Porphylipoprotein Accumulation and Porphylipoprotein Photodynamic Therapy Effects Involving Cancer Cell-Specific Cytotoxicity

In photodynamic therapy (PDT) for neoplasms, photosensitizers selectively accumulate in cancer tissue. Upon excitation with light of an optimal wavelength, the photosensitizer and surrounding molecules generate reactive oxygen species, resulting in cancer cell-specific cytotoxicity. Porphylipoprotein (PLP) has a porphyrin-based nanostructure. The porphyrin moiety of PLP is quenched because of its structure. When PLP is disrupted, the stacked porphyrins are separated into single molecules and act as photosensitizers. Unless PLP is disrupted, there is no photosensitive disorder in normal tissues. PLP can attenuate the photosensitive disorder compared with other photosensitizers and is ideal for use as a photosensitizer. However, the efficacy of PLP has not yet been evaluated. In this study, the mechanism of cancer cell-specific accumulation of PLP and its cytotoxic effect on cholangiocarcinoma cells were evaluated. The effects were investigated on normal and cancer-like mutant cells. The cytotoxicity effect of PLP PDT in cancer cells was significantly stronger than in normal cells. In addition, reactive oxygen species regulated intracellular PLP accumulation. The cytotoxic effects were also investigated using a cholangiocarcinoma cell line. The cytotoxicity of PLP PDT was significantly higher than that of laserphyrin-based PDT, a conventional type of PDT. PLP PDT could also inhibit tumor growth in vivo.     

Extracellular Environment-Controlled Angiogenesis,and Potential Application for Peripheral Nerve Regeneration

Endothelial cells acquire different phenotypes to establish functional vascular networks. Vascular endothelial growth factor (VEGF) signaling induces endothelial proliferation, migration, and survival to regulate vascular development, which leads to the construction of a vascular plexuses with a regular morphology. The spatiotemporal localization of angiogenic factors and the extracellular matrix play fundamental roles in ensuring the proper regulation of angiogenesis. This review article highlights how and what kinds of extracellular environmental molecules regulate angiogenesis. Close interactions between the vascular and neural systems involve shared molecular mechanisms to coordinate developmental and regenerative processes. This review article focuses on current knowledge about the roles of angiogenesis in peripheral nerve regeneration and the latest therapeutic strategies for the treatment of peripheral nerve injury.     

Differences between Human and Mouse IgM Fc Receptor (FcµR)

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since the bona fide IgM Fc receptor (FcµR) was identified in humans by a functional cloning strategy in 2009, the roles of FcµR in these IgM effector functions have begun to be explored. In this short essay, we describe the differences between human and mouse FcµRs in terms of their identification processes, cellular distributions and ligand binding activities with emphasis on our recent findings from the mutational analysis of human FcµR. We have identified at least three sites of human FcµR, i.e., Asn66 in the CDR2, Lys79 to Arg83 in the DE loop and Asn109 in the CDR3, responsible for its constitutive IgM-ligand binding. Results of computational structural modeling analysis are consistent with these mutational data and a model of the ligand binding, Ig-like domain of human FcµR is proposed. Serendipitously, substitution of Glu41 and Met42 in the CDR1 of human FcµR with mouse equivalents Gln and Leu, either single or more prominently in combination, enhances both the receptor expression and IgM binding. These findings would help in the future development of preventive and therapeutic interventions targeting FcµR.     

Effect of microstructure on discharge performance of Al–0.8Sn–0.05Ga–0.9Mg–1.0Zn (wt%) alloy as anode for seawater-activated battery

The electrochemical performance and discharge behavior of Al–0.8Sn–0.05Ga–0.9Mg–1.0Zn (wt%) alloys in as-cast, homogenized, and annealed states were investigated through electrochemical means, corrosion rate test, and discharge test in a 3.5 wt% NaCl solution. Results suggest that the discharge performance of this alloy is enhanced by rolling and subsequent annealing treatment. This is attributed to the fact that the microstructure of the alloy is greatly improved through rolling and subsequent annealing treatment. The 400°C-annealed alloy exhibits the most excellent discharge activity than alloys in other states, which is due to more regions being activated by a finer and more uniform Sn-rich phase. Furthermore, the anode efficiency of the 400°C-annealed alloy is higher than that of as-cast and homogeneous alloys due to the more uniform distribution of Sn in the aluminum matrix.     

