Severe hepatitis treated with an artificial liver support system

We designed an artificial liver support system (ALSS) including plasma exchange, charcoal hemoperfusion, plasma bilirubin absorption, charcoal plasma perfusion, hemofiltration and hemodialysis. We chose different methods or their combinations according to the patients’ conditions. We investigated the effect of ALSS in 154 patients with severe hepatitis, 72 of whom survived. All data were analyzed by SPSS. The effectiveness of ALSS treatment was compared at different stages (i.e. early, middle and end stages). After each ALSS treatment, the liver function of these patients greatly improved, serum endotoxin and HBV-DNA concentrations were significantly decreased, and the serum concentration of aromatic amino acids (AAA) such as methionine decreased while BCAA/AAA ratio increased. Patients treated with ALSS in the early or middle stages of disease had much higher survival rates than patients in the end stage of disease. Thus, we concluded that ALSS is a reliable therapy for advanced liver diseases and treatment in early or middle stages is appropriate.

Transcriptome analysis and molecular signature of human retinal pigment epithelium

Retinal pigment epithelium (RPE) is a polarized cell layer critical for photoreceptor function and survival. The unique physiology and relationship to the photoreceptors make the RPE a critical determinant of human vision. Therefore, we performed a global expression profiling of native and cultured human fetal and adult RPE and determined a set of highly expressed ‘signature’ genes by comparing the observed RPE gene profiles to the Novartis expression database (SymAtlas: http://wombat.gnf.org/index.html) of 78 tissues. Using stringent selection criteria of at least 10-fold higher expression in three distinct preparations, we identified 154 RPE signature genes, which were validated by qRT-PCR analysis in RPE and in an independent set of 11 tissues. Several of the highly expressed signature genes encode proteins involved in visual cycle, melanogenesis and cell adhesion and Gene ontology analysis enabled the assignment of RPE signature genes to epithelial channels and transporters (ClCN4, BEST1, SLCA20) or matrix remodeling (TIMP3, COL8A2). Fifteen RPE signature genes were associated with known ophthalmic diseases, and 25 others were mapped to regions of disease loci. An evaluation of the RPE signature genes in a recently completed AMD genomewide association (GWA) data set revealed that TIMP3, GRAMD3, PITPNA and CHRNA3 signature genes may have potential roles in AMD pathogenesis and deserve further examination. We propose that RPE signature genes are excellent candidates for retinal diseases and for physiological investigations (e.g. dopachrome tautomerase in melanogenesis). The RPE signature gene set should allow the validation of RPE-like cells derived from human embryonic or induced pluripotent stem cells for cell-based therapies of degenerative retinal diseases.

Irreversible pressure-induced transformation of boron nitride nanotubes

We have used Raman spectroscopy to study the behavior of multi-walled boron nitride nanotubes and hexagonal boron nitride crystals under high pressure. While boron nitride nanotubes show an irreversible transformation at about 12 GPa, hexagonal boron nitride exhibits a reversible phase transition at 13 GPa. We also present molecular dynamics simulations which suggest that the irreversibility of the pressure-induced transformation in boron nitride nanotubes is due to the polar nature of the bonds between boron and nitrogen.

Effects of tea polyphenols on telomerase activity of a tongue cancer cell line: a preliminary study

The aim of this study was to determine, at the mRNA and protein levels, whether tea polyphenols (TPs) affect the expression of the human telomerase reverse transcriptase (hTERT) gene in the Tca8113 cancerous cell line. The expression of this gene was determined at the mRNA level by reverse transcription and polymerase chain reaction and at the protein level by Western blotting. The semi-quantitative scores of hTERT mRNA expression were analyzed by one-way analysis of variance. After 72 h of exposure to TPs, the mean (+/-SD) scores of hTERT mRNA expression in TP 0.1g/l, TP 0.05 g/l and a control group were 0.32+/-0.05, 0.41+/-0.04 and 0.72+/-0.05, respectively (P<0.05). The Western blot assay showed that TPs also decreased the expression of hTERT at the protein level. These results indicate that TPs reduce hTERT activity in the human Tca8113 cell line in a time- and dose-dependent manner, disabling telomerase activity and thereby terminating unlimited cancer cell proliferation. These findings suggest a mechanism behind TP's anticancer activity.

Severe hepatitis treated with an artificial liver support system

We designed an artificial liver support system (ALSS) including plasma exchange, charcoal hemoperfusion, plasma bilirubin absorption, charcoal plasma perfusion, hemofiltration and hemodialysis. We chose different methods or their combinations according to the patient's conditions. We investigated the effect of ALSS in 154 patients with severe hepatitis, 72 of whom survived. All data were analyzed by SPSS. The effectiveness of ALSS treatment was compared at different stages (i.e. early, middle and end stages). After each ALSS treatment, the liver function of these patients greatly improved, serum endotoxin and HBV-DNA concentrations were significantly decreased, and the serum concentration of aromatic amino acids (AAA) such as methionine decreased while BCAA/AAA ratio increased. Patients treated with ALSS in the early or middle stages of disease had much higher survival rates than patients in the end stage of disease. Thus, we concluded that ALSS is a reliable therapy for advanced liver diseases and treatment in early or middle stages is appropriate.

