RESUMEN
Chondrogenesis is a complex cellular process that involves the transformation of mesenchymal stem cells (MSCs) into chondrocytes, the specialised cells that form cartilage. In recent years, three-dimensional (3D) culture systems have emerged as a promising approach to studying cell behaviour and development in a more physiologically relevant environment compared to traditional two-dimensional (2D) cell culture. The use of these systems provided insights into the molecular mechanisms that regulate chondrogenesis and has the potential to revolutionise the development of new therapies for cartilage repair and regeneration. This study demonstrates the successful application of Raman microspectroscopy (RMS) as a label-free, non-destructive, and sensitive method to monitor the chondrogenic differentiation of bone marrow-derived rat mesenchymal stem cells (rMSCs) in a collagen type I hydrogel, and explores the potential benefits of 3D hydrogels compared to conventional 2D cell culture environments. rMSCs were cultured on 3D substrates for 3 weeks and their differentiation was monitored by measuring the spectral signatures of their subcellular compartments. Additionally, the evolution of high-density micromass cultures was investigated to provide a comprehensive understanding of the process and complex interactions between cells and their surrounding extracellular matrix. For comparison, rMSCs were induced into chondrogenesis in identical medium conditions for 21 days in monolayer culture. Raman spectra showed that rMSCs cultured in a collagen type I hydrogel are able to undergo a distinct chondrogenic differentiation pathway at a significantly higher rate than the 2D culture cells. 3D cultures expressed stronger and more homogeneous chondrogenesis-associated peaks such as collagens, glycosaminoglycans (GAGs), and aggrecan while manifesting changes in proteins and lipidic content. These results suggest that 3D type I collagen hydrogel substrates are promising for in vitro chondrogenesis studies, and that RMS is a valuable tool for monitoring chondrogenesis in 3D environments.
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Diferenciación Celular , Células Madre Mesenquimatosas , Espectrometría Raman , Espectrometría Raman/métodos , Animales , Ratas , Células Madre Mesenquimatosas/citología , Condrogénesis , Hidrogeles/química , Células Cultivadas , Técnicas de Cultivo de Célula/métodos , Colágeno Tipo I/metabolismo , Colágeno Tipo I/química , Técnicas de Cultivo Tridimensional de Células/métodosRESUMEN
HYPOTHESIS: In order to understand the basic mechanisms affecting emulsion stability, the intrinsic dynamics of the drop population must be investigated. We hypothesize that transient ballistic motion can serve as a marker of interactions between drops. In 1G conditions, buoyancy-induced drop motion obscures these interactions. The microgravity condition onboard the International Space Station enable this investigation. EXPERIMENTS: We performed Diffusing Wave Spectroscopy (DWS) experiments in the ESA Soft Matter Dynamics (SMD) facility. We used Monte Carlo simulations of photon trajectory to support data analysis. The analysis framework was validated by ground-based characterizations of the initial drop size distribution (DSD) and the properties of the oil/water interface in the presence of surfactant. FINDINGS: We characterized the drop size distribution and found to be bi-disperse. Drop dynamics shows transient ballistic features at early times, reaching a stationary regime of primarily diffusion-dominated motion. This suggests different ageing mechanisms: immediately after emulsification, the main mechanism is coalescence or aggregation between small drops. However at later times, ageing proceeds via coalescence or aggregation of small with large drops in some emulsions. Our results elucidate new processes relevant to emulsion stability with potential impact on industrial processes on Earth, as well as enabling technologies for space exploration.
