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1.
Chaos ; 34(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38598674

RESUMO

Functional networks have emerged as powerful instruments to characterize the propagation of information in complex systems, with applications ranging from neuroscience to climate and air transport. In spite of their success, reliable methods for validating the resulting structures are still missing, forcing the community to resort to expert knowledge or simplified models of the system's dynamics. We here propose the use of a real-world problem, involving the reconstruction of the structure of flights in the US air transport system from the activity of individual airports, as a way to explore the limits of such an approach. While the true connectivity is known and is, therefore, possible to provide a quantitative benchmark, this problem presents challenges commonly found in other fields, including the presence of non-stationarities and observational noise, and the limitedness of available time series. We explore the impact of elements like the specific functional metric employed, the way of detrending the time series, or the size of the reconstructed system and discuss how the conclusions here drawn could have implications for similar analyses in neuroscience.

2.
Rev Med Chil ; 151(6): 742-752, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38801383

RESUMO

OBJECTIVES: To characterize clinical aspects, evaluate the diagnostic opportunity, and identify factors associated with mortality in patients hospitalized for tuberculosis (TB). METHODS: Retrospective study of patients admitted for TB to a Regional Hospital in Chile between 2011 and 2019. RESULTS: 142 TB events required hospitalization in this period (38.2% of total cases). All risk groups were identified, with a significant increase in patients with diabetes mellitus. The pulmonary location was the most frequent (71.1%), followed by disseminated forms (16.2%). The sensitivity of microscopy smear in cases of pulmonary TB (isolated or combined) was 78.8% and lower in cases of bronchoalveolar lavage (58.3%). PCR was only occasionally applied (< 10%) with a sensitivity of 100% in sputum samples. Its use increased progressively and reached a positivity of 33% (6 out of 18 cases) in cases with negative sputum staining. The median time between symptom onset and diagnosis was prolonged (9 weeks), and 32.5% of all regional events were diagnosed at the hospital. Dose adjustments (22.1%), corticosteroid use (25%), and treatment interruptions were frequent (11%). Lethality reached 19%, and by multivariate analysis, only shock was associated with a fatal outcome. CONCLUSIONS: In this case series, the diagnosis of TB cases was delayed, scarcely diagnosed by molecular methods, highly concentrated at the hospital level, required admission in a large percentage of cases, and had a high case-fatality rate.


Assuntos
Tuberculose Pulmonar , Humanos , Estudos Retrospectivos , Masculino , Feminino , Pessoa de Meia-Idade , Chile/epidemiologia , Adulto , Fatores de Risco , Idoso , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/mortalidade , Adulto Jovem , Hospitalização/estatística & dados numéricos , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/mortalidade , Adolescente , Escarro/microbiologia
3.
Rev Med Chil ; 151(1): 23-31, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37906743

RESUMO

BACKGROUND: The SARS-CoV-2 pandemic is associated with morbidity, hospitalizations, absenteeism, and mortality among healthcare workers (HCW). AIM: To evaluate the seroconversion rate in HCW exposed to SARS-CoV-2 in the early pandemic phase in 2020 at a regional reference hospital. MATERIAL AND METHODS: One hundred seventy-nine HCW working at a regional hospital were invited to a longitudinal study performed between April-July 2020. A serological analysis by ELISA IgG for viral nucleoprotein and protein S with a secondary analysis by ELISA IgG protein S1/S2 for samples with positive or doubtful result was carried out together with a complementary online survey to inquire about occupational or community exposures to SARS-CoV-2. RESULTS: Two cases with baseline infection were detected (1.1%, one symptomatic and one asymptomatic) and no cases of seroconversion were detected. During the study period, there were 136 patients hospitalized with COVID-19, and regional weekly COVID-19 incidence ranged from 2.7 to 24.4 per 100,000 inhabitants. No SARS-CoV-2 cases were detected by PCR among 27 HCW who consulted for respiratory symptoms in the period. Online surveys confirmed direct care of COVID-19 patients and also detected a high degree of unprotected social interaction at work. CONCLUSIONS: There was no evidence of seroconversion in this group of HCW exposed to the risk of infection by SARS-CoV-2 during the onset of the COVID-19 pandemic. Personal protective equipment and other measures used by the HCW were extremely useful for their protection in the initial phase of the pandemic.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiologia , Pandemias/prevenção & controle , Estudos Longitudinais , Soroconversão , Pessoal de Saúde , Imunoglobulina G
4.
Rev Med Chil ; 151(6): 717-724, 2023 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-38801380

