Liposomal Carrier Conjugated to APP-Derived Peptide for Brain Cancer Treatment

Brain tumors are hard to treat with the currently available therapy. The major obstacle in the treatment of brain tumors is the lack of therapeutic strategies capable to penetrate the blood-brain barrier (BBB). The BBB is an endothelial interface that separates the brain from the circulatory blood system and prevents the exposure of the central nervous system (CNS) to circulating toxins and potentially harmful compounds. Unfortunately, the BBB prevents also the penetration of therapeutic compounds into the brain. We present here a drug-delivery liposomal carrier, conjugated to a peptide inserted in the liposomal membrane, which is putatively recognized by BBB transporters. The peptide is a short sequence of 5 amino acids (RERMS) present in the amyloid precursor protein (APP). This APP-targeted liposomal system was designed specifically for transporting compounds with anti-cancer activity via the BBB into the brain in an effective manner. This drug-delivery liposomal carrier loaded with the anti-cancer compounds temozolomide (TMZ), curcumin, and doxorubicin crossed the BBB in an in vitro model as well as in vivo (mice model). In the in vitro model, the targeted liposomes crossed the BBB model fourfold higher than the non-targeted liposomes. Labeled targeted liposomes penetrated the brain in vivo 35% more than non-targeted liposomes. Treatment of mice that underwent intracranial injection of human U87 glioblastoma, with the targeted liposomes loaded with the three tested anti-cancer agents, delayed the tumor growth and prolonged the mice survival in a range of 45% -70%. It appears that the targeted liposomal drug-delivery system enables better therapeutic efficacy in a SCID mouse model of glioblastoma compared to the corresponding non-targeted liposomes and the free compounds.

Liposome-based targeting of dopamine to the brain: a novel approach for the treatment of Parkinson's disease

Delivery of drugs into the brain is poor due to the blood brain barrier (BBB). This study describes the development of a novel liposome-based brain-targeting drug delivery system. The liposomes incorporate a diacylglycerol moiety coupled through a linker to a peptide of 5 amino acids selected from amyloid precursor protein (APP), which is recognized by specific transporter(s)/receptor(s) in the BBB. This liposomal system enables the delivery of drugs across the BBB into the brain. The brain-directed liposomal system was used in a mouse model of Parkinson's disease (PD). Intra-peritoneal (IP) administration of liposomes loaded with dopamine (DA) demonstrated a good correlation between liposomal DA dose and the behavioral effects in hemiparkinsonian amphetamine-treated mice, with an optimal DA dose of 60 µg/kg. This is significantly lower dose than commonly used doses of the DA precursor levodopa (in the mg/kg range). IP injection of the APP-targeted liposomes loaded with a DA dose of 800 µg/kg, resulted in a significant increase in striatal DA within 5 min (6.9-fold, p < 0.05), in amphetamine-treated mice. The increase in striatal DA content persisted for at least 3 h after administration, which indicates a slow DA release from the delivery system. No elevation in DA content was detected in the heart or the liver. Similar increases in striatal DA were observed also in rats and mini-pigs. The liposomal delivery system enables penetration of compounds through the BBB and may be a candidate for the treatment of PD and other brain diseases.

The TSPO Ligands MGV-1 and 2-Cl-MGV-1 Differentially Inhibit the Cigarette Smoke-Induced Cytotoxicity to H1299 Lung Cancer Cells

Simple Summary

In this study, we investigated the impact of CS on various TSPO-related mitochondrial processes, and the protective ability of our novel TSPO ligands against such CS-induced cellular damages. Our results support the previously reported role of TSPO in apoptotic cell death. Moreover, the present data demonstrate the protective effect of our TSPO ligands against CS-induced cellular damage.

Abstract

TSPO is involved in cigarette smoke (CS)-induced cellular toxicity, which may result in oral and pulmonary diseases and lung cancer. H1299 lung cancer cells were exposed directly to CS. The H1299 cells were pretreated with our TSPO ligands MGV-1 and 2-Cl-MGV-1 (Ki = 825 nM for both) at a concentration of 25 µM 24 h prior to CS exposure. Cell death and apoptotic markers were measured, in addition to TSPO expression levels, ATP synthase activity, generation of reactive oxygen species (ROS), depolarization of mitochondrial membrane potential (ΔΨm), cAMP and LDH levels. Pretreatment with MGV-1 and 2-Cl-MGV-1 (25 µM), 24 h prior to CS exposure, differentially attenuated the CS-induced cellular insult as well as cell death in H1299 lung cancer cells. These protective effects included prevention of ATP synthase reversal, ROS generation, depolarization of the mitochondrial membrane and elevation in LDH. The preventive efficacy of 2-Cl-MGV-1 was superior to that achieved by MGV-1. Both ligands did not prevent the elevation in cAMP. These findings may indicate a mild protective effect of these TSPO ligands in CS-related pulmonary and keratinocyte cellular pathology.

