Photocytotoxicity of a 5-nitrofuran-ethenyl-quinoline antiseptic (Quinifuryl) to P388 mouse leukemia cells

Quinifuryl (MW 449.52), 2-(5' - nitro - 2' - furanyl) ethenyl - 4 - {N - [4' - (N, N - diethylamino) - 1' - methylbutyl] carbamoyl} quinoline, is a water soluble representative of a family of 5 - nitrofuran - ethenyl - quinoline drugs which has been shown to be highly toxic to various lines of transformed cells in the dark. In the present study, the toxicity of Quinifuryl to P388 mouse leukemia cells was compared in the dark and under illumination with visible light (390 - 500 nm). Illumination of water solutions of Quinifuryl (at concentrations ranging from 0.09 to 9.0 aeg/ml ) in the presence of P388 cells resulted in its photodecomposition and was accompanied by elevated cytotoxicity. A significant capacity to kill P388 cells was detected at a drug concentration as low as 0.09 aeg/ml. The toxic effect detected at this drug concentration under illumination exceeded the effect observed in the dark by more than three times. Moreover, the general toxic effect of Quinifuryl, which included cell proliferation arrest, was nearly 100 percent. Both dose- and time-dependent toxic effects were measured under illumination. The LC50 value of Quinifuryl during incubation with P388 cells was approximately 0.45 aeg/ml under illumination for 60 min and less than 12 aeg/ml in the dark. We have demonstrated that the final products of the Quinifuryl photolysis are not toxic, which means that the short-lived intermediates of Quinifuryl photodecomposition are responsible for the phototoxicity of this compound. The data obtained in the present study are the first to indicate photocytotoxicity of a nitroheterocyclic compound and demonstrate the possibility of its application as a photosensitizer drug for photochemotherapy.

Uma nova proposta para o estudo do trânito esofagiano através das técnicas biomagnéticas e cintilográficas / New proposal for esophageal transit study by biomagnetic and scintigraphic techniques

Apresentamos neste trabalho os resultados iniciais de uma nova proposta de aparato para o estudo do tempo de trânsito esofagiano em voluntários assintomáticos de um bolus de alimento-teste AT (10 ml de iogurte) marcado com 5g de pó de ferrita (estudo biomagnético, B) e com 350 MBq de (99m)Tc (estudo cintilográfico, C). Para B este novo aparato consiste de uma configuração de espiras em oposição de fase excitada por um sinal senoidal de 10 kHz. O sinal de resposta é obtido quando o AT passa entre os arranjos de bobinas posicionadas sobre as regiões de interesse (ROIs) do esôfago (fúrcula, F, e apêndice xifóide, X) produzindo um sinal de tensão medido por um amplificador lock-in Stanford SR530. Para C marcamos as ROIs com reparos posicionados sobre F e X. Usamos uma câmara de circulação Orbiter Siemens para as aquisições dinâmicas de deglutição. A análise dos dados foi feita em um microcomputador PC 386. Os resultados foram (4.1+0.7)s para B e (3.7+0.9) s para C (R=0.6, P<0.07)

Abstract - This work shows the initial results for a new apparatus to study the esophageal transit time in assymptomatic persons for a yogurt bolus ( 1 O mi) uniformely labeled with 5g of ferrite powder (biomagnetic study. B) or 350MBq of 99mTc (scintigraphic study, C). For the B study the detection is made by means two pair of coils in opposite phase excited by a 1 O kHz sinusoidal voltage. We obtainted the signal response when the bolus traverses the coils placed on the regions-of-interest (RO!s) of the esophagus (furcula, F, and xiphoid process, X) and produces a signal voltage that is measured by a lock-in amplifier Stanford SR530. For C studies an Orbiter Siemens scintilation camera is used linked to a computer. The data analysis shows a (4.1±0.7)s in B studies and (3.7±0.9) s in C studies ( R=0.6, P<0.07 )