Carboxy-terminal dendrimers with phenylalanine for a pH-sensitive delivery system into immune cells including T cells.

Although T cells play important roles in various immune reactions, there are only a few reports on delivery systems into T cells. Our previous study showed that carboxy-terminal phenylalanine (Phe)-modified polyamidoamine (PAMAM) dendrimers have both temperature- and pH-sensitive properties, which are affected by the chemical structure. The self-assembled structures of Phe, observed in phenylketonuria, enhance the protein aggregation, the association with the cell membrane and the membrane permeability. In this study, we applied the Phe-modified dendrimers to a pH-sensitive drug delivery system into T cells. Dendrimers with different amino acids and acid anhydrides were synthesized, and their pH-responsive association with T cells and their subsets was investigated. The dendrimers modified with Phe and cyclohexanedicarboxylic acid (CHex) showed higher uptake into various cells, including Jurkat cells, CD3+ T cells, CD3 + CD4+ helper T cells and CD3 + CD8+ killer T cells. These dendrimers were internalized into T cells via endocytosis, and their cellular uptake was enhanced under weak acidic conditions (pH 6.5). Our results showed that Phe- and CHex-modified dendrimers have a delivery potential to T cells and their subsets, which may be useful for cancer immunotherapy.

Different hydration states and passive tumor targeting ability of polyethylene glycol-modified dendrimers with high and low PEG density.

It has been reported that the amount of intermediate water, defined as water molecules loosely bound to a material, is a useful index of the material's bio-inert properties. Polyethylene glycol (PEG) is a well-known biocompatible polymer with a large amount of intermediate water. Many researchers have showed that PEGylated nanoparticles are passively accumulated in tumor tissues owing to their enhanced permeability and retention (EPR) effects. Dendrimers are regularly branched polymers with highly controllable size and structure, which can be exploited as potent drug carriers. In this study, we investigated the tripartite relationship among the PEG density, the hydration state, and the passive tumor targeting property, using PEGylated dendrimers. The fully PEGylated dendrimer, PEG64-den, showed similar hydration behavior to PEG and a passive tumor targeting property. In contrast, the hydration state of the partly PEGylated dendrimer, PEG5-den, was different from that of PEG64-den, and the passive tumor targeting property was not observed. This is the first report to show the hydration state of a drug carrier as well as discuss a relationship between the hydration state and biodistribution.

Induction of metallothionein isoforms in cultured bovine aortic endothelial cells exposed to cadmium.

Metallothionein (MT) is an inducible protein with cytoprotective activity against heavy metals such as cadmium, zinc, and copper. MT-1 and MT-2 are the isoforms of MT induced by and bind the heavy metals. Bovine aortic endothelial cells contain three types of MT genes, namely, MT-1A, MT-1E, and MT-2A; however, the associated protein expression of these MT isoforms has not been identified. In the present study, the expression of MT subisoform proteins in cells treated with cadmium chloride was identified using a high-performance liquid chromatography-inductively coupled plasma-mass spectrometry system. It was revealed that: (1) transcriptional induction of MT-1A by cadmium was markedly more sensitive than that of MT-1E/2A; (2) MT-1A and MT-2A proteins were the predominant MT subisoforms induced by cadmium; and (3) there might be differentiation in the functions of MT-1 and MT-2 against cadmium cytotoxicity, although the actual roles of the MT isoforms in the cells were not distinct. This is the first study to show the differential induction of isoforms of MT proteins in vascular endothelial cells by cadmium.

Association of Hydrophobic Carboxyl-Terminal Dendrimers with Lymph Node-Resident Lymphocytes.

Delivery systems to lymph node-resident T cells around tumor tissues are essential for cancer immunotherapy, in order to boost the immune responses. We previously reported that anionic dendrimers, such as carboxyl-, sulfonyl-, and phosphate-terminal dendrimers, were efficiently accumulated in lymph nodes via the intradermal injection. Depending on the terminal structure, their cell association properties were different, and the carboxyl-terminal dendrimers did not associate with any immune cells majorly. In this study, we investigated the delivery of carboxyl-terminal dendrimers with different hydrophobicity to lymph node-resident lymphocytes. Four types of carboxyl-terminal dendrimers-succinylated (C) and 2-carboxy-cyclohexanoylated (Chex) dendrimers with and without phenylalanine (Phe)-were synthesized and named C-den, C-Phe-den, Chex-den, and Chex-Phe-den, respectively. Chex-Phe-den was well associated with lymphocytes, but others were not. Chex-Phe-den, intradermally injected at the footpads of mice, was accumulated in the lymph node, and was highly associated with the lymphocytes, including T cells. Our results suggest that Chex-Phe-den has the potential for delivery to the lymph node-resident T cells, without any specific T cell-targeted ligands.