RESUMO

INTRODUCTION: COVID-19 claimed millions of lives, mainly in the pre-vaccine era. Preliminary studies showed promising efficacy of convalescent plasma against SARS-CoV-2 (CP). OBJECTIVE: To evaluate the efficacy of CP in patients hospitalized for COVID-19 with moderate severity. METHODS: Retrospective, bicentric study including adults hospitalized for moderate (non-critical) COVID-19 who required oxygen therapy. CP donated by survivors of mild cases (600 cc) were searched for IgG anti-SARS-CoV-2. Its impact on mortality, hospital stay (days), and need for mechanical ventilation (IMV) was evaluated. RESULTS: Of the 119 patients included, 58% were men (median age 60 years), 88% had comorbidity, and 43% had a high-risk CALL score. Forty-three patients (36%) received CP, only 15 (12.6%) early (< 7 days). Twenty-two patients had to be transferred to the intensive care unit; 18 received IMV, and 15 died (12.6%). The use of CP was not associated with changes in mortality (p = 0.16), need for IMV (p = 0.79), or hospital stay (p = 0.24). Its early administration (< 7 days of symptoms) did not show a significant association either. The presence of heart disease and subsequently requiring IMV were independent factors of mortality. CONCLUSIONS: The use of CP in patients hospitalized for moderately severe COVID-19 was not associated with lower mortality, hospital stay, or the need for IMV.


Assuntos
Soroterapia para COVID-19 , COVID-19 , Hospitalização , Imunização Passiva , Tempo de Internação , SARS-CoV-2 , Índice de Gravidade de Doença , Humanos , COVID-19/terapia , COVID-19/mortalidade , Masculino , Estudos Retrospectivos , Pessoa de Meia-Idade , Feminino , Idoso , Hospitalização/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Resultado do Tratamento , Adulto , Respiração Artificial/estatística & dados numéricos
5.
Rev Med Chil ; 149(4): 559-569, 2021 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-34479344

RESUMO

Approximately 5% of COVID-19 patients will have a severe disease requiring invasive or non-invasive mechanical ventilation. In this conditions, sedatives and analgesics are fundamental to promote tolerance, comfort and synchrony with the mechanical ventilator. High and unusual requirements for sedation, analgesics and neuromuscular blockers have been reported in these patients, contributing to prolonged exposure, a high rate of delirium and prolongation of mechanical ventilation. These factors, added to the progressive shortage of these drugs, a high demand for care and less capacity for personalized attention, have created an adverse scenario for their proper and rational use. This paper proposes different pharmacotherapeutic optimization strategies for a rational management of sedation, analgesia and neuromuscular block in critically ill patients with COVID-19, with the therapeutic alternatives available in Chile.


Assuntos
Analgesia , COVID-19 , Chile , Estado Terminal/terapia , Humanos , Hipnóticos e Sedativos , Respiração Artificial , SARS-CoV-2
6.
Rev Med Chil ; 148(6): 778-786, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33480376

