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A challenge of any biosensing technology is the detection of very low concentrations of analytes. The fluorescence interference contrast (FLIC) technique improves the fluorescence-based sensitivity by selectively amplifying, or suppressing, the emission of a fluorophore-labeled biomolecule immobilized on a transparent layer placed on top of a mirror basal surface. The standing wave of the reflected emission light means that the height of the transparent layer operates as a surface-embedded optical filter for the fluorescence signal. FLIC extreme sensitivity to wavelength is also its main problem: small, e.g., 10 nm range, variations of the vertical position of the fluorophore can translate in unwanted suppression of the detection signal. Herein, we introduce the concept of quasi-circular lenticular microstructured domes operating as continuous-mode optical filters, generating fluorescent concentric rings, with diameters determined by the wavelengths of the fluorescence light, in turn modulated by FLIC. The critical component of the lenticular structures was the shallow sloping side wall, which allowed the simultaneous separation of fluorescent patterns for virtually any fluorophore wavelength. Purposefully designed microstructures with either stepwise or continuous-slope dome geometries were fabricated to modulate the intensity and the lateral position of a fluorescence signal. The simulation of FLIC effects induced by the lenticular microstructures was confirmed by the measurement of the fluorescence profile for three fluorescent dyes, as well as high-resolution fluorescence scanning using stimulated emission depletion (STED) microscopy. The high sensitivity of the spatially addressable FLIC technology was further validated on a diagnostically important target, i.e., the receptor-binding domain (RBD) of the SARS-Cov2 via the detection of RBD:anti-S1-antibody.
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COVID-19 , RNA Viral , Humanos , Microscopia de Fluorescência/métodos , SARS-CoV-2 , Corantes Fluorescentes/químicaRESUMO
Network-based biocomputation (NBC) relies on accurate guiding of biological agents through nanofabricated channels produced by lithographic patterning techniques. Here, we report on the large-scale, wafer-level fabrication of optimized microfluidic channel networks (NBC networks) using electron-beam lithography as the central method. To confirm the functionality of these NBC networks, we solve an instance of a classical non-deterministic-polynomial-time complete ("NP-complete") problem, the subset-sum problem. The propagation of cytoskeletal filaments, e.g., molecular motor-propelled microtubules or actin filaments, relies on a combination of physical and chemical guiding along the channels of an NBC network. Therefore, the nanofabricated channels have to fulfill specific requirements with respect to the biochemical treatment as well as the geometrical confienement, with walls surrounding the floors where functional molecular motors attach. We show how the material stack used for the NBC network can be optimized so that the motor-proteins attach themselves in functional form only to the floor of the channels. Further optimizations in the nanolithographic fabrication processes greatly improve the smoothness of the channel walls and floors, while optimizations in motor-protein expression and purification improve the activity of the motor proteins, and therefore, the motility of the filaments. Together, these optimizations provide us with the opportunity to increase the reliability of our NBC devices. In the future, we expect that these nanolithographic fabrication technologies will enable production of large-scale NBC networks intended to solve substantially larger combinatorial problems that are currently outside the capabilities of conventional software-based solvers.
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Case of a patient with acute myeloid leukemia (AML) positive for mutations in both genes NPM1 and FLT3-ITD who underwent two allogeneic haematopoietic stem cell transplants (HSCT); the second allograft one was followed by extramedullary relapse (granulocytic sarcoma of right breast), with blast cells positive for FLT3-ITDmutation. Treatment with Gilteritinib, a second generation selective oral type I FLT3 inhibitor, was started after the second HSCT with complete regression of breast granulocytic sarcoma in absence of hematological and extra hematologic toxicity. We conclude that Gilteritinib can represent an effective therapy for extra hematologic relapse, with acceptable toxicity and outpatient management.
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[This corrects the article DOI: 10.1098/rsfs.2018.0034.].
