Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 321
Filtrar
1.
Ann Dermatol Venereol ; 150(3): 189-194, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37225615

RESUMO

BACKGROUND: The factors associated with early relapse of infantile haemangioma (IH) after a first course of treatment with oral propranolol for at least six months (initiated after the marketing authorization had been granted) have not previously been investigated. OBJECTIVES: To identify factors associated with the risk of early relapse in children with IH treated with oral propranolol according to the current prescribing guidelines. METHODS: We performed a multicentre, retrospective, case-control study, using the Ouest Data Hub database. All children treated for at least 6 months with oral propranolol for IH between 31 June 2014 and 31 December 2021, and with a follow-up visit at least three months after treatment discontinuation were included. A case was defined as relapse of IH within three months of treatment discontinuation; each case was matched for age at treatment initiation and for centre, with four (relapse-free) controls. The association between relapse and treatment or IH characteristics was expressed as an odds ratio (OR) from univariate and multivariate conditional logistic regressions. RESULTS: A total of 225 children were included. Of these, 36 (16%) relapsed early. In a multivariate analysis, a deep IH component was a risk factor for early relapse [OR = 8.93; 95%CI: 1.0-78.9, p = 0.05]. A propranolol dosage level of less than 3 mg/kg/day protected against early relapse [OR = 0.11; 95%CI: 0.02-0.7, p = 0.02]. Tapering before propranolol discontinuation was not associated with a lower risk of early relapse. CONCLUSION: The risk factors for late and early relapse are probably different. Investigation of the risk factors for early vs. late IH relapse is now warranted.


Assuntos
Hemangioma Capilar , Neoplasias Cutâneas , Criança , Humanos , Lactente , Estudos de Casos e Controles , Estudos Retrospectivos , Propranolol/uso terapêutico , Doença Crônica , Resultado do Tratamento , Administração Oral , Neoplasias Cutâneas/tratamento farmacológico
2.
Ann Intensive Care ; 10(1): 138, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33052476

RESUMO

BACKGROUND: Persistent swallowing disorders (SD) are non-pulmonary complications of mechanical ventilation (MV). However, there are few clinical studies on persistent SD in critically ill patients undergoing tracheal intubation for MV. The aim of the present study was to assess the incidence and characteristics of clinical manifestations associated with persistent SD. METHODS: We prospectively evaluated in patients requiring more than 7 days of invasive MV the incidence and characteristics of clinical manifestations related to persistent SD. For this purpose, quality of swallowing was assessed within 24 h after extubation by an experienced physical therapist not directly involved in patient management. Swallowing assessment consisted in a specific standardized test combining a swallowing test and a full clinical evaluation of the cranial nerves involved in swallowing. In patients with SD on the first test, a second test was done within 48 h in order to discriminate between transient and persistent SD. RESULTS: Among the 482 patients mechanically ventilated more than 7 days, 138 were enrolled in this study. The first test performed 24 h after extubation revealed SD in 35 patients (25%). According to the second test performed 48 h later, SD were considered transient in 21 (15%) and persistent in 14 (10%) cases. Patients with persistent SD were older (66 ± 16 vs 58 ± 15 years), had lower bodyweight at admission (76 ± 15 vs 87 ± 23 kg) and received less often neuromuscular blocking agents (36% vs 66%) compared to patients without or with only transient SD. Patients with persistent SD had longer duration of Intensive Care Unit (ICU) stay after first extubation and longer delay to oral feeding than patients without or with only transient SD, respectively, 11 ± 9 vs 7 ± 6 days and 23 ± 33 vs 5 ± 7 days. CONCLUSIONS: Based on a specific standardized clinical test, 25% of patients mechanically ventilated more than 7 days exhibited clinical manifestations of SD. However, SD were considered as persistent after extubation in only 10% of them. Persistent SD were associated with longer duration of ICU stay after extubation and longer time of enteral feeding. TRIAL REGISTRATION: The study is registered with Clinical Trials (NCT01360580).

