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1.
Artículo en Inglés | MEDLINE | ID: mdl-38739907

RESUMEN

OBJECTIVE: This study aimed to explore the association between occupational psychosocial exposures and chronic low-back pain (LBP) by conducting a systematic review and meta-analysis. METHODS: The research protocol was registered in PROSPERO. A systematic literature search was performed in six databases, identifying articles complying with predefined inclusion criteria. In our PECOS, we defined outcome as chronic LBP ≥3 months, exposures as occupational psychosocial exposures, and restricted study design to case-control and cohort studies. Two authors independently excluded articles, extracted data, assessed risk of bias, and graded evidence levels. Meta-analyses were performed using random-effects models. RESULTS: The 20 included articles encompassed six different occupational psychosocial exposures (job control, demand, strain, support, stress, and satisfaction), only 1 had low risk of bias. For all occupational psychosocial exposures, odds ratios ranged from 0.8 to 1.1. Sensitivity analyses based on risk of bias was conducted for two outcomes ie, job control and job demand, finding no differences between high and low-to-moderate risk of bias studies. Using GRADE, we found a very low level of evidence of the association for all occupational psychosocial exposures. CONCLUSION: In this study, we found no association between occupational psychosocial exposures and chronic LBP. However, it is important to underline that the level of evidence was very low. High quality studies are highly warranted.

2.
Scand J Work Environ Health ; 50(4): 244-256, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38483209

RESUMEN

OBJECTIVES: The aim was to conduct a systematic review and meta-analysis investigating the association between occupational mechanical exposures and hip osteoarthritis. METHODS: The study was registered in PROSPERO. A systematic literature search was conducted in six databases to identify relevant articles. Two authors independently excluded articles, extracted data, assessed the risk of bias of each included article, and graded the level of evidence. We conducted a meta-analysis using random-effects model and performed a sensitivity analysis stratifying articles based on the risk of bias assessment, study design, and the outcome measurement. RESULTS: Twenty-four articles were eligible for inclusion. The highest pooled odds ratio (OR) was found for combined mechanical exposures [OR 1.7, 95% confidence interval (CI) 1.4-2.0], non-neutral postures (OR 1.7, 95% CI 1.4-2.1), lifting/carrying loads (OR 1.6, 95% CI 1.3-1.9), and climbing stairs (OR 1.6, 95% CI 1.1-2.2). The range of pooled OR for the remaining mechanical exposures (eg, standing, walking, kneeling, squatting, and sitting) was 0.6-1.6. Grading the quality of evidence, a moderate level of evidence was found for the combined mechanical exposures and for lifting/carrying loads. The remaining exposure categories were graded as having either low or very low levels of evidence. CONCLUSIONS: Considerable heterogeneity was observed across the included studies, and high-quality literature using objective exposure measurements is warranted. Despite various limitations affecting the comparability, occupational mechanical exposures seem to influence the likelihood of developing hip osteoarthritis.


Asunto(s)
Exposición Profesional , Osteoartritis de la Cadera , Humanos , Osteoartritis de la Cadera/epidemiología , Osteoartritis de la Cadera/etiología , Exposición Profesional/efectos adversos , Postura , Enfermedades Profesionales/epidemiología , Enfermedades Profesionales/etiología , Elevación/efectos adversos
4.
Int Arch Occup Environ Health ; 97(2): 207-215, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38175230

RESUMEN

OBJECTIVE: The aim was to conduct a systematic review and meta-analysis to study the association between night work and the development of prostate cancer. METHODS: A systematic literature search was conducted in CINAHL, Embase, MEDLINE, and Web of Science. Studies were included based on a PECOS; the population included men in/above the working age, exposure defined as night work, outcome defined as prostate cancer, and study design restricted to cohort studies. The exclusion of articles, risk-of-bias assessment, and data extraction were performed by two reviewers. A meta-analysis was conducted using a random-effects model, including a sensitivity analysis stratified based on the risk-of-bias assessment. We evaluated publication bias using a funnel plot and Egger´s test, and the level of evidence was assessed using GRADE. RESULTS: A total of 528 articles were identified, and eight cohort studies were included. Three studies had a moderate risk of bias, while five studies had a high risk of bias. The meta-analysis showed a pooled hazard ratio (HR) of 1.0 (95% CI 0.6-1.7). In the sensitivity analysis, moderate vs. high risk-of-bias studies showed a pooled HR of 1.2 (95% CI 0.3-4.1) and 0.9 (95% CI 0.6-1.3), respectively. Based on GRADE, the level of evidence was rated low. CONCLUSION: We found no association between night work and the development of prostate cancer. The evidence was assessed as limited and inconsistent. Future studies encompassing consistent definitions of night work, including objective exposure data, are highly warranted.


