The secondary structure and composition of
protein in the tissues of benign and malignant
astrocytomas were determined by reflectance Fourier-transform infrared (FT-IR) microspectroscopy. The peak maximum of IR spectra of the tissues from recurrent malignant
astrocytoma markedly appeared at higher frequency (1655 or 1663 cm(-1)), which was significantly different from that of the tissues from benign
astrocytoma at 1651 cm(-1) and tissues from malignant
astrocytoma at 1652 cm(-1). Malignant
astrocytoma indicated slightly different compositions in the
protein secondary structure from benign
astrocytoma. However, a significant increase in beta-turn structure but a marked decrease in beta-sheet and random coil structures were observed in the
protein secondary structure of the recurrent malignant
astrocytoma. The phenomenon was more pronounced in recurrent malignant
astrocytoma pretreated with radiation and
chemotherapy. The rapid cell proliferation and cell differentiation of malignant
astrocytoma with or without recurrence might be the possible explanations for the different compositions of
protein conformational structures.