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A methodological framework is proposed for participatory scenario development on the basis of evidence from the literature, and is tested and refined through the development of scenarios for the future of UK uplands. The paper uses a review of previous work to justify a framework based around the following steps: i) define context and establish whether there is a basis for stakeholder engagement in scenario development; ii) systematically identify and represent relevant stakeholders in the process; iii) define clear objectives for scenario development with stakeholders including spatial and temporal boundaries; iv) select relevant participatory methods for scenario development, during initial scenario construction, evaluation and to support decision-making based on scenarios; and v) integrate local and scientific knowledge throughout the process. The application of this framework in case study research suggests that participatory scenario development has the potential to: i) make scenarios more relevant to stakeholder needs and priorities; ii) extend the range of scenarios developed; iii) develop more detailed and precise scenarios through the integration of local and scientific knowledge; and iv) move beyond scenario development to facilitate adaptation to future change. It is argued that participatory scenario development can empower stakeholders and lead to more consistent and robust scenarios that can help people prepare more effectively for future change.
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Participación de la Comunidad/métodos , Conservación de los Recursos Naturales/métodos , Modelos Teóricos , Reino UnidoRESUMEN
The objective of this prospective study was to investigate the transition from primary (PRP) to secondary (SRP) Raynaud's phenomenon (RP), in a large cohort of patients affected by isolated RP. A total of 2065 patients with RP were investigated by clinical interview, laboratory examinations, and nailfold videocapillaroscopy (NVC). Patients with negative NVC at first visit were yearly followed to monitor either the appearance of specific morphological alterations at NVC, or clinical manifestations of an underlying disease. Capillary abnormalities at NVC were scored, as well as the qualitative patterns of microangiopathy (Early, Active and Late). NVC was found negative at first visit in 1500 subjects; among them, 412 patients were evaluable and they were followed for a mean time of 5±4 years (range 2-13 years). Sixty-eight patients (16%) achieved a diagnosis of SRP during follow-up, showing normal or not specific capillary alterations at NVC 4% of patients (the diagnosis was undifferentiated connective tissue diseases), Early scleroderma-pattern 57%, Active scleroderma-pattern 7%, Late scleroderma-pattern 12%, and scleroderma-like pattern 18% of patients. The time of transition from normal/not specific capillary alterations to Early scleroderma-pattern was 4.4±3.8 years. Enlarged capillaries (diameter between 20 and 50 microns) and mild reduction of capillary density were found the more frequent markers at first NVC visit in patients who progressed to a scleroderma pattern (P=0.01). This study demonstrates in a large cohort, that almost 16% of patients initially diagnosed as affected by RP with negative NVC may transit to SRP during a mean follow-up of 4.4 years. PRP patients showing major notspecific alterations of nailfold capillaries at first NVC should be strictly monitored at least once a year since at higher risk of transition to SRP.
Asunto(s)
Angioscopía Microscópica , Enfermedad de Raynaud/patología , Progresión de la Enfermedad , Humanos , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios ProspectivosRESUMEN
Osteopoikilosis (OPK) is a rare autosomal dominant bone disorder characterized by numerous hyperostotic areas that tend to localize in periarticular osseous regions. It is usually asymptomatic and is often diagnosed incidentally during X-rays. OPK may be an isolated finding or associated with other pathologies, e.g. skin manifestations, rheumatic and/or skeletal disorders. We report a literature review and, for the first time, the coexistence of OPK with seronegative spondyloarthritis and Raynaud's phenomenon in a 48-year old female. To the best of our knowledge, this is the first case of OPK studied by videocapillaroscopy, demonstrating the absence of specific microvascular abnormalities of nailfold capillaries.
