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Costa MI, Cipriano A, Santos FV, Valdoleiros SR, Furtado I, Machado A, Abreu M, Bastos HN. Clinical profile and microbiological aetiology diagnosis in adult patients hospitalized with community-acquired pneumonia. Pulmonology 2020; 28:358-367. [PMID: 33358259 DOI: 10.1016/j.pulmoe.2020.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 10/22/2022] Open
Abstract
Early introduction of appropriate antibiotherapy is one of the major prognostic-modifying factors in community acquired pneumonia (CAP). Despite established guidelines for empirical therapy, several factors may influence etiology and, consequently, antibiotic choices. The aims of this study were to analyze the etiology of CAP in adults admitted to a northern Portugal University Hospital and evaluate the yield of the different methods used to reach an etiological diagnosis, as well as analyze of the impact of patient demographic and clinical features on CAP etiology. We retrospectively analyzed 1901 cases of CAP with hospitalization. The diagnostic performance increased significantly when blood and sputum cultures were combined with urinary antigen tests. The most frequent etiological agent was Streptococcus pneumoniae (45.7%), except in August, when it was overtaken by gram-negative bacilli (GNB) and Legionella pneumophila infections. Viral infections were almost exclusive to winter and spring. A negative microbiological result was associated with increasing age, non-smoking and lack of both blood/sputum cultures. Younger age was a predictor for S. pneumoniae, Influenza and L. pneumophila infections. Active smoking without any previously known respiratory disease was a risk factor for legionellosis. COPD was associated with Haemophilus influenzae cases, while dementia was typical in GNB and S. aureus patients. Diabetes mellitus (DM) and heart disease were negative predictors of S. pneumoniae and H. influenzae, respectively. P. aeruginosa was an independent risk factor for mortality (OR 13.02, 95% CI 2.94-57.7). This study highlights the importance of a comprehensive microbiological diagnostic workup and provides clues to predicting the most probable CAP causative agents, based on a patient's clinical profile. These may be taken into account when establishing first line antibiotherapy.
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Affiliation(s)
- M I Costa
- Department of Pulmonology of Porto Hospital Center, Porto, Portugal.
| | - A Cipriano
- Department of Infectious Diseases of Porto Hospital Center, Porto, Portugal
| | - F V Santos
- Department of Infectious Diseases of Porto Hospital Center, Porto, Portugal
| | - S R Valdoleiros
- Department of Infectious Diseases of Porto Hospital Center, Porto, Portugal
| | - I Furtado
- Department of Infectious Diseases of Porto Hospital Center, Porto, Portugal
| | - A Machado
- Department of Internal Medicine of Porto Hospital Center, Porto, Portugal
| | - M Abreu
- Department of Infectious Diseases of Porto Hospital Center, Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar, Univesity of Porto, Portugal
| | - H N Bastos
- Department of Pulmonology of São João Hospital Center, Porto, Portugal; Faculty of Medicine of University of Porto, Porto, Portugal; IBMC/i3S - Instituto de Biologia Molecular e Celular/Instituto de Investigação e Inovação em Saúde, University of Porto, Porto, Portugal
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Corrêa JL, Veiga FF, Jarros IC, Costa MI, Castilho PF, de Oliveira KMP, Rosseto HC, Bruschi ML, Svidzinski TIE, Negri M. Propolis extract has bioactivity on the wall and cell membrane of Candida albicans. J Ethnopharmacol 2020; 256:112791. [PMID: 32234352 DOI: 10.1016/j.jep.2020.112791] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/10/2020] [Accepted: 03/21/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The use of natural products such as propolis extract (PE) is a promising alternative when topically administered to replace conventional antifungals, mostly due to its therapeutic applications, ease of access and low toxicity. However, despite being the subject of several mycology studies, they focus primarily on exploiting their antimicrobial activity, lacking information on the mechanisms of action of PE on Candida spp., characterizing its antifungal potential. AIM OF THE STUDY To elucidate the bioactivity of PE on the cellular structure of Candida albicans. MATERIALS AND METHODS A total of seven C. albicans clinical isolates plus a reference strain of C. albicans ATCC 90028 were used in this study. The PE was characterized and its effect on C. albicans was determined by susceptibility and growth kinetics assays; interference on C. albicans germination and filamentation; evaluation of the integrity of the C. albicans cell wall and membrane, as well as its mutagenic potential. RESULTS The PE presented strong inhibitory activity, which showed its greatest antifungal activity at 12 h with dose and time dependent fungistatic characteristics, effectively inhibiting and interfering on C. albicans filamentation. In addition, PE caused membrane and cell wall damage with intracellular content extravasation. Moreover, PE was not mutagenic. CONCLUSIONS The bioactivity of PE is mainly related to the loss of integrity membrane as well as the integrity of the cell wall and consequent increase in permeability, without mutagenic effects.
