Integrating Both Parallax and Latency Compensation into Video See-through Head-mounted Display.

This work introduces a perspective-corrected video see-through mixed-reality head-mounted display with edge-preserving occlusion and low-latency capabilities. To realize the consistent spatial and temporal composition of a captured real world containing virtual objects, we perform three essential tasks: 1) to reconstruct captured images so as to match the user's view; 2) to occlude virtual objects with nearer real objects, to provide users with correct depth cues; and 3) to reproject the virtual and captured scenes to be matched and to keep up with users' head motions. Captured image reconstruction and occlusion-mask generation require dense and accurate depth maps. However, estimating these maps is computationally difficult, which results in longer latencies. To obtain an acceptable balance between spatial consistency and low latency, we rapidly generated depth maps by focusing on edge smoothness and disocclusion (instead of fully accurate maps), to shorten the processing time. Our algorithm refines edges via a hybrid method involving infrared masks and color-guided filters, and it fills disocclusions using temporally cached depth maps. Our system combines these algorithms in a two-phase temporal warping architecture based upon synchronized camera pairs and displays. The first phase of warping is to reduce registration errors between the virtual and captured scenes. The second is to present virtual and captured scenes that correspond with the user's head motion. We implemented these methods on our wearable prototype and performed end-to-end measurements of its accuracy and latency. We achieved an acceptable latency due to head motion (less than 4 ms) and spatial accuracy (less than 0.1° in size and less than 0.3° in position) in our test environment. We anticipate that this work will help improve the realism of mixed reality systems.

Aqueous microwave-assisted solid-phase peptide synthesis using Fmoc strategy: in-water synthesis of "difficult sequences".

A microwave assisted peptide synthesis in water using nanosized Fmoc-amino acids was developed. 5, 7, and 10 mer peptides (Leu-enkephalinamide, dermorphinamide, and a typical difficult sequence, ACP (65-74) peptide) were successfully synthesized in water according to Fmoc chemistry using water-dispersible nanoparticles with microwave irradiation.

Development of a method for environmentally friendly chemical peptide synthesis in water using water-dispersible amino acid nanoparticles.

Due to the vast importance of peptides in biological processes, there is an escalating need for synthetic peptides to be used in a wide variety of applications. However, the consumption of organic solvent is extremely large in chemical peptide syntheses because of the multiple condensation steps in organic solvents. That is, the current synthesis method is not environmentally friendly. From the viewpoint of green sustainable chemistry, we focused on developing an organic solvent-free synthetic method using water, an environmentally friendly solvent. Here we described in-water synthesis technology using water-dispersible protected amino acids.

Peptide synthesis 'in water' by a solution-phase method using water-dispersible nanoparticle Boc-amino acid.

Regulatory pressure has compelled the chemical manufacturing industry to reduce the use of organic solvents in synthetic chemistry, and there is currently a strong focus on replacing these solvents with water. Here, we describe an efficient in-water solution-phase peptide synthesis method using Boc-amino acids. It is based on a coupling reaction utilizing suspended water-dispersible nanoparticle reactants. Using this method, peptides were obtained in good yield and with high purity.

Evaluation of synthetic cell-penetrating peptides, Pro-rich peptide and octaargine derivatives, as adenovirus vector carrier.

Two cell-penetrating peptides, a Pro-rich peptide derivative, acetyl-(Val-Arg-Leu-Pro-Pro-Pro)(3)-Gly-Cys amide, and an octaarginine derivative, acetyl-Arg-Arg-Arg-Arg-Arg-Arg-Arg-Arg-Gly-Cys amide, were prepared by the solid phase method. Each peptide was coupled to the heterobifunctional cross-linking reagent, 6-maleimidohexanoic acid N-hydroxysuccinimide ester, and then conjugated to the Adenovirus vector containing luciferase gene. Peptide-modified Ad, as compared with wild-type Ad, exhibited excellent luciferase activity in B16BL6 cells.

Transduction of adenovirus vectors modified with cell-penetrating peptides.

