Johanna Sápi

Johanna Sápi
Obudai University · Physiological Controls Research Center

MSc in Biomedical Engineering, PhD in Applied Informatics

About

47
Publications
5,122
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
609
Citations
Citations since 2016
20 Research Items
472 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Additional affiliations
April 2016 - present
Óbudai Egyetem
Position
  • Professor (Associate)
April 2015 - March 2016
Óbudai Egyetem
Position
  • Lecturer
February 2013 - February 2015
Óbudai Egyetem
Position
  • PhD Student
Education
February 2013 - September 2014
Óbudai Egyetem
Field of study
February 2012 - February 2013
January 2010 - February 2012

Publications

Publications (47)
Article
Full-text available
The self-limited nature of nodular fasciitis (NF) is well-known but its precise mechanism has not yet been clarified. We observed that “young” NF (preoperative duration <1 month) consistently contains a higher percentage (~80%) of USP6 break-apart FISH signals than “old” NF (preoperative duration >3 months) (~20%). Thus, we hypothesized that our or...
Article
MiR-206 is a remarkable miRNA because it functions as a suppressor miRNA in rhabdomyosarcoma while at the same time, as previously showed, it can act as an oncomiRNA in SMARCB1 immunonegative soft tissue sarcomas. The aim of this study was to investigate the effect of miR-206 on its several target genes in various human tumorous and normal cell lin...
Article
In the past few decades cancer research has delivered several new treatment options, of which can be highly expensive thus reducing its applicability in medical practice. However, advances in control engineering can tackle this issue by the use of an appropriate optimal controller. In this paper a Computed Torque Control (CTC) based PID controller...
Article
There are many systems in practice that can have only positive (nonnegative) input, typical examples for such systems are physiological systems. Moreover, the parameters of these systems are usually not known exactly or may vary over time, thus application of robust controllers represents a reasonable possibility. Most model-based controller design...
Article
Full-text available
Tumor growth models are important to create an engineering background for cancer treatment either by using the models for simulations and evaluation of treatment protocols or, if combined with control engineering, by designing treatment protocols. A well-defined tumor growth model must describe the physiological processes and the measurements as we...
Conference Paper
Full-text available
Cancerous diseases are being responsible for the death of many around the globe. Treating these illnesses pose a significant challenge to the medical professionals. While conventional methods, chemotherapy or radiotherapy for example, provide a remedy to the issue their side effects are not negligible. In the past few decades new methods have emerg...
Article
The efficiency of therapeutic cancer treatment protocols can be increased by incorporating knowledge about the underlying physiological processes into the design of the protocol. The aim of this work is to find the optimal protocol resulting in minimal drug usage for fixed resting time between measurements and treatments (the sampling time) and pre...
Article
The input of physiological control systems is positive in almost every case (i.e. it is the concentration of a drug), thus the application of controllers which guarantee positive input is crucial. However, most of the controller design methods can not incorporate the constraint that the input has to be positive. We propose a method based on the dyn...
Article
We introduce a simple nonlinear dynamic tumor growth model which distinguishes between a core and a peripherial compartment, and accounts for nutrient and congestion-dependent cell proliferation, necrosis and volume growth. The model synthesis procedure considers that later the model shall be extended with mechanisms describing angiogenesis and wil...
Conference Paper
Application of model-based control strategies for physiological control problems, like tumor therapy, may greatly improve the efficiency of clinical treatments. Our aim is to design a positive path tracking controller for a minimal model of tumor growth under angiogenic inhibition with bevacizumab treatment. We extend the dynamics of the system to...
Conference Paper
Modeling the tumor growth under angiogenic inhibition is an important step towards designing tumor treatment therapies based on mathematical tools. Our goal is to create a model for tumor growth that describes the underlying physiological processes adequately while being as simple as possible. We propose a second-order model containing linear terms...
Article
Full-text available
In medical practice, the effectiveness of fighting cancer is not only determined by the composition of the used drug, but determined by the administration method as well. As a result, having drugs with a suitable action profile is just a promising beginning, but without appropriate delivery methods, the therapy still can be ineffective. Finding the...
Article
Full-text available
Angiogenesis inhibitors offer a promising new treatment modality in oncology. However, the optimal administration regimen is often not well-established, despite the fact that it might have substantial impact on the outcome. The aim of the present study was to investigate this issue. Eight weeks old male C57Bl/6 mice were implanted with C38 colon ad...
Conference Paper
In the medical practice, there are several methods to administer anti-cancer drugs. A commonly used method is the intermittent bolus doses (BD) administration when the patient receives drug on given days and the therapy has rest periods between the injections. The amount of bolus doses can be the maximum tolerated dose (MTD) or less. Anti-cancer dr...
Article
Full-text available
Background: Bevacizumab is an exogenous inhibitor which inhibits the biological activity of human VEGF. Several studies have investigated the effectiveness of bevacizumab therapy according to different cancer types but these days there is an intense debate on its utility. We have investigated different methods to find the best tumor volume estimat...
Conference Paper
Full-text available
Tumor growth model identification under antiangio-genic therapy is a very current issue since the existing models in the literature have some limitations and usually they are not clinically validated. We have carried out animal experiments to observe valid data; mice were transplanted with C38 colon adenocarcinoma and they were treated with bevaciz...
Article
Every therapy that fights against cancer aims to reduce the tumor volume as far as possible. However, the price of low tumor volume has to be paid twice: as financial cost and also as side effect cost. In this article, we present qualitative correlation between the steady-state tumor volume and inhibitor serum concentration based on the tumor growt...
Conference Paper
Full-text available
