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1.
Eur J Heart Fail ; 26(5): 1201-1214, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38450858

RESUMO

AIMS: Evaluating the benefit of telemonitoring in heart failure (HF) management in real-world settings is crucial for optimizing the healthcare pathway. The aim of this study was to assess the association between a 6-month application of the telemonitoring solution Chronic Care Connect™ (CCC) and mortality, HF hospitalizations, and associated costs compared with standard of care (SOC) in patients with a diagnosis of HF. METHODS AND RESULTS: From February 2018 to March 2020, a retrospective cohort study was conducted using the largest healthcare insurance system claims database in France (Système National des Données de Santé) linked to the CCC telemonitoring database of adult patients with an ICD-10-coded diagnosis of HF. Patients from the telemonitoring group were matched with up to two patients from the SOC group based on their high-dimensional propensity score, without replacement, using the nearest-neighbour method. A total of 1358 telemonitored patients were matched to 2456 SOC patients. The cohorts consisted of high-risk patients with median times from last HF hospitalization to index date of 17.0 (interquartile range: 7.0-66.0) days for the telemonitoring group and 27.0 (15.0-70.0) days for the SOC group. After 6 months, telemonitoring was associated with mortality risk reduction (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.56-0.89), a higher risk of first HF hospitalization (HR 1.81, 95% CI 1.55-2.13), and higher HF healthcare costs (relative cost 1.38, 95% CI 1.26-1.51). Compared with the SOC group, the telemonitoring group experienced a shorter average length of overnight HF hospitalization and fewer emergency visits preceding HF hospitalizations. CONCLUSION: The results of this nationwide cohort study highlight a valuable role for telemonitoring solutions such as CCC in the management of high-risk HF patients. However, for telemonitoring solutions based on weight and symptoms, consideration should be given to implement additional methods of assessment to recognize imminent worsening of HF, such as impedance changes, as a way to reduce mortality risk and the need for HF hospitalizations. Further studies are warranted to refine selection of patients who could benefit from a telemonitoring system and to confirm long-term benefits in high-risk and stable HF patients.


Assuntos
Insuficiência Cardíaca , Hospitalização , Telemedicina , Humanos , Insuficiência Cardíaca/terapia , Insuficiência Cardíaca/mortalidade , Feminino , Masculino , Hospitalização/estatística & dados numéricos , Idoso , Estudos Retrospectivos , França/epidemiologia , Padrão de Cuidado , Pessoa de Meia-Idade
2.
JMIR Form Res ; 7: e35790, 2023 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-37548994

RESUMO

BACKGROUND: In South Africa, diabetes prevalence is expected to reach 5.4 million by 2030. In South Africa, diabetes-related complications severely impact not only patient health and quality of life but also the economy. OBJECTIVE: The Diabetes Nurse Educator (DNE) study assessed the benefit of adding the MyDiaCare program to standard of care for managing patients with type 1 and type 2 diabetes in South Africa. An economic study was also performed to estimate the budget impact of adding MyDiaCare to standard of care for patients with type 2 diabetes older than 19 years treated in the South African private health care sector. METHODS: The real-world DNE study was designed as an observational, retrospective, multicenter, single-group study. Eligible patients were older than 18 years and had at least 6 months of participation in the MyDiaCare program. The MyDiaCare program combines a patient mobile app and a health care professional platform with face-to-face visits with a DNE. The benefit of MyDiaCare was assessed by the changes in glycated hemoglobin (HbA1c) levels, the proportion of patients achieving clinical and biological targets, adherence to care plans, and satisfaction after 6 months of participating in the MyDiaCare program. A budget impact model was performed using data from the DNE study and another South African cohort of the DISCOVERY study to estimate the economic impact of MyDiaCare. RESULTS: Between November 25, 2019, and June 30, 2020, a total of 117 patients (8 with type 1 diabetes and 109 with type 2 diabetes) were enrolled in 2 centers. After 6 months of MyDiaCare, a clinically relevant decrease in mean HbA1c levels of 0.6% from 7.8% to 7.2% was observed. Furthermore, 54% (43/79) of patients reached or maintained their HbA1c targets at 6 months. Most patients achieved their targets for blood pressure (53/79, 67% for systolic and 70/79, 89% for diastolic blood pressure) and lipid parameters (49/71, 69% for low-density-lipoprotein [LDL] cholesterol, 41/71, 58% for high-density-lipoprotein [HDL] cholesterol, and 59/71, 83% for total cholesterol), but fewer patients achieved their targets for triglycerides (32/70, 46%), waist circumference (12/68, 18%), and body weight (13/76, 17%). The mean overall adherence to the MyDiaCare care plan was 93%. Most patients (87/117, 74%) were satisfied with the MyDiaCare program. The net budget impact per patient with type 2 diabetes, older than 19 years, treated in the private sector using MyDiaCare was estimated to be approximately South African Rands (ZAR) 71,023 (US $4089) during the first year of introducing MyDiaCare. CONCLUSIONS: The results of using MyDiaCare program, which combines digital tools for patients and health care professionals with DNE support, suggest that it may be a clinically effective and cost-saving solution for diabetes management in the South African private health care sector.