In vitro antimicrobial activities of novel anilinouracils which selectively inhibit DNA polymerase III of gram-positive bacteria

The 6-anilinouracils are novel dGTP analogs that selectively inhibit the replication-specific DNA polymerase III of gram-positive eubacteria. Two specific derivatives, IMAU (6-[3'-iodo-4'-methylanilino]uracil) and EMAU (6-[3'-ethyl-4'-methylanilino]uracil), were substituted with either a hydroxybutyl (HB) or a methoxybutyl (MB) group at their N3 positions to produce four agents: HB-EMAU, MB-EMAU, HB-IMAU, and MB-IMAU. These four new agents inhibited Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus faecalis, and Enterococcus faecium. Time-kill assays and broth dilution testing confirmed bactericidal activity. These anilinouracil derivatives represent a novel class of antimicrobials with promising activities against gram-positive bacteria that are resistant to currently available agents, validating replication-specific DNA polymerase III as a new target for antimicrobial development.

Novel nonsubstrate inhibitors of human thymidine phosphorylase, a potential target for tumor-dependent angiogenesis

Thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) is an enzyme involved in thymidine metabolism and homeostasis, and its catalytic activity appears to play an important role in angiogenesis. Here we describe the cloning and expression of a His-tagged human TP/PD-ECGF and its assay with uracil and thymine analogues. We present the design, synthesis, and biological evaluation of novel 6-(phenylalkylamino)uracil derivatives which, at micromolar concentrations, inhibit both catabolic and anabolic reactions of human TP in vitro. These base analogues are not converted by the enzyme into the nucleoside form, thus representing pure nonsubstrate inhibitors of the enzyme.

Inhibitors of DNA polymerase III as novel antimicrobial agents against gram-positive eubacteria

6-Anilinouracils are selective inhibitors of DNA polymerase III, the enzyme required for the replication of chromosomal DNA in gram-positive bacteria (N. C. Brown, L. W. Dudycz, and G. E. Wright, Drugs Exp. Clin. Res. 12:555-564, 1986). A new class of 6-anilinouracils based on N-3 alkyl substitution of the uracil ring was synthesized and analyzed for activity as inhibitors of the gram-positive bacterial DNA polymerase III and the growth of gram-positive bacterial pathogens. Favorable in vitro properties of N-3-alkyl derivatives prompted the synthesis of derivatives in which the R group at N-3 was replaced with more-hydrophilic methoxyalkyl and hydroxyalkyl groups. These hydroxyalkyl and methoxyalkyl derivatives displayed K(i) values in the range from 0.4 to 2.8 microM against relevant gram-positive bacterial DNA polymerase IIIs and antimicrobial activity with MICs in the range from 0.5 to 15 microg/ml against a broad spectrum of gram-positive bacteria, including methicillin-resistant staphylococci and vancomycin-resistant enterococci. Two of these hydrophilic derivatives displayed protective activity in a simple mouse model of lethal staphylococcal infection.

Molecular modeling and synthesis of inhibitors of herpes simplex virus type 1 uracil-DNA glycosylase

We recently reported the properties of the first selective inhibitors of herpes simplex virus type 1 (HSV1) uracil-DNA glycosylase (UDG), an enzyme of DNA repair that has been proposed to be required for reactivation of the virus from latency. 6-(4-Octylanilino)uracil (octAU) was the most potent inhibitor among a series of 6-(4-alkylanilino)uracils, acting in the micromolar range and without effect against human UDG. A 28.5-kDa catalytic fragment of HSV1 UDG has been crystallized in the presence of uracil, and the structure was recently solved. We have used the coordinates of this structure in order to study interaction of our inhibitors with the enzyme, and a model of binding between octAU and UDG has been derived. Starting with the optimized model, the activity of several octAU analogues was predicted, and the values compared favorably with experimental results found for the synthetic compounds. Several hydrophilic derivatives were predicted and found to be active as UDG inhibitors. These compounds will be useful to determine if UDG, like the viral thymidine kinase, is required for reactivation of HSV1 from latency in nerve cells.

6-Anilinouracil-based inhibitors of Bacillus subtilis DNA polymerase III: antipolymerase and antimicrobial structure-activity relationships based on substitution at uracil N3

6-Anilinouracils (6-AUs) are dGTP analogues which selectively inhibit the DNA polymerase III of Bacillus subtilis and other Gram-positive bacteria. To enhance the potential of the 6-AUs as antimicrobial agents, a structure-activity relationship was developed involving substitutions of the uracil N3 position in two 6-AU platforms: 6-(3,4-trimethyleneanilino)uracil (TMAU) and 6-(3-ethyl-4-methylanilino)uracil (EMAU). Series of N3-alkyl derivatives of both 6-AUs were synthesized and tested for their ability to inhibit purified B. subtilis DNA polymerase III and the growth of B. subtilis in culture. Alkyl groups ranging in size from ethyl to hexyl enhanced the capacity of both platforms to bind to the polymerase, and with the exception of hexyl, they also significantly enhanced their antimicrobial potency. N3 substitution of the EMAU platform with more hydrophilic hydroxyalkyl and methoxyalkyl groups marginally enhanced anti-polymerase III activity but enhanced antibacterial potency severalfold. In sum, the results of these studies indicate that the ring N3 of 6-anilinouracils can tolerate substituents of considerable size and structural variety and, thus, can be manipulated to significantly enhance the antibacterial potency of this novel class of polymerase III-specific inhibitors.

Synthesis and molecular modeling of novel HSV1 uracil-DNA glycosylase inhibitors

In a recent paper the first selective inhibitors of HSV1 uracil-DNA glycosylase (UDG) acting in the micromolar range have been reported. A 28.5 kDa catalytic fragment of HSV1 UDG has been crystallized in the presence of uracil, and the structure was recently solved. Starting with the optimized model of binding between 6-(4'-n-octylanilino)uracil (octAU) and UDG some new derivatives have been predicted to be active. In vitro studies with the novel synthetized compounds confirm the plausibility of the model and define the structure features for UDG inhibitors.