Effects of Cigarette Smoke on TSPO-related Mitochondrial Processes

The 18 kDa translocator protein (TSPO) is an initiator of the mitochondrial apoptosis cascade. Cigarette smoke (CS) exposure provokes alterations in TSPO expression as well as upregulation of its related functions such as mitochondrial membrane potential (ΔψM) and reactive oxygen species generation, which are associated with cell death. In the current study, H1299 lung cancer cell line exposed to CS for various time periods (30 mins, 60 mins and 120 mins) and TSPO expression and cell death processes were studied. CS exposure for 30 mins resulted in a non-significant increase in TSPO expression by 24% (p > 0.05 vs. control). CS exposure for 60 mins and 120 mins resulted in a significant increase by 43% (p < 0.05 vs. control) and by 47% (p < 0.01 vs. control), respectively. Furthermore, TSPO-related mitochondrial functions were upregulated at the 120 mins time point following CS exposure. TSPO expression is upregulated by CS, suggesting that TSPO plays a role in cell death processes induced by CS exposure. Alterations in TSPO-related cell death processes suggest that TSPO may be involved in the tissue damage caused by CS.

A spin-orbit playground: surfaces and interfaces of transition metal oxides

Within the last twenty years, the status of the spin-orbit interaction has evolved from that of a simple atomic contribution to a key effect that modifies the electronic band structure of materials. It is regarded as one of the basic ingredients for spintronics, locking together charge and spin degrees of freedom and recently it is instrumental in promoting a new class of compounds, the topological insulators. In this review, we present the current status of the research on the spin-orbit coupling in transition metal oxides, discussing the case of two semiconducting compounds, [Formula: see text] and [Formula: see text], and the properties of surface and interfaces based on these. We conclude with the investigation of topological effects predicted to occur in different complex oxides.

Spin-Orbit Semimetal SrIrO_{3} in the Two-Dimensional Limit

We investigate the thickness-dependent electronic properties of ultrathin SrIrO_{3} and discover a transition from a semimetallic to a correlated insulating state below 4 unit cells. Low-temperature magnetoconductance measurements show that spin fluctuations in the semimetallic state are significantly enhanced while approaching the transition point. The electronic properties are further studied by scanning tunneling spectroscopy, showing that 4 unit cell SrIrO_{3} is on the verge of a gap opening. Our density functional theory calculations reproduce the critical thickness of the transition and show that the opening of a gap in ultrathin SrIrO_{3} requires antiferromagnetic order.

Anaerobic metabolism of the agro-pesticide nitroxinil by bovine ruminal fluid

Metabolism of three different agro-pesticides widely used in Uruguay, the insecticides imidacloprid and thiamethoxam and the antiparasite nitroxinil, by bovine ruminal fluid, as supply of anaerobic microorganims, was studied. Complete ruminal fluid was incubated with each of the agrochemicals in different conditions, varying time, nutrients, and nitroethane supplementation as methanogenesis modificator. Only biotransformation was detected for nitroxinil in some of the studied variables. In the optimized condition only one product was generated and the chemical structure of this main metabolite was elucidated using combined spectroscopies evidencing a structural motive unrelated with the products of the corresponding mammal biotransformation results of reduction, and substitution processes. The ruminal generation of the metabolite was confirmed. In order to employ this anaerobic microbial system as potential bioremediator of agrochemical-contaminated soils, the toxicity, against mammal cells, and the mutagenicity, using Ames test, of the product of biotransformation were studied. The lack of toxic effects encouraged us to propose the ruminal system as a plausible system for agrochemicals bioremediation.