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On-chip network-based computation, using biological agents, is a new hardware-embedded approach which attempts to find solutions to combinatorial problems, in principle, in a shorter time than the fast, but sequential electronic computers. This analytical review starts by describing the underlying mathematical principles, presents several types of combinatorial (including NP-complete) problems and shows current implementations of proof of principle developments. Taking the subset sum problem as example for in-depth analysis, the review presents various options of computing agents, and compares several possible operation 'run modes' of network-based computer systems. Given the brute force approach of network-based systems for solving a problem of input size C, 2C solutions must be visited. As this exponentially increasing workload needs to be distributed in space, time, and per computing agent, this review identifies the scaling-related key technological challenges in terms of chip fabrication, readout reliability and energy efficiency. The estimated computing time of massively parallel or combinatorially operating biological agents is then compared to that of electronic computers. Among future developments which could considerably improve network-based computing, labelling agents 'on the fly' and the readout of their travel history at network exits could offer promising avenues for finding hardware-embedded solutions to combinatorial problems.
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The combinatorial nature of many important mathematical problems, including nondeterministic-polynomial-time (NP)-complete problems, places a severe limitation on the problem size that can be solved with conventional, sequentially operating electronic computers. There have been significant efforts in conceiving parallel-computation approaches in the past, for example: DNA computation, quantum computation, and microfluidics-based computation. However, these approaches have not proven, so far, to be scalable and practical from a fabrication and operational perspective. Here, we report the foundations of an alternative parallel-computation system in which a given combinatorial problem is encoded into a graphical, modular network that is embedded in a nanofabricated planar device. Exploring the network in a parallel fashion using a large number of independent, molecular-motor-propelled agents then solves the mathematical problem. This approach uses orders of magnitude less energy than conventional computers, thus addressing issues related to power consumption and heat dissipation. We provide a proof-of-concept demonstration of such a device by solving, in a parallel fashion, the small instance {2, 5, 9} of the subset sum problem, which is a benchmark NP-complete problem. Finally, we discuss the technical advances necessary to make our system scalable with presently available technology.
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Human acetylcholinesterase (AChE) is a widely studied target enzyme in drug discovery for Alzheimer's disease (AD). In this paper we report evaluation of the optimum structure and chemistry of the supporting material for a new AChE-based fluorescence sensing surface. To achieve this objective, multilayered silicon wafers with spatially controlled geometry and chemical diversity were fabricated. Specifically, silicon wafers with silicon oxide patterns (SiO(2)/Si wafers), platinum-coated silicon wafers with SiO(2) patterns (SiO(2)/Pt/Ti/Si wafers), and Pt-coated wafers coated with different thicknesses of TiO(2) and SiO(2) (SiO(2)/TiO(2)/Pt/Ti/Si wafers) were labelled with the fluorescent conjugation agent HiLyte Fluor 555. Selection of a suitable material and the optimum pattern thickness required to maximize the fluorescence signal and maintain chemical stability was performed by confocal laser-scanning microscopy (CLSM). Results showed that the highest signal-to-background ratio was always obtained on wafers with 100 nm thick SiO(2) features. Hence, these wafers were selected for covalent binding of human AChE. Batch-wise kinetic studies revealed that enzyme activity was retained after immobilization. Combined use of atomic-force microscopy and CLSM revealed that AChE was homogeneously and selectively distributed on the SiO(2) microstructures at a suitable distance from the reflective surface. In the optimum design, efficient fluorescence emission was obtained from the AChE-based biosensing surface after labelling with propidium, a selective fluorescent probe of the peripheral binding site of AChE.
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Acetilcolinesterase/química , Técnicas Biossensoriais/instrumentação , Enzimas Imobilizadas/química , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Humanos , Cinética , Dióxido de Silício/químicaRESUMO
Competition regulation in taekwondo has experienced several changes during the last few years, for example, kicks to the head score more points than kicks to the chest. In addition, some external factors such as the height of target and execution distance seem to affect the kick performance. The aim of this study was to analyse selected biomechanical parameters (impact force, reaction time, and execution time) according to the height and execution distance in two different male groups (experts (n = 12) and novices (n = 21)). Athletes kicked twice from every execution distance (short, normal and long) and towards two different heights of target (chest and head) in a random order. Novices kicked to the head with a longer reaction time than to the chest (p < 0.05) but experts were able to kick with similar performance for both heights. From short and normal distances experts kicked with similar performance; whereas from the normal distance novices had longer reaction and execution time than from the short distance (p < 0.05). In conclusion, in counterattacking situations, experts should perform the roundhouse kick to the head instead of to the chest, because it produces better scores with similar performance; whereas novice athletes should avoid kicking to the head because they are not able to kick with similar performance. Moreover, it is recommended that during counterattacks higher-level taekwondo athletes should intend to kick from normal distances.