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Affiliation(s)
- Jakeline L Corrêa
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil; Graduate Program in Health Sciences, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Flavia F Veiga
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil; Graduate Program in Health Sciences, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Isabele C Jarros
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil; Graduate Program in Health Sciences, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Maiara Ignacio Costa
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Pamella F Castilho
- Applied Microbiology Laboratory, Faculty of Health Sciences, Federal University of Grande Dourados, Street João Rosa Góes, 1761, Dourados, MS, Brazil
| | - Kelly Mari P de Oliveira
- Applied Microbiology Laboratory, Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Street João Rosa Góes, 1761, Dourados, MS, Brazil
| | - Hélen Cássia Rosseto
- Laboratory of Research and Development of Drug Delivery Systems, Department of Pharmacy, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Marcos L Bruschi
- Laboratory of Research and Development of Drug Delivery Systems, Department of Pharmacy, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Terezinha I E Svidzinski
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil; Graduate Program in Health Sciences, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil
| | - Melyssa Negri
- Medical Mycology Laboratory, Department of Clinical Analysis and Biomedicine, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil; Graduate Program in Health Sciences, State University of Maringá, Colombo Avenue, 5790, Maringá, PR, Brazil.
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3
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Costa MI, Vilugron Rodrigues FA, Veiga FF, Jarros IC, Kischkel B, Negri M, Alexandrino Becker TC, Svidzinski TIE. Effects of intratracheal Fusarium solani inoculation in immunocompetent mice. Microb Pathog 2019; 128:317-322. [PMID: 30660735 DOI: 10.1016/j.micpath.2019.01.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 12/20/2022]
Abstract
Fusariosis is an infection that is caused by fungi of the Fusarium genus. It is the second most common fungus that is associated with human fungal infections, usually in immunocompromised individuals. The incidence of such infections has been increasing, including in immunocompetent hosts. Studies of host-pathogen interactions are scarce, and the pathophysiology of the disease is unknown. One limitation of such studies is the lack of adequate techniques for mammalian infection, in which no standardized protocols have been established with fungi with a focus on the respiratory tract. The aim of the present study was to assess the first 24 h of infection after the intratracheal inoculation of F. solani microconidia in immunocompetent mice. Colony-forming units (CFU) were counted, and histopathological analysis was performed. Under conditions of high fungal burden, F. solani caused lethal tissue damage in the lungs. Under conditions of low fungal burden, the infection was not lethal, but several alterations of pulmonary tissue and the presence of the fungus in the lungs were observed. No evidence of fungal dissemination was found in the kidneys, spleen, liver, or heart 24 h after infection. The present intratracheal model effectively established fungal infection and appears to be suitable for studies of Fusarium spp.
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Affiliation(s)
- Maiara Ignacio Costa
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Franciele Abigail Vilugron Rodrigues
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Flávia Franco Veiga
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Isabele Carrilho Jarros
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Brenda Kischkel
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Melyssa Negri
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Tânia Cristina Alexandrino Becker
- Department of Basic Health Sciences, Laboratory of General Pathology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil
| | - Terezinha Inez Estivalet Svidzinski
- Department of Clinical Analysis and Biomedicine, Laboratory of Medical Mycology, State University of Maringá, Brazil, Avenida. Colombo, 5790, CEP: 87020-900, Maringá, Paraná, Brazil.
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Jarros IC, Okuno É, Costa MI, Veiga FF, de Souza Bonfim-Mendonça P, Negri MFN, Svidzinski TIE. Yeasts from skin colonization are able to cross the acellular dermal matrix. Microb Pathog 2018; 117:1-6. [PMID: 29428422 DOI: 10.1016/j.micpath.2018.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 10/18/2022]
Abstract
In recent decades, the prognosis for burn patients has improved considerably with the development of specialized care. The acellular dermal matrix (ADM) is a totally artificial acellular device that functions to control water loss, prevent penetration by bacteria and allow migration of endothelial cells and fibroblasts from patient tissues. However, little is known about its effectiveness against yeasts. The present study evaluated the capacity of colonization and migration of some human commensal yeasts. Three clinical isolates from skin scales, identified as Candida parapsilosis, Candida glabrata and Rhodotorula mucilaginosa, were used. Their ability to cross the ADM was evaluated. After three days, all isolates had crossed the ADM. C. parapsilosis showed the lowest growth, while R. mucilaginosa showed intermediate and C. glabrata the highest growth. In the plates incubated for seven days, the growth of C. parapsilosis and C. glabrata increased by 1 log over the third day. All isolates have the capacity to colonize and migrate through the matrix, increasing the potential risk to burn patients, who can develop severe and even fatal infections by invasive fungi.
