78 research outputs found
Non-Holonomic Control IV : Coherence Protection in a Rubidium isotope
In this paper, we present a realistic application of the coherence protection
method proposed in the previous article. A qubit of information encoded on the
two spin states of a Rubidium isotope is protected from the action of electric
and magnetic fields
Non-Holonomic Control I
In this paper, we present a universal control technique, the non-holonomic
control, which allows us to impose any arbitrarily prescribed unitary evolution
to any quantum system through the alternate application of two well-chosen
perturbations
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A case of bilateral acute depigmentation of the Iris in one of two identical twins
Background
Bilateral Acute Depigmentation of the Iris (BADI) is a condition which was first described in a case series from Turkey by Tugal-Tutkin and Urgancioglu in (Graefes Arch Clin Exp Ophthalmol 244:742-6, 2006). The condition is characterized by bilateral acute depigmentation and discoloration of the iris stroma, pigment dispersion, and deposition of pigment in the angle. In our case we report a patient who developed BADI after receiving pitcher plant extract injections for chronic migraine, while her identical twin sister has normal iris architecture and pigmentation and never received any pitcher plant injections.
Case presentation
Patient is a 41-year-old female with history of pitcher plant extract injections to her face for chronic migraine, who later developed bilateral depigmentation of the iris. She did not have any signs of anterior segment uveitis or iridocyclitis. She has an identical twin sister who maintained normal iris pigmentation during the entire course.
Conclusions
Bilateral Acute depigmentation of the is a recently discovered condition described in the literature in Turkish patients (Tugal-Tutkun and Urgancioglu, Graefes Arch Clin Exp Ophthalmol 244:742-6, 2006; Tugal-Tutkun et al., Ophthalmology 116(8):1552-7, 2009). This condition affects mainly young females and is characterized by acute bilateral stromal depigmentation, without other pathologic ocular findings. These patients usually maintain normal vision and do not develop significant glaucoma from pigment collecting in the anterior chamber angle. This condition can be mistaken for Fuchsâ heterochromic iridocyclitis, pigment dispersion syndrome, pseudoexfoliation syndrome, and viral iridocyclitis. This is the first reported case in North America and is important for differentiation from the above pathologies. Our patient had a history of pitcher plant extract injections to the face but it is unclear if this is associated with our patientâs development of BADI. As awareness of this condition progresses, a possible etiology may be elucidated
Solid lipid nanoparticles self-assembled from spray dried microparticles
We report the self-assembly of anti-cancer drug-loaded solid lipid nanoparticles (SLNs) from spray dried microparticles comprising poly(vinylpyrrolidone) (PVP) loaded with glyceryl tristearate (GTS) and either indomethacin (IMC) or 5-fluorouracil (5-FU). When the spray dried microparticles are added to water, the PVP matrix dissolves and the GTS and drug self-assemble into SLNs. The SLNs provide a non-toxic delivery platform for both hydrophobic (indomethacin) and hydrophilic (5-fluorouracil) drugs. They show extended release profiles over more than 24 h, and in permeation studies the drug cargo is seen to accumulate inside cancer cells. This overcomes major issues with achieving local intestinal delivery of these active ingredients, in that IMC permeates well and thus will enter the systemic circulation and potentially lead to side effects, while 5-FU remains in the lumen of the small intestine and will be secreted without having any therapeutic benefit. The SLN formulations are as effective as the pure drugs in terms of their ability to induce cell death. Our approach represents a new and simple route to the fabrication of SLNs: by assembling these from spray-dried microparticles on demand, we can circumvent the low storage stability which plagues SLN formulations
A Novel Tropically Stable Oral Amphotericin B Formulation (iCo-010) Exhibits Efficacy against Visceral Leishmaniasis in a Murine Model
Visceral leishmaniasis (VL) is a systemic form of a vector-borne parasitic disease caused by obligate intra-macrophage protozoa of the genus Leishmania. VL is always fatal in humans if left untreated and treatment options are limited. Amphotericin B (AmB), a polyene antibiotic, is the most active antileishmanial agent that currently exists. Liposomal AmB (AmBisome) is used as first-line treatment in developed countries [1], [7], [8], [9], [10]; however, the requisite parenteral administration and the high cost of the liposomal formulation prevents this treatment from reaching the majority of patients in developing nations [3]. A stable, efficacious oral treatment for VL that is able to withstand the rigors of tropical climates would overcome many of the current barriers to treatment that exist in countries with large VL-infected patient populations. In this study we have developed an oral formulation of AmB that is stable in tropical conditions and exhibits significant antileshimanial activity in mice
ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the universe using the baryon acoustic
oscillations technique. The spectra of 35 million galaxies and quasars over
14,000 square degrees will be measured during a 5-year survey. A new prime
focus corrector for the Mayall telescope at Kitt Peak National Observatory will
deliver light to 5,000 individually targeted fiber-fed robotic positioners. The
fibers in turn feed ten broadband multi-object spectrographs. We describe the
ProtoDESI experiment, that was installed and commissioned on the 4-m Mayall
telescope from August 14 to September 30, 2016. ProtoDESI was an on-sky
technology demonstration with the goal to reduce technical risks associated
with aligning optical fibers with targets using robotic fiber positioners and
maintaining the stability required to operate DESI. The ProtoDESI prime focus
instrument, consisting of three fiber positioners, illuminated fiducials, and a
guide camera, was installed behind the existing Mosaic corrector on the Mayall
telescope. A Fiber View Camera was mounted in the Cassegrain cage of the
telescope and provided feedback metrology for positioning the fibers. ProtoDESI
also provided a platform for early integration of hardware with the DESI
Instrument Control System that controls the subsystems, provides communication
with the Telescope Control System, and collects instrument telemetry data.