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Angioscopía Microscópica , Microscopía por Video , Uñas/irrigación sanguínea , Osteopoiquilosis/complicaciones , Enfermedad de Raynaud/complicaciones , Espondiloartritis/complicaciones , Artroplastia de Reemplazo de Cadera , Sedimentación Sanguínea , Proteína C-Reactiva/análisis , Capilares/patología , Femenino , Humanos , Angioscopía Microscópica/métodos , Persona de Mediana Edad , Osteoartritis de la Cadera/complicaciones , Osteoartritis de la Cadera/diagnóstico por imagen , Osteoartritis de la Cadera/cirugía , Osteopoiquilosis/sangre , Osteopoiquilosis/diagnóstico por imagen , Huesos Pélvicos/diagnóstico por imagen , Radiografía , Enfermedad de Raynaud/patología , Sacroileítis/complicaciones , Sacroileítis/diagnóstico por imagen , Espondiloartritis/sangre , Espondiloartritis/diagnóstico por imagenRESUMEN
The theoretical description of the adsorption of surfactants at interfaces between aqueous solutions and oil was based over a very long time on models derived for the solution/air interface. Thus, most of the experimentally observed peculiarities could not be specifically considered but were merely interpreted in terms of a penetration of oil molecules into the alkyl chain layer of the adsorbed surfactant molecules. These penetrating oil molecules enhance the surfactant adsorption as compared to the water/air interface. Later on, for the special situations at water/oil interfaces a competitive adsorption of surfactant and oil molecules was postulated, allowing a much better description of experimental data. This picture, however, was unable to explain why the interfacial tension of the water/oil interface decreases very quickly when extremely small amounts of surfactants are added to the water. This effect cannot be of competitive nature, but a cooperativity of surfactant and oil molecules forming a mixed adsorption layer is required instead. This cooperative effect means that already few surfactant molecules adsorbed at the interface can induce a significant ordering of oil molecules in the interfacial layer. This new interfacial structure, in turn, attracts further surfactant molecules to adsorb. Improving the theoretical description of experimental data was finally achieved by applying suitable adsorption models for the two adsorbing compounds, i.e. a Frumkin adsorption model for the oil molecules and a Langmuir, Frumkin, or reorientation model for the adsorbing surfactant molecules. Here, the progress in modelling surfactant adsorption at water/oil interfaces is discussed mainly for the homologous series of the cationic surfactants CnTAB, of the anionic surfactant SDS, and members of the homologous series of the non-ionic surfactants CnDMPO at water/alkane interfaces.
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In Italy, referral of diabetic patients for pancreas transplantation (PT) is an unstructured process, resulting in a low rate of activity and late referrals, often when the patient has already undergone dialysis. In addition, the continuous improvement in pancreas transplant alone, offering the opportunity to reduce cardiovascular risk due to proteinuria and reduced glomerular filtration rate (GFR), is rarely appreciated. We therefore analyzed (1) referral activity to PT during the time frame 2001-2005 in Emilia-Romagna, Italy (four million inhabitants), by collecting ICD 9 CM codes (55.69 + 52.80; 52.86 and 52.80 alone) by residence of the patient; (2) demand for PT among a sample population of 1670 diabetes patients, whose charts were reviewed for the type of diabetes and presence of overt diabetic nephropathy (DN: proteinuria >300 mg/24 h and/or GFR <60 mL/min); (3) potential pancreas availability as the ratio between pancreas and hearts utilized (UP/HR) in different areas of our country. As a results, (1) referral activity reached 8.4 PT per million people in 5 years in the whole region, ranging from 2.6 in the province where a PT program is active, to a maximum value of 20.7 in the province where a devoted outpatient clinic is operated by nephrologists. (2) Prevalence of overt DN was 6% in our cohort, corresponding to 510 D1 patients worthy of evaluation for PT inside Emilia-Romagna region. (3) During 2006, UP/HR was 0.58 in Associazione Inter-Regionale Trapianti agency, 1.16 in Tuscany, 0.30 in Piedmont, and 0.26 in our region. Taken together, our data showed that (1) the referral of D1 to PT has to be empowered, keeping in touch with all patients suffering from diabetic nephropathy; (2) the outpatient clinic devoted to evaluation and recruitment of D1 with nephropathy plays the key role in this program of timely and widespread referral; (3) the availability of pancreata can be increased by utilizing broader criteria for harvesting, increased consent rate to donation and increased the demand for PT (recipient pool). Pancreas grafts need to increase, since the current low demand produces underutilization of the pancreas resource, due to the frequent lack of a suitable recipient.
