induced apoptosis, and this rescue was blocked in Ad5CMV-BP-3-infected H1299 NSCLC cells. Transient transfection with activated Akt or constitutively active MAPK kinase-1, an upstream activator of MAPK, partially blocked IGFBP-3-induced apoptosis of NSCLC cells. These findings suggested that the growth-regulatory effect of IGFBP-3 on NSCLC cells was attributable in part to the inhibition of the IGF-induced survival pathway. These data demonstrate the importance of IGFBP-3 in the regulation of NSCLC cell proliferation, clonogenicity, and tumor growth, suggesting that IGFBP-3 is a target for the treatment of lung cancer and that Ad5CMV-BP3 is a potential therapeutic agent.
24763110
Clinic blood pressure responses to two amlodipine salt formulations, adipate and besylate, in adult Korean patients with mild to moderate hypertension: a multicenter, randomized, double-blind, parallel-group, 8-week comparison.
BACKGROUND
The commercially available formulation of amlodipine is conjugated with besylate salt to increase water solubility. Recently, a new amlodipine salt formulation has been developed in which the free base of amlodipine is conjugated with a chemically different salt, adipate.


OBJECTIVE
The goal of this study was to compare the antihypertensive effect and tolerability of amlodipine adipate with those of amlodipine besylate in patients with mild to moderate hypertension.


METHODS
This was a multicenter, randomized, doubleblind, parallel-group study in which patients received 8 weeks of treatment with either amlodipine adipate or amlodipine besylate. The primary efficacy variable was noninferiority of the difference in mean changes from baseline in trough diastolic blood pressure (DBP) after 8 weeks of treatment. Secondary efficacy variables included mean changes in DBP, systolic blood pressure (SBP), and response rate (defined as the proportion of patients whose DBP was <90 mm Hg or whose DBP had decreased from baseline by > or =10 mm Hg). The incidence of adverse events (AEs) was also assessed.


RESULTS
Two hundred eleven patients were randomly assigned to receive amlodipine adipate (n = 106) or amlodipine besylate (n = 105). Study patients were primarily female (54.5%), with a mean (SD) age of 52.2 (9.6) years and a mean body weight of 67.1 (10.2) kg; there were no between-group differences in demographic profiles. After 4 weeks of randomized treatment, 58 (27.5%) patients (29 [27.4%] amlodipine adipate, 29 [27.6%] amlodipine besylate) had not achieved a mean DBP <90 mm Hg, and their dose was doubled. Mean DBP changes at 8 weeks were -15.2 (7.3) mm Hg in the amlodipine adipate group and -14.2 (7.4) mm Hg in the amlodipine besylate group (P = NS). Because the 95% CI for the difference in mean DBP changes between groups (-0.53 to 2.55) was within the prespecified lower limit (-4 mm Hg), amlodipine adipate was considered noninferior to amlodipine besylate. Mean SBP changes were -24.9 (12.1) mm Hg in the amlodipine adipate group and -22.0 (14.7) mm Hg in the amlodipine besylate group (P = NS). The response rates were 92.0% for amlodipine adipate and 95.4% for amlodipine besylate (P = NS). The overall incidence of clinical AEs was 20.8% in the amlodipine adipate group and 25.7% in the amlodipine besylate group (P = NS). Drug-related clinical AEs occurred in 5.7% and 12.4% of patients in the respective treatment groups (P = NS). Serum uric acid levels decreased significantly from base-line in both groups (P < 0.001).