RESUMO

BACKGROUND: Cytomegalovirus (CMV) is an opportunistic infection (OI) in immunosuppressed patients. However, there are no clear cut-off values available for quantitative plasmatic CMV measures (viral load [VL]) to discriminate those with CMV illness from those infected suffering a transient viral reactivation. AIM: To estimate a CMV VL cut-off point that discriminates infected patients and those with CMV related diseases, and to clinically characterize AIDS patients with this OI. PATIENTS AND METHODS: Retrospective analysis of AIDS patients admitted by any reason between years 2017 and 2019 and who had a positive plasma CMV VL at any titer. Cases were categorized with illness or infected using accepted criteria and the cut-off value was obtained by receiver operating characteristic curve (ROC) analysis. RESULTS: Twelve patients were identified as having a CMV-associated illness and seven with CMV infection. A CMV VL of 3,800 copies/mL had a sensitivity of 91.6% and 100% specificity to discriminate both states. Of the 12 patients with CMV illness, all were in AIDS stage and only five were receiving HIV therapy. Predominant clinical presentations were gastrointestinal (50%), followed by liver involvement (25%) and CMV disease (25%). All patients were treated with ganciclovir or valganciclovir. Ten patients had a favorable response (83.3%), one patient only had a laboratory improvement (8.3%) and one died during treatment (8.3%). Drug toxicity was recorded in nine patients but in only three cases, a dose adjustment was necessary. CONCLUSIONS: The predominant clinical manifestation in our series was gastrointestinal. A CMV VL cutoff level of CMV VL of 3,800 copies / mL is useful to discriminate infected patients from those with CMV related disease.


Assuntos
Síndrome da Imunodeficiência Adquirida , Infecções por Citomegalovirus , Síndrome da Imunodeficiência Adquirida/complicações , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Antivirais/uso terapêutico , Citomegalovirus , Infecções por Citomegalovirus/complicações , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/tratamento farmacológico , Ganciclovir/uso terapêutico , Humanos , Estudos Retrospectivos , Carga Viral
7.
Rev Med Chil ; 148(11): 1577-1588, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33844763

RESUMO

BACKGROUND: During the first pandemic wave, Covid-19 reached Latin America cities. AIM: To report clinical features and outcomes of a group of patients with Covid-19 admitted to a Chilean regional reference Center. MATERIAL AND METHODS: Cases were identified by a compatible clinical picture and a positive PCR or serological test. Clinical features of patients were retrieved from medical records. RESULTS: Forty-seven adult patients (45 diagnosed by PCR, 2 by serology) were admitted between epidemiological weeks 13 to 33, corresponding to 4.4% of total regional cases. Hospitalization occurred at a median of 10 days after onset of symptoms. Fifty one percent of patients had 60 years or more. Hypertension, obesity and diabetes mellitus were present in 57, 45 and 32 % of cases, respectively. Nineteen percent of patients had no comorbid condition nor were elderly. Two cases were women in their second trimester of pregnancy. Positive IgM or IgM/IgG results obtained by rapid serological testing, had limited sensitivity during the first week (67%). Seventeen patients (36.2%) were transferred to an intensive care unit (ICU) due to respiratory failure. Chest imaging demonstrated a classical COVID-19 pattern in 87%. By univariate analysis, admission to ICU was significantly associated with tachypnea and higher CALL (comorbidity, age, lymphocyte count and lactate dehydrogenase) score. Four patients died (rendering a hospital mortality of 8.5%) and length of stay was ≥ 14 days in 46.8% of patients. By univariate analysis, mortality was associated with immunosuppression and ICU admission. CONCLUSIONS: In our regional Center, patients admitted with COVID-19 had usual risk factors and had a prolonged stay. Hospital mortality was associated with immunosuppression and ICU admission.