Asunto(s)
Neoplasias de la Próstata , Masculino , Humanos , Neoplasias de la Próstata/epidemiología , Neoplasias de la Próstata/etiología , Estudios de Cohortes
5.
Nat Commun ; 14(1): 7314, 2023 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-37951990

RESUMEN

Holographic quantum-error correcting codes are models of bulk/boundary dualities such as the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, where a higher-dimensional bulk geometry is associated with the code's logical degrees of freedom. Previous discrete holographic codes based on tensor networks have reproduced the general code properties expected from continuum AdS/CFT, such as complementary recovery. However, the boundary states of such tensor networks typically do not exhibit the expected correlation functions of CFT boundary states. In this work, we show that a new class of exact holographic codes, extending the previously proposed hyperinvariant tensor networks into quantum codes, produce the correct boundary correlation functions. This approach yields a dictionary between logical states in the bulk and the critical renormalization group flow of boundary states. Furthermore, these codes exhibit a state-dependent breakdown of complementary recovery as expected from AdS/CFT under small quantum gravity corrections.

6.
Scand J Work Environ Health ; 49(7): 453-465, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37581384

RESUMEN

OBJECTIVES: The association between occupational mechanical exposures and low-back pain (LBP) has been studied in several systematic reviews. However, no systematic review addressing chronic LBP exists. The aim of this systematic review and meta-analysis was to examine the association between occupational mechanical exposures and chronic LBP. METHODS: The study was registered in PROSPERO. We used an existing systematic review to identify articles published before January 2014. For studies published between January 2014 and September 2022, a systematic literature search was conducted in six databases. Two authors independently excluded articles, extracted data, and assessed risk of bias and level of evidence (GRADE). Meta-analyses were conducted using random-effects models comparing highest versus lowest exposure group with sensitivity analyses based on study quality (low/moderate versus high risk of bias), study design (cohort versus case-control), and outcome definition (non-specific LBP versus specific chronic LBP). RESULTS: Twenty-six articles were included. Highest pooled odd ratios (OR) were found for combined mechanical exposures [OR 2.2, 95% confidence interval (CI) 1.4-3.6], lifting/carrying loads (OR 1.7, 95% CI 1.4-2.2), and non-neutral postures (OR 1.5, 95% CI 1.2-1.9). For the remaining mechanical exposures (ie, whole-body vibrations, standing/walking, and sitting), OR ranged between 1.0 and 1.4. In the sensitivity analyses, generally, higher pooled OR were found in low/moderate risk of bias studies, case-control studies, and studies of specific chronic LBP. CONCLUSIONS: Moderate evidence of an association was found for lifting/carrying loads, non-neutral postures, and combined mechanical exposures. Low or very low evidence was found for whole-body vibrations, standing/walking, and sitting. Studies using standardized exposure definition, metric, and technical measurements are highly warranted.


Asunto(s)
Dolor Crónico , Dolor de la Región Lumbar , Exposición Profesional , Humanos , Dolor de la Región Lumbar/epidemiología , Dolor de la Región Lumbar/etiología , Dolor de Espalda , Factores de Riesgo , Sedestación , Exposición Profesional/efectos adversos , Dolor Crónico/complicaciones
7.
PLoS One ; 18(5): e0285327, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37146040