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Diabetes Mellitus Tipo 1/cirugía , Trasplante de Páncreas/estadística & datos numéricos , Donantes de Tejidos/estadística & datos numéricos , Nefropatías Diabéticas/cirugía , Predicción , Humanos , Italia , Fallo Renal Crónico/etiología , Fallo Renal Crónico/cirugía , Trasplante de Riñón/estadística & datos numéricos , Selección de Paciente , Derivación y Consulta/estadística & datos numéricosRESUMEN
Autoantibody against phospholipase A2 receptor (anti-PLA2R) is a sensitive and specific biomarker of idiopathic membranous nephropathy (iMN), being found in approximately 70% of iMN patients and only occasionally in other glomerular diseases. However, whereas its diagnostic specificity vs. normal controls and other glomerulonephritides (GN) has been firmly established, its specificity vs. membranous nephropathy associated with various diseases (sMN) has given inconsistent results. The aim of our study was to evaluate the prevalence of anti-PLA2R antibodies in iMN in comparison with various control groups, including sMN. A total of 252 consecutive iMN patients, 184 pathological and 43 healthy controls were tested for anti-PLA2R antibody using indirect immunofluorescence (PLA2R IIFT, Euroimmun). Anti-PLA2R autoantibodies were detectable in 178/252 iMN patients, 1/80 primary GN, 0/72 secondary GN, 9/32 sMN and 0/43 healthy controls, with a diagnostic sensitivity of 70.6%. The diagnostic specificity of anti-PLA2R antibody vs. normal and pathological controls was 100 and 94.6% respectively. However, when the diagnostic specificity was calculated only vs. secondary forms of MN, it decreased considerably to 71.9%. Interestingly enough, 9 out of 10 anti-PLA2R positive patients in the disease control groups had membranous nephropathy associated with various diseases (7 cancer, 1 Crohn's disease, 1 scleroderma). In conclusion, anti-PLA2R positivity in a patient with MN, should not be considered sufficient to abstain from seeking a secondary cause, especially in patients with risk factors for neoplasia. The causal relationship between tumors and anti-PLA2R-induced MN remains to be established, as well as the possible mechanisms through which malignancies provoke autoimmunity.
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Autoanticuerpos/sangre , Glomerulonefritis/sangre , Glomerulonefritis/diagnóstico , Neoplasias/complicaciones , Receptores de Fosfolipasa A2/inmunología , Anciano , Enfermedad de Crohn/complicaciones , Diagnóstico Diferencial , Femenino , Glomerulonefritis/etiología , Glomerulonefritis por IGA/sangre , Glomerulonefritis por IGA/diagnóstico , Glomerulonefritis Membranoproliferativa/sangre , Glomerulonefritis Membranoproliferativa/diagnóstico , Glomerulonefritis Membranosa/sangre , Glomerulonefritis Membranosa/diagnóstico , Glomerulonefritis Membranosa/patología , Glomeruloesclerosis Focal y Segmentaria/sangre , Glomeruloesclerosis Focal y Segmentaria/diagnóstico , Humanos , Nefritis Lúpica/sangre , Nefritis Lúpica/diagnóstico , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: In ceramics, "Terzo fuoco" (Third fire) means a third firing of clay to fix colors on tiles or pottery. The low firing temperatures (800-900 degrees C) and the use of a spray gun are risk factors for lead poisoning. Because of their small size, handicraft companies often fail to implement the preventive measures that are utilized efficiently in large tile factories. We report a case of chronic lead poisoning with special emphasis on diagnostic tools and treatment goals. CASE REPORT: A 38-year-old woman was hospitalized in 2005 because of grade 3 chronic renal failure (serum creatinine 1.69 mg%, Cockroft-Gault glomerular filtration rate [GFR] 45 mL/min), hypertension and elevated serum uric acid (13.4 mg%) without gout. She had been