Assuntos
COVID-19 , Adulto , Idoso , Chile/epidemiologia , Estado Terminal , Feminino , Hospitalização , Humanos , Unidades de Terapia Intensiva , Gravidez , SARS-CoV-2
8.
Lasers Surg Med ; 51(6): 509-515, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30779363

RESUMO

OBJECTIVE: This PUBA study aimed to assess the efficacy of fractional CO2 laser in the treatment of genitourinary syndrome of menopause (GSM). METHODS: GSM symptoms were assessed before, 1 month after the first session and 1 month after the third session of laser (3 sessions with a 30 days interval between them) in 60 women (median, interquartile range: 55, 49-69). Subjective (visual analog scale) and objective (Vaginal Health Index, VHIS; Vaginal Maturity Index/Frost Index; Spanish Overactive Bladder Questionnaire-Short Form, USMEX Spanish OAB-qSF and Female Sexual Function Index, FSFI) measures were used during the study period to assess CO2 fractionated laser treatment outcomes compared to baseline. RESULTS: Fractional CO2 laser treatment was effective to improve GSM symptoms (vaginal dryness, vaginal itching, vaginal burning, dyspaurenia, dysuria, urinary urgency; P < 0.001) after three sessions, as well as VHIS (median, interquartile range: 13, 10-15 at baseline vs. 21, 20-23 at the fourth month follow up; P < 0.001), Frost Index (median, interquartile range: 28, 24-31 at baseline vs. 8, 6-10 at the fourth month follow up; P < 0.001), USMEX (median, interquartile range: 56, 46-68 at baseline vs 14, 13-16 at the fourth month follow up: P < 0,001) and FSFI (median, interquartile range: 5, 2-14 at baseline vs 30, 28-32). CONCLUSIONS: In this sample, the data suggests that fractionated CO2 laser is an effective alternative for GSM treatment with positive outcomes that persists over time. Lasers Surg. Med. 51:509-515, 2019. © 2019 Wiley Periodicals, Inc.


Assuntos
Doenças Urogenitais Femininas/terapia , Terapia a Laser , Lasers de Gás/uso terapêutico , Menopausa , Idoso , Feminino , Doenças Urogenitais Femininas/etnologia , Doenças Urogenitais Femininas/etiologia , Humanos , Pessoa de Meia-Idade , Peru , Avaliação de Sintomas , Síndrome , Resultado do Tratamento
9.
Artigo em Inglês | MEDLINE | ID: mdl-31093225

RESUMO

OBJECTIVE: To 1) describe clinical characteristics of adult patients in Chile with severe acute respiratory infections (SARI) associated with influenza viruses, and 2) analyze virus subtypes identified in specimens collected from those patients, hospital resources used in clinical management, clinical evolution, and risk factors associated with a fatal outcome, using observational data from the SARI surveillance network (SARInet). METHODS: Adults hospitalized from 1 July 2011 to 31 December 2015 with influenza-associated SARI at a SARI sentinel surveillance hospital in Santiago were identified and the presence of influenza in all cases confirmed by reverse transcription polymerase chain reaction (RT-PCR), using respiratory samples. RESULTS: A total of 221 patients (mean age: 74.1 years) were hospitalized with influenza-associated SARI during the study period. Of this study cohort, 91.4% had risk factors for complications and 34.3% had been vaccinated during the most recent campaign. Pneumonia was the most frequent clinical manifestation, occurring in 57.0% of the cohort; other manifestations included influenza-like illness, exacerbated chronic bronchitis, decompensated heart failure, and asthmatic crisis. Cases occurred year-round, with an epidemic peak during autumn-winter. Both influenza A (H1N1pdm09 and H3N2) and B virus co-circulated. Critical care beds were required for 26.7% of the cohort, and 19.5% needed ventilatory assistance. Multivariate analysis identified four significant factors associated with in-hospital mortality: 1) being bedridden (adjusted odds ratio (aOR): 22.3; 95% confidence interval (CI): 3.0-164); 2) admission to critical care unit (aOR: 8.9; CI: 1.44-55); 3) Pa02/Fi02 ratio < 250 (aOR: 5.8; CI: 1.02-33); and 4) increased serum creatinine concentration (> 1 mg/dL) (aOR: 5.47; CI: 1.20-24). Seasonal influenza vaccine was identified as a significant protective factor (aOR: 0.14; CI: 0.021-0.90). CONCLUSIONS: Influenza-associated SARI affected mainly elderly patients with underlying conditions. Most patients evolved to respiratory failure and more than one-quarter required critical care beds. Clinical presentation was variable. Death was associated with host characteristics and disease-associated conditions, and vaccine was protective. Virus type did not influence outcome.