3.
Artigo em Inglês | MEDLINE | ID: mdl-36901372

RESUMO

Remote patient monitoring (RPM) for the management of patients with chronic heart failure (CHF) has been widely studied from clinical and health-economic points of view. In contrast, data on the organisational impact of this type of RPM are scarce. The objective of the present study of cardiology departments (CDs) in France was to describe the organisational impact of the Chronic Care ConnectTM (CCCTM) RPM system for CHF. An organisational impact map for health technology assessment was used to identify and define the criteria evaluated in the present survey, including the care process, equipment, infrastructure, training, skill transfers, and the stakeholders' abilities to implement the care process. In April 2021, an online questionnaire was sent to 31 French CDs that were using CCCTM for CHF management: 29 (94%) completed the questionnaire. The survey results showed that CDs progressively modified their organisational structures upon or shortly after the implementation of the RPM device. Twenty-four departments (83%) had created a dedicated team, sixteen (55%) had provided dedicated outpatient consultations for patients with an emergency alert, and twenty-five (86%) admitted patients directly (i.e., avoiding the need to attend the emergency department). The present survey is the first to have assessed the organisational impact of the implementation of the CCCTM RPM device for CHF management. The results highlighted the variety of organisational structures, which tended to structure with the use of the device.


Assuntos
Cardiologia , Insuficiência Cardíaca , Humanos , Monitorização Fisiológica/métodos , Serviço Hospitalar de Emergência , Doença Crônica , França
4.
ESC Heart Fail ; 9(6): 3888-3897, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35950267

RESUMO

AIMS: We aim to evaluate the costs associated with healthcare resource consumption for chronic heart failure (HF) management in patients allocated to telemonitoring versus standard of care (SC). METHODS AND RESULTS: OSICAT-ECO involved 745 patients from the OSICAT trial (NCT02068118) who were successfully linked to the French national healthcare database through an indirect deterministic data linkage approach. OSICAT compared a telemonitoring programme with SC follow-up in adults hospitalized for acute HF ≤ 12 months. Healthcare resource costs included those related to hospital and ambulatory expenditure for HF and were restricted to direct costs determined from the French health data system over 18 months of follow-up. Most of the total costs (69.4%) were due to hospitalization for HF decompensation, followed by ambulatory nursing fees (11.8%). During 18-month follow-up, total costs were 2% lower in the telemonitoring versus the SC group, due primarily to a 21% reduction in nurse fees. Among patients with NYHA class III/IV, a 15% reduction in total costs (€3131 decrease) was observed over 18-month follow-up in the telemonitoring versus the SC group, with the highest difference in hospital expenditure during the first 6 months, followed by a shift in costs from hospital to ambulatory at 12 months. CONCLUSIONS: HF hospitalization and ambulatory nursing fees represented most of the costs related to HF. No benefit was observed for telemonitoring versus SC with regard to cost reductions over 18 months. Patients with severe HF showed a non-significant 15% reduction in costs, largely related to hospitalization for HF decompensation, nurse fees, and medical transport.