previously hospitalized elsewhere and diagnosed as suffering from hypertensive nephropathy. Her occupational history included acute lead poisoning 12 years before, which was treated with a short leave from work. She subsequently continued her job, using a spray gun for decorative drawing in a small tile company until 2004. Because of a low GFR she underwent a 3-day chelation test with 750 mg CaNaEDTA i.v., and excreted 1056 microg Pb (n.v < 600 microg) -- (PbU/EDTA ratio 1.41; n.v < 0.6). A renal biopsy showed chronic interstitial nephropathy with severe arteriolosclerosis. The patient was treated with 5 courses of EDTA, resulting in a final Pb excretion of 517 microg/72 h (PbU/EDTA 0.69). Her serum creatinine fell to 1.32 mg% (CFR 58 mL/min). A further course of chelation therapy is planned. DISCUSSION AND CONCLUSIONS: The EDTA chelation test allows to determine the lead body burden (PbBB) and to titrate subsequent chelation therapy. Recent papers have shown that PbBB is a major factor in the progression of chronic renal failure besides pressure control, and have indicated a PbBB safety level of less than 100 microg/test (PbU/EDTA < 0.1). In order to prevent the development of chronic renal failure, it is important that not only occupational but also environmental lead exposure be identified and adequately treated.
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Fallo Renal Crónico/inducido químicamente , Intoxicación por Plomo/complicaciones , Plomo/efectos adversos , Enfermedades Profesionales/inducido químicamente , Adulto , Quelantes/uso terapéutico , Terapia por Quelación/métodos , Progresión de la Enfermedad , Ácido Edético/uso terapéutico , Femenino , Humanos , Fallo Renal Crónico/terapia , Intoxicación por Plomo/terapia , Enfermedades Profesionales/terapia , Índice de Severidad de la Enfermedad , Resultado del TratamientoAsunto(s)
Capilares/fisiopatología , Síndrome de Marfan/fisiopatología , Microcirculación/fisiología , Capilares/metabolismo , Femenino , Hemosiderina/metabolismo , Humanos , Síndrome de Marfan/metabolismo , Angioscopía Microscópica , Microscopía por Video , Persona de Mediana Edad , Uñas/irrigación sanguíneaRESUMEN
The interfacial tension response to dilational deformation of interfacial area exhibits a (more or less) nonlinear behavior, depending on the amplitude of the deformation. Studies of such observable interfacial properties in the nonlinear domain suggest valuable information about the two-dimensional microstructure of the interfacial layer, as well as about the structure time-evolution. In this article, the emphasis is centered on the available mathematical methods for quantitatively analyzing and describing the magnitude and the characteristics of the nonlinear interfacial viscoelastic properties. Specifically, in periodic oscillation experiments the nonlinear behavior can be represented by the combination of a linear part (the surface dilational modulus), with an additional complementary Fourier analysis parameterizing the nonlinearity. Also asymmetric Lissajous plots, of interfacial tension versus deformation, are useful tools for expanding the response nonlinearity into four distinct components relevant to significant points of the cyclic loop. In connection with the mathematical methods, nonequilibrium thermodynamic formulations provide a powerful theoretical framework for investigating the interfacial dynamic properties of multiphase systems. Experimental results for adsorption layers of complex components, available in the literature, show notable nonlinear interfacial viscoelastic behavior. In particular in this review, data are illustrated for solutions of polymers and of polyelectrolyte/surfactant complexes. The observed nonlinear findings reveal formation of complexes, patches, and other different interfacial structures.
