Abstract-Elevated total plasma homocysteine is an independent risk factor in the development of vascular disease in humans. Cystathionine ␤-synthase (CBS) is an enzyme that condenses homocysteine with serine to form cystathionine. In this article, we describe the effects of modulating CBS activity using a transgenic mouse that contains the human CBS cDNA under control of the zinc-inducible metallothionein promoter (Tg-CBS). In the presence of zinc, Tg-CBS mice have a 2-to 4-fold increase in liver and kidney CBS activity compared with nontransgenic littermates. Transgenic mice on standard mouse chow had a 45% decrease in their serum homocysteine (12.1 to 7.2 mol/L; PϽ0.0001) when zinc was added to drinking water, although zinc had minimal effect on their nontransgenic siblings (13.2 mol/L versus 13.0 mol/L; PϭNS). Tg-CBS mice maintained on a high-methionine, low-folate diet also had significantly lower serum homocysteine compared with control animals (179 mol/L versus 242 mol/L; PϽ0.02). CBS overexpression also significantly lowered serum cysteinylglycine (3.6 versus 2.8 mol/L; PϽ0.003) levels and reduced the levels of many amino acids in the liver. We also found that expression of Tg-CBS rescued the severe hyperhomocysteinemia and neonatal lethality of Cbs deletion animals. Our results show that elevating CBS activity is an effective method to lower plasma homocysteine levels. In addition, the creation of an inducible mouse system to modulate plasma homocysteine will also be useful in the study of homocysteine-related vascular disease.

Summary The essential oil of silver fir (Abies alba) is known to help respiratory system and have easing and soothing effect for muscle. In the present study, we investigated the chemical composition, cytotoxicity and its biological activities of silver fir (Abies alba) essential oil. The composition of the oil was analyzed by GC-MS and bornyl acetate (30.31%), camphene (19.81%), 3-carene (13.85%), tricyclene (12.90%), dl-limonene (7.50%), α-pinene (2.87%), caryophyllene (2.18%), β-phellandrene (2.13%), borneol (1.74%), bicyclo[2.2.1]hept-2-ene,2,3-dimethyl (1.64%) and α-terpinene (1.24%) were the major components in the oil. The results tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that the oil showed no cytotoxic effect, at concentrations of 1 and 5%, for as long as 24 and 3 h, respectively. The antiradical capacity was evaluated by measuring the scavenging activity of the essential oil on the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals. The oil was able to reduce the both radicals dose-dependently, and the concentration required for 50% reduction (RC50) against DPPH radicals (2.7 ± 0.63%) was lower than ABTS radicals (8.5 ± 0.27%). The antibacterial activity of the oil was also evaluated using disc diffusion method against Staphylococcus aureus, Streptococcus mutans, Listeria monocytogenes, Acinetobacter baumannii, Escherichia coli, and Vibrio parahaemolyticcus. The oil exhibited no antibacterial activity against all the bacterial strains tested except S. aureus of mild activity.

We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/ TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.