Assuntos
Insuficiência Cardíaca , Telemedicina , Adulto , Humanos , Hospitalização , Custos de Cuidados de Saúde , Armazenamento e Recuperação da Informação
5.
Pain ; 163(9): e1021-e1029, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35050957

RESUMO

ABSTRACT: Experimental studies have suggested that nitrous oxide-induced analgesia depends on interactions with opioids. On the basis of these results, we hypothesized that the effects of inhaled nitrous oxide/oxygen (N 2 O/O 2 ) 50%-50% equimolar mixture (EMONO) on patients with neuropathic pain would be higher in those receiving concomitant opioids. To test this hypothesis, we did exploratory post hoc analyses of our recently published ProtoTOP study to compare the effects of EMONO and placebo in patients with or without concomitant opioid treatment. A total of 92 patients of the 221 (ie, 41.6%) included in the ProtoTOP study were concomitantly treated with opioids. In contrast with our previous analyses, average pain intensity was significantly decreased in comparison with placebo one week after the last treatment administration in patients treated with opioids, but not in those treated without opioid, and this effect was maintained over the 4-week follow-up period. Neuropathic pain symptom inventory (NPSI total and subscores) was also significantly more decreased after inhalation of EMONO in comparison with placebo only in patients receiving opioids. The proportion of patients with at least 30% pain reduction and of those reporting an overall improvement with the Patient Global Impression of Change were significantly higher only in this population of patients. In conclusion, these results complement our previous analyses with the identification of a specific population of responders to EMONO inhalation in patients with neuropathic pain. As suggested by experimental studies, we hypothesized that these long-lasting analgesic effects could depend on the anti-N-methyl-D-aspartate properties of N 2 O.


Assuntos
Analgésicos Opioides , Neuralgia , Óxido Nitroso , Analgésicos Opioides/administração & dosagem , Humanos , Neuralgia/tratamento farmacológico , Óxido Nitroso/administração & dosagem , Manejo da Dor/métodos , Medição da Dor
6.
Pain ; 162(4): 1104-1115, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33044394

RESUMO

ABSTRACT: Nitrous oxide (N2O) is an odorless and colorless gas routinely used as an adjuvant of anesthesia and for short-duration analgesia in various clinical settings mostly in the form of an N2O/O2 50%-50% equimolar mixture (EMONO). Experimental studies have suggested that EMONO could also induce long-lasting analgesic effects related to the blockade of N-methyl-D-aspartate receptors. We designed the first international multicenter proof of concept randomized, placebo-controlled study to assess the efficacy and safety of a 1-hour administration of EMONO or placebo (medical air) on 3 consecutive days up to 1 month after the last administration in patients with chronic peripheral neuropathic pain. A total of 240 patients were recruited in 22 centers in France and Germany and randomly assigned to 1 study group (120 per group). Average pain intensity (primary outcome), neuropathic pain characteristics (Neuropathic Pain Symptom Inventory), Patient Global Impression of Change, anxiety, depression, and quality of life were systematically assessed before and after treatment. The changes in average pain intensity between baseline and 7 days after the last administration were not significantly different between the 2 groups. However, evoked pain intensity (predefined secondary endpoint) and Patient Global Impression of Change (exploratory endpoint) were significantly improved in the EMONO group, and these effects were maintained up to 4 weeks after the last treatment administration. Mostly transient side effects were reported during the treatment administration. These encouraging results provide a basis for further investigation of the long-term analgesic effects of EMONO in patients with neuropathic pain.