Two-dimensional electron gas with six-fold symmetry at the (111) surface of KTaO3

Two-dimensional electron gases (2DEGs) at transition-metal oxide (TMO) interfaces, and boundary states in topological insulators, are being intensively investigated. The former system harbors superconductivity, large magneto-resistance, and ferromagnetism. In the latter, honeycomb-lattice geometry plus bulk spin-orbit interactions lead to topologically protected spin-polarized bands. 2DEGs in TMOs with a honeycomb-like structure could yield new states of matter, but they had not been experimentally realized, yet. We successfully created a 2DEG at the (111) surface of KTaO3, a strong insulator with large spin-orbit coupling. Its confined states form a network of weakly-dispersing electronic gutters with 6-fold symmetry, a topology novel to all known oxide-based 2DEGs. If those pertain to just one Ta-(111) bilayer, model calculations predict that it can be a topological metal. Our findings demonstrate that completely new electronic states, with symmetries not realized in the bulk, can be tailored in oxide surfaces, promising for TMO-based devices.

Metal-insulator transition in ultrathin LaNiO3 films

Transport in ultrathin films of LaNiO(3) evolves from a metallic to a strongly localized character as the film's thickness is reduced and the sheet resistance reaches a value close to h/e(2), the quantum of resistance in two dimensions. In the intermediate regime, quantum corrections to the Drude low-temperature conductivity are observed; they are accurately described by weak localization theory. Remarkably, the negative magnetoresistance in this regime is isotropic, which points to magnetic scattering associated with the proximity of the system to either a spin-glass state or the charge ordered antiferromagnetic state observed in other rare earth nickelates.

Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces

We report on a study of magnetotransport in LaAlO3 /SrTiO3 interfaces characterized by mobilities of the order of several thousands cm2/V s. We observe Shubnikov-de Haas oscillations whose period depends only on the perpendicular component of the magnetic field. This observation directly indicates the formation of a two-dimensional electron gas originating from quantum confinement at the interface. From the temperature dependence of the oscillation amplitude we extract an effective carrier mass m* ≃ 1.45 m(e). An electric field applied in the back-gate geometry increases the mobility, the carrier density, and the oscillation frequency.

Tunable Rashba spin-orbit interaction at oxide interfaces

The quasi-two-dimensional electron gas found at the LaAlO{3}/SrTiO{3} interface offers exciting new functionalities, such as tunable superconductivity, and has been proposed as a new nanoelectronics fabrication platform. Here we lay out a new example of an electronic property arising from the interfacial breaking of inversion symmetry, namely, a large Rashba spin-orbit interaction, whose magnitude can be modulated by the application of an external electric field. By means of magnetotransport experiments we explore the evolution of the spin-orbit coupling across the phase diagram of the system. We uncover a steep rise in Rashba interaction occurring around the doping level where a quantum critical point separates the insulating and superconducting ground states of the system.

Superconducting Interfaces Between Insulating Oxides

At interfaces between complex oxides, electronic systems with unusual electronic properties can be generated. We report on superconductivity in the electron gas formed at the interface between two insulating dielectric perovskite oxides, LaAlO3 and SrTiO3. The behavior of the electron gas is that of a two-dimensional superconductor, confined to a thin sheet at the interface. The superconducting transition temperature of congruent with 200 millikelvin provides a strict upper limit to the thickness of the superconducting layer of congruent with 10 nanometers.

Local switching of two-dimensional superconductivity using the ferroelectric field effect

Correlated oxides display a variety of extraordinary physical properties including high-temperature superconductivity and colossal magnetoresistance. In these materials, strong electronic correlations often lead to competing ground states that are sensitive to many parameters--in particular the doping level--so that complex phase diagrams are observed. A flexible way to explore the role of doping is to tune the electron or hole concentration with electric fields, as is done in standard semiconductor field effect transistors. Here we demonstrate a model oxide system based on high-quality heterostructures in which the ferroelectric field effect approach can be studied. We use a single-crystal film of the perovskite superconductor Nb-doped SrTiO3 as the superconducting channel and ferroelectric Pb(Zr,Ti)O3 as the gate oxide. Atomic force microscopy is used to locally reverse the ferroelectric polarization, thus inducing large resistivity and carrier modulations, resulting in a clear shift in the superconducting critical temperature. Field-induced switching from the normal state to the (zero resistance) superconducting state was achieved at a well-defined temperature. This unique system could lead to a field of research in which devices are realized by locally defining in the same material superconducting and normal regions with 'perfect' interfaces, the interface being purely electronic. Using this approach, one could potentially design one-dimensional superconducting wires, superconducting rings and junctions, superconducting quantum interference devices (SQUIDs) or arrays of pinning centres.