3.
Intensive Care Med ; 44(1): 22-37, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29218379

RESUMO

INTRODUCTION: While prone positioning (PP) has been shown to improve patient survival in moderate to severe acute respiratory distress syndrome (ARDS) patients, the rate of application of PP in clinical practice still appears low. AIM: This study aimed to determine the prevalence of use of PP in ARDS patients (primary endpoint), the physiological effects of PP, and the reasons for not using it (secondary endpoints). METHODS: The APRONET study was a prospective international 1-day prevalence study performed four times in April, July, and October 2016 and January 2017. On each study day, investigators in each ICU had to screen every patient. For patients with ARDS, use of PP, gas exchange, ventilator settings and plateau pressure (Pplat) were recorded before and at the end of the PP session. Complications of PP and reasons for not using PP were also documented. Values are presented as median (1st-3rd quartiles). RESULTS: Over the study period, 6723 patients were screened in 141 ICUs from 20 countries (77% of the ICUs were European), of whom 735 had ARDS and were analyzed. Overall 101 ARDS patients had at least one session of PP (13.7%), with no differences among the 4 study days. The rate of PP use was 5.9% (11/187), 10.3% (41/399) and 32.9% (49/149) in mild, moderate and severe ARDS, respectively (P = 0.0001). The duration of the first PP session was 18 (16-23) hours. Measured with the patient in the supine position before and at the end of the first PP session, PaO2/FIO2 increased from 101 (76-136) to 171 (118-220) mmHg (P = 0.0001) driving pressure decreased from 14 [11-17] to 13 [10-16] cmH2O (P = 0.001), and Pplat decreased from 26 [23-29] to 25 [23-28] cmH2O (P = 0.04). The most prevalent reason for not using PP (64.3%) was that hypoxemia was not considered sufficiently severe. Complications were reported in 12 patients (11.9%) in whom PP was used (pressure sores in five, hypoxemia in two, endotracheal tube-related in two ocular in two, and a transient increase in intracranial pressure in one). CONCLUSIONS: In conclusion, this prospective international prevalence study found that PP was used in 32.9% of patients with severe ARDS, and was associated with low complication rates, significant increase in oxygenation and a significant decrease in driving pressure.


Assuntos
Respiração com Pressão Positiva , Decúbito Ventral , Síndrome do Desconforto Respiratório , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Síndrome do Desconforto Respiratório/terapia
4.
Br J Anaesth ; 119(5): 1022-1029, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29028921

RESUMO

BACKGROUND: Both under-dosage and over-dosage of general anaesthetics can harm frail patients. We hypothesised that computer-assisted anaesthesia using pharmacokinetic/pharmacodynamic models guided by SmartPilot® View (SPV) software could optimise depth of anaesthesia and improve outcomes in patients undergoing hip fracture surgery. METHODS: This prospective, randomized, single-centre, blinded trial included patients undergoing hip fracture surgery under general anaesthesia. In the intervention group, anaesthesia was guided using SPV with predefined targets. In the control group, anaesthesia was delivered by usual practice using the same agents (propofol, sufentanil and desflurane). The primary endpoint was the time spent in the "appropriate anaesthesia zone" defined as bispectral index (BIS) (blinded to the anaesthetist during surgery) of 45-60 and systolic arterial pressure of 80-140 mm Hg. Postoperative complications were recorded for one month in a blinded manner. RESULTS: Of 100 subjects randomised, 97 were analysed (n=47 in SPV and 50 in control group). Anaesthetic drug consumption was reduced in the SPV group (for propofol and desflurane). Intraoperative duration of low BIS (<45) was similar, but cumulative time of low systolic arterial pressure (<80 mm Hg) was significantly shorter in the SPV group (median (Q1-Q3); 3 (0-40) vs 5 (0-116) min, P=0.013). SPV subjects experienced fewer moderate or major postoperative complications at 30-days (8 (17)% vs 18 (36)%, P=0.035) and shorter length of hospitalisation (8 (2-20) vs 8 (2-60) days, P=0.017). CONCLUSIONS: SmartPilot® View-guided anaesthesia reduces intraoperative hypotension duration, occurrence of postoperative complications and length of stay in hip fracture surgery patients. CLINICAL TRIAL REGISTRATION: NCT 02556658.