RESUMEN

INTRODUCTION: The association between occupational mechanical exposures and chronic low back pain (LBP) has been widely studied, however, few systematic reviews have evaluated the evidence of an association. Furthermore, little is known of the impact of occupational psychosocial exposures on chronic LBP. The aim of this systematic review and meta-analysis is to study the association between occupational mechanical and psychosocial exposures and chronic LBP. METHODS: The study will be conducted as a systematic review using another systematic review published in 2014 as basis and has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42021281996. A systematic literature search will be performed in 6 scientific databases to identified potential relevant studies published after 2014. Studies will systematically be excluded through a screening process performed independently by 2 reviewers. Exposures will include occupational mechanical and psychosocial exposures, and outcome will include chronic LBP (LBP ≥3 months, "degenerative" diseases, and lumbosacral radiculopathy). Study population will include persons in or above working age, and study designs will comprise cohort and case-control studies. The quality of each included study will be methodologically assessed by 2 independent reviewers and level of evidence of an association will be graded using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system. In meta-analyses, effect sizes will be addressed using random-effect models, sensitivity analyses will explore the robustness of the meta-analysis, and heterogeneity assessed. DISCUSSION: This systematic review and meta-analysis will assess the evidence available of the association between occupational mechanical and psychosocial exposures and chronic LBP. The review can provide essential knowledge on the association, exposure-response relationships, thresholds, which may pave the way for political decisions on the occupational environment and the labour market insurance policy.


Asunto(s)
Dolor de la Región Lumbar , Enfermedades Profesionales , Exposición Profesional , Radiculopatía , Humanos , Dolor de la Región Lumbar/epidemiología , Dolor de la Región Lumbar/etiología , Revisiones Sistemáticas como Asunto , Metaanálisis como Asunto , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Enfermedades Profesionales/epidemiología , Enfermedades Profesionales/etiología
8.
Phys Rev Lett ; 127(14): 141604, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34652185

RESUMEN

Quantifying entanglement properties of mixed states in quantum field theory via entanglement of purification and reflected entropy is a new and challenging subject. In this work, we study both quantities for two spherical subregions far away from each other in the vacuum of a conformal field theory in any number of dimensions. Using lattice techniques, we find an elementary proof that the decay of both the entanglement of purification and reflected entropy is enhanced with respect to the mutual information behavior by a logarithm of the distance between the subregions. In the case of the Ising spin chain at criticality and the related free fermion conformal field theory, we compute also the overall coefficients numerically for the both quantities of interest.

10.
BMC Public Health ; 21(1): 895, 2021 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-33975578

RESUMEN

BACKGROUND: Negative life events (re) occurring during childhood is often described as adverse childhood experiences (ACEs) and may have long-lasting negative effects on health. Previous studies on the association between ACEs and self-rated health (SRH) have primarily been focusing on chronic diseases in elderly, non-Scandinavian populations using a cross-sectional design. The aim of the study was to examine the associations between ACEs and SRH in early adulthood and to investigate if disadvantageous health-behavioral strategies explain the association between ACEs and SRH. METHODS: A prospective cohort study using data from The West Jutland Cohort Study (N = 2.255). Baseline data on exposure to ACEs were collected from surveys at the age of 15 and 18 and respondents were categorized into having experienced 0, 1-2, 3 or > 4 ACEs. The outcome SRH stems from surveys at the age of 21 and 28 and was dichotomized into moderate and good SRH. The association between ACE-categories and SRH at age 21 and 28 were analyzed separately by logistic regression with a two-step adjustment model, adjusting for potential confounders and disadvantageous health-behavioral strategies. RESULTS: More than half of the participants reported at least one ACE (56.3%) with "bullying" and "loss of parent, parental separation or divorce" being the most prevalent. Participants who reported > 4 ACEs, compared to those with 0 ACEs, had a 2.6-fold increased odds (95% CI 1.3; 5.1) of having moderate SRH at the age of 21, and a 2.7-fold increased odds (95% CI 1.4; 5.4) of moderate SRH at the age of 28 years, when adjusted for potential confounders. Further, small attenuations of the estimates were seen when adjusting for disadvantageous health-behavioral strategies. A significant exposure response relationship between the ACE-categories and moderate SRH were seen both at age 21 and 28. CONCLUSION: The study showed an association between ACEs and moderate SRH in young adulthood, and experiencing multiple ACEs increased the odds of reporting moderate SRH. Information on ACEs could help identifying people with a higher risk of future health problems and accentuates a growing need for early prevention in homes with children who has experienced adverse events.


