RESUMEN
In this work, a tumor microenvironment (TME)-responsive biodegradable MnSiO3@Fe3O4 nanoplatform for dual-mode magnetic resonance imaging (MRI)-guided combinatorial cancer therapy was constructed. Fe3O4 nanoparticles decorated on the surface of MnSiO3 could effectively obstruct the pores of MnSiO3 and reduce the leakage of anticancer drugs under physiological conditions. The structure of the nanoplatform was broken under the weakly acidic and high-concentration glutathione conditions in the TME, resulting in the separation of the Fe3O4 nanoparticles from the nanoplatform and rapid drug release. In addition, the exfoliated Fe3O4 and released Mn2+ can help reduce the interference between their T1 and T2 contrast abilities, resulting in dual-mode MRI contrast enhancement. Furthermore, during the exfoliation process of the Fe3O4 nanocrystals, the catalytic activity of the Fe3O4 nanocrystals toward a Fenton-like reaction within cancer cells could be improved because of the increase in specific surface area, which led to the generation of highly toxic hydroxyl radicals and induced HeLa cell apoptosis. The nanoplatform also displayed excellent T1-T2 dual-mode MRI contrast enhancement and anticancer activity in vivo with reduced systemic toxicity. Thus, this multifunctional nanoplatform could be a potential nanotheranostic for dual-mode MRI-guided combinatorial cancer therapy.
Asunto(s)
Antineoplásicos/uso terapéutico , Cisplatino/uso terapéutico , Silicatos de Magnesio/uso terapéutico , Nanopartículas de Magnetita/uso terapéutico , Neoplasias/terapia , Animales , Materiales Biocompatibles/uso terapéutico , Células HeLa , Humanos , Imagen por Resonancia Magnética/métodos , Ratones Desnudos , Neoplasias/diagnóstico por imagen , Nanomedicina Teranóstica/métodosRESUMEN
Nanoclays have potential applications in biomedicine raising the need to evaluate their toxicity in in vitro models as a first approach to its biocompatibility. In this study, in vitro toxicity of clinoptilolite and sepiolite nanoclays (NC) was analyzed in highly phagocytic cultures of amoebas and human and mice macrophages. While amebic viability was significantly affected only by sepiolite NC at concentrations higher than 0.1 mg/mL, the effect on macrophage cultures was dependent on the origin of the cells. Macrophages derived from human peripheral blood monocytes were less affected in viability (25% decrease at 48 h), followed by the RAW 264.7 cell line (40%), and finally, macrophages derived from mice bone marrow monocytes (98%). Moreover, the cell line and mice macrophages die mainly by necrosis, whereas human macrophages exhibit increased apoptosis. Cytokine expression analysis in media of sepiolite NC treated cultures showed a proinflammatory profile (INFγ, IL-1α, IL-8, and IL-6), in contrast with clinoptilolite NC that induced lees cytokines with concomitant production of IL-10. The results show that sepiolite NC is more toxic to amoebas and macrophages than clinoptilolite NC, mostly in a time and dose-dependent manner. However, the effect of sepiolite NC was comparable with talc powder suggesting that both NC have low cytotoxicity in vitro.
Asunto(s)
Silicatos de Aluminio/efectos adversos , Silicatos de Magnesio/efectos adversos , Zeolitas/efectos adversos , Silicatos de Aluminio/uso terapéutico , Animales , Diferenciación Celular/efectos de los fármacos , Arcilla , Expresión Génica/efectos de los fármacos , Humanos , Interleucina-10/biosíntesis , Interleucina-6/biosíntesis , Interleucina-8/biosíntesis , Macrófagos/efectos de los fármacos , Silicatos de Magnesio/uso terapéutico , Ratones , Factor de Necrosis Tumoral alfa/biosíntesis , Zeolitas/uso terapéuticoRESUMEN
Formation of calculi in efferent urinary passages is always due to supersaturation of urinary calculi substances and associated increased crystallization. Apart from the typical calculi, consisting of calcium oxalate, inorganic phosphates, uric acid or cystine, there are occasional signs of rare substance classes. Although more than 50 silicate stones have already been reported internationally, this stone entity remains relatively unknown. In particular, the occurrence of silicate stones in the absence of magnesium trisilicate abuse is extremely rare. A medium-sized left-sided ureterolith was removed from a 54-year-old male patient using a ureteroscope. X-ray diffraction showed it to be a compound stone consisting of 40% silicate. The patient, who in 1986 was living close to the nuclear reactor accident in Chernobyl, showed no signs of a constant uptake of magnesium trisilicate. However, he had undergone partial (2/3) gastrectomy 4 months before for a drug-refractory gastric ulcer, which had been diagnosed at the end of the 1980s and treated with excessive dosages of a magnesium trisilicate antacid preparation until the time of the operation. The patient had also been suffering from unstable angina pectoris since 1986 and treated with Pentalong (pentaerythrityltetranitrate) for 17 years. We were also able to detect silicium dioxide in components of this drug using X-ray diffraction. Silicate uroliths are extremely rare but they can be clearly identified by X-ray diffraction or infrared spectroscopy and distinguished from artifacts or quartz pebbles. Formation of calculi can be prevented by increasing diuresis as well as switching to a different drug and reducing the dosage.