RESUMEN
Suramin, a polyanionic drug used in the treatment of trypanosomiasis and onchocerciasis, inhibits growth factor-induced mitogenesis in several human tumours. We have investigated the effect of suramin on human breast cancer cell lines (HBCCL). By cell counts and thymidine incorporation we found that 50 to 400 micrograms/ml suramin inhibits the proliferation of HBCCL in a dose-dependent and reversible fashion (ID50 approximately 200 micrograms/ml for MCF-7 and MDA-MB 231). Radioreceptor and affinity cross-linking assays showed that suramin was also able to reduce the binding of insulin-like growth factor I (IGF-I) to its receptor (40-50% inhibition at 100 micrograms/ml). Our results indicate that the drug does not affect the IGF-I receptor (IGF-I-R), but binds directly to the IGF-I peptide. In conclusion, the strict correlation observed between suramin inhibition of proliferation and IGF-I binding on HBCCL suggests a possible therapeutic role for this molecule as an antineoplastic drug in human breast tumours.
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Neoplasias de la Mama/tratamiento farmacológico , Factor I del Crecimiento Similar a la Insulina/metabolismo , Receptor IGF Tipo 1/metabolismo , Suramina/uso terapéutico , Neoplasias de la Mama/química , Neoplasias de la Mama/metabolismo , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Mitosis/efectos de los fármacos , Unión Proteica , Receptor IGF Tipo 1/efectos de los fármacos , Receptores de Somatomedina/análisis , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
The purpose of our study was to evaluate the effects of 5 alpha-dihydrotestosterone (DHT) and hydroxyflutamide (HF), alone or in combination, on androgen receptor (AR) dynamics and on cellular growth in cultured breast cancer cells (EVSA-T). The incubation of cells with DHT increased the concentration of nuclear AR after 24 and 48 h. HF was also able to promote the nuclear accumulation of AR after 24 and 48 h of treatment. When HF-treated cells are incubated with DHT, the nuclear AR concentration is lower than that found in cells treated with DHT alone. We conclude that HF acts by increasing nuclear accumulation of receptor-antiandrogen complexes. Moreover, DHT stimulates cell growth while HF has an inhibitory effect. Thymidine incorporation in cells also increased after DHT treatment and decreased after HF incubation. The HF-induced inhibition of cell growth persisted both after renewal of the medium and after the addition of DHT to cultures. It may be hypothesized that either DHT is converted to inactive metabolites or that HF exerts a persistent inhibitory effect. In the latter case, the antiandrogen action of HF could be exerted by retention of high levels of antiandrogen in cells or by such a depressed protein synthesis that the renewal of growth is slower than the 48 h period studied.
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Antagonistas de Andrógenos/farmacología , Neoplasias de la Mama/patología , Dihidrotestosterona/farmacología , Flutamida/análogos & derivados , Receptores Androgénicos/efectos de los fármacos , Neoplasias de la Mama/metabolismo , División Celular/efectos de los fármacos , Flutamida/farmacología , Humanos , Células Tumorales CultivadasRESUMEN
Human non-small cell lung cancer (N-SCLC), a common malignancy generally unmanageable by conventional cytotoxic chemotherapy, represents a major world health burden. Suramin, a polyanionic drug which appears to interfere with growth-factor/receptor interaction, has recently been shown to be cytostatic for small cell lung cancer cells; it may also be effective for N-SCLC. As insulin-like growth factor I (IGF-I) is a known progression agent for N-SCLC, we have examined the effects of suramin on the 'IGF-I system' in a panel of human N-SCLC cell lines. Colorimetric and thymidine incorporation assays were used to assess cell chemosensitivity whereas a radio-receptor assay was employed to evaluate IGF-I/receptor binding. Suramin reversibly reduced, in a concentration- and time-dependent manner, the growth of each N-SCLC cell line examined either cultured in serum-containing or serum-free medium. Furthermore, suramin caused a concentration-related inhibition of labeled IGF-I peptide specific binding on all cell lines studied. Suramin caused a significant reduction in the Bmax values with only weak variations in the affinity constants (Kd). We hypothesize that suramin interference with IGF-I mitogenic activity is a pathway by which this drug produces its effect in vitro. These data indicate further studies on the mechanism of action and pharmacology of suramin in vivo are warranted.