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Affiliation(s)
- Isabele Carrilho Jarros
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Érika Okuno
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Maiara Ignacio Costa
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Flávia Franco Veiga
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Patricia de Souza Bonfim-Mendonça
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Melyssa Fernanda Norman Negri
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil
| | - Terezinha Inez Estivalet Svidzinski
- Division of Medical Mycology, Teaching and Research Laboratory in Clinical Analyses, Department of Clinical Analysis of State University of Maringá, Paraná, Brazil.
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Brandão JL, Pinheiro J, Pinho D, Correia da Silva D, Fernandes E, Fragoso G, Costa MI, Silva A. [Mushroom poisoning in Portugal]. ACTA MEDICA PORT 2011; 24 Suppl 2:269-278. [PMID: 22849912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The renewed interest in mycology has been reflected in growing use of wild mushrooms in culinary, driven by its nutritional, organoleptic and commercial value. However, the international scientific literature describes several syndromes of poisoning by mushrooms. We live, therefore, a paradigm conducive to an increase of mycetism, whose diagnosis requires a high level of suspicion and knowledge of clinical profiles. In Portugal, the real dimension of this problem is unknown. Although some mycetisms, such as the hepatotoxic syndrome, have high morbidity and mortality, their relative incidences are unknown. Add up to the shortage of international scientific literature, often outdated and inappropriate to clinical practice. In this context, this article provides an updated epidemiological and clinical perspective emphasizing a narrative and descriptive information on the forms of presentation, differential diagnosis and therapeutic approach, with the ultimate goal of the elaboration of a national diagram-oriented approach to decision-making diagnosis. We analyzed all the clinical records of patients admitted into ten hospitals between 1990 and 2008, notified with the code 988.1 of GDH (acute poisoning by mushrooms). There were registered demographic data, way of presentation, time between ingestion and onset of symptoms, the annual distribution, clinical profile, clinical and analytical treatment performed and complications. We identified 93 cases of acute poisoning by mushrooms, with equal gender distribution and inclusion of individuals of all age groups (from 1 to 85 years), but with greater representation from 21 to 50 years. There was a bimodal seasonal pattern, with a higher peak between September and December and a second in the spring. The hepatotoxic profile presentation corresponded to 63.4% and 31.7% of the cases to gastroenteritis syndrome. The mortality in cases of hepatotoxicity was 11.8%. The developmental profile of the rate of prothrombin time (PT), aspartate aminotransferase (AST) and bilirubin, was an important setting for diagnosis and prognosis. TGO increases early, always within 48 hours, having an essential role in the diagnosis of hepatotoxicity. Despite the late elevation of bilirubin, the cases of death revealed that there was an earlier increase, reaching higher values, which seems to have a prognostic value, to be evaluated with further studies. Finally, we propose a diagram of diagnostic performance, considerating the generalized lack of mycological diagnosis in Portugal, which emphasizes the need for a careful history, focused on quantifying the latency period.
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Affiliation(s)
- José Luís Brandão
- Serviço de Medicina Intensiva, Instituto de Ciências Biomédicas de Abel Salazar, CHP, Porto, Portugal
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Boldrini JL, Costa MI. Therapy burden, drug resistance, and optimal treatment regimen for cancer chemotherapy. IMA J Math Appl Med Biol 2000; 17:33-51. [PMID: 10757031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Three nonlinear models of tumour cell growth under continuous delivery of cycle nonspecific anticancer agents are studied. A dynamical optimization problem with the objective of minimizing the final level of tumour cells is posed for these mathematical setups. The simplest setup does not possess toxicity constraints, whereas the other setups contain a dynamical equation describing the therapy burden as a toxicity criterion. In addition, the third setting contains the dynamics of drug resistant cells. A discussion concerning the optimal strategies of the respective models is performed.
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Affiliation(s)
- J L Boldrini
- Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica, SP, Brasil.
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Abstract
A system of differential equations for the control of tumor cells growth in a cycle nonspecific chemotherapy is presented. Spontaneously acquired drug resistance is accounted for, as well as the evolution in time of normal cells. In addition, optimization of conflicting objectives forms the aim of the chemotherapeutic treatment. For general cell growth, some results are given, whereas for the special case of Malthusian (exponential) growth of tumor cells and rather general growth rate for normal cells, the optimal strategy is worked out. The latter, from the clinical standpoint, corresponds to maximum drug concentration throughout the treatment.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica-CNPq, Rio de Janiero, Brazil.