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INTRODUCTION: We report a case of treatment of anaplastic thyroid carcinoma spread over the trachea with mediastinal extension. METHODS: Case report and review of the world literature concerning the treatment of anaplastic thyroid carcinoma are presented. DISCUSSION: The role of surgery in treatment of anaplastic carcinoma remains controversial. Our case we underlined two questions: the appropriateness of the surgery options with extra-thyroid spread and the better surgery approach to anaplastic thyroid carcinoma interesting the mediastinum controlling the great vessels of the neck. Even if curative resection cannot be achieved, surgical resection can immediately reduce the tumor bulk to facilitate the efficacy of post-operative radiotherapy and/or chemotherapy and to achieve a good local control to avoid the need of a subsequent palliative tracheostomy. Tumor upper mediastinal involvement made mandatory to open the sternum in order to allow a more complete resection of the macroscopic mass. The mini-sternotomy represents a valuable alternative that allows reduction in surgical trauma increasing patient's comfort. CONCLUSION: The complete resection of the tumor mass without scarifying vital structures can lead to some prolonged survival. Even if complete resection cannot be achieved, surgical resection can immediately reduce the tumour bulk and achieve good local control of the disease to avoid the palliative tracheotomy.
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Carcinoma/cirurgia , Neoplasias do Mediastino/cirurgia , Esternotomia , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/cirurgia , Neoplasias da Traqueia/cirurgia , Carcinoma/secundário , Evolução Fatal , Feminino , Humanos , Laringectomia , Neoplasias do Mediastino/metabolismo , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Tireoidectomia , Neoplasias da Traqueia/metabolismoRESUMO
To fight bone diseases characterized by poor bone quality like osteoporosis and osteoarthritis, as well as in reconstructive surgery, there is a need for a new generation of implantable biomaterials. It is envisioned that implant surfaces can be improved by mimicking the natural extracellular matrix of bone tissue, which is highly a organized nano-composite. In this study we aimed to get a better understanding of osteoblast response to nanometric grooved substrates varying in height, width and spacing. A throughput screening biochip was created using electron beam lithography. Subsequently, uniform large-scale nanogrooved substrates were created using laser interference lithography and reactive ion etching. Results showed that osteoblasts were responsive to nanopatterns down to 75 nm in width and 33nm in depth. SEM and TEM studies showed that an osteoblast-driven calcium phosphate (CaP) mineralization was observed to follow the surface pattern dimensions. Strikingly, aligned mineralization was found on even smaller nanopatterns of 50 nm in width and 17 nm in depth. A single cell based approach for real time PCR demonstrated that osteoblast-specific gene expression was increased on nanopatterns relative to a smooth control. The results indicate that nanogrooves can be a very promising tool to direct the bone response at the interface between an implant and the bone tissue.
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Matriz Extracelular , Nanoestruturas , Osteoblastos/citologia , Animais , Sequência de Bases , Materiais Biocompatíveis , Células Cultivadas , Primers do DNA , Imunofluorescência , Adesões Focais , Expressão Gênica , Masculino , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Osteoblastos/ultraestrutura , Reação em Cadeia da Polimerase , Ratos , Ratos WistarRESUMO
PURPOSE: The purpose of our study was to make an evaluation of the effective cost of a session of deflexible ureteroscopy with laser to cure kidney stones and kidney urothelials tumors. MATERIAL: This cost was calculated based on 103 sessions (83 kidney stones, 18 urothelials tumors, one cyst and one endopyelotomy) carried out on 73 patients and was including (1) staff expenses in the operation room (based on work time stated on the anesthesia sheet); (2) material expenses: technically specific or not. Reusable or single use; (3) amortisement of medical supply calculated on a seven year basis; (4) hospital stay. In this study medical logistic expenses and administrative expenses were not taken into account as well as structural expenses which were considered apart of this activity. RESULTS: Cost of a laser deflexible ureteroscopy was estimated by more or less 4237.3euro, including 1677.6euro for hospital charges. The cost of a session was 4490.5euro for a tumor and 4141.4euro for a stone, however the difference was not significant. Cost without hospital charges was estimated by 1196.5euro. CONCLUSION: The main part of a laser deflexible ureteroscopy session cost was the consequence of hospital expenses. It could only be obtained in a structure running a sufficient activity level depend on amortisement of medical supply.