Lacking a spectrograph, ProtoDESI monitored the output of the fibers using a
Fiber Photometry Camera mounted on the prime focus instrument. ProtoDESI was
successful in acquiring targets with the robotically positioned fibers and
demonstrated that the DESI guiding requirements can be met.Comment: Accepted versio
Linking in vitro lipolysis and microsomal metabolism for the quantitative prediction of oral bioavailability of BCS II drugs administered in lipidic formulations
Lipidic formulations (LFs) are increasingly utilized for the delivery of drugs that belong to class II of the Biopharmaceutics Classification System (BCS). The current work proposes, for the first time, the combination of in vitro lipolysis and microsomal metabolism studies for the quantitative prediction of human oral bioavailability of BCS II drugs administered in LFs. MarinolÂŽ and NeoralÂŽ were selected as model LFs and their observed oral bioavailabilities (Fobserved) obtained from published clinical studies in humans. Two separate lipolysis buffers, differing in the level of surfactant concentrations, were used for digestion of the LFs. The predicted fraction absorbed (Fabs) was calculated by measuring the drug concentration in the micellar phase after completion of the lipolysis process. To determine first-pass metabolism (FgâFh), drug depletion studies with human microsomes were performed. Clearance values were determined by applying the âin vitro half-life approachâ. The estimated Fabs and FgâFh values were combined for the calculation of the predicted oral bioavailability (Fpredicted). Results showed that there was a strong correlation between Fobserved and Fpredicted values only when Fabs was calculated using a buffer with surfactant concentrations closer to physiological conditions. The general accuracy of the predicted values suggests that the novel in vitro lipolysis/metabolism approach could quantitatively predict the oral bioavailability of lipophilic drugs administered in LFs
Probucol Suppresses Enterocytic Accumulation of Amyloid-β Induced by Saturated Fat and Cholesterol Feeding
Amyloid-β (Aβ) is secreted from lipogenic organs such as intestine and liver as an apolipoprotein of nascent triacylglycerol rich lipoproteins. Chronically elevated plasma Aβ may compromise cerebrovascular integrity and exacerbate amyloidosisâa hallmark feature of Alzheimerâs disease (AD). Probucol is a hypocholesterolemic agent that reduces amyloid burden in transgenic amyloid mice, but the mechanisms for this effect are presently unclear. In this study, the effect of Probucol on intestinal lipoprotein-Aβ homeostasis was explored. Wild-type mice were fed a control low-fat diet and enterocytic Aβ was stimulated by high-fat (HF) diet enriched in 10% (w/w) saturated fat and 1% (w/w) cholesterol for the duration of 1 month. Mice treated with Probucol had the drug incorporated into the chow at 1% (w/w). Quantitative immunofluorescence was utilised to determine intestinal apolipoprotein B (apo B) and Aβ abundance. We found apo B in both the perinuclear region of the enterocytes and the lacteals in all groups. However, HF feeding and Probucol treatment increased secretion of apo B into the lacteals without any change in net villi abundance. On the other hand, HF-induced enterocytic perinuclear Aβ was significantly attenuated by Probucol. No significant changes in Aβ were observed within the lacteals. The findings of this study support the notion that Probucol suppresses dietary fat induced stimulation of Aβ biosynthesis and attenuate availability of apo B lipoprotein-Aβ for secretion
Oral particle uptake and organ targeting drives the activity of amphotericin B nanoparticles
There are very few drug delivery
systems that target key organs
via the oral route, as oral delivery advances normally address gastrointestinal
drug dissolution, permeation, and stability. Here we introduce a nanomedicine
in which nanoparticles, while also protecting the drug from gastric
degradation, are taken up by the gastrointestinal epithelia and transported
to the lung, liver, and spleen, thus selectively enhancing drug bioavailability
in these target organs and diminishing kidney exposure (relevant to
nephrotoxic drugs). Our work demonstrates, for the first time, that
oral particle uptake and translocation to specific organs may be used
to achieve a beneficial therapeutic response. We have illustrated
this using amphotericin B, a nephrotoxic drug encapsulated within <i>N</i>-palmitoyl-<i>N</i>-methyl-<i>N</i>,<i>N</i>-dimethyl-<i>N</i>,<i>N</i>,<i>N</i>-trimethyl-6-<i>O</i>-glycol chitosan
(GCPQ) nanoparticles, and have evidenced our approach in three separate
disease states (visceral leishmaniasis, candidiasis, and aspergillosis)
using industry standard models of the disease in small animals. The
oral bioavailability of AmB-GCPQ nanoparticles is 24%. In all disease
models, AmB-GCPQ nanoparticles show comparable efficacy to parenteral
liposomal AmB (AmBisome). Our work thus paves the way for others to
use nanoparticles to achieve a specific targeted delivery of drug
to key organs via the oral route. This is especially important for
drugs with a narrow therapeutic index
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