Adenovirus vectors (Advs) are widely used for basic and clinical research because of their high transduction efficiency. However, they are poorly transduced into cells lacking the primary adenovirus receptor, the coxsackievirus and adenovirus receptor (CAR). Here, we generated Adv conjugated with cell-penetrating peptides (CPPs), such as Tat, octaarginine (R8) or proline-rich (Pro) peptides, and compared the transduction properties of these constructs. We constructed the Advs conjugated to the CPPs (CPP-Adv) by chemical conjugation. The CPP-conjugated Advs created with optimal modification ratios led to gene expression 1-2log orders higher than unmodified Adv in CAR-negative cells. Tat-Adv and R8-Adv were taken up into the cells mainly through macropinocytosis, independently of the CAR. In addition, the cellular uptake of Tat-Adv was highly dependent on heparan sulfate on the cell surface, whereas that of R8-Adv was dependent on chondroitin sulfate B. These data suggest that the use of CPP-Advs with different cellular uptake pathways might create new methods for the delivery of Adv. The results obtained in this research encourage the use of CPP-peptide-modified Advs as an attractive tool for transducing cells and as useful platform vectors for gene therapy and basic research.

Chordoid glioma of the third ventricle: a report of two cases, one with ultrastructural findings.

Chordoid glioma, which generally occurs in adults, is a rare CNS tumor arising in the anterior part of the third ventricle. We report two cases of chordoid glioma of the third ventricle in a 42-year-old woman and a 51-year-old man, respectively. Both tumors showed essentially the same histological and immunohistochemical features; the tumors were composed of cords and nests of epithelioid, GFAP-immunoreactive cells in a mucinous stroma with lymphoplasmacytic infiltrates at the tumor periphery. Ultrastructural examination in one case revealed that the tumor cells were characterized by the presence of hemidesmosomes and associated focal basal lamina formation, intermediate junctions, microvilli and cilia, and intercellular microrosettes with microvilli. Of interest was that small blood vessels with fenestrated endothelial cells were present in the stroma. In the brain, the presence of fenestrated endothelial cells is a feature of the circumventricular organs (except the subcommissural organ), among which the organum vasculosum of the lamina terminalis is located in the anterior part of the third ventricular floor that is lined by specialized ependymal cells known as tanycytes. These findings further strengthen the hypothesis that chordoid glioma may represent a peculiar clinicopathological subtype of ependymoma (chordoid ependymoma) originating from the lamina terminalis area.

Tat conjugation of adenovirus vector broadens tropism and enhances transduction efficiency.

AIMS: Adenovirus vectors (Advs) have been very useful for basic research and clinical gene therapy because they propagate to high titers and efficiently transduce cells and tissues regardless of the mitotic status. However, poor transduction of cells that lack the coxsackievirus and adenovirus receptor (CAR), the primary receptor for Advs, has limited Adv application. In this study, we attempted to generate novel Tat-Advs (Advs conjugated with the HIV Tat-derived peptide, a protein-transduction domain (PTD)) to broaden Adv tropism and enhance transduction efficiency. MAIN METHODS: We constructed Tat-Advs by chemically conjugating Tat peptide to the surface-exposed lysine residues on Advs. We compared the gene transfer activity of Tat-Advs with that of unmodified Advs by measuring the luciferase expression in several types of cell lines. KEY FINDINGS: Tat-Advs showed gene expression 1 to 3 log orders higher than unmodified Advs in CAR-negative adherent cells and blood cells, which are refractory to conventional Advs. The inhibition of Tat-Adv-mediated gene expression by heparin and macropinocytosis inhibitor confirms that binding of Tat-Adv to cellular HSPGs and macropinocytosis are essential for efficient CAR-independent transduction. We also demonstrated that Adv modified with another PTD (R8) had the same high transduction efficiency as Tat-Adv. SIGNIFICANCE: These data suggest that Tat-Advs are important tools for transducing cells and will be useful as platform vectors for gene therapy.

Preparation of a Tat-related transporter peptide for carrying the adenovirus vector into cells.

