INFLUENCE OF CORRELATED NOISES ON GROWTH OF A TUMOR IN A MODIFIED VERHULST MODEL

2006 ◽  
Vol 06 (04) ◽  
pp. L349-L358 ◽  
Author(s):  
WEI-RONG ZHONG ◽  
YUAN-ZHI SHAO ◽  
ZHEN-HUI HE
Keyword(s):  
Tumor Growth ◽  
Tumor Cells ◽  
Multiplicative Noise ◽  
Stable State ◽  
Logistic Growth ◽  
Tumor Treatment ◽  
Steady State Probability ◽  
Multiplicative Noises ◽  
The Relationship ◽  
Correlated Noises

We studied the effect of additive and multiplicative noises on the growth of a tumor based on a logistic growth model. The steady-state probability distribution and the average population of the tumor cells were given to explain the important roles of correlated noises in the tumor growth. We explored that multiplicative noise induces a phase transition of the tumor growth from a uni-stable state to a bi-stable state; the relationship between the intensity of multiplicative noise and the population of the tumor cells shows a stochastic resonance-like characteristic. It was also confirmed that additive noise weakened rather than extinguish the tumor growth. Homologous noises, however, promote the growth of a tumor. We also discussed about the relationship between the tumor treatment and the model.

EFFECTS OF CORRELATED NOISES IN A SATURATION LASER MODEL

2006 ◽  
Vol 20 (23) ◽  
pp. 1481-1488 ◽  
Author(s):  
P. ZHU ◽  
S. B. CHEN ◽  
D. C. MEI
Keyword(s):  
Steady State ◽  
Intensity Fluctuation ◽  
Laser System ◽  
Planck Equation ◽  
Steady State Probability ◽  
Multiplicative Noises ◽  
Analytic Expressions ◽  
Laser Model ◽  
Correlation Strength ◽  
Correlated Noises

The effects of correlations between additive and multiplicative noises in a saturation laser model are investigated. The approximative Fokker–Planck equation and analytic expressions of the steady-state probability distribution function (SPD) of the laser system are derived. Based on the SPD, the normalized mean, the normalized variance, and the normalized skewness of the steady-state laser intensity are calculated numerically. Our results indicate that: (i) For the laser being operated above threshold, the correlation strength λ reduces the intensity fluctuation; (ii) For the laser being operated near threshold and below threshold, the correlation strength λ enhances the intensity fluctuation.

Melatonin modifies tumor hypoxia and metabolism by inhibiting HIF-1α and energy metabolic pathway in the in vitro and in vivo models of breast cancer

2019 ◽  
Vol 2 (4) ◽  
pp. 83-98 ◽  
Author(s):  
André De Lima Mota ◽  
Bruna Vitorasso Jardim-Perassi ◽  
Tialfi Bergamin De Castro ◽  
Jucimara Colombo ◽  
Nathália Martins Sonehara ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Glucose Metabolism ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Carbonic Anhydrases ◽  
In Vivo Models ◽  
Ca Ix ◽  
Gene And Protein Expression

Breast cancer is the most common cancer among women and has a high mortality rate. Adverse conditions in the tumor microenvironment, such as hypoxia and acidosis, may exert selective pressure on the tumor, selecting subpopulations of tumor cells with advantages for survival in this environment. In this context, therapeutic agents that can modify these conditions, and consequently the intratumoral heterogeneity need to be explored. Melatonin, in addition to its physiological effects, exhibits important anti-tumor actions which may associate with modification of hypoxia and Warburg effect. In this study, we have evaluated the action of melatonin on tumor growth and tumor metabolism by different markers of hypoxia and glucose metabolism (HIF-1α, glucose transporters GLUT1 and GLUT3 and carbonic anhydrases CA-IX and CA-XII) in triple negative breast cancer model. In an in vitro study, gene and protein expressions of these markers were evaluated by quantitative real-time PCR and immunocytochemistry, respectively. The effects of melatonin were also tested in a MDA-MB-231 xenograft animal model. Results showed that melatonin treatment reduced the viability of MDA-MB-231 cells and tumor growth in Balb/c nude mice (p <0.05). The treatment significantly decreased HIF-1α gene and protein expression concomitantly with the expression of GLUT1, GLUT3, CA-IX and CA-XII (p <0.05). These results strongly suggest that melatonin down-regulates HIF-1α expression and regulates glucose metabolism in breast tumor cells, therefore, controlling hypoxia and tumor progression. 