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Terapia a Laser/economia , Ureteroscopia/economia , Ureteroscopia/métodos , Custos e Análise de Custo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
OBJECTIVE: To evaluate diagnostic properties of the Frontal Behavioural Inventory (FBI) in patients suffering from different forms of dementia. METHODS: The FBI was administered with other psychometric tests investigating cognitive performances and behavioral scales to the caregivers of 35 patients with the frontal variant of frontotemporal dementia (fv-FTD), 22 patients with Alzheimer's disease (AD) and 15 with vascular dementia (VaD). All patients were comparable for degree of dementia severity and level of executive impairment. RESULTS: The FBI showed high concurrent validity, internal consistency and good inter-rater and test-retest reliability. The discriminant validity was also very high. A new FBI cut-off score of 23 gave 97% sensitivity and 95% specificity in distinguishing fv-FTD from non-FTD patients. Conversely, the Neuropsychiatic Inventory (NPI) score was unable to differentiate fv-FTD from AD. CONCLUSIONS: The FBI is a neurobehavioral tool suitable to distinguish fv-FTD from other forms of dementia also when data from cognitive testing or other behavioral scales fail to support the differential diagnosis.
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Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Demência/diagnóstico , Demência/psicologia , Lobo Frontal/fisiopatologia , Testes Neuropsicológicos/normas , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/psicologia , Comportamento/fisiologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Transtornos Cognitivos/classificação , Demência/classificação , Demência Vascular/diagnóstico , Demência Vascular/psicologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Transtornos Mentais/classificação , Transtornos Mentais/diagnóstico , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Variações Dependentes do Observador , Valor Preditivo dos Testes , Psicometria , Reprodutibilidade dos TestesRESUMO
Epilepsy is a relatively frequent chronic condition with an important impact on the health perception and quality of life (QOL) of patients. The aim of the present study was to identify variables related to health status perception and QOL in persons with epilepsy. Participants were 200 persons with epilepsy, 53.5% of whom were males. The mean age was 39.6; 95% had seizures, and 99% were taking antiepileptic medication. The self-report questionnaire administered assessed four types of variables: demographic, disease, epilepsy-specific optimistic attitude, and outcome variables. Results demonstrated that an optimistic orientation is related to better perception of physical and mental health status and better perception of QOL. The variables that best predict positive outcomes are optimistic orientation, perception of cognitive functioning, and perception of seizure control. These results question the importance attributed to seizure characteristics for everyday functioning and everyday life of individuals with epilepsy, and stress the importance of facilitating an epilepsy-specific optimistic orientation.
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Epilepsia/psicologia , Nível de Saúde , Qualidade de Vida/psicologia , Temperamento , Adaptação Psicológica , Adulto , Afeto , Cognição , Epilepsia/complicações , Feminino , Humanos , Masculino , Personalidade , Convulsões/psicologia , Autoavaliação (Psicologia) , Índice de Gravidade de Doença , Perfil de Impacto da DoençaRESUMO
It has been carried out a survey to evaluate the appropriateness of hospital stay in a university hospital. The aims of the study were: to determine the amount of inappropriate hospital admissions and inappropriate days of stay in relation to either wards and characteristics of admission; to analyse the reasons for inappropriate patient stay. A randomised sample stratified by ward of discharge of 224 medical records were analysed using the Italian version of the Appropriateness Evaluation Protocol. 37.9% of the hospital admissions and 18.9% of hospitalisation days were judged to be inappropriate. The main reasons for categorising an admission or a day of stay as inappropriate were a) delay in performing elective surgery procedures; b) that the patient's problem could be treated on an outpatient basis; c) delay in performing diagnostic examinations. The univariate statistical analysis showed an association between appropriateness of hospital stay and gender age, ward of discharge, length of hospital stay and DRG type (medical/surgical). The study highlights a lower level of inappropriateness compared to the results of other investigations. Hints were also identified for achieving an improved efficiency at hospital level.