We synthesized a Tat-related peptide acetyl-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg-Pro-Pro-Gln-Gly-Cys amide, Ac-Tat(48-60)-Gly-Cys-NH(2), having high intracellular permeability, and conjugated this peptide to adenovirus vector to enhance gene transfer efficiency of adenovirus vector into cells. The peptide was prepared by the solid-phase peptide synthesis method and a bifunctional crosslinker 6-maleimidohexanoic acid N-hydroxysuccinimide ester was used to conjugate the peptide to adenovirus vector containing luciferase gene. The novel conjugate of adenovirus vector and Ac-Tat(48-60)-Gly-Cys-NH(2) peptide exhibited excellent gene transfer efficacy in B16BL6 cells.

Solid-phase peptide synthesis using nanoparticulate amino acids in water.

Solid-phase peptide synthesis has many advantages compared with solution peptide synthesis. However, this procedure requires a large amount of organic solvents. Since safe organic solvent waste disposal is an important environmental problem, a technology based on coupling reaction of suspended nanoparticle reactants in water was studied. Fmoc-amino acids are used widely, but most of them show low solubility in water. We prepared well-dispersible Fmoc-amino acid nanoparticles in water by pulverization using a planetary ball mill in the presence of poly(ethylene glycol). Leu-enkephalin amide was prepared successfully using the nanoparticulate Fmoc-amino acid on a poly(ethylene glycol)-grafted Rink amide resin in water.

Studies on heterobifunctional cross-linking reagents, 6-maleimidohexanoic acid active esters.

6-maleimidohexanoic acid N-hydroxysuccinimide ester has been used widely for preparation of enzyme immunoconjugates as a unique heterobifunctional cross-linking reagent. Its heterobifunctional reactivity is good, but its ester portion hydrolyzes easily in the presence of water. Several 6-maleimidohexanoic acid active esters (6-maleimidohexanoic acid 4-nitrophenyl ester, 6-maleimidohexanoic acid N-hydroxy-5-norbornene-endo-2,3-dicarboximide ester, and 6-maleimidohexanoic acid pentafluorophenyl ester) were prepared and their reactivity and stability in an aqueous media were tested. Of the synthetic esters, the pentafluorophenyl ester exhibited the highest reactivity and stability in aqueous media.

Mechanism of liver tyrosine aminotransferase increase in ethanol-treated mice and its effect on serum tyrosine level.

Liver tyrosine aminotransferase (TAT) activity is known to increase with ethanol treatment; however, the mechanism of this increase is unclear. Upon investigation we found that TAT activity and mRNA levels started to increase 2 h after ethanol administration and continued to increase until 6 h after ethanol administration. The increase in ethanol-induced TAT activity could not be explained by calorie loading after fasting, since ethanol loading increased TAT expression, while glucose loading decreased TAT expression. In addition, liver TAT activity was not related to serum tyrosine levels. TAT activity increased when an adenosine A2 agonist, 5'-N-ethylcarboxamide adenosine, was given. Since TAT activity is increased by cAMP, and ethanol increases cAMP production via an adenosine receptor-dependent mechanism, this increase in ethanol-induced TAT activity may occur via an adenosine receptor-dependent mechanism.

Solid phase peptide synthesis in water VI: evaluation of water-soluble coupling reagents for solid phase peptide synthesis in aqueous media.

Solid phase peptide synthesis requires large amounts of organic solvents, the safe disposal of which is an important environmental issue. Peptide synthesis, if performed in water and using less or nontoxic reagents, circumvents the disposal problem. Our ultimate aim is to develop an "environment-friendly" solid phase peptide synthesis (SPPS) methodology. Previously, we showed that SPPS in water is feasible. To perform SPPS in water, the coupling reagent must be water-soluble and maintain its reactivity in water. For this report, we tested the efficacy of the water-soluble coupling reagents, 2-(5-norbornene-2,3-dicarboximido)-1,1,3,3-tetramethyluronium tetrafluoroborate (TNTU) and 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM), towards SPPS in water. We successfully synthesized Leu-enkephalin amide on a solid support suspended in aqueous 50% EtOH using DMT-MM and 2-(4-sulfophenylsulfonyl)ethoxycarbonylamino acids.