Tumor cells need a set of functional capabilities for development and growth. One of these capabilities is angiogenesis; tumor cells have to become able to force new vessel formation to ensure oxygen and nutrient supply. In the literature, there are several different growth models which aim to describe the growth characteristics. The model creation...
Conference Paper
Full-text available
The paper gives a summary of 2014 year results in the topic of physiological modeling and control achieved by the Physiological Controls Group of the Obuda University. The presentation is integrated in the tradition established years ago at IEEE INES conferences and 2014's IEEE SACI conference summarizing the latest results obtained by the group. F...
Article
Full-text available
Model identification allows to design different control strategies for antiangiogenic cancer therapy, and create model-based treatment protocols. These model-based protocols can be more effective than the current ones, since they provide individual treatment for the patients. The aim of this paper is to investigate C38 colon adenocarcinoma growth i...
Conference Paper
Full-text available
Cancer treatment is one of the most important research fields of modern medicine. In the last decades, targeted molecular therapies showed prosperous results. These treatments achieve tumor regression with limited side-effects. Mathematical models were posed which describe the dynamics of tumor regression under the applied control. The current pape...
Conference Paper
Full-text available
Following the tradition established at previous IEEE INES conferences, this paper presents the results achieved by the Physiological Controls Group of Óbuda University in the field of physiological control last year (2013). The application target was focused on diabetes (artificial pancreas), tumor (antiangiogenic therapy), and hemodialysis (contro...
Article
Full-text available
Fighting tumors is one of the most important problems of medical research. In this paper, antiangiogenic cancer therapy is investigated through its mathematical model. This tumor treatment method targets the endothelium of a growing tumor and belongs to the targeted molecular therapies. The aim of the therapy is not to eliminate the entire tumor, b...
Chapter
Full-text available
In the last decades beside conventional cancer treatment methods, molecular targeted therapies show prosperous results. These therapies have limited side-effects, and in comparison to chemotherapy, tumorous cells show lower tendency of becoming resistant to the applied antiangiogenic drugs. In clinical research, antiangiogenic therapy is one of the...
Conference Paper
Full-text available
According to the fact that cancer diseases are leading causes of death all around the world, development of cancer fighting therapies is necessary. Beside the medical knowledge, there is an extra need for engineering approach to solve this complex problem. The aim of this paper is to design controller for tumor growth under angiogenic inhibition, w...
Conference Paper
Full-text available
Modern approaches of cancer therapies have specific effect on the typical mechanisms of uncontrollably growing and multiplying tumor cells. These targeted therapies can be more efficient than commonly applied methods in clinical practice. Antiangiogenic therapy prevents tumors from forming new blood vessels to ensure sufficient oxygen and nutrients...
Conference Paper
Full-text available
The current paper represents a continuation of the conference papers presented at the INES 2011 and 2012 conferences. A brief summary of the newest results in the field of physiological modeling and control are presented focusing on high public health impact diseases: diabetes, tumor and obesity. In the case of diabetes control, preliminary model-f...
Conference Paper
Full-text available
Cancer fighting treatments are expanding, and a promising type, targeted molecular therapies have a new approach. The aim of these therapies is not to eliminate the whole tumor, but to control the tumor into a given state and keep it there. Explicit knowledge of tumor growth dynamics and the effects of targeted molecular therapies is crucial in tum...
Article
Full-text available
Background Enhancer of zeste homologue 2 (EZH2) is a polycomb group (PcG) family protein. Acting as a histone methyltransferase it plays crucial roles in maintaining epigenetic stem cell signature, while its deregulation leads to tumor development. EZH2 overexpression is commonly associated with poor prognosis in a variety of tumor types including...
Data
Table S1. Clinical data, immunohistochemical scores, and EZH2 gene expression values of 55 synovial sarcoma cases. Legend: gender: M: male; F: female; size: 0, <5cm; 1, ≥5cm; location: P, peripheral; C: central; end point: 1, deceased; 0, alive at the indicated time point (months post op.); NA: data not available.
Conference Paper
Full-text available
Cancer is one of the most destructive and lethal illnesses of the modern civilization. In the last decades, clinical cancer research shifted towards molecular targeted therapies which have limited side effects in comparison to conventional chemotherapy and radiation therapy. Anti-angiogenic therapy is one of the most promising cancer treatment meth...
Conference Paper
Full-text available
The current paper represents a continuation of the conference paper presented at the INES 2011 conference. It summarizes the updated results of research tasks in the field of physiological modeling and control of diseases with high public health impact carried out by the Biomedical Engineering Laboratory of the Budapest University of Technology and...
Conference Paper
Full-text available
Cancer represents nowadays one of the most destructive and lethal illnesses of our civilization. In the last decades, clinical cancer research shifted towards molecular targeted therapies which have limited side effects in comparison to conventional chemotherapy and radiation therapy. Antiangiogenic therapy is proved to be one of the most promising...
Conference Paper
Full-text available
Cancer diseases are one of the most lethal, incurable diseases today, thus fighting cancer is an actual and urgent problem in clinical practice. Beside classical therapies, a new approach is represented by model-based therapies, where human body works as a complex system. These therapies are called targeted molecular therapies (TMTs). TMTs are figh...
Conference Paper
Anti-angiogenic theraphy is a promising method to fight cancer, however the special therapeutic drugs applied are quite expernsive. The aim of this paper is to define simple therapeutical guidelines for sufficient treatment with the usage of the least amount of drugs possible with the help of control theory. We analyse a nonlinear tumor growth mode...
Conference Paper
Full-text available
This paper summarizes the results of research tasks in the field of physiological modeling and control of diseases with high public health impact carried out by the Biomedical Engineering Laboratory of the Budapest University of Technology and Economics. The developed and presented optimal algorithms and strategies focus on three diseases with high...