10.
Opt Lett ; 41(24): 5696-5699, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27973492

RESUMO

At the foundation of the problem of light propagation through optical turbulence is the classical Obukhov-Kolmogorov theory. It rests in the requirement that the refractive index fluctuations should be homogeneous and isotropic. These, with other necessary assumptions, lead to the very well-known -11/3-power exponent spectrum on the inertial range; although departures have been found, they are usually associated with partially developed turbulence or its intrinsic intermittency. Recently, in optics, the interest in anisotropic fluctuations of the refractive index has gained attention. These studies are mostly theoretical, and reduce anisotropic effects to a dilatation along a coordinate direction in the three-dimensional wavenumber space. Few experimental works exists, but all of them employ simulated turbulence. In this Letter, we describe an experiment to produce anisotropic turbulence under controlled conditions; moreover, we observe anisotropy by studying the spectral power exponent of a temporal series of laser beam wandering.

11.
Bioorg Med Chem Lett ; 26(20): 5103-5109, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-27614414

RESUMO

Temozolomide is a chemotherapeutic agent that is used in the treatment of glioblastoma and other malignant gliomas. It acts through DNA alkylation, but treatment is limited by its systemic toxicity and neutralization of DNA alkylation by upregulation of the O6-methylguanine-DNA methyltransferase gene. Both of these limiting factors can be addressed by achieving higher concentrations of TMZ in the brain. Our research has led to the discovery of new analogs of temozolomide with improved brain:plasma ratios when dosed in vivo in rats. These compounds are imidazotetrazine analogs, expected to act through the same mechanism as temozolomide. With reduced systemic exposure, these new agents have the potential to improve efficacy and therapeutic index in the treatment of glioblastoma.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Encéfalo/metabolismo , Dacarbazina/análogos & derivados , Animais , Antineoplásicos Alquilantes/sangue , Antineoplásicos Alquilantes/farmacocinética , Área Sob a Curva , Linhagem Celular Tumoral , Cromatografia Líquida , Dacarbazina/sangue , Dacarbazina/farmacocinética , Dacarbazina/farmacologia , Humanos , Ratos , Espectrometria de Massas em Tandem , Temozolomida
12.
Rev Chilena Infectol ; 32(4): 476-81, 2015 Aug.
Artigo em Espanhol | MEDLINE | ID: mdl-26436798

RESUMO

Disseminated encephalomyelitis (ADEM) is an infrequent condition with considerable morbidity and mortality in adult patients. It requires a high level of suspicion and diagnosis emerges by gathering clinical information, laboratory exams and images studies. ADEM is related to an immunological phenomena occurring after a bacterial/viral infection or recent vaccination. Glucocorticoids are the first line treatment, reserving immunoglobulins and plasmapheresis to refractory cases. We report a male patient aged 25, with ADEM associated to parainfluenza 3 virus respiratory infection that required mechanical ventilation and that had a complete recovery only after plasmapheresis.


Assuntos
Encefalomielite Aguda Disseminada/virologia , Vírus da Parainfluenza 3 Humana , Infecções por Respirovirus/complicações , Adulto , Encefalomielite Aguda Disseminada/terapia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Plasmaferese , Respiração Artificial , Infecções por Respirovirus/terapia , Índice de Gravidade de Doença
13.
Plants (Basel) ; 13(3)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38337949