Design and synthesis of a Tat-related gene transporter: a tool for carrying the adenovirus vector into cells.

A Tat-related peptide, acetyl-Gly-Arg-Arg-Arg-Arg-Arg-Gln-Arg-Arg-Arg-Pro-Pro-Gln-Gly-Cys amide, designed to transport an Adenovirus vector (Ad) into cells, was synthesized. The synthetic peptide was conjugated to Ad, which potentially can act as an efficient carrier of heterologous genes into cells. The Tat-related peptide was synthesized using the solid phase method and then was coupled to the heterofunctional cross-linking reagent, 6-maleimidohexanoic acid N-hydroxysuccinimide ester. The resulting peptide-succinimidohexanoic acid N-hydroxysuccinimide ester was conjugated to Ad containing the luciferase gene. B16BL6 cells infected with the peptide-conjugated Ad luciferase gene construct exhibit a 50-fold greater luciferase activity than B16BL6 cells infected with wild-type Ad containing the luciferase gene.

Effect of fasting on methionine adenosyltransferase expression and the methionine cycle in the mouse liver.

The effect of fasting on mouse liver methionine adenosyltransferase (MAT I/ III) expression and the regulation of methionine metabolism were investigated. The mRNA level, protein level, and activity of MAT I/III were increased by fasting for 10 or 16 h. In spite of the increase of MAT I/III activity, S-adenosylmethionine, the product of methionine due to MAT I/III, decreased. S-Adenosylhomocysteine, which is made from S-adenosylmethionine by its coupling to methyltransferase, increased as a result of fasting for 16 h. These results suggest that the total methylation reactions using S-adenosylmethionine are stimulated in the fasting mouse liver. However, the DNA methylation level was not changed by fasting for 16 h. Glutathione, which is made by the transsulfuration pathway from homocysteine, decreased due to fasting. Regulation of supplementation of S-adenosylmethionine may occur in the fasting mouse because MAT I/III activity increases and the flow to glutathione is decreased.

Design and synthesis of a peptide-PEG transporter tool for carrying adenovirus vector into cells.

The adenovirus vector is a promising carrier for the efficient transfer of genes into cells via the coxackie-adenovirus receptor (CAR) and integrins (alphavbeta3 and alphavbeta5). The clinical use of the adenovirus vector remains problematic however. Successful administration of this vector is associated with side effects because antibodies to this vector are commonly found throughout the human body. To make the adenovirus vector practicable for clinical use, it is necessary to design an auxiliary transporter. The present study describes the use of Arg-Gly-Asp(RGD)-related peptide, a peptide that binds to integrins, as an auxiliary transporter to aid efficient transport of adenovirus vector. Furthermore, poly(ethylene glycol) (PEG) was also used as a tool to modify the adenovirus such that the risk of side effects incurred during clinical application was reduced. The present study describes the design, preparation and use of (acetyl-Tyr-Gly-Gly-Arg-Gly-Asp-Thr-Pro-(beta)Ala)(2)Lys-PEG-(beta)Ala-Cys-NH(2)[(Ac-YGGRGDTP(beta)A)(2)K-PEG-(beta)AC] as an efficient peptide-PEG transporter tool for carrying adenovirus vector into cells. (Ac-YGGRGDTP(beta)A)(2)K-PEG-(beta)AC was coupled with 6-maleimidohexanoic acid N-hydroxysuccinimide ester and the resulting 6-[(Ac-YGGRGDTP(beta)A)(2)K-PEG-(beta)AC-succinimido]hexanoic acid N-hydroxysuccinimide ester reacted with adenovirus. The modified adenovirus with the peptide-PEG hybrid exhibited high gene expression even in a CAR-negative cell line, DC2.4.

PEGylated adenovirus vectors containing RGD peptides on the tip of PEG show high transduction efficiency and antibody evasion ability.