Asunto(s)
Silicatos de Magnesio/efectos adversos , Tetranitrato de Pentaeritritol/análogos & derivados , Dióxido de Silicio/análisis , Cálculos Ureterales/química , Angina Inestable/tratamiento farmacológico , Cristalografía por Rayos X , Gastrectomía , Humanos , Cuidados a Largo Plazo , Silicatos de Magnesio/química , Silicatos de Magnesio/uso terapéutico , Masculino , Persona de Mediana Edad , Tetranitrato de Pentaeritritol/efectos adversos , Tetranitrato de Pentaeritritol/química , Tetranitrato de Pentaeritritol/uso terapéutico , Úlcera Gástrica/cirugía , Cálculos Ureterales/inducido químicamente , Cálculos Ureterales/cirugía , UreteroscopíaRESUMEN
A papaína (Carica papaya) vem sendo empregada na forma de solução aquosa e salina no tratamento de feridas de várias etiologias, para acelerar o processo de cicatrização. Considerando esta técnica trabalhosa, comecei a utilizar a papaína associada ao silicato de magnésio, obtendo resultados satisfatórios, mas sem ter fundamentado em achados de pesquisa. Motivo pelo qual desenvolvi este estudo com 20 clientes, 8 homens e 12 mulheres, que estavam predominantemente (85%) na faixa etária dos 50 aos 80 anos e foram por mim atendidos em ambulatório do Hospital Universitário Pedro Ernesto da Universidade do Estado do Rio de Janeiro, no período de abril de 2003 a janeiro de 2004.0 estudo, de natureza quantitativa, do tipo exploratório descritivo (Wood & Haber, 2001), teve como objetivo criar e avaliar a eficácia da tecnologia do cuidado que alia interação enfermeira-cliente e a utilização da papaína associada ao silicato de magnésio na maximização da cicatrização de feridas. O referencial do estudo é fundamentado nos conceitos de interação (KING,1981), tecnologia de cuidado (NIETSCHE; LEOPARDI, 2000), procedimento de curativo (ROGENSKI, 1996; MONETA, 1998; ALMEIDA,2000). A amostra foi não probabilística acidental; os sujeitos que atendiam aos critérios assinavam o consentimento livre e esclarecido conforme resoluções 196 e 251 do CNS e eram acompanhados pela pesquisadora, semanalmente e conforme a evolução quinzenalmente, e tomada das medidas lineares da ferida. Foram analisados por meio de estatística descritiva. Os resultados segundo o índice de aproveitamento, utilizando como critério o percentual de comparecimento às consultas agendadas e realização do curativo em domicílio e no consultório, permitiu destacar dois grupos, o A (9 sujeitos, aproveitamento parcial, 74,7% de presença nas consultas previamente agendadas e 95,3% de realização dos curativos) e o B (11 sujeitos, 100%). Este resultado demonstra a eficácia da tecnologia de cuidado no que se refere à intera
Asunto(s)
Humanos , Persona de Mediana Edad , Cicatrización de Heridas , Atención de Enfermería/métodos , Heridas y Lesiones/enfermería , Heridas y Lesiones/terapia , Relaciones Enfermero-Paciente , Papaína/uso terapéutico , Silicatos de Magnesio/uso terapéutico , Brasil , Investigación en Enfermería Clínica , Epidemiología Descriptiva , Teoría de Enfermería , MuestreoRESUMEN
Two cases of silica stones, without previous oral intake of magnesium trisilicate, are reported. A 64-year-old Japanese woman had bilateral renal stones. Infrared spectrophotoscopy revealed that one of the fragments consisted of silicate and the others consisted of calcium oxalate. A 75-year-old woman had right renal stones. The composition of 1 stone was a mixture of silicate and unspecified matrices. Silicate urolithiasis may not necessarily be related to oral intake of silicate-containing antacids.
Asunto(s)
Antiácidos/uso terapéutico , Cálculos Renales/etiología , Silicatos de Magnesio/uso terapéutico , Dióxido de Silicio/análisis , Anciano , Femenino , Humanos , Cálculos Renales/química , Cálculos Renales/diagnóstico por imagen , Cálculos Renales/orina , Persona de Mediana Edad , Radiografía , Dióxido de Silicio/efectos adversos , Dióxido de Silicio/orina , Espectrofotometría InfrarrojaRESUMEN
The relative efficacy of 6 shower dip chemicals most frequently used for the treatment of sheep lice (Bovicola ovis) in Western Australia was examined. Groups of 20 sheep infested with lice were treated with products containing either alphamethrin, cyhalothrin, diazinon or diazinon plus piperonyl butoxide and rotenone, formulated as emulsifiable concentrates, and with products containing either coumaphos or magnesium fluorosilicate, formulated as wettable powders. All treatments were applied through a shower dip (Sunbeam model SSD). Inspections for lice were conducted until 9 months after dipping. No lice were found on sheep treated with the 4 emulsifiable concentrate products. In contrast, treatment with the wettable powders, which contained either coumaphos or magnesium fluorosilicate as the active ingredient, did not eradicate the lice infestations. The degree to which the fleece was wetted was assessed 20 minutes after dipping and showed that the wettable powder dips penetrated the fleece less than the emulsifiable concentrate dips. Less fluid was retained by wool staples in an in-vitro test when dip wash was made with the wettable powders. It was concluded that the degree of wetting attained at dipping was an important factor in achieving eradication of sheep lice.