Measurement of metallothionein in rat tissues by a chromatographic method using the fluorometry of thiol groups.

The estimation of metallothionein (MT) levels in a biological sample is required to study the physiological role or the induction of MT, which is a multifunctional protein. MT contains 61 amino acids with 20 homologous cysteines. The high selectivity, sensitivity and stability of N-[4-(dimethylamino-2-benzofuranyl)phenyl]maleimide (DBPM) for the determination of SH groups was very useful for the determination of MT. The detection limit of MT by this method was 10 ng/0.5 ml. This method made it possible to measure MT levels in normal tissues in combination with gel filtration chromatography. The age-dependent change in MT levels in normal rat tissues was also investigated by the present method. MT levels in normal rat tissues vary with age. It is thought that this fact is correlated with the biological roles of MT.

[Croton oil-induced hemorrhoid model in rat: comparison of anti-inflammatory activity of diflucortolone valerate with other glucocorticoids].

A hemorrhoid model was prepared by means of application of croton oil onto the recto-anus of rats. Cotton swab soaked with the inducer, which consisted of water, pyridine, diethylether and 6% croton oil in diethylether, was inserted into the anus. The following conditions were found to be optimal for preparing the model: cotton swab containing 0.16 ml of the inducer solution was applied to the anus of a 6 week-old rat (body wt. about 140 g) for 10 sec. The edema developed linearly until 7-8 hr after application, and the severity of the edema was sustained almost constantly for more than 24 hr. Macroscopic observations at 6 hr p. a. revealed homogeneous and consistent inflammation in the recto-anus applied region. Histological observation showed appearance of edema, infiltration of fibrin, inflammatory cells, vasodilation, blood congestion and medium to high degrees of necrosis in the mucosal epithelium. Thus this model was useful for evaluating the effect of anti-hemorrhoidal drugs on intumescence and vasodilatation. The efficacy of diflucortolone valerate, hydrocortisone caproate and hydrocortisone was evaluated in this model. Wet weight and vasopermeability increased by the inducer was suppressed strongly by simultaneous application of the corticoids, and the degree of suppression was parallel with the potency of the glucocorticoid activity. Compared to Scheriproct, Posterisan forte, Posterisan and Borraginol N, Neriproct showed the strongest effects in the protection against and treatment of the experimental hemorrhoid. Scheriproct, which was less active than Neriproct, was also found to have higher efficacy than the others.

[Neriproct: its anti-inflammatory effect on an experimentally induced hemorrhoid model in the rat].

Several glucocorticoids as a cream formulation were applied to the recto-anus of the croton-oil-induced hemorrhoid rat. Among the steroids tested, i.e. diflucortolone valerate (DFV), prednisolone (PS), hydrocortisone caproate (HC), and hydrocortisone (H), DFV was found to suppress inflammation most effectively. The effect of DFV was not affected by combination with lidocaine. In this model, the analgesic effect of lidocaine was apparently prolonged by an increase of the threshold for pain by the anti-inflammatory effect of DFV. This additive effect is regarded as a merit of the combination in Neriproct. Therapeutic effects of Neriproct and several anti-hemorrhoid drugs were also examined by using a hemorrhoid model with abrasive irritation compared to those obtained by the croton-oil model. In both models, efficacy of Neriproct was superior to that of the other drugs such as Scheriproct, Proctosedyl, Posterisan forte, Borraginol N, Posterisan and Borraza G. Microscopic observation showed that destruction of the mucus epithelium, necrosis of the mucus layer, infiltration of inflammatory cells and vasodilatation in the croton-oil model were also suppressed markedly by Neriproct application. No difference was observed in the efficacy between the cream and suppository formulation of Neriproct. Suppression of wound healing was found with a dosage of DFV lower than those of PS, HC and H. However, the efficacy ratio of the wound-healing suppression and anti-inflammation of DFV was the largest among the steroids tested.

Conformational states of 18 S rRNA from HeLa cells detected by gel electrophoresis.

Gel electrophoretic analysis has been used to study some of the conformational properties of 18 S rRNA from HeLa cells. After isolation and treatment by heat or denaturants, the mobility of the RNA in 3% acrylamide/0.5% agarose composite gels was found to be altered; often there were two or more distinct components. Several of these forms could be interconverted by heating to 40 degrees C or by use of dimethyl sulfoxide. Although these comformers were easily distinguishable (by their electrophoretic properties), their melting profiles were very similar. Only a single electrophoretic form was detected when electrophoresis was performed at 40 degrees C. The conformational differences observed are probably derived by variations in base pairing and stacking that result when the parent form is cooled.