Asunto(s)
Experiencias Adversas de la Infancia , Adulto , Anciano , Niño , Estudios de Cohortes , Estudios Transversales , Divorcio , Humanos , Estudios Prospectivos , Adulto Joven
11.
Bioprocess Biosyst Eng ; 44(8): 1671-1684, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33860849

RESUMEN

Ever since the potential of algae in biotechnology was recognized, models describing the growth of algae inside photobioreactors have been proposed. These models are the basis for the optimization of process conditions and reactor designs. Over the last few decades, models became more and more elaborate with the increase of computational capacity. Thus far, these models have been based on light attenuation due to the absorption and scattering effects of the biomass. This manuscript presents a new way of predicting the apparent growth inside photobioreactors using simple models for enzymatic kinetics to describe the reaction between photons and the photosynthetic unit. The proposed model utilizes an inhibition kinetic formula based on the surrounding biomass to describe the average growth rate of a culture, which is determined by the local light intensities inside the reactor. The result is a mixed-inhibition scheme with multiple inhibition sites. The parameters of the new kinetic equation are replaced by empirical regression functions to correlate their dependency on incident light intensity and reactor size. The calibrations of the parameters and the regression functions are based on the numerical solutions of the growth rate computed with a classical Type II model. As a final verification, we apply the new equation in predicting the growth behavior of three phototrophic organisms in reactors of three different sizes.


Asunto(s)
Biomasa , Biotecnología/métodos , Microalgas/crecimiento & desarrollo , Algoritmos , Reactores Biológicos , Calibración , Cinética , Luz , Modelos Biológicos , Fotobiorreactores , Fotoquímica/métodos , Fotosíntesis , Sensibilidad y Especificidad
12.
Phys Rev Lett ; 122(20): 201601, 2019 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-31172758

RESUMEN

We study the entanglement of purification (EOP), a measure of total correlation between two subsystems A and B, for free scalar field theory on a lattice and the transverse-field Ising model by numerical methods. In both of these models, we find that the EOP becomes a nonmonotonic function of the distance between A and B when the total number of lattice sites is small. When it is large, the EOP becomes monotonic and shows a plateaulike behavior. Moreover, we also show that the original reflection symmetry which exchanges A and B can get broken in optimally purified systems. We provide an interpretation of our results in terms of the interplay between classical and quantum correlations.

13.
Biomed Chromatogr ; 31(2)2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27432781

RESUMEN

Anacetrapib is a potent and selective CETP inhibitor and is undergoing phase III clinical trials for the treatment of dyslipidemia. A simple and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the quantification of anacetrapib in rat plasma was developed and validated using an easily purchasable compound, chlorpropamide, as an internal standard (IS). A minimal volume of rat plasma sample (20 µL) was prepared by a single-step deproteinization procedure with 80 µL of acetonitrile. Chromatographic separation was performed using Kinetex C18 column with a gradient mobile phase consisting of water and acetonitrile containing 0.1% formic acid at a flow rate of 0.3 mL/min. Mass spectrometric detection was performed using selected reaction monitoring modes at the mass/charge transitions m/z 638 → 283 for anacetrapib and m/z 277 → 175 for IS. The assay was validated to demonstrate the selectivity, linearity, precision, accuracy, recovery, matrix effect and stability. The lower limit of quantification was 5 ng/mL. This LC-MS/MS assay was successfully applied in the rat plasma protein binding and pharmacokinetic studies of anacetrapib. The fraction of unbound anacetrapib was determined to be low (ranging from 5.66 to 12.3%), and the absolute oral bioavailability of anacetrapib was 32.7%.