Assuntos
Neuralgia , Óxido Nitroso , Administração por Inalação , França , Alemanha , Humanos , Neuralgia/tratamento farmacológico , Óxido Nitroso/uso terapêutico , Oxigênio , Qualidade de Vida , Resultado do Tratamento
7.
Eur J Heart Fail ; 22(6): 985-994, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32438483

RESUMO

AIMS: The aim was to assess the effect of a telemonitoring programme vs. standard care (SC) in preventing all-cause deaths or unplanned hospitalisations in heart failure (HF) at 18 months. METHODS AND RESULTS: OSICAT was a randomised, multicentre, open-label French study in 937 patients hospitalised for acute HF ≤12 months before inclusion. Patients were randomised to telemonitoring (daily body weight measurement, daily recording of HF symptoms, and personalised education) (n = 482) or to SC (n = 455). Mean ± standard deviation number of events for the primary outcome was 1.30 ± 1.85 for telemonitoring and 1.46 ± 1.98 for SC [rate ratio 0.97, 95% confidence interval (CI) 0.77-1.23; P = 0.80]. In New York Heart Association (NYHA) class III or IV HF, median time to all-cause death or first unplanned hospitalisation was 82 days in the telemonitoring group and 67 days in the SC group (P = 0.03). After adjustment for known predictive factors, telemonitoring was associated with a 21% relative risk reduction in first unplanned hospitalisation for HF [hazard ratio (HR) 0.79, 95% CI 0.62-0.99; P = 0.044); the relative risk reduction was 29% in patients with NYHA class III or IV HF (HR 0.71, 95% CI 0.53-0.95; P = 0.02), 38% in socially isolated patients (HR 0.62, 95% CI 0.39-0.98; P = 0.043), and 37% in patients who were ≥70% adherent to body weight measurement (HR 0.63, 95% CI 0.45-0.88; P = 0.006). CONCLUSION: Telemonitoring did not result in a significantly lower rate of all-cause deaths or unplanned hospitalisations in HF patients. The pre-specified subgroup results suggest the telemonitoring approach improves clinical outcomes in selected populations but need further confirmation.


Assuntos
Insuficiência Cardíaca , Padrão de Cuidado , Telemedicina , Idoso , Idoso de 80 Anos ou mais , Feminino , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/terapia , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade
8.
J Diabetes Sci Technol ; 13(2): 261-267, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30241444

RESUMO

In the last 10 years tremendous progress has been made in the development of artificial pancreas (AP) systems for people with type 1 diabetes (T1D). The pan-European consortium CLOSE (Automated Glu cose Contro l at H ome for People with Chronic Disea se) is aiming to develop integrated AP solutions (APplus) tailored to the needs of people with type 2 diabetes (T2D). APplus comprises a product and service package complementing the AP system by obligatory training as well as home visits and telemedical consultations on demand. Outcome predictors and performance indicators shall help to identify people who could benefit most from AP usage and facilitate the measurement of AP impact in diabetes care. In a first step CLOSE will establish a scalable APplus model case working at the interface between patients, homecare service providers, and payers in France. CLOSE will then scale up APplus by pursuing geographic distribution, targeting additional audiences, and enhancing AP functionalities and interconnectedness. By being part of the European Institute of Innovation and Technology (EIT) Health public-private partnership, CLOSE is committed to the EIT "knowledge triangle" pursuing the integrated advancement of technology, education, and business creation. Putting stakeholders, education, and impact into the center of APplus advancement is considered key for achieving wide AP use in T2D care.


Assuntos
Automonitorização da Glicemia/instrumentação , Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Sistemas de Infusão de Insulina , Pâncreas Artificial , Animais , Biomarcadores , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Desenho de Equipamento , Europa (Continente) , Humanos , Sistemas de Infusão de Insulina/efeitos adversos , Pâncreas Artificial/efeitos adversos , Projetos de Pesquisa , Participação dos Interessados , Resultado do Tratamento
9.
Therapie ; 70(1): 37-55, 2015.
Artigo em Inglês, Francês | MEDLINE | ID: mdl-25679193

RESUMO

A biosimilar is a biological medicinal product claimed to be similar to a reference biological medicinal product. Its development plan includes studies comparing it with the reference product in order to confirm its similarity in terms of quality, preclinical safety, clinical efficacy, and clinical safety, including immunogenicity. Biosimilars differ from generics both in their molecular complexity and in the specific requirements that apply to them. Since patents on many biological medicinal products will expire within the next 5 years in major therapeutic areas such as oncology, rheumatology and gastroenterology and as those products are so costly to the French national health insurance system, the availability of biosimilars would have a considerable economic impact. The round table has issued a number of recommendations intended to ensure that the upcoming arrival of biosimilars on the market is a success, in which prescribing physicians would have a central role in informing and reassuring patients, an efficient monitoring of the patients treated with biologicals would be set up and time to market for biosimilars would be speeded up.