Assuntos
Anestesia Geral/métodos , Anestesiologia/métodos , Quimioterapia Assistida por Computador/métodos , Fraturas do Quadril/cirurgia , Complicações Intraoperatórias/prevenção & controle , Complicações Pós-Operatórias/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Quimioterapia Assistida por Computador/instrumentação , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Estudos Prospectivos , Método Simples-Cego
5.
Ann Fr Anesth Reanim ; 32(4): 220-4, 2013 Apr.
Artigo em Francês | MEDLINE | ID: mdl-23481271

RESUMO

OBJECTIVE: Indications for short-term circulatory and/or respiratory support (STCRS) increased during the last years. The goal of this survey was to characterize this activity in France in 2009. STUDY DESIGN: Observational retrospective pluricentral. MATERIAL AND METHODS: Each center of cardiothoracic surgery received a questionnaire validated by the Société française de perfusion about the activity, materials and organization used for STCRS. Data were expressed as percentages or median (25-75 percentiles). RESULTS: Forty-one centers on 61 (67%) answered. STCRS was performed respectively by 33 (80.5 %), 36 (87.8 %) and 39 (95.1 %) of centers in 2007, 2008 and 2009 including 10 [4-26], 18 [6-29] and 18 [5-33] cases/center per year. In 2009, types of STCRS installed were veno-arterial in 39 centres (95.1 %), veno-venous in 27 (65.9 %) and Novalung(®) in four (9.8 %), including 18 [5-32], five [2-7] and 15 [1-17] cases respectively. Twenty-nine centers (70.7%) installed STCRS outside the operating theater, and 24 (58.5%) in non-cardiothoracic surgery. A mobile circulatory support unit was created in eight centers (19.5%), however 21 (51.2%) have installed STCRS externally, at distances between 10 [5-55] to 100 [15-200] km, using emergency vehicles in most of the cases (90.5%), but helicopter seldom (19%). CONCLUSION: STCRS has increased over the last few years in France. Externalized activity outside the operating theater was important, time-consuming and used hospital resources therefore modifying the professional activity of perfusionists.


Assuntos
Circulação Extracorpórea/estatística & dados numéricos , Respiração Artificial/estatística & dados numéricos , Anticoagulantes/uso terapêutico , Cateterismo/estatística & dados numéricos , Oxigenação por Membrana Extracorpórea/estatística & dados numéricos , França , Humanos , Salas Cirúrgicas/organização & administração , Ressuscitação/estatística & dados numéricos , Estudos Retrospectivos , Centro Cirúrgico Hospitalar/organização & administração , Procedimentos Cirúrgicos Torácicos/estatística & dados numéricos
6.
J Biomed Inform ; 43(2): 332-41, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19961957

RESUMO

Modern information and communications technologies (ICTs) are now so feature-rich and widely available that they can be used to "capture," or collect and transmit, health data from remote settings. Electronic data capture can reduce the time necessary to notify public health authorities, and provide important baseline information. A number of electronic health data capture systems based on specific ICTs have been developed for remote areas. We expand on that body of work by defining and applying an assessment process to characterize ICTs for remote-area health data capture. The process is based on technical criteria, and assesses the feasibility and effectiveness of specific technologies according to the resources and constraints of a given setting. Our characterization of current ICTs compares different system architectures for remote-area health data capture systems. Ultimately, we believe that our criteria-based assessment process will remain useful for characterizing future ICTs.


Assuntos
Coleta de Dados/métodos , Informática Médica/métodos , Vigilância da População/métodos , População Rural , Redes de Comunicação de Computadores/instrumentação , Coleta de Dados/instrumentação , Bases de Dados Factuais , Humanos , Serviços de Saúde Rural , Telecomunicações/instrumentação
7.
J Med Genet ; 43(12): 917-23, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16840570