ANTITUMOR EFFECT OF COLLOIDAL SILVER BISILICATE IN EXPERIMENTAL IN VITRO AND IN VIVO STUDIES

2019 ◽  
Vol 65 (5) ◽  
pp. 760-765
Author(s):  
Margarita Tyndyk ◽  
Irina Popovich ◽  
A. Malek ◽  
R. Samsonov ◽  
N. Germanov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Human Tumor ◽  
Significant Inhibition ◽  
In Vivo Studies ◽  
Ehrlich Carcinoma ◽  
In Vivo Experiments

The paper presents the results of the research on the antitumor activity of a new drug - atomic clusters of silver (ACS), the colloidal solution of nanostructured silver bisilicate Ag6Si2O7 with particles size of 1-2 nm in deionized water. In vitro studies to evaluate the effect of various ACS concentrations in human tumor cells cultures (breast cancer, colon carcinoma and prostate cancer) were conducted. The highest antitumor activity of ACS was observed in dilutions from 2.7 mg/l to 5.1 mg/l, resulting in the death of tumor cells in all studied cell cultures. In vivo experiments on transplanted Ehrlich carcinoma model in mice consuming 0.75 mg/kg ACS with drinking water revealed significant inhibition of tumor growth since the 14th day of experiment (maximally by 52% on the 28th day, p < 0.05) in comparison with control. Subcutaneous injections of 2.5 mg/kg ACS inhibited Ehrlich's tumor growth on the 7th and 10th days of the experiment (p < 0.05) as compared to control.

The Role of Reactive Oxygen Species in Tumor Treatment and its Impact on Bone Marrow Hematopoiesis

2020 ◽  
Vol 21 (5) ◽  
pp. 477-498
Author(s):  
Yongfeng Chen ◽  
Xingjing Luo ◽  
Zhenyou Zou ◽  
Yong Liang
Keyword(s):  
Reactive Oxygen Species ◽  
Bone Marrow ◽  
Oxidative Damage ◽  
Tumor Cells ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Tumor Treatment ◽  
Normal Cells ◽  
Treatment And Prevention

Reactive oxygen species (ROS), an important molecule inducing oxidative stress in organisms, play a key role in tumorigenesis, tumor progression and recurrence. Recent findings on ROS have shown that ROS can be used to treat cancer as they accelerate the death of tumor cells. At present, pro-oxidant drugs that are intended to increase ROS levels of the tumor cells have been widely used in the clinic. However, ROS are a double-edged sword in the treatment of tumors. High levels of ROS induce not only the death of tumor cells but also oxidative damage to normal cells, especially bone marrow hemopoietic cells, which leads to bone marrow suppression and (or) other side effects, weak efficacy of tumor treatment and even threatening patients’ life. How to enhance the killing effect of ROS on tumor cells while avoiding oxidative damage to the normal cells has become an urgent issue. This study is a review of the latest progress in the role of ROS-mediated programmed death in tumor treatment and prevention and treatment of oxidative damage in bone marrow induced by ROS.

Evolutionary game analysis of information sharing by institutional investors

2021 ◽  
pp. 1-9
Author(s):  
Hua Li ◽  
Qingqing Lou ◽  
Qiubai Sun ◽  
Bowen Li
Keyword(s):  
Information Sharing ◽  
Institutional Investors ◽  
Information Exchange ◽  
Evolutionary Game ◽  
Stable State ◽  
Point Of View ◽  
Game Model ◽  
Game Analysis ◽  
Relationship Network ◽  
The Relationship

In order to solve the conflict of interests of institutional investors, this paper uses evolutionary game model. From the point of view of information sharing, this paper discusses four different situations. Only when the sum of risk and cost is less than the penalty of free riding, the evolution of institutional investors will eventually incline to the stable state of information sharing. That is, the phenomenon of hugging. The research shows that the institutional investors are not independent of each other, but the relationship network of institutional investors for the purpose of information exchange. The content of this paper enriches the research on information sharing of institutional investors.

scholarly journals Optimal Linear Estimators for Time-Delay Systems with Fading Measurements and Correlated Noises

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Yazhou Li ◽  
Jiayi Li ◽  
Xin Wang
Keyword(s):  
Time Delay ◽  
Minimum Variance ◽  
Delay Systems ◽  
Multiplicative Noises ◽  
Linear Estimators ◽  
Discrete Linear Systems ◽  
Estimation Problems ◽  
Optimal Linear ◽  
State Augmentation ◽  
Correlated Noises

The optimal linear estimation problems are investigated in this paper for a class of discrete linear systems with fading measurements and correlated noises. Firstly, the fading measurements occur in a random way where the fading probabilities are regulated by probability mass functions in a given interval. Furthermore, time-delay exists in the system state and observation simultaneously. Additionally, the multiplicative noises are considered to describe the uncertainty of the state. Based on the projection theory, the linear minimum variance optimal linear estimators, including filter, predictor, and smoother are presented in the paper. Compared with conventional state augmentation, the new algorithm is finite-dimensionally computable and does not increase computational and storage load when the delay is large. A numerical example is provided to illustrate the effectiveness of the proposed algorithms.

scholarly journals Three-dimensional relationships between tumor cells and microcirculation with double cyanine immunolabeling, laser scanning confocal microscopy, and computer-assisted reconstruction: an alternative to cast corrosion preparations.