Influence of alkylpyridine additives in electrolyte solution on the performance of dye-sensitized solar cell

The influence of alkylpyridines additive to an I⁻/I₃⁻ redox electrolyte in acetonitrile on the performance of a bis(tetrabutylammonium)cis-bis(thiocyanato)bis(2,2′-bipyridine-4-carboxylic acid, 4′-carboxylate)ruthenium(II) dye-sensitized TiO₂ solar cell was studied. I–V measurements were performed using more than 30 different alkylpyridines. The alkylpyridine additives showed a significant influence on the performance of the cell. All the additives decreased the short-circuit photocurrent (J_sc), but most of the alkylpyridines increased the open-circuit photovoltage (V_oc) and fill factor (ff) of the solar cell. The results of the molecular orbital calculations suggest that the dipole moment of the alkylpyridine molecules correlate with the J_sc of the cell. These results also suggest that both the size and ionization energy of pyridines correlate with the V_oc of the cell. Under AM 1.5 (100 mW/cm²), the highest solar energy conversion efficiency (η) of 7.6% was achieved by using 2-propylpyridine as an additive, which was more effective than the previously reported additive, 4-t-butylpyridine.     

Comparative anatomy of the podocyte: A scanning electron microscopic study

The three-dimensional structure of the renal glomerular podocyte was comparatively analyzed with special reference to its cellular interdigitation. Kidneys of lampreys, carps, eels, xenopuses, bullfrogs, iguanas, rats, and rabbits were used as materials. Urinary and basal surfaces of podocytes were exposed by a conventional freeze-fracture method and by NaOH maceration, respectively, and subsequently examined by scanning electron microscopy. In accordance with previous reports, each podocyte consisted of a round cell body protruding into Bowman's space, four to six major processes embracing glomerular capillary, and numerous pedicels on both sides of the major processes. The podocyte pedicels exhibited uniform needle-like shapes, about 0.2 microm thick, interdigitated with those of adjoining cells along the entire length of the cell margins in all the animal species examined. This finding suggests that the fine pedicel interdigitation is a primary event in morphogenesis of the podocyte. The basal aspect of the glomerular epithelium was mosaicked with pedicels which were laid at various angles to the capillary axis, in favor of its possible role as a mechanical support of the capillary wall.     

An Intrinsically Fluorescent Recognition Ligand Scaffold Based on Chaperonin Protein and Semiconductor Quantum‐Dot Conjugates

Genetic engineering of a novel protein–nanoparticle hybrid system with great potential for biosensing applications and for patterning of various types of nanoparticles is described. The hybrid system is based on a genetically modified chaperonin protein from the hyperthermophilic archaeon Sulfolobus shibatae. This chaperonin is an 18‐subunit double ring, which self‐assembles in the presence of Mg ions and ATP. Described here is a mutant chaperonin (His‐β‐loopless, HBLL) with increased access to the central cavity and His‐tags on each subunit extending into the central cavity. This mutant binds water‐soluble semiconductor quantum dots, creating a protein‐encapsulated fluorescent nanoparticle. The new bioconjugate has high affinity, in the order of strong antibody–antigen interactions, a one‐to‐one protein–nanoparticle stoichiometry, and high stability. By adding selective binding sites to the solvent‐exposed regions of the chaperonin, this protein–nanoparticle bioconjugate becomes a sensor for specific targets.     

Relationship between oxidative stability of vitamin E and production of fatty acids in oils during microwave heating

Effects of microwave heating on the oxidative stability ofd-tocopherols were studied in relation to the production of fatty acids in oils. During microwave heating, the stability of tocopherols decreased in the orderδ>β>γ>α. This order did not depend on the types of ethyl esters of fatty acids or oils present. But, the shorter the chainlength and the lower the degree of unsaturation of the fatty acid ethyl esters, the greater was the reduction in amount of individual tocopherols. A similar tendency was observed when tocopherol-stripped vegetable oils, with equimolar mixtures of tocopherols added, were treated under the same conditions. The reduction in tocopherols became greater with increasing levels of free fatty acids.     

Depolymerization of fluoroalkyl methacrylate polymers as studied with thermogravimetry

Thermal behaviors of a few kinds of poly(fluoroalkyl methacrylate) prepared by γ-or UV-ray polymerization were investigated by using thermogravimetric measurements with the intermittent analysis of the gaseous products. The degradation of fluoroalkyl methacrylate polymers, monomeric units of which were CH₂=C(CH₃)COOCH₂(CF₂CF₂)_nH, n = 1, 2, and 3, proceeded according to the depolymerization mechanism reproducing the pristine monomer exclusively, but the thermogram in inert atmosphere showed the features of a two-step reaction. Two species of polymer differing in the heat stability were supposed to exist in the polymeric substance produced by γ- or UV-ray irradiation, and the fraction of polymer having lower heat stability increased with the increasing length of the fluoroalkyl ester group. In air, however, the thermogram of poly(fluoroalkyl methacrylate) showed no such a stepwise weight decrease as was observed in inert atomsphere with the elevating temperature, and the temperatures at which the depolymerization was introduced shifted to a much higher region. The results were ascribed to the reaction of initiating polymer radicals produced on polymer having lower stability with oxygen to form hydroperoxide, which once stabilized the polymer radicals and obstructed the initiaition of the unzipping reaction till higher temperature.