RESUMO

BACKGROUND: The extent which universally common or population-specific alleles can explain between-population variations in phenotypes is unknown. The heritable coronary heart disease risk factor lipoprotein(a) (Lp(a)) level provides a useful case study of between-population variation, as the aetiology of twofold higher Lp(a) levels in African populations compared with non-African populations is unknown. OBJECTIVE: To evaluate the association between LPA sequence variations and Lp(a) in European Americans and African Americans and to determine the extent to which LPA sequence variations can account for between-population variations in Lp(a). METHODS: Serum Lp(a) and isoform measurements were examined in 534 European Americans and 249 African Americans from the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease Study. In addition, 12 LPA variants were genotyped, including 8 previously reported LPA variants with a frequency of >2% in European Americans or African Americans, and four new variants. RESULTS: Isoform-adjusted Lp(a) level was 2.23-fold higher among African Americans. Three single-nucleotide polymorphisms (SNPs) were independently associated with Lp(a) level (p<0.02 in both populations). The Lp(a)-increasing SNP (G-21A, which increases promoter activity) was more common in African Americans, whereas the Lp(a)-lowering SNPs (T3888P and G+1/inKIV-8A, which inhibit Lp(a) assembly) were more common in European Americans, but all had a frequency of <20% in one or both populations. Together, they reduced the isoform-adjusted African American Lp(a) increase from 2.23 to 1.37-fold(a 60% reduction) and the between-population Lp(a) variance from 5.5% to 0.5%. CONCLUSIONS: Multiple low-prevalence alleles in LPA can account for the large between-population difference in serum Lp(a) levels between European Americans and African Americans.


Assuntos
Negro ou Afro-Americano/genética , Lipoproteína(a)/genética , Polimorfismo de Nucleotídeo Único/genética , População Branca/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Estudos de Coortes , Frequência do Gene , Humanos , Falência Renal Crônica/sangue , Falência Renal Crônica/genética , Falência Renal Crônica/terapia , Desequilíbrio de Ligação , Lipoproteína(a)/sangue , Pessoa de Meia-Idade
8.
SAR QSAR Environ Res ; 17(2): 225-51, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16644559

RESUMO

Classification models were established on four endpoints, i.e. trout, daphnia, quail and bee, including from 100 to 300 pesticides subdivided into 3 toxicity classes. For each species, five separate sets of molecular descriptors, computed by several software, were compared, including parameters related to 2D or 3D structures. The most relevant descriptors were selected with help of a procedure based on genetic algorithms. Then, structure-activity relationships were built by Adaptive Fuzzy Partition (AFP), a recursive partitioning method derived from Fuzzy Logic concepts.Globally, satisfactory results were obtained for each animal species. The best cross-validation and test set scores reached values of about 70-75%. More important, the relationships derived from the descriptors calculated from 2D structures were superior or similar to those computed from 3D structures. These results underline that the long computational time employed to compute 3D descriptors is often useless to improve the prediction ability of the ecotoxicity models. Finally, the differences in the prediction ability between the different software used were quite reduced and show the possibility to use different descriptor packages for obtaining similar satisfactory models.


Assuntos
Lógica Fuzzy , Modelos Biológicos , Praguicidas/toxicidade , Animais , Abelhas , Biologia Computacional , Daphnia , Dose Letal Mediana , Praguicidas/classificação , Codorniz , Relação Quantitativa Estrutura-Atividade , Reprodutibilidade dos Testes , Software , Truta
10.
J Chromatogr A ; 1068(2): 307-14, 2005 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-15830937

RESUMO

This paper describes how different multivariate analysis and classification methods can be used, to characterize the gas chromatographic separation of complex hydrocarbon mixtures in three columns coupled in series. Principal component analysis (PCA), correspondence factor analysis (CFA), and hierarchical ascending classification (HAC) were used as potential tools for evaluating the experiments on single columns and on column series. It has been demonstrated that: (1) multivariate analysis with PCA and CFA offers a powerful strategy to search for the main factors influencing the separation of hydrocarbons without a priori knowledge of the key factors of the separation. (2) With CFA the contribution of retention due to vapour pressure can be minimized. The use of retention indices, which use the n-alkanes as reference compounds, also helps to decrease the dominant focus on vapour pressure in favor of the more selectivity-based interaction forces. (3) CFA helps to analyze the degree of relevance of the chosen experimental design to the most important factors, controlling chromatographic selectivity.