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Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Factor I del Crecimiento Similar a la Insulina/efectos de los fármacos , Neoplasias Pulmonares/metabolismo , Suramina/farmacología , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Unión Competitiva , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/metabolismo , División Celular/efectos de los fármacos , ADN/biosíntesis , Relación Dosis-Respuesta a Droga , Formazáns/química , Humanos , Factor I del Crecimiento Similar a la Insulina/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Mitógenos/efectos adversos , Ensayo de Unión Radioligante , Suramina/administración & dosificación , Suramina/uso terapéutico , Sales de Tetrazolio/química , Timidina/metabolismo , Células Tumorales CultivadasRESUMEN
The adsorption at liquid-liquid interfaces is a phenomenon with a remarkable impact on many scientific and technological fields concerning multiphasic systems. Though in principle similar to liquid-vapour, the study and the description of the dynamic aspects of the adsorption processes at liquid-liquid interfaces deserves some specific considerations. In fact, these systems are often characterised by the partitioning of the surfactant between the two liquid phases, which makes much more complex both their modelling and investigation. In some conditions, the partitioning can be the main process controlling the adsorption dynamics. This paper is aimed at reviewing the state-of-the-art of the theoretical modelling and experimental investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. After a brief introduction to the problem of adsorption dynamics, the principal models utilised to describe the process at liquid-liquid interfaces under different assumptions are critically presented, underlining the influence of the surfactant partitioning, with respect to the relative volumes of the liquid phases and of the initial partitioning conditions. The most important experimental methodologies for the measurement of the dynamic interfacial tension are also critically reviewed by pointing out the specific problems related with the investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. Moreover, the problem of the measurement of the thermodynamic quantities characterising the partitioning--mainly the partition coefficient--is also addressed, reporting some literature data. Finally, a review of the literature about the experimental work on the subject and an overview of the needs and of the open questions is given.
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The effects induced by the antiandrogen Cyproterone Acetate (CPA) on the proliferation of EVSA-T human breast cancer cells endowed with androgen receptors were studied. Kinetic analyses were carried out by two autoradiographic techniques measuring the percentage of cells in S-phase and the growth fraction (GF). The exposure of the cultures to CPA for 24 h caused a marked inhibition on S-phase cells without significantly affecting the CF. The accumulation of cells in G1-phase, confirmed by cytometric analysis, was rescued to the S compartment by replacing the culture medium 24 h after CPA administration. Exposure of EVSA-T to Doxorubicin or Methotrexate after CPA and medium change at the time of maximal proliferative recruitment, led to an enhancement of cytotoxicity as demonstrated by colony survival assay.
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Antagonistas de Andrógenos/farmacología , Antineoplásicos/farmacología , Ciproterona/análogos & derivados , Receptores de Esteroides/metabolismo , Células Tumorales Cultivadas/citología , Neoplasias de la Mama , Ciclo Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Línea Celular , Núcleo Celular/metabolismo , Ciproterona/farmacología , Acetato de Ciproterona , Citosol/metabolismo , ADN de Neoplasias/efectos de los fármacos , ADN de Neoplasias/metabolismo , Doxorrubicina/farmacología , Sinergismo Farmacológico , Femenino , Humanos , Metotrexato/farmacología , Receptores Androgénicos/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Receptores de Esteroides/efectos de los fármacos , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
Adsorption layers of n-dodecanol at the water/air interface show phase transitions at low temperatures [Vollhardt, Fainerman, Emrich, J. Phys. Chem. B 104 (2000) 8536]. Using a drop shape technique it is shown that the dilational elasticity disappears in the coexistence region of the adsorption layer. The relaxation time between the condensed and liquid-like surface states is in the sub-second time range.
