Improved optical properties of silica/UV-cured polymer composite films made of hollow silica nanoparticles with a hierarchical structure for light diffuser film applications

This study successfully improved the optical properties of silica/UV-cured polymer composite films made of hollow silica nanoparticles having a hierarchical structure.

Fabrication of unique hollow silicate nanoparticles with hierarchically micro/mesoporous shell structure by a simple double template approach

An innovative type of hollow silicate nanoparticle with a micro/mesoporous shell wall (NSHPMS) was synthesized at room temperature via an eco-friendly double template approach, followed by simple acid reflux. TEM observations of NSHPMSs showed hollow interior nanoparticles (<100 nm) with a wormhole-like shell structure. The nitrogen gas (N(2)) adsorption/desorption isotherm exhibited a unique two-step pattern: the first step (0.2 < P/P(o) < 0.35) signifies the presence of the micro/mesoporous shell wall while the second step (0.85 < P/P(o) < 0.99) represents the void space in between the NSHPMSs. This resulted to an improved specific surface area up to ~2055.5 m(2) g(-1) and a total pore volume as high as ~6.59 cm(3) g(-1) which is better compared with the usual reported data for hollow particles with a mesoporous shell wall. The stable wormhole mesoporous shell wall provided sufficient spaces that contribute to high adsorption capacities and faster adsorption rates. One can envision that larger quantities of framework composition can be obtained using our NSHPMSs.

Complete nucleotide sequence of the linear DNA plasmid pRS224 with hairpin loops from Rhizoctonia solani and its unique transcriptional form

The complete nucleotide sequence of the linear DNA plasmid (pRS224-1) from the plant-pathogenic fungus Rhizoctonia solani isolate H-16 was determined; and its unique RNA transcripts were characterized. The pRS224-1 DNA consists of 4,986 nucleotides. A computer-based study of the folding of pRS224-1 at both termini predicted hairpin-loop structures. The hairpin loops consisted of the left and right termini of 236 and 264 nucleotides, respectively, and share no sequence homology. Unique poly(A) RNAs, 4.7 kb and 7.4 kb in length and hybridizing with the pRS224 DNA, were found in mycelial cells of R. solani H-16. Transcript product-mapping allowed the prediction of the locations of different expression signals. The 7.4-kb transcript is generated from the left terminal region of the complementary strand, via the full-length sense-strand, to the right terminal region of the complementary strand. The 4.7-kb transcript is generated from the center region of the sense strand to the right terminal region of the complementary strand. One open reading frame (ORF) found in pRS224-1 is 887 amino acids long and has a potential coding capacity of 102 kDa. The ORF contains the highly conserved domains characteristic of reverse transcriptase sequences, including the highly conserved YXDD sequence.

Highly selective and orally active inhibitors of type IV collagenase (MMP-9 and MMP-2): N-sulfonylamino acid derivatives

Various N-sulfonylamino acid derivatives were synthesized and evaluated for their in vitro and in vivo activities to inhibit type IV collagenase (MMP-9 and MMP-2). When the amino acid residue and the sulfonamide moiety were modified, their inhibitory activities were greatly affected by the structure of the sulfonamide moiety. A series of aryl sulfonamide derivatives containing biaryl, tetrazole, amide, and triple bond were found to be potent and highly selective inhibitors of MMP-9 and MMP-2. In addition, these compounds were orally active in animal models of tumor growth and metastasis. These results revealed the potential of the N-sulfonylamino acid derivatives as a new type of candidate drug for the treatment of cancer.

Cytotoxic activity of CD4+ T cells against autologous tumor cells

The 51Cr-release assay is mostly applied to detecting the cytotoxic activity of CD8+ T cells, and little is known about the activity of CD4+ T cells. Therefore, the correlation between the cytotoxic activity of CD4+ or CD8+ T cells and the incubation period with autologous tumor cells was analyzed by two methods. The incubation periods were 4 and 20 h (4 h and 20 h assay) for the 51Cr-release assay. Eight pairs of tumor cells and T cells were assayed. T cells were fractionated into CD4+ and CD8+ T cells by using magnetic beads and panning methods, and those cells were activated by culture with recombinant interleukin-2 and immobilized anti-CD3 monoclonal antibody. In 6 out of 8 cases, no cytotoxic activity of CD4+ T cells was detected by the 4 h assay, whereas cytotoxic activity was detected in all cases in the 20 h assay. The cytotoxic activities in 20 h assay of CD4+ T cells were increased 67-fold in comparison with the activities in 4 h assay (range: 5-197). In the case of CD8+ T cells, cytotoxic activities were detected in 6 out of 8 cases in the 4 h assay. The lytic unit ratio of CD4+ and CD8+ T cells was calculated as 1.5 in the 20 h assay (range: 0.2- > 7.2) versus 0.4 in the 4 h assay (range: < 0.1-1.3). Cytotoxic activities in colorimetric assay using Crystal Violet with a 24 h incubation were similar to those in the 20 h 51Cr-release assay in all eight cases. These results indicate that CD4+ T cells have cytotoxic activity as strong as that of CD8+ T cells towards autologous tumor cells.