RESUMO

Rice (Oryza sativa) varieties are generated through breeding programs focused on local requirements. In Chile, the southernmost rice producer, rice productivity relies on the use and generation of temperate japonica germplasms, which need to be adapted to the intensifying effects of climate change. Advanced biotechnological tools can contribute to these breeding programs; new technologies associated with precision breeding, including gene editing, rely on procedures such as regeneration and gene transfer. In this study, the local rice varieties Platino, Cuarzo, Esmeralda, and Zafiro were evaluated for somatic embryogenesis potential using a process that involved the combined use of auxins and cytokinins. An auxin-based (2,4-D) general medium (2N6) allowed for the induction of embryogenic masses in all the genotypes. After induction, masses required culturing either in N6R (kinetin; Platino) or N6RN (BAP, kinetin, IBA, and 2,4-D; Cuarzo, Esmeralda, and Zafiro) to yield whole plants using regeneration medium (N6F, no hormone). The sprouting rates indicated Platino as the most responsive genotype; for this reason, this variety was evaluated for gene transfer. Fifteen-day-old embryo masses were assayed for Agrobacterium-mediated transformation using the bacterial strain EHA105 harboring pFLC-Myb/HPT/GFP, a modified T-DNA vector harboring a geminivirus-derived replicon. The vector included the green fluorescent protein reporter gene, allowing for continuous traceability. Reporter mRNA was produced as early as 3 d after agroinfiltration, and stable expression of the protein was observed along the complete process. These achievements enable further biotechnological steps in these and other genotypes from our breeding program.

14.
Rev Chilena Infectol ; 29(6): 664-71, 2012 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-23412038

RESUMO

UNLABELLED: Influenza A (H1N1) 2009 infection was an important cause of morbidity and mortality in Chile. AIM: To characterize the clinical pattern of hospitalized patients, identify risk factors associated with ICU admission or death, and evaluate its economic impact. PATIENTS AND METHODS: Twenty five adult patients admitted to 2 hospitals in the Metropolitan Area from May 2009 to December 2010 with PCR confirmed H1N1 infection were analyzed. Total hospital charges were obtained and, using data of registered cases, expenses for the whole country during the first epidemic wave were estimated. RESULTS: Aill cases presented a risk factor: age over 60 years old (n = 13, 52%), co-morbid conditions (n = 24, 96%) or pregnancy (n = 1, 4%). Pneumonia was present in 64% (n = 16) and 16% (n = 4) had hypotension. Only 6 patients (24%) had a CURB-65 score ≥ 2 and 36% (n = 9) requiring ICU admission. Case fatality rate was 16% (n = 4). By multivariate analysis, diabetes mellitus type 2 was independently associated with ICU admission or death (OR 8.12; IC95 1.11-59.2, p < 0.05). Hospital charges for those admitted to ICU or the intermediate care unit reached US$ 20,304, and US$ 1,262 for those admitted in general wards. We estimated US$ 20 million in hospital charges for influenza related hospitalizations during the first wave for the whole country. CONCLUSIONS: A high proportion of patients affected by influenza A (H1N1) 2009 infection required ICU admission during 2009-2010. Case fatality rate associated to this infection was high, and diabetes mellitus type 2 was a risk factor for ICU admission or death. Hospital charges were higher for those admitted in critical care units and represented an important expenditure for Chile during the first wave. The CURB-65 score was inappropriate to recognize patients at risk of hospitalization or ICU admission.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/mortalidade , Pandemias/economia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Chile/epidemiologia , Efeitos Psicossociais da Doença , Feminino , Hospitalização , Humanos , Influenza Humana/economia , Masculino , Pessoa de Meia-Idade , Gravidez , Fatores de Risco , População Urbana , Adulto Jovem
15.
Phys Rev E ; 105(4-2): 045310, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35590550

RESUMO

The main motivation of this paper is to introduce the permutation Jensen-Shannon distance, a symbolic tool able to quantify the degree of similarity between two arbitrary time series. This quantifier results from the fusion of two concepts, the Jensen-Shannon divergence and the encoding scheme based on the sequential ordering of the elements in the data series. The versatility and robustness of this ordinal symbolic distance for characterizing and discriminating different dynamics are illustrated through several numerical and experimental applications. Results obtained allow us to be optimistic about its usefulness in the field of complex time-series analysis. Moreover, thanks to its simplicity, low computational cost, wide applicability, and less susceptibility to outliers and artifacts, this ordinal measure can efficiently handle large amounts of data and help to tackle the current big data challenges.