Assuntos
Medicamentos Biossimilares , Medicamentos Biossimilares/economia , Medicamentos Biossimilares/provisão & distribuição , Medicamentos Biossimilares/uso terapêutico , Custos de Medicamentos , França , Humanos , Marketing de Serviços de Saúde/legislação & jurisprudência , Prontuários Médicos/normas , Programas Nacionais de Saúde/economia , Farmácias/organização & administração , Farmácias/normas , Vigilância de Produtos Comercializados/normas , Mecanismo de Reembolso , Gestão de Riscos/normas
10.
Therapie ; 70(1): 21-36, 2015.
Artigo em Inglês, Francês | MEDLINE | ID: mdl-25679191

RESUMO

In May 2014, the European Union Parliament and Council published a new regulation on clinical trials on medicinal products for human use, which is designed to replace Directive 2001/20/EC. It will not come into effect until 2016. Nevertheless, it is essential to examine its relationship with national legislation, i.e. the Jardé Act, whose implementation has been delayed pending publication of the European regulation. The Giens workshop identified and examined the various issues that this relationship is bound to raise. In particular, it looked at trial methodology assessment procedures, the working relationship between the French National Agency of Drug Safety and Health Products (Agence Nationale de Sécurité du Médicament et des Produits de Santé, ANSM) and ethics committees during the authorization application evaluation phase, review of post-authorization/registration studies on medicinal products and medical devices, and data transparency.


Assuntos
Ensaios Clínicos como Assunto/legislação & jurisprudência , Acesso à Informação/legislação & jurisprudência , Ensaios Clínicos como Assunto/normas , Segurança Computacional/legislação & jurisprudência , Comitês de Ética Clínica/legislação & jurisprudência , Comitês de Ética Clínica/organização & administração , Comitês de Ética Clínica/normas , Comitês de Ética em Pesquisa/legislação & jurisprudência , Comitês de Ética em Pesquisa/organização & administração , Comitês de Ética em Pesquisa/normas , União Europeia , França , Órgãos Governamentais , Experimentação Humana/legislação & jurisprudência , Humanos , Idioma , Legislação de Dispositivos Médicos , Estudos Observacionais como Assunto/legislação & jurisprudência , Projetos de Pesquisa/normas
11.
Clin Immunol ; 157(2): 277-93, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25562703

RESUMO

The Milieu Intérieur Consortium has established a 1000-person healthy population-based study (stratified according to sex and age), creating an unparalleled opportunity for assessing the determinants of human immunologic variance. Herein, we define the criteria utilized for participant enrollment, and highlight the key data that were collected for correlative studies. In this report, we analyzed biological correlates of sex, age, smoking-habits, metabolic score and CMV infection. We characterized and identified unique risk factors among healthy donors, as compared to studies that have focused on the general population or disease cohorts. Finally, we highlight sex-bias in the thresholds used for metabolic score determination and recommend a deeper examination of current guidelines. In sum, our clinical design, standardized sample collection strategies, and epidemiological data analyses have established the foundation for defining variability within human immune responses.


Assuntos
Infecções por Citomegalovirus/imunologia , Sistema Imunitário/imunologia , Síndrome Metabólica/imunologia , Fumar/imunologia , Adulto , Fatores Etários , Idoso , Estudos de Coortes , Estudos Transversais , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores Sexuais , Fatores Socioeconômicos , Adulto Jovem
14.
Therapie ; 70(1): 47-55, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27393396

RESUMO

A biosimilar is a biological medicinal product claimed to be similar to a reference biological medicinal product. Its development plan includes studies comparing it with the reference product in order to confirm its similarity in terms of quality, preclinical safety, clinical efficacy, and clinical safety, including immunogenicity. Biosimilars differ from generics both in their molecular complexity and in the specific requirements that apply to them. Since patents on many biological medicinal products will expire within the next 5 years in major therapeutic areas such as oncology, rheumatology and gastroenterology and as those products are so costly to the French national health insurance system, the availability of biosimilars would have a considerable economic impact. The round table has issued a number of recommendations intended to ensure that the upcoming arrival of biosimilars on the market is a success, in which prescribing physicians would have a central role in informing and reassuring patients, an efficient monitoring of the patients treated with biologicals would be set up and time to market for biosimilars would be speeded up.