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Dodecanol/química , Agua/química , Adsorción , Aire , Reología/métodos , Propiedades de Superficie , TemperaturaRESUMEN
The experimental data on the surface rheological characteristics of dodecyl dimethyl phosphine oxide solutions obtained in a fully automatic oscillating bubble device under microgravity conditions in the frequency range 0.01-100 Hz are presented. The complex surface elasticity modulus is obtained form the amplitude- and phase-frequency characteristics of established pressure oscillations in a closed cell without calibration experiments by direct calculation of the necessary coefficients. The characteristics of the adsorption layers obtained from the elasticity modulus are in good agreement with adsorption isotherms and equations of state accounting for the intrinsic (2D) monolayer compressibility.
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BACKGROUND: Despite continuing glucose absorption and stimulation of insulin secretion, wasting is common in patients with chronic renal failure (CRF) treated with peritoneal dialysis. METHODS: To evaluate if peritoneal dialysis per se has any effect(s) on muscle protein turnover we employed the forearm perfusion method associated with the kinetics of 3H-phenylalanine in seventeen patients with CRF in the basal state and: a) during the systemic hyperinsulinemia associated with peritoneal dialysis (6 patients) (200-240 min); b) during locally-induced hyperinsulinemia, without systemic effects on aminoacid (AA) availability (6 patients) (80-120 min); c) in time-controls (5 patients) (80-240 min). RESULTS: Peritoneal dialysis and local infusion of insulin in the brachial artery (0.01 mU/min/kg) induced a similar degree of systemic or local, moderate hyperinsulinemia (19+/-4 e 21+/-3 microU/ml, respectively). During both protocols an insulin-related inhibition of muscle protein degradation occurred; however peritoneal dialysis caused a 20% decrease in forearm phenylalanine rate of disposal (an index of muscle protein synthesis), which correlated with the decline of arterial BCAA and potassium, which were removed via the peritoneal fluid. Furthermore, a persistent negative net phenylalanine and AA balance across the forearm was observed during peritoneal dialysis, while the negative basal net phenylalanine and AA balance was reversed to a positive or neutral one during local hyperinsulinemia. CONCLUSIONS: We conclude that in CRF patients even a modest elevation in local insulin levels is followed by an anabolic muscle response, while the same effect is not observed during the systemic hyperinsulinemia associated with substrate removal which occurs during peritoneal dialysis. In this setting the antiproteolytic effect of hyperinsulinemia is offset by a decrease in muscle protein synthesis which is accounted for by a decrease in AA availability. Our data indicate that protein metabolism during peritoneal dialysis is characterized not only by decreased, but also less efficient, turnover rates.
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Diálisis Peritoneal , Proteínas/metabolismo , Aminoácidos/metabolismo , Arteria Braquial , Soluciones para Diálisis/efectos adversos , Antebrazo , Glucosa/administración & dosificación , Glucosa/efectos adversos , Humanos , Hiperinsulinismo/inducido químicamente , Hiperinsulinismo/metabolismo , Infusiones Intraarteriales , Insulina/administración & dosificación , Insulina/farmacología , Fallo Renal Crónico/metabolismo , Fallo Renal Crónico/terapia , Proteínas Musculares/metabolismo , Fenilalanina/farmacocinética , Desnutrición Proteico-Calórica/complicaciones , Desnutrición Proteico-Calórica/metabolismo , Tritio/análisisRESUMEN
For the understanding of short-time adsorption phenomena and high-frequency relaxations at liquid interfaces particular experimental techniques are needed. The most suitable method for respective studies is the capillary pressure tensiometry. However, under gravity conditions there are rather strong limitations, in particular due to convections and interfacial deformations. This manuscript provides an overview of the state of the art of experimental tools developed for short-time and high-frequency investigations of liquid drops and bubbles under microgravity. Besides the brief description of instruments, the underlying theoretical basis will be presented and limits of the applied methods under ground and microgravity conditions will be discussed. The results on the role of surfactants under highly dynamic conditions will be demonstrated by some selected examples studied in two space shuttle missions on Discovery in 1998 and Columbia in 2003.