Network

Cited By

Projects

Project (1)
Project
Imagine if tumor growth would be reduced and then kept in a minimal and safe volume in an automated manner and in a personalized way, i.e. cancer drug would be injected using a continuous therapy improving the patient’s quality of life. By control engineering approaches it is possible to create model-based strategies for health problems. Artificial pancreas is an adequate example for this, where by continuous glucose measurement device and insulin pump it is possible to improve diabetes treatment. Gaining expertise from this problem, the current proposal focuses on taming the cancer by developing an engineering-based medical therapy. The interdisciplinary approach focuses on modern robust control algorithm development in order to stop the angiogenesis process (i.e. vascular system development) of the tumor; hence, to stop tumor growth, maintaining it in a minimal, “tamed” form. This breakthrough concept could revitalize cancer treatment. It is the right time to do it as some investigations regarding tumor growth modeling have been already done; now, it should be refined by model identification tools and validated on animal trials. The benefit of robust control was already demonstrated in artificial pancreas; hence, it could be adapted to cancer research. The result could end with a personalized healthcare approach for drug-delivery in cancer, improving quality of life, optimizing drug infusion and minimizing treatment costs. This interdisciplinary approach combines control engineering with mathematics, computer science and medical sciences. As a result, the model-based robust control approach envisage refining the currently existing tumor growth modeling aspects, design an optimal control algorithm and extend it by robust control theory to guarantee its general applicability. Based on our research background, validation will be done first in a manually controlled way, but then in an automatic mode to propose it for further human investigations.