Synthesis and evaluation of novel nonpeptide angiotensin II receptor antagonists: imidazo[4,5-c]pyridine derivatives with an aromatic substituent

Starting from recently reported nonpeptidic angiotensin II (AII) receptor antagonists, we have designed and prepared a new series of 6-arylimidazo[4,5-c]pyridine derivatives. Variation of phenyl groups at the 4-, 6- or 7-position of imidazo[4,5-c]pyridine showed that substitution at the 6-position resulted in receptor-binding activity almost as potent as that of DuP 753. This led to synthesis and evaluation of an extensive series of 6-aryl-imidazo[4,5-c]pyridine derivatives. Some of them were 4-fold more potent in vitro than DuP 753, but only showed weak antihypertensive activity in vivo when given orally to rats.

Beneficial effects of the synthetic trypsin inhibitor camostate in cerulein-induced acute pancreatitis in rats

The therapeutic effect and the mechanism of action of the synthetic trypsin inhibitor camostate were studied in a rat model of acute interstitial pancreatitis induced by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals. Rats with acute pancreatitis were given either 100 mg/kg body weight camostate or volume- and pH-adjusted water via an orogastric tube 30 min after the last cerulein injection. The elevation of serum amylase activity was significantly reduced by camostate treatment and the peak value was seen 1 hr earlier than that observed in the rats that did not receive camostate. Camostate also inhibited the reduction in pancreatic content of lipase and amylase seen during experimental pancreatitis. These effects were accompanied by alleviation of the histologic signs of acute pancreatitis such as cellular infiltration and acinar cell vacuolization. After oral administration, camostate and its metabolite were absorbed from the intestine and were detectable in plasma for more than 6 hr in concentrations high enough to have antiprotease activity. In addition, camostate in the duodenum was able to increase pancreatic juice flow and protein output and to stimulate endogenous secretin release. These results suggest that oral administration of camostate reduces the severity of cerulein-induced acute pancreatitis by releasing endogenous secretin and by its antiprotease activity.

Novel receptor-mediated internalization of interleukin 2 in B cells

Novel IL-2-binding molecules (p70 and p75) mediating internalization and degradation of IL-2 were examined by employing a human B lymphoblastoid line, SKW6-4 cells. High concentrations of IL-2 induced IgM secretion in these cells through a receptor distinct from Tac antigen. The acid-wash technique revealed that more than 60% of 125I-labeled IL-2 bound to the cells became acid-unremovable in the first 30 min of incubation at 37 degrees C and degradation products of 125I-IL-2 increased after 30 min of incubation. Treatment of the cells with NaN3 buffer inhibited the appearance of acid-unremovable 125I-IL-2, suggesting that acid-unremovable 125I-IL-2 was not due to fluid-phase pinocytosis but due to internalization. Loss of labeled bands by incubation of cells with 125I-IL-2 at 37 degrees C before affinity cross-linking demonstrated that 125I-IL-2 was internalized via novel IL-2-binding molecules. These results suggest that novel IL-2-binding molecules are responsible for internalization and may mediate signal transduction in B cells in the absence of Tac antigen.

Novel receptor-mediated internalization of interleukin 2 in B cells

Novel IL-2-binding molecules (p70 and p75) mediating internalization and degradation of IL-2 were examined by employing a human B lymphoblastoid line, SKW6-4 cells. High concentrations of IL-2 induced IgM secretion in these cells through a receptor distinct from Tac antigen. The acid-wash technique revealed that more than 60% of 125I-labeled IL-2 bound to the cells became acid-unremovable in the first 30 min of incubation at 37 degrees C and degradation products of 125I-IL-2 increased after 30 min of incubation. Treatment of the cells with NaN3 buffer inhibited the appearance of acid-unremovable 125I-IL-2, suggesting that acid-unremovable 125I-IL-2 was not due to fluid-phase pinocytosis but due to internalization. Loss of labeled bands by incubation of cells with 125I-IL-2 at 37 degrees C before affinity cross-linking demonstrated that 125I-IL-2 was internalized via novel IL-2-binding molecules. These results suggest that novel IL-2-binding molecules are responsible for internalization and may mediate signal transduction in B cells in the absence of Tac antigen.