Magnetic nanoparticles: inner ear targeted molecule delivery and middle ear implant

Superparamagnetic iron oxide nanoparticles (SNP) composed of magnetite (Fe(3)O(4)) were studied preliminarily as vehicles for therapeutic molecule delivery to the inner ear and as a middle ear implant capable of producing biomechanically relevant forces for auditory function. Magnetite SNP were synthesized, then encapsulated in either silica or poly (D,L,-Lactide-co-glycolide) or obtained commercially with coatings of oleic acid or dextran. Permanent magnetic fields generated forces sufficient to pull them across tissue in several round window membrane models (in vitrocell culture, in vivo rat and guinea pig, and human temporal bone) or to embed them in middle ear epithelia. Biocompatibility was investigated by light and electron microscopy, cell culture kinetics, and hair cell survival in organotypic cell culture and no measurable toxicity was found. A sinusoidal magnetic field applied to guinea pigs with SNP implanted in the middle ear resulted in displacements of the middle ear comparable to 90 dB SPL.

Relation between the particle size distribution and the kinetic performance of packed columns

To study the influence of the particle size distribution (PSD), we measured the chromatographic performance of a series of sub-2 microm particle high performance liquid chromatography (HPLC) columns packed with four different particle mixtures having a purposely imposed different size distribution. Using the reduced kinetic plot representation by plotting the separation impedance (E(0)) versus the plate number ratio (N(opt)/N), the different columns could be classified according to their chromatographic performance without the need to specify a mean particle diameter or a molecular diffusion coefficient, as is needed in the classical reduced plate height and flow resistance analysis. The present analysis shows that it is not so much the width or span of the particle size distribution, but rather the presence of fines that greatly determines the chromatographic performance of particulate columns.

Telepsychiatry "coverage" to a rural inpatient psychiatric unit

OBJECTIVE

Rural psychiatrists responsible for inpatient psychiatry units in general hospitals often have trouble getting coverage for training, vacations, and periods of illness. This article describes telepsychiatry "coverage" to a rural general hospital psychiatric unit for 1 week.

MATERIALS AND METHODS

All adult patients meeting criteria for inpatient mental health treatment in the emergency room were offered admission to the general hospital after obtaining informed consent regarding the use of inpatient telepsychiatry. The number of patients on the inpatient psychiatric unit ranged from three to nine, with an average daily census of seven. All psychiatric care was provided via video teleconferencing (VTC) at a bandwidth of 512 kilobits per second using Internet Protocol.

RESULTS

Patients with psychosis reported more difficulty hearing the doctor than patients without psychosis and incorporated VTC into delusions in a congruent manner. Patients rated development of rapport and effectiveness of treatment higher than staff ratings. Two staff thought telepsychiatry was either not effective for acutely psychotic patients or more effective with higher functioning patients.

CONCLUSIONS

Short-term coverage of rural inpatient psychiatric units for purposes of vacation, training, and illness is possible using telepsychiatry. Psychiatrist's efficiency and consistency are enhanced with instantaneous connections possible from hospital, office, or home. Significant increases in staff workload will occur without remote access to electronic medical records, electronic physician ordering, and an adequate physical layout of the inpatient psychiatric unit. Adequate educational preparation of unit staff regarding telepsychiatry and a staff process group during implementation is recommended.

Features associated with speaking in tongues (glossolalia)

Reports of the frequency, context, associated behaviours, feelings and meaning associated with glossolalia were collected from three groups of informants: speakers (N = 14, who practised glossolalia), witnesses (N = 15, who had witnessed but had never practised glossolalia), and controls (N = 16, who had neither witnessed nor practised glossolalia). All informants were practising Christians. Speakers reported glossolalia as a regular, daily, private activity, usually accompanying mundane activities, as a special form of prayer associated with calm, pleasant emotions. By contrast, witnesses and controls were more likely to describe glossolalia as an exceptional activity, usually occurring in the religious group, and associated with excitement. The views of witnesses were closer to those of speakers than were the views of controls. It is suggested that there may be two types of glossolalia, of which one is more likely to be associated with psychopathology.