1994 ◽  
Vol 42 (5) ◽  
pp. 681-686 ◽  
Author(s):  
V Rummelt ◽  
L M Gardner ◽  
R Folberg ◽  
S Beck ◽  
B Knosp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Blood Vessels ◽  
Tumor Cells ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Melanoma Cells ◽  
Tumor Blood Vessels ◽  
The Relationship ◽  
Scanning Electron

The morphology of the microcirculation of uveal melanomas is a reliable market of tumor progression. Scanning electron microscopy of cast corrosion preparations can generate three-dimensional views of these vascular patterns, but this technique sacrifices the tumor parenchyma. Formalin-fixed wet tissue sections 100-150 microns thick from uveal melanomas were stained with the lectin Ulex europaeus agglutinin I (UEAI) and proliferating cell nuclear antigen (PCNA) to demonstrate simultaneously the tumor blood vessels and proliferating tumor cells. Indocarbocyanine (Cy3) was used as a fluorophore for UEAI and indodicarbocyanine (Cy5) was used for PCNA. Double labeled sections were examined with a laser scanning confocal microscope. Images of both stains were digitized at the same 5-microns intervals and each of the two images per interval was combined digitally to form one image. These combined images were visualized through voxel processing to study the relationship between melanoma cells expressing PCNA and various microcirculatory patterns. This technique produces images comparable to scanning electron microscopy of cast corrosion preparations while permitting simultaneous localization of melanoma cells expressing PCNA. The microcirculatory tree can be viewed from any perspective and the relationship between tumor cells and the tumor blood vessels can be studied concurrently in three dimensions. This technique is an alternative to cast corrosion preparations.

Efficacy of DAN-222, a novel investigational polymeric nanoparticle with topoisomerase I inhibitor, as monotherapy in breast cancer models and when combined with PARP inhibitor.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1081-1081
Author(s):  
Ashley P Wright ◽  
Jodi D Bradley ◽  
Timothy Hagerty ◽  
Emily A Wyatt
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Growth Inhibition ◽  
Tumor Cells ◽  
Topoisomerase I ◽  
Parp Inhibitor ◽  
Parp Inhibitors ◽  
Topoisomerase I Inhibitor ◽  
Polymeric Nanoparticle ◽  
Cancer Tumor

1081 Background: Patients with BRCA-positive HER2-negative breast cancer benefit from PARP inhibitor therapy, but additional benefit is still desired. PARP inhibition alone does not prevent all mechanisms for repairing damage to DNA such as homologous recombination repair. An attractive combination for treating such patients would be combining a topoisomerase I inhibitor with a PARP inhibitor given the dual mechanism this would provide for DNA damage and inhibited repair, leading to tumor cell death. This combination has been tried in multiple phase 1 studies, but myelotoxicity prevented the combination from being evaluated further. DAN-222 is a novel investigational polymeric nanoparticle conjugated with camptothecin, a topoisomerase I inhibitor, that provides significant accumulation of drug in tumor tissues via the enhanced permeability and retention (EPR) effect and significantly reduced bone marrow exposure compared to native chemotherapy. These observations underscore the potential advantages of DAN-222 alone as well as in combination with other agents such as PARP inhibitors in solid tumors. Here, we report the effects of DAN-222 monotherapy and in combination with a PARP inhibitor on the growth inhibition in an HRD+ TNBC breast cancer (MDA-MB-436) and an HRD- ovarian (OVCAR3) xenograft mouse model. Methods: HRD+ breast cancer tumor cells (MDA-MB-436) were implanted into female NCr nu/nu mice and HRD- ovarian cancer tumor cells (OVCAR3) were implanted into female CB.17 SCID mice. Mice were randomized to vehicle or treatment arms until tumors reached 2000 mm3 or day 45 (MDA-MB-436) or 1000mm3 or day 45 (OVCAR3). The groups evaluated include multiple dose levels of DAN-222 as monotherapy and those also combined with niraparib. Results: Results were consistent in both the HRD+ and HRD- tumor models with profound dose-response of DAN-222 monotherapy inhibiting tumor growth. Additionally, synergy was demonstrated when DAN-222 was combined with niraparib, clearly evident with low doses of both products when used in combination. The table below highlights the synergy of the combination of DAN-222 at 0.3 mg/kg and niraparib at 25 mg/kg above each agent alone on the tumor growth inhibition in the MDA-MB-436 xenograft. Conclusions: Combining a PARP inhibitor with a topoisomerase I inhibitor delivered via this polymeric nanoparticle delivery system (DAN-222) has synergistic efficacy in both HRD+ and HRD- xenograft tumor models. These data support continued development of DAN-222 to treat solid tumors and its combination use with PARP inhibitors.[Table: see text]

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