Arylamine N-acetyltransferase (NAT) activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori, a gram-negative rod bacteria collected from peptic ulcer patients. The NAT activity was determined using a acetyl CoA recycling assay and HPLC. Cytosols or suspensions of H. pylori with and without selected concentrations of emodin co-treatment showed different percentages of 2-aminofluorene and p-aminobenzoic acid acetylation. The data indicate that there were decreased NAT activity associated with increased emodin in H. pylori cytosols. As 400 microns of emodin can obviously inhibit NAT activity both in vitro and in vivo (inhibition rate 90% and 93% for 2-aminofluorene and p-aminobenzoic acid in vitro, and 90% and 92%, respectively, for both substrate in vivo). For in vitro examination, the apparent values of Km and Vmax were 3.12 +/- 0.38 mM and 15.20 +/- 3.16 nmol/min/mg protein for 2-aminofluorene, and 0.56 +/- 0.12 mM and 0.74 +/- 0.09 nmol/min mg protein for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 2.40 +/- 0.32 mM and 10.62 +/- 0.04 nmol/min/mg protein for 2-aminofluorene, and 0.23 +/- 0.02 mM and 0.62 +/- 0.08 nmol/min/mg protein for p-aminobenzoic acid. For in vivo examination, the apparent Km and Vmax were 0.82 +/- 0.18 mM and 0.92 +/- 0.21 nmol/min/10 x 10(10) colony forming units (CFU) for 2-aminofluorene, and 0.78 +/- 0.14 mM and 0.52 +/- 0.06 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 0.50 +/- 0.08 mM and 0.62 +/- 0.22 nmol/min/ 10 x 10(10) (CFU) for 2-aminofluorene, and 0.52 +/- 0.21 mM and 0.26 +/- 0.04 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. This report is the first finding of emodin inhibition of arylamine N-acetyltransferase activity in a strain of H. pylori.

4-Aminobenzoic Acid↗

PubMedDate not supplied

Quantitative measurement of corneal haze after myopic PRK.

OBJECTIVE: To design and evaluate an instrument for the objective measurement of haze in rabbits after myopic PRK. METHODS: A circular fluorescent lamp bulb projected light onto the cornea through a circular collimating aperture covered with an orange filter. The image was collected on a centrally mounted CCD camera and the profile of the haze circle along its horizontal diameter determined. RESULTS: Haze circles were observed and quantitated. In the first weeks, they were donut-shaped, frequently with a central bright area, but later they became square-topped. The instrument reproduced measurements with an error of a few percentage points and showed good long-term stability.

Animals↗

PubMedDate not supplied

Cardiovascular effect of skimmianine in rats.

Skimmianine, a general component contained in the plants of Rutaceae, was found to have a selective inhibitory effect on the 5-hydroxytryptamine-induced vasopressor responses of rats. A similar inhibitory action was also observed in the isolated atria. Moreover, skimmianine produced a nonspecific blockade of the cardiovascular functions at higher concentration.

Animals↗