Liposome-encapsulated EF24-HPβCD inclusion complex: a preformulation study and biodistribution in a rat model

3,5-Bis(2-fluorobenzylidene)-4-piperidone (EF24) is an anti-proliferative diphenyldifluoroketone analog of curcumin with more potent activity. The authors describe a liposome preparation of EF24 using a "drug-in-CD-in liposome" approach. An aqueous solution of EF24 and hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complex (IC) was used to prepare EF24 liposomes. The liposome size was reduced by a combination of multiple freeze-thaw cycles. Co-encapsulation of glutathione inside the liposomes conferred them with the capability of labeling with imageable radionuclide Tc-99m. Phase solubility analysis of EF24-HPβCD mixture provided k(1:1) value of 9.9 M(-1). The enhanced aqueous solubility of EF24 (from 1.64 to 13.8 mg/mL) due to the presence of HPβCD helped in the liposome preparation. About 19% of the EF24 IC was encapsulated inside the liposomes (320.5 ± 2.6 nm) by dehydration-rehydration technique. With extrusion technique, the size of 177 ± 6.5 nm was obtained without any effect on encapsulation efficiency. The EF24-liposomes were evaluated for anti-proliferative activity in lung adenocarcinoma H441 and prostate cancer PC-3 cells. The EF24-liposomes demonstrated anti-proliferative activity superior to that of plain EF24 at 10 μM dose. When injected in rats, the Tc-99m-labeled EF24-liposomes cleared from blood with an α-t(1/2) of 21.4 min and β-t(1/2) of 397 min. Tissue radioactivity counting upon necropsy showed that the majority of clearance was due to the uptake in liver and spleen. The results suggest that using "drug-in-CD-in liposome" approach is a feasible strategy to formulate an effective parenteral preparation of EF24. In vitro studies show that the liposomal EF24 remains anti-proliferative, while presenting an opportunity to image its biodistribution.

High thermal conductivity through simultaneously aligned polyethylene lamellae and graphene nanoplatelets

The effect of simultaneous alignment of polyethylene (PE) lamellae and graphene nanoplatelets (GnP) on the thermal conductivity (k) of PE-GnP composites is investigated. Measurements reveal a large increase of 1100% in k of the aligned PE-GnP composite using 10 wt% GnPs relative to unoriented pure PE. The rate of increase of k with applied strain for the pure PE-GnP composite with 10 wt% GnP is found to be almost a factor of two higher than the pure PE sample, pointing to the beneficial effect of GnP alignment on k enhancement. Aligned GnPs are further found to be 3 times as effective in enhancing k as in the randomly oriented configuration. Enhancement in k is correlated with the alignment of PE lamellae and GnPs through wide-angle X-ray scattering and polarized Raman spectroscopy. At the maximum applied strain of 400% and using 10 wt% GnPs, a composite k of 5.9 W mK^-1 is achieved. These results demonstrate the great potential of simultaneous alignment effects in achieving high k polymer composites.

Incorporation, Release, and Effectiveness of Dexamethasone in Poly(Lactic-Co-Glycolic Acid) Nanoparticles for Inner Ear Drug Delivery

Poly (D,L-lactide-co-glycolide) (PLGA) particles have been widely used as drug delivery carriers for a variety of payloads. Three forms of dexamethasone (DEX), namely, acetate, base, and phosphate, were incorporated into a PLGA matrix. First, we compared the drug loading efficiency and release kinetics of drug-loaded PLGA particles. Dexamethasone acetate (DEX-Ac) loaded particles exhibited a higher loading efficiency and a more linear release profile of drug as compared with the other forms of DEX particles. Also, we coincorporated oleic acid-coated superparamagnetic iron oxide nanoparticles (SPION) with DEX-Ac into PLGA submicron particles. No differences in size, zeta potential, drug loading, or release kinetics were found between particles prepared with and without SPION. Additionally, particles were applied to an in vitro cochlear, organotypic culture. DEX-Ac PLGA nanoparticles showed a protective effect against 4-hydroxynonenal induced hair cell damage. These results suggest a promising method for inner ear magnetic targeted treatment.