16.
Comput Struct Biotechnol J ; 20: 3257-3267, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35782747

RESUMO

Human gait is a fundamental activity, essential for the survival of the individual, and an emergent property of the interactions between complex physical and cognitive processes. Gait is altered in many situations, due both to external constraints, as e.g. paced walk, and to physical and neurological pathologies. Its study is therefore important as a way of improving the quality of life of patients, but also as a door to understanding the inner working of the human nervous system. In this review we explore how four statistical physics concepts have been used to characterise normal and pathological gait: entropy, maximum Lyapunov exponent, multi-fractal analysis and irreversibility. Beyond some basic definitions, we present the main results that have been obtained in this field, as well as a discussion of the main limitations researchers have dealt and will have to deal with. We finally conclude with some biomedical considerations and avenues for further development.

17.
Biochem Biophys Res Commun ; 406(4): 633-7, 2011 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-21362400

RESUMO

Copper is a micronutrient that is required for proper metabolic functioning of most prokaryotic and eukaryotic organisms. To sustain an adequate supply of copper, a cell requires molecular mechanisms that control the metal content to avoid copper toxicity. This toxicity comes primarily from the reactivity of copper, which can lead to the generation of free radicals. In bacteria, two independent systems are responsible for maintaining the balance of copper within the cells (Cop and Cut family proteins). Previous studies describe CutC as a member of the Cut family that is probably involved in copper homeostasis. However, the role of CutC in copper homeostasis is still unclear. In this work, a homolog of CutC was studied in Enterococcus faecalis, a bacterial model for copper homeostasis. The molecular 3D model of efCutC shows the presence of triose phosphate isomerase (TIM) barrel motifs, previously described in CutC crystals from other organisms, which illustrates the conservation of amino acids with the potential ability to coordinate copper. Through quantitative real-time PCR (qPCR), it was demonstrated that efcutC expression is induced late by copper stimulus, Interestingly this transcriptional response directly correlates with a significant increase in the intracellular copper concentration when the protein is absent in the bacteria, suggesting its participation in mechanisms related to efflux of the metal. Our results describe efCutC as a protein able to respond transcriptionally to copper and to participate in the control of copper homeostasis in E. faecalis. This bacterium is the first reported organism containing a cop operon and an active member of the Cut protein family.


Assuntos
Proteínas de Transporte/biossíntese , Cobre/metabolismo , Enterococcus faecalis/metabolismo , Sequência de Aminoácidos , Proteínas de Transporte/química , Proteínas de Transporte/genética , Cobre/toxicidade , Enterococcus faecalis/efeitos dos fármacos , Homeostase , Dados de Sequência Molecular , Conformação Proteica , Transcrição Gênica/efeitos dos fármacos
18.
Front Plant Sci ; 12: 791030, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35003180