Asunto(s)
Anticolesterolemiantes/sangre , Cromatografía Líquida de Alta Presión/métodos , Oxazolidinonas/sangre , Espectrometría de Masas en Tándem/métodos , Animales , Anticolesterolemiantes/metabolismo , Disponibilidad Biológica , Límite de Detección , Masculino , Oxazolidinonas/metabolismo , Unión Proteica , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados
14.
Pharm Res ; 33(1): 206-16, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26337769

RESUMEN

PURPOSE: To evaluate the anti-tumor effect of ceramide or trimethylphytosphingosine-iodide (TMP-I) containing solid lipid nanoparticles (SLNs) prepared using trymyristin, phosphatidylcholine (PC), and Pluronic P85 (P85) for intravenous delivery of docetaxel. METHODS: Docetaxel-loaded SLNs using ceramide or TMP-I at 3.22% (w/w) with a mean diameter of 89-137 nm were successfully prepared by high pressure homogenization. The prepared nanoparticles were characterized by particle size, zeta potential, drug content, and TEM analysis. Cellular uptake and cytotoxicity were studied using adriamycin-resistant breast cancer (MCF-7/ADR) cells. The optimized formulation's dissolution profile, pharmacokinetics, and antitumor effect in mice tumor model were compared with that of control (Taxotere(®)). RESULTS: The drug release rate of docetaxel from SLNs was lower than that of control (Taxotere(®)). The prepared SLNs showed higher cellular uptake of docetaxel compared to that of Taxotere(®) in MCF-7/ADR cell lines, which was further confirmed by the confocal laser scanning microscopy (CLSM) study using coumarin 6 (C6). Prepared SLNs exhibited significantly increased antitumor efficacy, compared to Taxotere(®), in MCF-7/ADR cells. In vivo pharmacokinetic study in rats (at 10 mg/kg dose) showed that the SLNs significantly reduced in vivo clearance of drug than Taxotere(®). Interestingly, ceramide and TMP-I SLNs efficiently inhibited the tumor growth compared to Taxotere(®) in MCF-7/ADR tumor xenografted mouse model. CONCLUSION: This work showed that TMP-I and ceramide SLNs not only significantly enhanced systemic exposure of drug, but also increased antitumor efficacy compared to Taxotere(®) and control SLN.


Asunto(s)
Antineoplásicos/administración & dosificación , Antineoplásicos/uso terapéutico , Ceramidas/química , Nanopartículas/química , Neoplasias/tratamiento farmacológico , Compuestos de Amonio Cuaternario/química , Esfingosina/análogos & derivados , Animales , Antineoplásicos/farmacocinética , Antineoplásicos Fitogénicos/administración & dosificación , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/uso terapéutico , Línea Celular Tumoral , Química Farmacéutica , Preparaciones de Acción Retardada , Docetaxel , Excipientes , Masculino , Ratones , Tamaño de la Partícula , Fosfatidilcolinas/química , Poloxaleno , Ratas , Ratas Sprague-Dawley , Esfingosina/química , Taxoides/administración & dosificación , Taxoides/química , Taxoides/uso terapéutico
15.
J Microencapsul ; 31(8): 768-73, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25090594

RESUMEN

CONTEXT: Anti-inflammatory effect of advanced adipose stem cell derived protein extract (AAPE) could be improved by minimising protein degradation. OBJECTIVE: To develop a proliposomal formulation of AAPE for the treatment of topical atopic dermatitis. MATERIALS AND METHODS: Proliposomal powder was manufactured by evaporating a solution of soy phosphatidyl choline, AAPE and Poloxamer 407 in ethanol under vacuum on sorbitol powder. Characterisation of proliposomes (zeta potential, diameter, stability and flowability) as well as in vivo efficacy in a dermatitis mouse model was investigated. RESULTS AND DISCUSSION: Reconstitution of the proliposomal powder formed liposomes of 589 ± 3.6 nm diameter with zeta potential of -51.33 ± 0.36 mV. Protein stability was maintained up to 90 days at 25 °C as proliposomes. In vivo studies on atopic dermatitis mouse model showed a significant reduction in IgE levels after topical AAPE proliposome treatment. CONCLUSION: AAPE proliposomes maintained protein stability and showed promising results for atopic dermatitis treatment.