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Costa MI, Boldrini JL. Chemotherapeutic treatments: a study of the interplay among drug resistance, toxicity and recuperation from side effects. Bull Math Biol 1997; 59:205-32. [PMID: 9116600 DOI: 10.1007/bf02462001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A system of differential equations for the control of tumor growth cells in a cycle nonspecific chemotherapy is analyzed. Spontaneously acquired drug resistance is taken into account, and a criterion for the selection of chemotherapeutic treatment is used. This criterion purports to describe the possibility of improvement of the patient's health when treatment is discontinued. Contrary to our early results which also take drug resistance into account, in this context strategies of continuous chemotherapy in which rest periods take part may be better than maximum drug concentration throughout the treatment (which appears to be in accordance with clinical practice). This bears out our previous conjecture that when drug resistance is accounted for, the imperfections in the usual modelling of treatment criteria, which in general do not allow for patient recuperation, ruled out the possibility of rest periods in optimal continuous chemotherapy.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica--CNPq, Rio de Janeiro, Brasil.
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Sánchez EF, Costa MI, Chavez-Olortegui C, Assakura MT, Mandelbaum FR, Diniz CR. Characterization of a hemorrhagic factor, LHF-I, isolated from the bushmaster snake (Lachesis muta muta) venom. Toxicon 1995; 33:1653-67. [PMID: 8866622 DOI: 10.1016/0041-0101(95)00097-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hemorrhagic factor I (LHF-I) was previously purified from the venom of the bushmaster snake (Lachesis muta muta). In terms of biochemical and immunological properties, LHF-I is a glycoprotein (mol. wt 100,000, pI 4.7) consisting of two subunits; it loses its activity following mercaptoethanol treatment. LHF-I contains 0.7 g-atom zinc and 1.2 g-atom calcium per mole protein. The hemorrhagic and the proteinase activities are inhibited by EDTA; subsequent addition of Ca2+ or Mg2+ does not reverse the EDTA-induced inhibition of the hemorrhagic activity. The metalloenzyme does not hyrolyze arginine esters and is devoid of phospholipase A2 activity. It hydrolyzes the A alpha- > B beta-chain of fibrinogen without clot formation and hydrolyzes selectively the alpha-chain of fibrin, leaving the B beta- and tau-chains unaffected. Antibodies to the hemorrhagic factor in bushmaster venom were produced by immunizing rabbits with the purified protein. The antibody was purified by protein-A affinity chromatography. This antibody was also used to screen other Crotalinae venom samples for immunologically similar epitopes by ELISA assay. The purified antibody reacted only with LHF-I and two samples of bushmaster venom from different geographical locations.
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Affiliation(s)
- E F Sánchez
- Centro de Pesquisa e Desenvolvimento, Fundaçao Ezequiel Dias, Belo Horizonte, M.G., Brazil
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Abstract
A system of differential equations for the control of tumor cells growth in a cycle nonspecific chemotherapy is presented. Drug resistance and toxicity conveyed through the level of normal cells are taken into account in a class of optimal control problems. Alternative treatments for the exponential tumor growth are set forth for cases where optimal treatments are not available.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica-CNPq, R. Lauro Müller, Rio de Janeiro-RJ-Brasil
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Abstract
A system of differential equations for the control of tumor cells growth in a cycle nonspecific chemotherapy is presented. First-order drug kinetics and drug resistance are taken into account in a class of optimal control problems. The results show that the strategy corresponding to the maximum rate of drug injection is optimal for the Malthusian model of cell growth (which is a relatively good model for the initial phase of tumor growth). For more general models of cell growth, this strategy proved to be suboptimal under certain conditions.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica-CNPq, R. Lauro Müller, Rio de Janeiro-RJ-Brasil
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Costa MI, Boldrini JL, Bassanezi RC. Optimal chemotherapy: a case study with drug resistance, saturation effect, and toxicity. IMA J Math Appl Med Biol 1994; 11:45-59. [PMID: 8057040 DOI: 10.1093/imammb/11.1.45] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A system of differential equations for the control of tumour cell growth in a cycle-nonspecific chemotherapy is presented. A rate-of-kill term of saturation type, drug resistance, and toxicity are taken into account in a class of optimal control problems. Some results are obtained for general tumour cell growth rates. A detailed analysis is presented for the Malthusian cell growth, which shows a variety of optimal treatments according to the values of the model parameters and initial tumour level.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica-CNPq, Rio de Janeiro, Brazil
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Abstract
A system of differential equations for the control of the growth of certain populations by the use of chemical treatment is presented. Rather general growth rates and kill rates of drugs, as well as drug resistance, are considered. A class of optimal control problems with a performance criterion depending on a parameter is formulated and shown to admit the same basic optimal strategy. Applications to cycle nonspecific chemotherapy and control of the growth of bacterial populations in cellulose media in paper production plants are described.
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Affiliation(s)
- M I Costa
- Laboratório Nacional de Computação Científica, Rio de Janeiro, Brazil
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