Bone mineral density in juvenile systemic lupus erythematosus

We evaluated spine bone mineral density (BMD) in Brazilian children with juvenile systemic lupus erythematosus (JSLE) in order to detect potential predictors of reduction in bone mass. A cross-sectional study of BMD at the lumbar spine level (L2-L4) was conducted on 16 female JSLE patients aged 6-17 years. Thirty-two age-matched healthy girls were used as control. BMD at the lumbar spine was measured by dual-energy X-ray absorptiometry. Weight, height and pubertal Tanner stage were determined in patients and controls. Disease duration, mean daily steroid doses, mean cumulative steroid doses and JSLE activity measured by the systemic lupus erythematosus disease activity index (SLEDAI) were determined for all JSLE patients based on their medical charts. All parameters were used as potential determinant factors for bone loss. Lumbar BMD tended to be lower in the JSLE patients, however, this difference was not statistically significant (P = 0.10). No significant correlation was observed in JSLE girls between BMD and age, height, Tanner stage, disease duration, corticosteroid use or disease activity. We found a weak correlation between BMD and weight (r = 0.672). In the JSLE group we found no significant parameters to correlate with reduced bone mass. Disease activity and mean cumulative steroid doses were not related to BMD values. We did not observe reduced bone mass in female JSLE.

Nurse-midwifery. The beneficial alternative

The number of nurse-midwife-attended births in U.S. hospitals has jumped ten-fold in the last 20 years, rising from just 19,686 in 1975 to 196,977 in 1994. Certified nurse-midwives (CNMs) focus on childbirth as a normal event, emphasizing the educational and psychosocial aspects of care and the judicious use of technological interventions. CNM care appears particularly well suited to help solve two difficult problems in U.S. obstetric care--our country's slow progress in improving the health status of newborns and the excessive use of medical interventions during childbirth. Despite the fact that CNM care has been found to be safe and cost-effective, only a small fraction of those pregnant women who could benefit from CNM care use midwifery services. Lack of consumer awareness is part of the problem, but barriers also exist to accessing CNM services. Sixty-four percent of CNM practices responding to a survey reported practice restrictions, most commonly due to state laws, hospital policies, and inappropriately restrictive physician back-up. One state, Florida, is aggressively promoting the use of CNM care as the standard of practice for healthy pregnant women.

Hospital wage and price controls: lessons from the Economic Stabilization Program

The Clinton Administration has implied that short-run failures to control health care costs may cause a reexamination of wage and price controls as elements of comprehensive health care reform. The most recent imposition of mandatory wage and price controls was the Economic Stabilization Program (ESP) of the early 1970s. We analyze trends in hospitals' economic behavior and utilization before, during, and after ESP. We also review the relevant literature to estimate ESP's impact, considering other factors that influence hospital behavior. Noting important changes in the hospital industry since the 1970s, we conclude that ESP had limited effect and that similar controls would have little effect today.

Lessons for states in inpatient ratesetting under the Boren Amendment

Encouraged by a 1990 Supreme Court decision, Medicaid providers have challenged State inpatient ratesetting methodologies under the Boren Amendment. Procedurally, State assurances to the U.S. Department of Health and Human Services (DHHS) that payment rates meet the Amendment's requirements must be supported by findings based on a reasonably principled analysis. Substantively, rates may fall within a zone of reasonableness, but courts have differed in interpreting and applying the Amendment's terms. Although some courts have found special studies and written findings unnecessary, States that undertake economic analyses to support their findings are more likely to withstand judicial scrutiny. Several applicable economic analyses are proposed.

Health status and medical expenditures: more evidence of a link

The hypothesis that one must include life-style changes in order to accurately capture the true relationship between medical expenditures and health status is explored, using data from 22 countries over a 20-year period. A simultaneous model is estimated using a variety of indicators for life style as well as health status. Changes in life style, aging of the population and changes in occupational risk are modeled as influences on medical expenditures: medical expenditures and changes in life style are modeled as having direct influences on health status. The results are consistent with the existence of a positive link between medical expenditures and health status.