Asunto(s)
Tejido Adiposo/química , Dermatitis Atópica/tratamiento farmacológico , Poloxámero , Proteínas , Células Madre/química , Animales , Dermatitis Atópica/patología , Ratones , Poloxámero/química , Poloxámero/farmacología , Proteínas/química , Proteínas/farmacología
16.
Int J Pharm ; 434(1-2): 191-8, 2012 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-22643227

RESUMEN

Phytosphingosine and methyl derivatives are important mediators on cellular processes, and are associated with cell growth and death. The antitumor activity of N,N,N-trimethylphytosphingosine-iodide (TMP) as a novel potent inhibitor of angiogenesis and metastasis was evaluated in B16F10 murine melanoma cells. The results indicated that TMP itself effectively inhibited in vitro cell migration, tube formation, and the expression of angiogenic factors as well as in vivo lung metastasis. However, TMP slightly suppressed in vivo experimental tumor metastasis in its free form and induced side effects including hemolysis and local side effects. Therefore, in an attempt to reduce the toxicity and the undesirable side effects of TMP, a liposomal formulation was prepared and tested for its effectiveness. TMP liposomes retained the effectiveness of TMP in vitro while side effects were reduced, and both in vivo experimental and spontaneous tumor metastasis were significantly suppressed. These results support the conclusion that TMP effectively inhibits in vitro angiogenesis as well as in vivo metastasis, and a liposomal formulation is more efficient delivery system for TMP treatment than solution.


Asunto(s)
Inhibidores de la Angiogénesis/farmacología , Antineoplásicos/farmacología , Melanoma Experimental/tratamiento farmacológico , Compuestos de Amonio Cuaternario/farmacología , Esfingosina/análogos & derivados , Inhibidores de la Angiogénesis/administración & dosificación , Inhibidores de la Angiogénesis/toxicidad , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/toxicidad , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Hemólisis/efectos de los fármacos , Humanos , Liposomas , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/patología , Melanoma Experimental/irrigación sanguínea , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Metástasis de la Neoplasia , Neovascularización Patológica/tratamiento farmacológico , Neovascularización Patológica/patología , Compuestos de Amonio Cuaternario/administración & dosificación , Compuestos de Amonio Cuaternario/toxicidad , Ratas , Esfingosina/administración & dosificación , Esfingosina/farmacología , Esfingosina/toxicidad
17.
J Pharm Pharmacol ; 62(1): 91-7, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20723004

RESUMEN

OBJECTIVES: Vector-borne diseases are still a major mortality factor in Africa and South-east Asia and effective mosquito repellents are therefore needed. An efficient and safe in-vitro assay system using artificial blood and skin substitute could facilitate the development of novel repellents, as most assays currently rely on human subjects or vertebrate whole blood. Moreover, examining the skin permeation profiles could provide safer mosquito repellents. The new assay system could serve as an initial system for testing new repellent candidates upon validation with DEET and its analogues. METHODS: N,N-Diethyl-meta-toluamide (DEET) and five analogues were synthesised and used to validate a novel in-vitro bioassay using artificial blood and collagen membrane. Repellency against Aedes aegypti was correlated with lipophilicity and skin permeation. KEY FINDINGS: The new in-vitro assay showed good reproducibility (interday relative standard deviation <10% at high concentrations). Four of the five DEET analogues showed repellency similar or superior to that of DEET. Repellency correlated linearly with lipophilicity but stronger repellents tended to permeate skin better. CONCLUSIONS: The new in-vitro assay using blood substitute and collagen membrane significantly simplifies screening of possible mosquito repellents. Lipophilicity as well as skin permeation profiles should be considered before testing of compounds that are candidates for mosquito repellents.


