Cytotoxicity of cobalt complexes of furan oximes in murine and human tissue‐cultured cell lines

The copper complexes of 2‐furaldehyde and furan oximes have previously demonstrated potent cytotoxicity, L1210 DNA synthesis inhibition, DNA topoisomerase II inhibition and DNA fragmentation. Currently a series of cobalt metal complexes of 2‐furaldehyde oximes were compared with copper complexes of furan oximes to determine whether the type of metal is important to the cytotoxicity and mode of action of the complexes. The cobalt complexes of furan oximes, like the copper complexes, were shown to be cytotoxic to suspended tumor cell lines, e.g. leukemias, lymphomas, acute monocytic leukemia and HeLa‐S³ uterine carcinoma. The cobalt complexes did not demonstrate dramatic cytotoxicity against the growth of tumors derived from solid human tumor lines. The cobalt complexes preferentially inhibited L1210 DNA synthesis, followed by inhibition of RNA and protein synthesis from 25 to 100 µM over 60 min. These agents, like the copper complexes of 2‐furaldehyde and furan oximes, were inhibitors of DNA polymerase α activity and de novo purine synthesis with marginal inhibition of ribonucleoside reductase and dihydrofolate reductase activities with DNA fragmentation. Unlike the copper complexes, the cobalt complexes did not inhibit L1210 DNA topoisomerase II activity but did reduce thymidylate synthetase activity. Thus, varying the type of metal within the complexes of 2‐furaldehyde and furan oximes produces differences in both cytotoxicity and mode of action. Copyright © 1999 John Wiley & Sons, Ltd.     

Partition graphs for finite symmetric groups

This paper outlines an investigation of a class of arc-transitive graphs admitting a finite symmetric group S_n acting primitively on vertices, with vertex-stabilizer isomorphic to the wreath product S_m wr S_r (preserving a partition of {1,2,…n} into r parts of equal size m). Several properties of these graphs are considered, including their correspondence with r × r matrices with constant row- and column-sums equal to m, their girth, and the local action of the vertex-stabilizer. Also, it is shown that the only instance where S_n acts transitively on 2-arcs occurs in the case m = r = 2. © 1997 John Wiley & Sons, Inc. J Graph Theory 25: 107–117, 1997     

On the distance between distinct group Latin squares

In an article in 1992, Drápal addressed the question of how far apart the multiplication tables of two groups can be? In this article we continue this investigation; in particular, we study the interaction between partial equalities in the multiplication tables of the two groups and their subgroup structure. © 1997 John Wiley & Sons, Inc. J Combin Designs 5: 235–248, 1997     

Effect of Nasal Decongestion on Voice Spectrum of a Nasal Consonant-Vowel

The nasal cavity and its related structures make significant contributions to human phonation, especially the resonance of voice spectra. The voice spectra of the nasal consonant-vowel (CV), [md:], in the subjects with nasal obstruction were obtained and were compared with the spectra of the same CV vocalized by the same subjects after topical nasal decongestion treatment with 1:1000 epinephrine solution. Results revealed that the intensity damping was more marked in the high-frequency area (>1600 Hz) after the nasal decongestion. Moreover, the intensities of the spectral valleys damped more than the spectral peaks, especially the spectral valley of 1000-2700 Hz. Therefore, a more complex spectral pattern was formed by the resultant uneven damping effect after nasal decongestion. The nasal cavity plays an important role in the formation of spectral peaks and valleys, and such engraved voice spectra may also characterize nasal voices like the nasal CV [md:] demonstrated in our study.