N-[2-[(substituted chroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylamines: synthesis and wide range of antagonism at the human 5-HT1A receptor.

A series of N-[2-[(substituted chroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylamines was prepared and examined for their 5-HT1A receptor antagonist activity. The parent compound 3a and seven analogs bearing five kinds of substituents on the chroman ring were prepared from the corresponding 8-hydroxychroman intermediates. Radioligand binding assays proved the compounds 3a-h to have high affinity for the rat hippocampal 5-HT1A receptor with varied selectivity for adrenaline alpha1 and dopamine D2 receptors. Their antagonism was evaluated in a forskolin-stimulated adenylate cyclase assay performed with CHO cells expressing the human 5-HT1A receptor. Among the series, the C6-fluoro analog 3c showed both extremely potent affinity (Ki = 0.22 nM) and antagonism (EC50 = 13 nM) for the 5-HT1A receptor. Correlation analysis using substituent descriptors revealed a linear and negative correlation between molar refractivity of the C6-substituent and the binding affinity expressed in pKi.

Synthesis and pharmacological characterization of novel 6-fluorochroman derivatives as potential 5-HT1A receptor antagonists.

A series of novel 6-fluorochroman derivatives was prepared and evaluated as antagonists for the 5-HT1A receptor. N-2-[[(6-Fluorochroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylami ne (3; J. Med. Chem. 1997, 40, 1252-1257) was chosen as a lead, and structural modifications were done on the aliphatic portion of the chroman ring, the tether linking the middle amine and the terminal aromatic ring, the aromatic ring, and lastly the amine. Radioligand binding assays proved that the majority of the novel compounds behaved as good to excellent ligands at the 5-HT1A receptor, some of which were selective with respect to alpha1-adrenergic and D2-dopaminergic receptors. The antagonist activity of the compounds was assessed in the forskolin-stimulated adenylate cyclase assays in CHO cells expressing the human 5-HT1A receptors. Among the modifications attempted, introduction of an oxo or an optically active hydroxy moiety at the chroman C-4 position was effective in ameliorating the receptor selectivity. Six analogues were selected through the in vitro screens and further evaluated for their in vivo activities. A 4-oxochroman derivative (31n), having a terminal 1, 3-benzodioxole ring, demonstrated antagonist activities toward 8-OH-DPAT-induced behavioral and electrophysiological responses in rats.

A circular dichroic spectral study on disulfide-reduced pancreatic ribonuclease A and its renaturation to the active enzyme.

Disulfide-reduced RNase A, which could be reoxidized to give the native enzyme, was shown to have a CD spectrum quite different from that of the native enzyme or a random coil. Disulfide-reduced and fully cysteine-S-carboxamidomethylated RNase A because the derivative was stable and gave a spectrum identical to that of reduced RNase A. Curve-fitting analyses showed the presence of 14% alpha-helix and 25% beta-structure in this open chain derivative of RNase A. The time dependence of CD spectra during the oxidative renaturation of reduced RNase A was analyzed and changes in alpha-helical and beta-structure contents during the reaction were estimated. It was shown that the change in the content of beta-structure was slower than that of alpha-helix content and approximately paralleled the appearance of the enzymatic activity.

[Deep-seated fungal infection in surgery].

In surgery, deep-seated fungal infection is not rare. In our institute, fungal infection was analyzed during postoperative periods. As pathogen, fungus was the second frequent pathogen after the operations for esophageal cancer and gastric cancer, and the third pathogen after hepatobiliopancreatic cancer and colon cancer. Furthermore, fungus was found more frequently pathogen from distant infection than that from local foci. Especially in CV catheter sepsis, fungus was main pathogen (60 %). In order to inhibit CV catheter sepsis, nutrition support team (NST) has been induced in our institute for prevention of external pathway of fungus. After NST, the frequency of CV catheter sepsis decreased from 12 % to 3.6 %, and the isolated frequency of fungus in catheter sepsis patients also decreased from 84 % to 16 %, respectively. It demonstrates that the activity of NST successfully prevents the external pathway of fungus in CV catheter indwelling patients. However, internal pathway (fungal translocation) still remains, and that issue has to be overcome. Molecular biological technique was applied for diagnosis of fungemia. PCR-RFLPs was performed by using specific primer of 18s rRNA in V4 region. Clinical samples were applied for PCR-RFLPs, and antifungal therapy was performed according as the results of PCR-RFLPs. It indicated that molecular biological technique was useful for diagnosis of fungemia.

Drug resistance and cross-sensitivity in cultured human osteosarcoma cells.

The sensitivity, cross-sensitivity, acquired resistance and restoration of sensitivity to adriamycin (ADR) in cultured human osteosarcoma (OST) cells were studied from the viewpoints of cell proliferation and cell cycle pattern by flow cytometry. OST cells resistant to ADR were produced by a treatment which consists of a 40-hour exposure to high doses of ADR and subsequent cultivation for 6 weeks and was repeated five times. ADR-resistant cells showed cross-resistance to methotrexate (MTX), and vincristine (VCR), and collateral sensitivity to cisplatin (CDDP). Treatment of the ADR-resistant cells with ADR and verapamil, a Ca-antagonist, resulted in an increased inhibition of sarcoma cell growth.