15.
Regul Toxicol Pharmacol ; 69(3): 296-303, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24768990

RESUMO

In this study, we focused on the list of 33 chemicals that was established through a French national prioritisation strategy. Assessing the potential risks to the environment was a step-wise procedure: (i) we determined the Predicted Environmental Concentration (PEC) of all molecules measured in the national survey based on the highest recommended dose used, (ii) we used the Measured Environmental Concentration (MEC) and the Predicted No-Effect Concentration (PNEC) to establish the Risk Quotient (RQ) based on either a PEC/PNEC (estimated risk) or MEC/PNEC (real risk) ratio. The risk assessment was performed using a binary ecological classification suggesting that appreciable risk is likely (RQ⩾1). Of the 15 molecules quantified in the survey, 12 had a PEC higher than the action limit value of 0.01µg/L. According to the EU Guideline, environmental risk was estimated as likely for the following five compounds: acetaminophen (RQ=1.6), ibuprofen (RQ=600), diclofenac (RQ=15), oxazepam (RQ=2.1) and carbamazepine (RQ=3.2). Only ibuprofen was identified as posing real environmental risk based on its MEC (RQ=1.9).


Assuntos
Preparações Farmacêuticas/química , Poluentes Químicos da Água/efeitos adversos , Poluentes Químicos da Água/química , Água/análise , Monitoramento Ambiental/métodos , Medição de Risco
16.
Immunity ; 40(3): 436-50, 2014 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-24656047

RESUMO

Standardization of immunophenotyping procedures has become a high priority. We have developed a suite of whole-blood, syringe-based assay systems that can be used to reproducibly assess induced innate or adaptive immune responses. By eliminating preanalytical errors associated with immune monitoring, we have defined the protein signatures induced by (1) medically relevant bacteria, fungi, and viruses; (2) agonists specific for defined host sensors; (3) clinically employed cytokines; and (4) activators of T cell immunity. Our results provide an initial assessment of healthy donor reference values for induced cytokines and chemokines and we report the failure to release interleukin-1α as a common immunological phenotype. The observed naturally occurring variation of the immune response may help to explain differential susceptibility to disease or response to therapeutic intervention. The implementation of a general solution for assessment of functional immune responses will help support harmonization of clinical studies and data sharing.


Assuntos
Imunidade Adaptativa/imunologia , Imunidade Inata/imunologia , Monitorização Imunológica/métodos , Antígenos/imunologia , Citocinas/sangue , Citocinas/metabolismo , Voluntários Saudáveis , Humanos , Mediadores da Inflamação/sangue , Mediadores da Inflamação/metabolismo , Monitorização Imunológica/normas , Valores de Referência , Reprodutibilidade dos Testes
17.
Soft Matter ; 10(36): 6941-54, 2014 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-24675994