RESUMO

The woody nature of grapevine (Vitis vinifera L.) has hindered the development of efficient gene editing strategies to improve this species. The lack of highly efficient gene transfer techniques, which, furthermore, are applied in multicellular explants such as somatic embryos, are additional technical handicaps to gene editing in the vine. The inclusion of geminivirus-based replicons in regular T-DNA vectors can enhance the expression of clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) elements, thus enabling the use of these multicellular explants as starting materials. In this study, we used Bean yellow dwarf virus (BeYDV)-derived replicon vectors to express the key components of CRISPR/Cas9 system in vivo and evaluate their editing capability in individuals derived from Agrobacterium-mediated gene transfer experiments of 'Thompson Seedless' somatic embryos. Preliminary assays using a BeYDV-derived vector for green fluorescent protein reporter gene expression demonstrated marker visualization in embryos for up to 33 days post-infiltration. A universal BeYDV-based vector (pGMV-U) was assembled to produce all CRISPR/Cas9 components with up to four independent guide RNA (gRNA) expression cassettes. With a focus on fungal tolerance, we used gRNA pairs to address considerably large deletions of putative grape susceptibility genes, including AUXIN INDUCED IN ROOT CULTURE 12 (VviAIR12), SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER 4 (VviSWEET4), LESION INITIATION 2 (VviLIN2), and DIMERIZATION PARTNER-E2F-LIKE 1 (VviDEL1). The editing functionality of gRNA pairs in pGMV-U was evaluated by grapevine leaf agroinfiltration assays, thus enabling longer-term embryo transformations. These experiments allowed for the establishment of greenhouse individuals exhibiting a double-cut edited status for all targeted genes under different allele-editing conditions. After approximately 18 months, the edited grapevine plants were preliminary evaluated regarding its resistance to Erysiphe necator and Botrytis cinerea. Assays have shown that a transgene-free VviDEL1 double-cut edited line exhibits over 90% reduction in symptoms triggered by powdery mildew infection. These results point to the use of geminivirus-based replicons for gene editing in grapevine and other relevant fruit species.

19.
Phys Rev E ; 100(4-1): 042215, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31770914

RESUMO

In this paper, we introduce a model to describe the decay of the number of unobserved ordinal patterns as a function of the time series length in noisy chaotic dynamics. More precisely, we show that a stretched exponential model fits the decay of the number of unobserved ordinal patterns for both discrete and continuous chaotic systems contaminated with observational noise, independently of the noise level and the sampling time. Numerical simulations, obtained from the logistic map and the x coordinate of the Lorenz system, both operating in a totally chaotic dynamics were used as test beds. In addition, we contrast our results with those obtained from pure stochastic dynamics. The fitting parameters, namely, the stretching exponent and the characteristic decay rate, are used to distinguish whether the dynamical nature of the data sequence is stochastic or chaotic. Finally, the analysis of experimental records associated with the hyperchaotic pulsations of an optoelectronic oscillator allows us to illustrate the applicability of the proposed approach in a practical context.

20.
Rev Chilena Infectol ; 36(3): 392-395, 2019 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-31859761

RESUMO

We report a case of V. cholerae non-O1 / non-O139 bacteremia in an 81-year-old woman with abdominal pain, fever, vomiting, liquid stools, choluria and jaundice, while visiting a rural area without access to potable water. The identification was made by the MALDI-TOF mass spectrometry technique and subsequently the non-toxigenic non-O1 / non-139 strain was confirmed in the national reference laboratory. The molecular characterization demonstrated the absence of the cholera toxin gene (CTX), and the TCP pilus, however, presented 5 of 6 virulence genes present in an island of homologous pathogenicity named VPaI-7 of V. parahaemolyticus (vcs N2 +, vcs C2 +, vcs V2 +, toxR-, vspD +, T vopF +) and in addition it was positive for hylAy rtxA virulence genes recognized outside the island. This is the first case reported in Chile of a clinical strain of V. cholerae non-O1, non-O139 isolated from blood culture that carries in its genome a homologous segment of the pathogenicity island named VPaI-7 of V. parahaemolyticus, which codifies for a type III secretion system (TTSS) that probably contributes to his virulence.


Assuntos
Bacteriemia , Proteínas de Bactérias/química , Vibrio cholerae não O1/química , Vibrio cholerae/química , Idoso de 80 Anos ou mais , Bacteriemia/etiologia , Proteínas de Bactérias/isolamento & purificação , Cólera/complicações , Cólera/microbiologia , Feminino , Ilhas Genômicas , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/patogenicidade , Vibrio cholerae não O1/isolamento & purificação , Vibrio cholerae não O1/patogenicidade , Virulência
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