CONCLUSIONS
Eight weeks of treatment with amlodipine adipate produced significant reductions from baseline in blood pressure in these patients with mild to moderate hypertension. The efficacy of amlodipine adipate was not inferior to that of amlodipine besylate. Tolerability was comparable between the 2 treatment groups.
25306146
Response of Non–Small Cell Lung Cancer Cells to the Inhibitors of Phosphatidylinositol 3-Kinase/Akt- and MAPK Kinase 4/c-Jun NH2-Terminal Kinase Pathways: An Effective Therapeutic Strategy for Lung Cancer
Purpose: We previously showed that phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) pathways cooperate to promote non–small cell lung cancer (NSCLC) cell proliferation in vitro. This study was designed to explore whether inhibition of these pathways effectively inhibits NSCLC tumor growth in vivo. Experimental Design: The effects of PI3K/Akt inhibitors {LY294002, adenoviruses expressing dominant-negative mutant of the p85α adaptor subunit of PI3K (Ad-dnp85α), dominant-negative Akt [Ad-HA-Akt(KM)], or PTEN (Ad-PTEN)}, MKK4/c-jun NH2-terminal kinase (JNK) inhibitor [SP600215, adenovirus expressing dominant-negative MKK4, Ad-MKK4(KR)], and their combinations on proliferation and apoptosis in NSCLC cells were tested in vitro and in vivo using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a flow cytometry-based terminal deoxynucleotidyl transferase–mediated nick-end labeling assay, Western blot and immunohistochemical analyses, and an NSCLC xenograft tumor model. Results: Ad-dnp85α significantly inhibited proliferation of a subset of NSCLC cell lines used in our study. Intratumoral injection of Ad-dnp85α induced a significant decrease in the growth of H1299 NSCLC xenograft tumors. Concurrent inhibition of the PI3K/Akt and MKK4/JNK pathways showed enhanced antiproliferative effects on H1299 cells in vitro and in vivo by increasing apoptosis. Conclusions: PI3K/Akt and MKK4/JNK pathways cooperate to stimulate NSCLC cell proliferation by maintaining cell survival, suggesting that simultaneously targeting these two pathways might be an effective therapeutic strategy against NSCLC.
29037904
Initial presentation of DRESS: often misdiagnosed as infections.
related adverse effects, including edema, urticaria, vesicles, erosions, dermatitis, and lymphadenopathy were seen in 58 children (54%). Thirteen percent of children discontinued treatment after 2 months owing to a variety of factors, including adverse effects, difficulties commuting to the treatment center, and/or the disruption caused by weekly absences from school. Fourteen patients showed complete hair regrowth after 6 months of treatment (13%); 27 had partial regrowth (25%). At 12 months, 12 patients had complete hair regrowth (11%), and 23 had partial regrowth (21%). The remainder did not experience any hair growth or stopped treatment (Table 1). Twelve patients 10 years or younger had marked sensitization reactions (32%) compared with 11 patients aged 11 to 18 years (16%) (P=.07) (Table 2). Twenty-seven of 38 patients younger than 10 years had adverse effects during DPCP treatment (71%) compared with 31 of 70 patients aged 11 to 18 years (44%) (P=.01). None of the known prognostic factors, including age at onset, extent of involvement, atopy, coexistent autoimmune disease, family history, ophiasis pattern, or nail involvement, was associated with greater likelihood of having partial or complete response to DPCP therapy (data not shown).
43129468
Trends in Socioeconomic Disparities in Organized and Opportunistic Gastric Cancer Screening in Korea (2005-2009)
Background: A growth of consensus and increasing activities related to organized cancer screening programs has occurred in Korea since 1999. It is important to assess disparities in the fight against cancer, and it is crucial to identify particular groups that may be experiencing a high burden of cancer-related illness. Methods: Data from 8,160 men and women ages >40 years from the 2005 to 2009 Korean National Cancer Screening Survey were used to analyze the relationship between socioeconomic position and receiving upper gastrointestinal series or upper endoscopy within the past 2 years. We used absolute and relative concentration indexes, that is, summary measures of disparity based on both rate differences and rate ratios. Results: For organized screening, the education disparity declined, but the income disparity index increased, indicating that participation in organized screening was relatively more concentrated among the lower-income groups. For opportunistic screening, income and education disparities increased due to the widening of socioeconomic differences. Conclusions: The results of this study suggested progress toward socioeconomic disparity-related goals in organized screening for gastric cancer. However, the income disparity trends in organized screening may change in a manner similar to those in opportunistic screening in the future because of the much faster rate of organized screening uptake by those higher on the socioeconomic scale. Impact: This study addresses the routine monitoring of coverage of screening among different socioeconomic groups and could be used to inform polices to reduce disparity in coverage. Cancer Epidemiol Biomarkers Prev; 19(8); 1919–26. ©2010 AACR.