RESUMO

We have investigated a new class of food-grade particles, whey protein microgels, as stabilisers of triglyceride-water emulsions. The sub-micron particles stabilized oil-in-water emulsions at all pH with and without salt. All emulsions creamed but exhibited exceptional resistance to coalescence. Clear correlations exist between the properties of the microgels in aqueous dispersion and the resulting emulsion characteristics. For conditions in which the particles were uncharged, fluid emulsions with relatively large drops were stabilised, whereas emulsions stabilized by charged particles contained smaller flocculated drops. A combination of optical microscopy of the drops and spectrophotometry of the resolved aqueous phase allowed us to estimate the interfacial adsorption densities of the particles using the phenomenon of limited coalescence. We deduce two classes of particle arrangement. Complete adsorption of the particles was obtained when they were neutral or when their charges were screened by salt resulting in at least one particle monolayer at the interface. By contrast, only around 50% of the particles adsorbed when they were charged with emulsion drops being covered by less than half a monolayer. These findings were supported by direct visualization of drop interfaces using cryo-scanning electron microscopy. Uncharged particles were highly aggregated and formed a continuous 2-D network at the interface. Otherwise particles organized as individual aggregates separated by particle-free regions. In this case, we suggest that some particles spread at the interface leading to the formation of a continuous protein membrane. Charged particles displayed the ability to bridge opposing interfaces of neighbouring drops to form dense particle disks protecting drops against coalescence; this is the main reason for the flocculation and stability of emulsions containing sparsely covered drops.


Assuntos
Emulsões/química , Proteínas do Leite/química , Adsorção , Membrana Celular/metabolismo , Microscopia Crioeletrônica , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Óleos/química , Óptica e Fotônica , Polímeros/química , Conformação Proteica , Salinidade , Sais/química , Temperatura , Triglicerídeos/química , Água/química , Proteínas do Soro do Leite
18.
Langmuir ; 21(8): 3688-98, 2005 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-15807622

RESUMO

The adsorption of poly(vinylamine) (PVA) on poly(styrene sulfate) latex particles is studied, and its consequences on the charging behavior and suspension stability are investigated. The adsorption process is assessed by batch depletion experiments and time-resolved electrophoretic mobility measurements. The adsorption of PVA appears to be basically irreversible. The rate of adsorption decreases with decreasing polymer dose. At low polymer dose, the polymer coverage corresponds to the amount of the polyelectrolyte added, while at high polymer dose, the polymer coverage saturates the surface. Stability ratios are determined by dynamic light scattering, and strongly depend on the polymer dose and salt level. The aggregation is rapid near the isoelectric point (IEP), and it slows down when moving away from it. The charge neutralization is highly nonstoichiometric with charging ratios (CR) larger than unity, meaning that several charges on an adsorbed polyelectrolyte chain are necessary to neutralize a single charge on the particle surface. By comparing the IEP for particles and polyelectrolytes of different charge densities, we find a strong dependence of the CR on the mismatch between the average distances between individual charges on the surface and on the polyelectrolyte. A simple model is proposed to explain this trend.

19.
Spine (Phila Pa 1976) ; 27(14): 1487-93, 2002 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-12131705

RESUMO

BACKGROUND: The management of common low back pain has two principal objectives: to relieve acute pain and to attempt prevention of transition to chronicity. Several studies have shown the ineffectiveness of prolonged periods of bed rest. OBJECTIVE: To compare 4 days of bed rest with continued normal daily activity in acute low back pain, taking into account the type of work (physical or sedentary labor). METHODS: This open, comparative multicenter study enrolled 281 ambulatory patients, ages 18 to 65 years, with low back pain (onset < 72 hours). The subjects did not have pain radiating below the buttocks and did not have work-related injuries. They were randomized into two treatment groups: one instructed to continue normal activity (insofar as the pain allowed), and the other prescribed 4 days of bed rest. After inclusion, patients were seen at three visits: on day 6 or 7, after 1 month, and after 3 months. RESULTS: On day 6 or 7, pain intensity was similar for both groups, as was the overall judgment of the treatment by patients and physicians. At 1 and 3 months, the groups again had equivalent intensity of back pain, functional disability, and vertebral stiffness. A higher proportion of patients in the bed rest group than in the normal activity group had an initial sick leave (86% vs 52%; P < 0.0001). This difference was greater for the patients whose work was sedentary. CONCLUSIONS: For patients with acute low back pain, normal activity is at least equivalent to bed rest. The findings of this study indicate that prescriptions for bed rest, and thus for sick leaves, should be limited when the physical demands of the job are similar to those for daily life activities.


Assuntos
Atividades Cotidianas , Repouso em Cama , Dor Lombar/terapia , Adulto , Feminino , Humanos , Dor Lombar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento
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