1,721,385 research outputs found
Current Technological Approaches for a Wearable Artificial Kidney
No full textA wearable artificial kidney (WAN) is a device that continuously supports renal function during ambulation or social activities out of hospital. With the aim of improving dialysis patients' quality of life, WAK systems have been in development for several decades. Technological evolutions in dialysis membrane and dialysate regeneration have been paving the way to wearability, and the possibility of implantation, for renal replacement therapies. However, at present, there are many technical issues confronting the attempts to apply WAK systems in clinical practice. Here, we have reviewed the necessary technical requirements and the WAKs currently being developed that are trying to meet these. Aside from technical issues, ethical, legal and economic aspects should be also considered together, in order to minimize trial and error in the development of the WAN. Continuous follow-up, integration with emerging new technologies, and multidisciplinary approaches involving clinicians, engineers, economists and social scientists are required for the realization of WAK in clinical practice. Copyright (C) 2011 S. Karger AG, Base
Preparation by spray drying of amphotericin B-phospholipid composite particles and their anticellular activity
No full textAs a potent drug carrier for systemic fungal infections, amphotericin B(AmB)-phospholipid composite particles (APCPs) were prepared by the spray drying method. AmB and egg phosphatidylcholine, co-dissolved in methanol (0.0425-0.45 mg AmB/ml, 0.17-1.8 mg lipid/ml), was nebulized at 2 ml/min. The aerosol produced was carried by air at 1000 ml/min to the inner tubes of a serially connected distilling column system, of which the outer tubes were supplied with circulating water of 95 degreesC. The particles, by scanning electron microphotography, are spherical and submicron-sized. Upon hydration of the particles in phosphate-buffered saline for 30 min at room temperature, liposome-like bilayer vesicles were formed along with AmB-phospholipid complexes, evidenced by the transmission electron microphotographs and the positive peak around 330 nm of the circular dichroism spectrum, respectively. The hemolytic abilities of the APCPs were lower than those of free drug, without loss of the antifungal activity. The suppressed hemolysis could be ascribed to the liposomes and to the complexes that are reconstituted by hydration of APCPs. The dry composite particles could circumvent the inherent instability of liposomal formulations
Unusual Case of Scalp Sarcoidosis with Alopecia: An Only Manifestation of Cutaneous Sarcoidosis without Systemic Involvement
No full textRelease property of temperature-sensitive liposome containing poly(N-isopropylacrylamide)
No full textMultilamellar vesicles(MLVs) of Egg phosphatidylcholine (PC) were prepared by either reverse-phase evaporation or film hydration method, and dioleoylphosphatidylethanolamine (DOPE) liposomes by detergent removal. Their temperature-dependent release behaviours were investigated in the presence of copolymer of N-isopropylacrylamide and octadecylamine (poly(NIPAM-co-ODA)) or copolymer of N-isopropylacrylamide, acrylic acid and octadecylamine (poly(NIPAM-co-AA-co-ODA)) using calcein a fluorescence probe. By a temperature jump from 17 to 40 degreesC, crossing the transition temperature of poly(NIPAM-co-ODA), similar to29 degreesC, the release from reverse-phase evaporation vesicles (REVs) containing the polymer in 270 s increased in a saturation manner until the mixing ratio of polymer to lipid was 0.1, where the degree of release was similar to55%. For the film hydration vesicles (FHVs), the release pattern with polymer to lipid ratio was similar to that of REVs, but the degree of release under the same conditions was much less than in case of REVs, even though both are composed of the same phospholipid. Since the bilayers of REVs are less in number. and more closely stacked each other than those of FHVs, the defect in the bilayers of REVs would be induced more easily by a thermal contraction of the polymer. For DOPE liposomes, the degrees of releases under the same conditions as in the REVs and the FHVs of egg PC were >80%. The extensive release is probably because that the DOPE liposomes disintegrated into nonbilayer structure. On the other hand, in the temperature-dependent release from liposomes mixed with either poly(NIPAM-co-ODA) or poly(NIPAM-co-AA-co-ODA), of which the transition temperatures are similar to29 and 37 degreesC, respectively, REVs and FHVs started to release significantly around the transition temperature of each polymer. However, for DOPE liposomes the temperature where the liposomes start to release is not clear and an appreciable amount of calcein released below the transition temperature. Therefore, REVs and FHVs are expected to be more favorable than DOPE liposomes when the off-on behavior of release at a certain temperature is desired. Of the egg PC liposomes, REVs would be a better choice than FHVs in aspects of degree of release. (C) 2002 Elsevier Science B.V. All rights reserved
Hemolytic and antifungal activity of amphotericin B-entrapped liposomes by precipitation
No full textHemolytic characteristics of amphotericin B-phospholipid fine particles by aerosol method
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Dynamic Hemodialysis: A Potential Solution for Middle Molecule Removal
No full textBetter clearance of middle molecular weight solutes has been associated with improved patient outcomes. However, blood-membrane interaction during dialysis results in the development of secondary protein layers on the dialysis membrane surface, leading to impairments in middle molecular weight solute removal. The shear rate at the surface of the dialysis membrane is one of the important factors that influence blood-membrane surface interaction. In this paper, we discuss the concept of 'dynamic hemodialysis', i.e. using mechanical vibration to increase shear rate at the surface of dialysis membrane. For longitudinal and transverse vibratory motions, hemodynamic changes inside the membrane and their consequent effects on membrane morphology and dialysis efficiency are discussed. Longitudinal vibration generates a reverse flow by relative membrane motion, and transverse vibration generates a symmetric swirling flow inside the hollow fiber, which increases shear rate and enhances flow mixing. Additionally, the impulse induced by the vibration could sustain the absorption capacity of the membrane to specific uremic toxins. In conclusion, dynamic hemodialysis could enhance solute removal by minimizing the morphological changes in the dialysis membrane during hemodialysis. However, the operating conditions of dynamic hemodialysis (i.e. the amplitude and frequency of mechanical vibration) need to be optimized in terms of hemolysis and noise from the mechanical vibration. Copyright (C) 2011 S. Karger AG, Base
Halo-Like Disappearance of Café au Lait Spot: A Clue for the Role of Autoimmunity and Somatic Mosaicism in Segmental Vitiligo
No full textVitiligo, an autoimmune skin disease, is primarily driven by interferon- γ -CXCL10 signaling involving autoreactive CD8+ T cells targeting melanocytes. Although the pathogenesis of segmental vitiligo remains unclear, recent insights suggest neural, somatic mosaicism, and microvascular mechanisms as possible explanations. Here, we present a case of a 5-year-old boy with a cafe au lait macule that transformed into a hypopigmented patch, suggestive of segmental vitiligo. Biopsies showed early vitiligo features in the hypopigmented area, where there was high prevalence of CD8+ T cells, accompanied by CXCL10 expression. Growing evidence supports the autoimmune basis and cutaneous mosaicism in segmental vitiligo, with this case highlighting the role of vulnerable melanocytes, autoimmune attack, and the abrupt loss of repigmentation post-treatment. This case adds weight to the autoimmune and mosaicism theories in segmental vitiligo pathogenesis
The impact of appendectomy on the occurrence of alopecia areata: a retrospective cohort study
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