Rapid Photoinduced Single Cell Detachment from Gold Nanoparticle-Embedded Collagen Gels with Low Denaturation Temperature.

Cell Separation is important in various biomedical fields. We have prepared gold nanoparticle (AuNP)-embedded collagen gels as a visible-light-responsive cell scaffold in which photoinduced single cell detachment occurs through local thermal denaturation of the collagen gel via the photothermal effect of AuNP. Physicochemical properties of collagen materials depend on the origin of the collagen and the presence of telopeptides. In this study, we prepared various AuNP-embedded collagen gels by using different collagen materials with and without the telopeptides to compare their thermal denaturation properties and photoinduced single cell detachment behaviors. Cellmatrix type I-C without telopeptides exhibited a lower denaturation temperature than Cellmatrix type I-A and Atelocell IAC, as examined by Fourier transform infrared (FTIR) spectroscopy, rheological analysis, and sol-gel transition observation. Three-dimensional (3D) laser microscopic imaging revealed that collagen fibers shrank in Cellmatrix type I-A upon heating, but collagen fibers disappeared in Cellmatrix type I-C upon heating. Cells cultured on the Cellmatrix type I-C-based AuNP-embedded collagen gel detached with shorter photoirradiation than on the Cellmatrix type I-A-based AuNP-embedded collagen gel, suggesting that collagen gels without telopeptides are suitable for a photoinduced single cell detachment system.

A Retrospective Cohort Study of the Cumulative Survival Rate of Obturator Prostheses for Marsupialization.

PURPOSE: After marsupialization of benign tumors and jawbone cysts, insertion of an obturator prosthesis maintains the surgical opening and improves hygiene. To date, there have been no reports clarifying the relationship between the obturator design and treatment outcomes. The purpose of this study was to examine the survival rate of three types of obturator, and to investigate the factors that expedite the removal of the obturator. MATERIALS AND METHODS: The subject group comprised 100 patients who had an obturator inserted after marsupialization at Kagoshima University Hospital between May 31, 2012 and March 31, 2015; 73 patients with lesions in the mandible were eligible. Three types of mandibular obturator were designed and inserted, considering the teeth missing, the anteroposterior position of the lesion, and the buccolingual direction of marsupialization. The endpoint of this study was defined as the removal of the obturator. The analyzed predictor values for the endpoint were age, gender, remaining teeth, nature of primary disease, anteroposterior location of primary disease, buccolingual direction of marsupialization, type of obturator, and dates of insertion and removal. RESULTS: No significant differences were found in the cumulative survival rate among the three types of obturator. Early obturator removal was more frequent in patients with cysts, anterior lesions, and/or marsupialization from the occlusal direction CONCLUSIONS: Because obturator design had minimal effect on the ability of the appliance to maintain the surgical opening, it is preferable to use the least invasive design. Our findings also suggest that the follow-up examination should account for the type of primary disease, the anteroposterior location of the lesion, and the buccolingual direction of marsupialization.

Impact of Types of Moisturizer and Humidity on the Residual Weight and Viscosity of Liquid and Gel Oral Moisturizers.

PURPOSE: Oral moisturizers need to be selected based on their material properties. The purpose of this study was to investigate the effects of moisturizer type and humidity on the residual weight and viscosity of oral moisturizers. MATERIALS AND METHODS: The weight and viscosity of 17 oral moisturizers (7 liquid and 10 gel) at baseline and after 8 hours were measured using an incubator maintained at 37°C at either 85% or 40% relative humidity (RH). The rate of change in weight (RCW) and the rate of change in viscosity (RCV) were calculated. Data were analyzed with two-way analysis of variance (ANOVA) and Scheffe's test to evaluate the effect of the type of moisturizer (liquid or gel) and humidity (85% or 40% RH) on RCW and RCV. Pearson's correlation coefficient was used to evaluate the relationship between RCW and RCV. RESULTS: Two-way ANOVA results indicated that the type of moisturizer and RH had a significant effect on RCW and RCV (p < 0.05); however, the interaction between them was not significant. The results of multiple comparisons showed that gel moisturizers had a significantly lower RCW and higher RCV than liquid moisturizers (p < 0.05). The RCW and RCV at 40% RH were significantly higher than those at 85% RH (p < 0.05). There was no correlation between RCW and RCV in the liquid moisturizer group, but a significant negative correlation was found in the gel moisturizer group (pp = 0.01). CONCLUSION: Because viscosity of gel moisturizers increases as weight decreases, selecting gel moisturizers with a minimal change in weight and viscosity would be preferable in the case of a long-time application and severe dry mouth.