Assuntos
Cromatografia Gasosa/métodos , Hidrocarbonetos/isolamento & purificação , Alcanos/isolamento & purificação , Hidrocarbonetos Aromáticos/isolamento & purificação , Análise Multivariada , Análise de Componente Principal
11.
Am J Hum Genet ; 69(5): 1080-94, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11590548

RESUMO

Population linkage disequilibrium occurs as a consequence of mutation, selection, genetic drift, and population substructure produced by admixture of genetically distinct ethnic populations. African American and Hispanic ethnic groups have a history of significant gene flow among parent groups, which can be of value in affecting genome scans for disease-gene discovery in the case-control and transmission/disequilibrium test designs. Disease-gene discovery using mapping by admixture linkage disequilibrium (MALD) requires a map of polymorphic markers that differentiate between the founding populations, along with differences in disease-gene allele frequencies. We describe markers appropriate for MALD mapping by assessing allele frequencies of 744 short tandem repeats (STRs) in African Americans, Hispanics, European Americans, and Asians, by choosing STR markers that have large differences in composite delta, log-likelihood ratios, and/or I*(2) for MALD. Additional markers can be added to this MALD map by utilization of the rapidly growing single-nucleotide-polymorphism databases and the literature, to achieve a 3-10-cM scanning scale. The map will be useful for studies of diseases, including prostate and breast cancer, diabetes, hypertension, and end-stage renal disease, that have large differences in incidence between the founding populations of either Hispanics or African Americans.


Assuntos
População Negra/genética , Frequência do Gene/genética , Marcadores Genéticos/genética , Hispânico ou Latino/genética , Desequilíbrio de Ligação/genética , Grupos Raciais/genética , Negro ou Afro-Americano , Mapeamento Cromossômico/métodos , Efeito Fundador , Genoma Humano , Humanos , Internet , Funções Verossimilhança , Polimorfismo Genético/genética , Software , Sequências de Repetição em Tandem/genética
12.
Bioorg Khim ; 27(4): 303-13, 2001.
Artigo em Russo | MEDLINE | ID: mdl-11558265

RESUMO

A volume learning algorithm for artificial neural networks was developed to quantitatively describe the three-dimensional structure-activity relationships using as an example N-benzylpiperidine derivatives. The new algorithm combines two types of neural networks, the Kohonen and the feed-forward artificial neural networks, which are used to analyze the input grid data generated by the comparative molecular field approach. Selection of the most informative parameters using the algorithm helped to reveal the most important spatial properties of the molecules, which affect their biological activities. Cluster regions determined using the new algorithm adequately predicted the activity of molecules from a control data set.


Assuntos
Algoritmos , Piperidinas/química , Imageamento Tridimensional , Redes Neurais de Computação , Relação Estrutura-Atividade
13.
Eur J Med Chem ; 36(4): 349-59, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11461760

RESUMO

A data set of 389 compounds, active in the central nervous system (CNS) and divided into eight classes according to the receptor type, was extracted from the RBI database and analyzed by Self-Organizing Maps (SOM), also known as Kohonen Artificial Neural Networks. This method gives a 2D representation of the distribution of the compounds in the hyperspace derived from their molecular descriptors. As SOM belongs to the category of unsupervised techniques, it has to be combined with another method in order to generate classification models with predictive ability. The fuzzy clustering (FC) approach seems to be particularly suitable to delineate clusters in a rational way from SOM and to get an automatic objective map interpretation. Maps derived by SOM showed specific regions associated with a unique receptor type and zones in which two or more activity classes are nested. Then, the modeling ability of the proposed SOM/FC Hybrid System tools applied simultaneously to eight activity classes was validated after dividing the 389 compounds into a training set and a test set, including 259 and 130 molecules, respectively. The proper experimental activity class, among the eight possible ones, was predicted simultaneously and correctly for 81% of the test set compounds.


Assuntos
Sistema Nervoso Central/efeitos dos fármacos , Técnicas de Química Combinatória , Bases de Dados Factuais , Redes Neurais de Computação , Lógica Fuzzy , Humanos , Preparações Farmacêuticas/classificação , Relação Quantitativa Estrutura-Atividade
14.
Eur J Med Chem ; 36(1): 1-19, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11231045

RESUMO

Automated docking allowing protein-based alignment was performed for a series of 188 indole inhibitors of the human non-pancreatic secretory phospholipase A2 (hnps-PLA2). All the substituted indoles were docked to the crystal structure of hnps-PLA2 and a three-dimensional QSAR model was then established using the CoMFA method. The set of 188 compounds was divided into two subsets, the first one constituting the training set (126 compounds), while the second constituted the test set (62 compounds). The established CoMFA model derived from the training set was then applied to the test set. A good correlation between predicted and experimental activity data allows to validate the 3D QSAR model. A second and global 3D QSAR including all the compounds was established, allowing the creation of the hnps-PLA2 pharmacophore.