BACKGROUND: PEGylation of adenovirus vectors (Ads) is an attractive strategy in gene therapy. Although many types of PEGylated Ad (PEG-Ads), which exhibit antibody evasion activity and long plasma half-life, have been developed, their entry into cells has been prevented by steric hindrance by polyethylene glycol (PEG) chains. Likewise, sufficient gene expression for medical treatment could not be achieved. METHODS: A set of PEG-Ads, which have different PEG modification rates, was constructed, and gene expression was evaluated using A549 cells. A novel PEGylated Ad (RGD-PEG-Ad), which contained RGD (Arg-Gly-Asp) peptides on the tip of PEG, was developed. We evaluated gene expression both in Coxsackie-adenovirus receptor (CAR)-positive as well as -negative cells, and in vivo gene expression was also determined. Furthermore, the antibody evasion ability and the specificity of infection exhibited by this RGD-PEG-Ad were also evaluated. RESULTS: Whereas PEG-Ads decreased gene expression in CAR-positive cells, RGD-PEG-Ad enhanced gene expression notably, to a level about 200-fold higher than that of PEG-Ads. Moreover, gene expression of RGD-PEG-Ad was almost equal to that of Ad-RGD, which contains an RGD-motif in the fiber and exhibits among the highest gene expression of CAR-positive and -negative cells. Furthermore, although Ad-RGD gene expression decreased remarkably in the presence of anti-Ad antiserum, RGD-PEG-Ad maintained its activity against antibodies. In vivo experiments also demonstrated that the modification of Ads with RGD-PEG induced efficient gene expression. CONCLUSIONS: In the present study, we demonstrated that a new strategy, which combined integrin-targeting the RGD peptide on the tip of PEG and modified the Ad using this material, could enhance gene expression in both CAR-positive and -negative cells. At the same time, this novel PEGylated Ad maintained strong protective activity against antibodies. This strategy could also be easily modified for developing other vectors using other targeting molecules.

Peptide synthesis in water IV. Preparation of N-ethanesulfonylethoxycarbonyl (Esc) amino acids and their application to solid phase peptide synthesis.

A new N-protecting group, ethanesulfonylethoxycarbonyl (Esc), was designed to perform peptide synthesis in both aqueous and organic solvents. Esc-amino acids were prepared by the reaction of Esc-Cl and amino acids. Although Esc-Cl was a highly reactive reagent, it was not stable and decomposed during the purification procedure. A more stable reagent, ethanesulfonylethyl-4-nitrophenyl carbonate (Esc-ONp), was designed for preparation of Esc-amino acids. Esc-ONp was a stable reagent and could be purified by silica gel column chromatography or recrystallization. Esc-amino acids were prepared by the reaction of Esc-ONp and amino acids in good yield. To evaluate Esc-amino acids, Leu-enkephalin amide was synthesized using Esc-amino acids by the solid phase method in water. Removal of the Esc group was performed with 0.025 mol/l NaOH in 50% aqueous ethanol. Leu-enkephalin amide was successfully synthesized on a poly(ethylene glycol)-grafted polystyrene resin. Esc-amino acids have moderate solubility in organic solvents (such as dimethylformamide and acetonitrile). Leu-enkephalin amide was synthesized using Esc-amino acids by the solid phase method in dimethylformamide. Removal of the Esc group was performed with 0.05 mol/l tetrabutylammonium fluoride in dimethylformamide. Synthesis of Leu-enkephalin amide using Esc-amino acids in dimethylformamide was also successful. The yields of synthesis of Leu-enkephalin amide in water and dimethylformamide were 71% and 67%, respectively.

Is angiomatosis an intrinsic pathohistological feature of massive osteolysis? Report of an autopsy case and a review of the literature.

We report here an autopsied patient who had died during the clinical course of massive osteolysis (MO), which is a rare chronic disease that begins insidiously and is characterized by progressive regional loss of bone. Since the original description by Gorham and Stout in 1955, vascular proliferation, e.g., hemangiomatosis, has been considered to be the characteristic feature related to the pathogenesis. However, no such vascular changes were observed in the present patient. It was also important to note that a significant number of cases of MO that showed no vascular proliferation have been described previously. Therefore, we consider that vascular proliferation is not always associated with the osteolysis in MO and that the increased vascularity, if any, may be one of the results of the disease rather than the cause.