Asunto(s)
Aedes , Bioensayo/métodos , DEET/farmacología , Repelentes de Insectos/farmacología , Animales , Sustitutos Sanguíneos/metabolismo , Colágeno/metabolismo , DEET/análogos & derivados , DEET/síntesis química , Femenino , Repelentes de Insectos/síntesis química , Repelentes de Insectos/química , Control de Mosquitos/métodos , Reproducibilidad de los Resultados , Absorción Cutánea
18.
Crit Care ; 10(5): R131, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16970804

RESUMEN

INTRODUCTION: Complications of oesophagectomy and gastric tube reconstruction include leakage and stenosis, which may be due to compromised microvascular blood flow (MBF) in gastric tissue. We recently demonstrated that decreased MBF could be improved perioperatively by topical administration of nitroglycerin. The aim of the present study was to investigate whether nitroglycerin, administered intravenously during gastric tube reconstruction, could preserve tissue blood flow and oxygenation in the gastric fundus, and reduce the incidence of postoperative leakage. METHODS: In this single-centre, prospective, double-blinded study, we randomized 32 patients scheduled for oesophagectomy into two groups. The intervention group received intravenous nitroglycerin during gastric tube reconstruction, and the control group received normal saline. Baseline values for MBF, microvascular haemoglobin oxygen saturation and microvascular haemoglobin concentration were determined at the gastric fundus before and after gastric tube construction and after pulling up the gastric tube to the neck. RESULTS: MBF and microvascular haemoglobin oxygen saturation decreased similarly in both groups during gastric tube reconstruction and were comparable. The oesophageal anastomosis was controlled by contrast radiography before discharge from the hospital; leakage was observed in two patients (13%) in the nitroglycerin group and five patients (31%) in the control group (not significant). CONCLUSION: Under stable systemic haemodynamic conditions, continuous intravenous administration of nitroglycerin could not prevent deterioration in gastric microvascular perfusion and microvascular haemoglobin saturation during gastric tube reconstruction.


Asunto(s)
Nitroglicerina/administración & dosificación , Procedimientos de Cirugía Plástica , Estómago/irrigación sanguínea , Estómago/efectos de los fármacos , Anciano , Método Doble Ciego , Esofagectomía , Esófago/irrigación sanguínea , Esófago/efectos de los fármacos , Esófago/cirugía , Femenino , Humanos , Infusiones Intravenosas , Masculino , Microcirculación/efectos de los fármacos , Persona de Mediana Edad , Estudios Prospectivos , Flujo Sanguíneo Regional/efectos de los fármacos , Estómago/cirugía
19.
Anesth Analg ; 103(1): 239-43, table of contents, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16790660

RESUMEN

We investigated the usefulness of peripheral flow index (PFI) measurement using a standard pulse oximetry digit probe for early prediction of successful regional blocks. Sixty-six patients scheduled for limb surgery underwent either axillary or sciatic block using a nerve stimulator technique with mepivacaine 1.5%. PFI, which is the ratio of the pulsatile versus the nonpulsatile component of the pulse oximetry signal, was recorded from 10 min before block insertion until 30 min afterwards. PFI recordings of the unblocked limb were similarly recorded. Pinprick and cold sensation were assessed at 5-min intervals until 30 min after blockade. An increase in PFI by a factor of 1.55 at 10 min after axillary block placement (P = 0.006), and 12 min after sciatic block placement (P = 0.001) was required to predict a successful block. The sensitivity and specificity of PFI was 100% for predicting axillary block outcomes at this time. Positive predictive value was 95% and negative predictive value was 93%. For sciatic blocks, sensitivity and specificity were 90% and 100%, respectively. The calculated positive predictive value at time 12 min for sciatic blocks was 94% and negative predictive value was 92%. At 15 min after block placement, cold and pinprick sensations had the same calculated values for sensitivity and specificity at 71% and 100%, respectively, for axillary blocks. For sciatic blocks, cold sensation had a sensitivity of 77% and a specificity of 100%, whereas pinprick had a sensitivity of just 20% with a specificity of 100%. We conclude that PFI provides a simple, early, and objective assessment of the success and failure of nerve blocks.


Asunto(s)
Velocidad del Flujo Sanguíneo , Extremidades/irrigación sanguínea , Bloqueo Nervioso , Adulto , Anestésicos Locales , Axila , Extremidades/inervación , Extremidades/cirugía , Femenino , Humanos , Masculino , Mepivacaína , Persona de Mediana Edad , Oximetría , Valor Predictivo de las Pruebas , Flujo Pulsátil , Curva ROC , Nervio Ciático , Sensación , Sensibilidad y Especificidad
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