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Hospitais Universitários/estatística & dados numéricos , Tempo de Internação , Admissão do Paciente/normas , Adolescente , Adulto , Idoso , Análise de Variância , Criança , Pré-Escolar , Feminino , Inquéritos Epidemiológicos , Hospitalização/estatística & dados numéricos , Hospitais Universitários/normas , Humanos , Lactente , Recém-Nascido , Itália , Masculino , Prontuários Médicos , Pessoa de Meia-Idade , Revisão da Utilização de Recursos de SaúdeRESUMO
AIM: To test a non-invasive presurgical protocol for temporal lobe epilepsy (TLE) based on "anatomo-electro-clinical correlations". METHODS: All consecutive patients with suspected TLE and seizure history <2 years were entered into the protocol, which included video-electroencephalographic (EEG) monitoring and magnetic resonance imaging (MRI). Three different TLE subsyndromes (mesial, lateral, mesiolateral) were identified by combined anatomical, electrical, and clinical criteria. "Tailored" surgery for each subsyndrome was offered. Patients with seizure history <2 years, MRI evidence of temporal mass lesion, and concordant interictal EEG and clinical data bypassed video-EEG monitoring and were directly scheduled for surgery. RESULTS: Lesionectomy was performed without video-EEG recording in 11 patients with tumorous TLE. Of 146 patients studied with video-EEG, 133 received a TLE diagnosis. Four were excluded for neuropsychological risks, eight refused surgery, and 121 underwent surgery. Of 132 consecutive patients who underwent surgery, 101 had at least one year of follow up. They were divided into a "hippocampal sclerosis/cryptogenic" group (n = 57) and a "tumours/cortical organisation disorders" group (n = 44). In the first group, extensive temporal lobectomy (ETL) was performed in 40 patients, anteromesial temporal lobectomy (AMTL) in 17 patients. At follow up, 47 patients were seizure free. In the second group, lesionectomy plus ETL was performed in 23 patients, lesionectomy plus AMTL in six patients, and lesionectomy alone in 15 patients. Thirty nine patients were seizure free. CONCLUSIONS: These findings suggest that different TLE subsyndromes can be identified accurately using non-invasive anatomo-electro-clinical data and can be treated effectively and safely with tailored surgery.
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Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/cirurgia , Procedimentos Neurocirúrgicos/métodos , Adolescente , Adulto , Encéfalo/patologia , Encéfalo/fisiopatologia , Encéfalo/cirurgia , Criança , Eletroencefalografia , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Cuidados Pré-Operatórios , Gravação de VideoteipeRESUMO
In women with polycystic ovary syndrome (PCOS) weight loss is associated with an improvement in insulin sensitivity and a reduction of the insulin concentration in the plasma. It is clear, then, that the first therapeutic approach that can be considered in obese PCOS patients for restoration of the menstrual cycle should be a diet. The aim of our study was to examine the effect of long-term caloric restriction on the clinical and biochemical abnormalities in obese PCOS women. The results obtained make it clear that caloric restriction for 4 weeks causes an increase in SHBG and decreases of free testosterone and insulin, with consequent improvement of the clinical picture.
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Obesidade/dietoterapia , Obesidade/fisiopatologia , Síndrome do Ovário Policístico/fisiopatologia , Restrição Calórica , Feminino , Humanos , Insulina/sangue , Resistência à Insulina/fisiologia , Obesidade/complicações , Ovário/fisiopatologia , Síndrome do Ovário Policístico/complicações , Globulina de Ligação a Hormônio Sexual/análise , Testosterona/sangueRESUMO
Erythrocyte aggregability was determined by a laser backscattering light technique in 23 beta minor thalassemia carriers and in 36 age and sex matched controls. The aggregation time (Ta) was statistically higher in cases than in controls (2.8 +/- 1.0 vs 2.3 +/- 0.4, p < 0.05) and the aggregation index at 10 sec (AI10) was statistically lower (25.1 +/- 5.7 vs 28.2 +/- 3.8, p < 0.05), suggesting both parameters a statistically lower erythrocyte aggregability tendency. However, the total disaggregation threshold (gammaD) was statistically higher in cases than in controls (134.4 +/- 34.1 vs 105.1 +/- 33.1, p < 0.05), indicating that once aggregates are formed a higher shear rate is needed to break them up. No differences were observed in plasmatic factors, i.e., fibrinogen, total cholesterol and triglycerides, that could have influenced erythrocyte aggregation. A negative statistically significant correlation was found between erythrocyte indexes and the total disaggregation threshold. The lower erythrocyte aggregation found in minor thalassemia carriers could be attributed in part to the morphological alterations, although others mechanisms such as modifications in the membrane structure of the RBC can not be ruled out.