A role for endothelin and nitric oxide in the pressor response to diaspirin cross-linked hemoglobin

Diaspirin-cross-linked hemoglobin (DCLHb; Baxter Healthcare Corp) has potential for clinical use as a hemoglobin-based oxygen-carrying solution. We have previously shown that DCLHb administration is associated with a self-limiting increase in mean arterial pressure (MAP). Based on in vitro studies with other hemoglobin solutions, this vasopressor effect is thought to be mediated at least in part by the release or inhibition (or both) of endothelium-derived vasoactive substances. The purpose of our studies was to determine the role of endothelin (ET), a potent vasoconstrictor peptide, and nitric oxide, a vasodilator, in mediating the pressor effect of DCLHb in conscious rats. Intravenous administration of DCLHb has been shown to elicit an immediate increase in MAP that peaks within 30 minutes and returns to baseline by 300 minutes in a dose-dependent fashion. Phosphoramidon, an inhibitor of proendothelin conversion to ET, attenuated the elevation of MAP when administered before DCLHb. Administration of cyanomet DCLHb, a DCLHb molecule that is unable to interact with NO, was not associated with an elevation of MAP. L-arginine, the substrate for NO synthesis, and nitroglycerin, an NO donor, significantly reduced MAP when infused 15 minutes after DCLHb administration. Based on these findings, we conclude that the DCLHb-induced elevation of MAP in vivo is mediated at least in part by ET and the inhibition of NO. Although these data support earlier reports of hemoglobin binding NO, this is the first report of the pressor response to hemoglobin being attenuated by an agent that blocks the conversion of proendothelin to ET.

Frequently deleted loci on chromosome 9 may harbor several tumor suppressor genes in human renal cell carcinoma

PURPOSE

Loss of various loci on chromosome 9 has been reported in various cancers. To determine the frequency of deletions at different loci of chromosome 9 in renal cell carcinoma microdissected samples of normal renal epithelium and carcinoma from the same patients were analyzed.

MATERIALS AND METHODS

DNA was isolated from microdissected sections of normal and tumor cells of 60 renal specimens, amplified by polymerase chain reaction and analyzed for loss of heterozygosity on chromosome 9 using the 16 microsatellite markers D9S178, D9S157, D9S274, D9S168, D9S285, D9S156, D9S1839, D9S162, IFNA, D9S736, D9S171, D9S1749, D9S273D9S270, D9S153 and D9S170. Loss of heterozygosity was analyzed by a polymerase chain reaction based technique developed at our laboratory.

RESULTS

This study showed a high incidence of loss of heterozygosity on chromosome 9 in renal cell carcinoma. Of 60 cases 44 (73%), 24 (40%) and 14 (23%) showed loss of heterozygosity at a minimum of 1, at a minimum of 3 and at 4 or more loci, respectively. The main deletion was found on the 9p21 region at loci DS171 in 38% of cases, D9S1749 in 42% and DS270 in 14%. Overall deletion on chromosome 9p21 was noted in 57% of renal cancer cases. Other deleted regions were on chromosome 9p'0022 to 23 at loci D9S157 in 37% of cases, D9S274 in 20%, D9S168 in 27%, D9S285 in 20%, D9S156 in 12%, D9S1839 in 17% and D9S162 in 24%. Overall deletion at chromosome 9q32 to 33 was noted in 46% of renal cell carcinoma cases. Chromosome 9q32 to 33 also showed deletion at locus D9S170 in 22% of renal cell carcinoma cases. When we compared the incidence of deletion at various loci on chromosome 9 according to renal cell carcinoma grade, we found a higher rate of deletion in advanced grades of renal cell carcinoma. A candidate target tumor suppressor gene, p16 (MTS-1/CDKN2), has been identified within the 9p21 deleted region in various cancers. In our study the expression of p16 protein was absent or low in renal cell cancer samples, suggesting that loss of the p16 gene may be involved in renal cell carcinogenesis.

CONCLUSIONS

Our study demonstrates a high incidence of loss of heterozygosity on chromosome 9, mainly 9p21 and 9p22 to 23, in renal cell carcinoma, suggesting several putative tumor suppressor genes on these regions. The identification of other tumor suppressor genes on the 9p21 and 9p22 to 23 regions warrants further studies.