Assuntos
Anti-Inflamatórios/farmacologia , Simulação por Computador , Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Modelos Moleculares , Fosfolipases A/antagonistas & inibidores , Anti-Inflamatórios/química , Cristalização , Inibidores Enzimáticos/química , Humanos , Indóis/química , Pâncreas/metabolismo , Fosfolipases A/química , Fosfolipases A2 , Conformação Proteica , Reprodutibilidade dos Testes , Relação Estrutura-Atividade
15.
Eur J Med Chem ; 36(1): 21-30, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11231046

RESUMO

An automated docking procedure was applied on a series of 26 reversible and competitive indole inhibitors of human pancreatic phospholipase A2 (hp-PLA2). X-ray data of this enzyme are not available and the structure was then reconstructed exploiting its protein sequence and the crystallographic data of a bovine pancreatic source. The docking data were used to build a three-dimensional quantitative structure-activity relationship (3D QSAR) model, established using the comparative molecular field analysis (CoMFA) method. This model, joined to the previous one developed for the indole inhibitors of human non-pancreatic secretory phospholipase A2 (hnps-PLA2), an enzyme involved in inflammation processes, will allow for the selection of new strong anti-inflammatory drugs with negligible side effects, at least at the level of hp-PLA2.


Assuntos
Inibidores Enzimáticos/química , Indóis/química , Modelos Moleculares , Pâncreas/enzimologia , Pancreatina/antagonistas & inibidores , Fosfolipases A/antagonistas & inibidores , Animais , Anti-Inflamatórios/farmacologia , Bovinos , Simulação por Computador , Cristalização , Inibidores Enzimáticos/farmacologia , Humanos , Indóis/farmacologia , Conformação Molecular , Fosfolipases A2 , Reprodutibilidade dos Testes , Relação Estrutura-Atividade , Suínos
16.
SAR QSAR Environ Res ; 11(3-4): 281-300, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10969876

RESUMO

Kohonen neural networks, also known as Self Organizing Map (SOM), offer a useful 2D representation of the compound distribution inside a large chemical database. This distribution results from the compound organization in a molecular diversity hyperspace derived from a large set of molecular descriptors. Fuzzy techniques based on the "concept of partial truth" reveal to be also a valuable tool for the direct exploitation of chemical databases or SOM. In such cases a fuzzy clustering algorithm is used. In this paper, a complete hybrid system, combining SOM and fuzzy clustering, is applied. As example, a series of olfactory compounds was selected. The complexity of such information is that a same compound may exhibit different odors. It is shown how fuzzy logic helps to have a better understanding of the organization of the compounds. These hybrid systems, using simultaneously SOM and fuzzy clustering, are foreseen as powerful tools for "virtual pre-screening".


Assuntos
Lógica Fuzzy , Redes Neurais de Computação , Relação Quantitativa Estrutura-Atividade , Olfato/fisiologia , Software , Interface Usuário-Computador
17.
Eur J Med Chem ; 35(1): 123-36, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10733609

RESUMO

The predictive capabilities of protein-based alignment (PBA) and structure-based alignment (SBA) comparative molecular field analysis (CoMFA) models have been compared. 3D quantitative structure-activity relationship (3D QSAR) models have been derived for a series of N-benzylpiperidine derivatives which are potent acetylcholinesterase (AChE) inhibitors interesting for Alzheimer's disease. To establish a comparison with the classical SBA procedure, different assay models were derived by superposing ligand conformers that are docked to the AChE active site and by using the most active compound as the reference one. A Kohonen self organizing map (SOM) was applied to analyse the molecular diversity of the test set relative to that of the training set, in order to explain the influence of molecular diversity on the predictive power of the considered models. SBA 3D QSAR models have to be used to predict the inhibitory activity only for compounds belonging to subgroups included in the training set. The PBA 3D QSAR models appeared to have a higher predictability, even for compounds with a molecular diversity greater than that of the training set. This results from the fact that the protein helps to automatically select the active conformation which is fitting the 3D QSAR model.