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Agregação Eritrocítica , Nefelometria e Turbidimetria/métodos , Talassemia beta/sangue , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Criança , Feminino , Hemorreologia/instrumentação , Hemorreologia/métodos , Heterozigoto , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Espalhamento de RadiaçãoRESUMO
BACKGROUND: Endometriosis is considered a benign disease that has the ability to invade normal tissue. As in neoplastic growth, local extracellular proteolysis may take place. The aim of this study is to analyse several components of the plasminogen activator (PA) pathway and the matrix metalloproteinase (MMP) system in endometriotic tissue, endometrium and peritoneal fluid from women with and without endometriosis (controls). METHODS AND RESULTS: Thirty-nine women with endometriosis and 35 controls were studied. In eutopic endometrium of women with endometriosis, the antigenic levels of urokinase-type PA (uPA) and MMP-3 were elevated when compared with endometrium from controls. Ovarian endometriotic tissues had higher antigenic levels of PA inhibitor type 1 (PAI-1) and tissue inhibitor of metalloproteinases type 1 (TIMP-1) than endometrium. The peritoneal fluid from women with endometriosis showed a significant increase in uPA levels compared with controls. CONCLUSIONS: The increase in antigenic levels of uPA and MMP-3 in endometrium of women with endometriosis might contribute to the invasive potential of endometrial cells. Once the ovarian endometriotic cyst is developed, an increase in PAI-1 and TIMP-1 is detected and significant proteolytic activity is no longer observed. This increase in inhibitors and decrease in proteolytic activity could explain the frequent clinical finding of isolated endometriotic cyst without invasion of the surrounding ovarian tissue.
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Endometriose/metabolismo , Endométrio/metabolismo , Metaloproteinase 3 da Matriz/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Adulto , Líquido Ascítico/metabolismo , Fracionamento Celular , Membrana Celular/metabolismo , Citosol/metabolismo , Endometriose/patologia , Endométrio/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismoRESUMO
An association between an increase in plasminogen activator inhibitor type 1 (PAI-1) and obesity, and also between elevated levels of PAI-1 and the presence of PAI-1 promoter 4G allele has been described in adults and can contribute to increased risk of cardiovascular disease. It has also been suggested that in adults a decrease in adiposity has beneficial effects on the haemostatic system. However, less information is available regarding adiposity and fibrinolysis in children. The aim of the present study is to evaluate the effect of weight loss and the influence of the PAI-1 promoter 4G/5G genotype on the fibrinolytic system and lipid parameters in obese children. The clinical groups included 102 obese children and 105 controls of similar age and sex distribution. A significant decrease in fibrinolytic activity due to a significant increase in PAI-1 antigen and activity levels was observed in the obese children in comparison with the control group. In obese children, no significant differences in PAI-1 levels between the PAI-1 4G/5G genotypes were obtained. A significant correlation was observed between PAI-1 antigenic and functional levels and body mass index (BMI), as well as between PAI-1 levels and both triglyceride and insulin levels. No correlation between PAI-1 levels and either cholesterol or glucose levels was observed. After a three-month period of treatment to reduce weight, an increase in fibrinolytic activity due to a decrease in PAI- levels was observed in the obese children who had reduced their BMI in comparison with the group of obese children who did not show a decrease in their BMI. No significant differences between the two groups with respect to the variations in tissue type plasminogen activator and fibrinogen levels were obtained after three months of intervention to reduce weight. A significant correlation was observed between variations in BMI and variations in PAI-1 levels, and a significant inverse correlation was also observed between previous PAI-1 levels and variation in PAI-1 levels. Therefore, the largest decrease in PAI-1 levels was observed in the obese children with the highest previous PAI-1 levels. In conclusion, a decrease in BMI in obese children shows a favourable effect on the fibrinolytic system due to a decrease in PAI-1 levels. However, no influence of 4G/5G genotype on PAI-1 levels was observed.