Pharmacological Properties of Pteleprenine,a Quinoline Alkaloid Extracted from Orixa japonica,on Guinea-pig Ileum and Canine Left Atrium

We have investigated the pharmacological properties of pteleprenine, a quinoline alkaloid, on contractile responses of the guinea-pig ileum and on inotropic responses of the canine left atrium. Although pteleprenine (0·1–1 μM) had no effect on the contraction of the ileum induced by acetylcholine at 10 μM it significantly inhibited acetylcholine-induced contraction of the ileum. Pteleprenine (0·1–10 μM) reduced nicotine induced-contraction of the ileum in a concentration-dependent manner yet had no maximum relaxant effect even at a concentration of 10 μM From Schild analysis the pA₂ of pteleprenine on the guinea-pig ileum was found to be 6-6. The contraction of the ileum induced by 10 μM 1,1-dimethyl-4-phenylpiperazinium, a specific agonist of nicotinic acetylcholine. receptors, was concentration-dependently suppressed by 10 nM-10 μM pteleprenine. In contrast, 0.1–10 μM pteleprenine did not antagonize the acetylcholine- and nicotine-induced negative inotropic contractile responses of the canine left atrium. These results show that pteleprenine has inhibitory action against nicotinic acetylcholine receptors in the guinea-pig ileum but not in the canine left atrium. Our findings also suggest that pteleprenine might be a novel lead compound as a nicotinic receptor antagonist.     

Experience with flexible video cystoscope equipped with built-in high-frequency cauterizing element for transurethral resection of the bladder

We successfully treated three patients using the flexible video cystoscope (CYF-240A, Olympus, Japan) for superficial bladder cancer under local anesthesia and/or spinal anesthesia. The major advantage of this new technique is that surgeons can use digital pictures and high frequency cauterization. This new system provides good quality of life for bladder cancer patients experiencing frequent recurrences.     

Unfolding of tertiary structures of proteins

The unfolding pathway of lysozyme was investigated by carrying out the computer simulation. Taking into account the simultaneous change of both the dihedral angles ø and of a residue, we explore the detailed features of the conformational energy profiles. The triangle distance map shows that the lysozyme molecule is divided into three domains, 1–40, 41–101 and 102–129 in amino acid residue numbers (referred to as the domains I, II and III, respectively). The calculated unfolding process indicates that in the early stage of unfolding domain III located at the C-terminal begins to be detached from the other two, and then domain I can be unfolded. The long-range interactions between domains I and III stabilize the whole molecule and give the cooperative nature of the folding. The calculated unfolding pathway of lysozyme is consistent with the folding pathway proposed by Anderson & Wetlaufer [J. Biol. Chem. (1976). 251 , 3147–3153] who identified the disulfide bondings in the early stage of the glutathione regeneration. A simplified treatment of unfolding for myoglobin is also discussed in the Appendix.     

Analyses of proliferating cell nuclear antigen-positive cells in hepatocellular carcinoma: Comparisons with clinical findings

Abstract Proliferating tumour cells in 92 patients with hepatocellular carcinoma (HCC) were identified by an immunohistochemical method using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). The rate of PCNA-positive cells in HCC tissues was positively correlated with histological grade and the tumour size and T factor of the tumour.
In order to analyse the relationship between prognostic factors and cumulative survival rate after obtaining tumour specimens, 49 patients whose clinical courses could be followed after needle biopsy were selected for evaluation. These patients were treated by medical therapy alone. Analyses of prognostic factors by Cox's proportional hazard model revealed that the patient's prognosis was significantly correlated with PCNA-positive rates as well as the tumour size and mode of therapy. Moreover, the cumulative survival rates were significantly ( P < 0.001) higher in patients with rates of PCNA-positive cells <15% than in those with ≧ 15%, even when tumour sizes were under 50 mm or tumours demonstrated the same degree of histological differentiation.
These findings indicate that the PCNA-positive rate in biopsied tissues provides useful prognostic information in patients with HCC treated only by medical therapy.