Assuntos
Acetilcolinesterase/química , Inibidores da Colinesterase/química , Piperidinas/química , Piperidinas/farmacologia , Relação Estrutura-Atividade , Doença de Alzheimer/tratamento farmacológico , Animais , Sítios de Ligação , Camundongos , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Software , Eletricidade Estática
18.
J Comput Aided Mol Des ; 13(4): 355-71, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10425601

RESUMO

Automated docking and three-dimensional Quantitative Structure-Activity Relationship studies (3D QSAR) were performed for a series of 82 reversible, competitive and selective acetylcholinesterase (AChE) inhibitors. The suggested automated docking technique, making use of constraints taken from experimental crystallographic data, allowed to dock all the 82 substituted N-benzylpiperidines to the crystal structure of mouse AChE, because of short computational times. A 3D QSAR model was then established using the CoMFA method. In contrast to conventional CoMFA studies, the compounds were not fitted to a reference molecule but taken in their 'natural' alignment obtained by the docking study. The established and validated CoMFA model was then applied to another series of 29 N-benzylpiperidine derivatives whose AChE inhibitory activity data were measured under different experimental conditions. A good correlation between predicted and experimental activity data shows that the model can be extended to AChE inhibitory activity data measured on another acetylcholinesterase and/or at different incubation times and pH level.


Assuntos
Acetilcolinesterase/metabolismo , Inibidores da Colinesterase/metabolismo , Piperidinas/metabolismo , Animais , Inibidores da Colinesterase/química , Camundongos , Modelos Moleculares , Piperidinas/química , Ligação Proteica , Eletricidade Estática , Relação Estrutura-Atividade
19.
Curr Opin Pulm Med ; 5(3): 128-35, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10228736

RESUMO

Respiratory infections are a frequent burden to health despite the fact that cost-effective methods for their prevention and cure are available. Acute respiratory infections in children under 5 years of age are the most frequent cause of death from lung disease globally, causing more than 4 million deaths annually. Tuberculosis is the most frequent cause of death from a single pathogen in persons aged 15 to 49 years (a total of 2 million to 3 million deaths annually). Respiratory infections are the most frequent complications of immune deficiency (whether due to HIV infection or induced by chemotherapy). Where a "carrier state" occurs (as with many bacterial pathogens), the level of immune function is the key determinant in appearance of disease. Where there is no carrier state (as with many viruses), exposure is the key determinant. Characteristics of the pathogen, including virulence and bacterial load where there is a carrier state, also determine the probability of respiratory infections. Modifiers of these determinants include allergy and toxic exposures including tobacco smoke and ambient pollution.


Assuntos
Infecções Respiratórias/epidemiologia , Síndrome da Imunodeficiência Adquirida/epidemiologia , Síndrome da Imunodeficiência Adquirida/imunologia , Adolescente , Adulto , Distribuição por Idade , Comorbidade , Feminino , França/epidemiologia , Humanos , Hospedeiro Imunocomprometido , Incidência , Masculino , Pessoa de Meia-Idade , Infecções Respiratórias/imunologia , Fatores de Risco , Distribuição por Sexo , Taxa de Sobrevida , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/imunologia
20.
Curr Opin Drug Discov Devel ; 2(3): 213-23, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-19649949

RESUMO

The search for natural bioactive compounds has led to a renewal of interest in exploring the plant kingdom. Indeed, a more rational search for innovative natural active compounds has become a priority. This review describes the search for new, natural, active compounds by combining the classical ethnopharmacology approach with newer strategies. The proposed computer-aided molecular selection and design (CAMSD) strategy is based on an in-depth exploitation of all the ethnopharmacological, chemical and biological information available. In the first step, the information extracted from various complementary sources - private, literature, Internet - is organized within a database called Phytotech. In the second step, bioinformatic technologies are used to search for new leads based on the molecular and/or the botanical diversity analysis of the Phytotech database. Once a lead is found, the knowledge of involved protein/ligand interaction is improved by molecular modeling. Finally, the activity of the derived bioactive compounds is optimized by pharmacomodulation of the previously selected leads with the help of two- or three-dimensional quantitative structure-activity relationships (2D- or 3D-QSAR) database exploitation. This coherent and global strategy, specially designed for selecting and designing natural bioactive molecules, is based on the hybridization of various chemometric strategies and supported by our own recent examples dealing with acetylcholinesterase inhibition.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...