Identification of Raman spectroscopic markers for the characterization of normal and adenocarcinomatous colonic tissues.

Raman spectroscopy has been recognised as a valuable analytical tool in biological and medical research. This technique allows probing molecular vibrations of samples without external labels or extensive preparation. This non-destructive optical technique can provide rapid and objective and reproducible measurements of sample biochemistry and identify variations that occur between healthy and diseased tissues. In fact, biochemical changes within tissue may either initiate disease or occur as a result of the disease process. The qualitative analysis of such changes provides important clues in the search for a specific diagnosis and the quantitative analysis of biochemical abnormalities is important in measuring the extent of the disease process, designing therapy and evaluating the efficacy of treatment. In this paper, we discuss one medical application of near-infrared Raman microspectroscopic imaging as a diagnostic tool to investigate, ex vivo, the changes between normal and adenocarcinomatous human colonic tissues. Multivariate statistical analysis was applied on these measured data to identify the molecular composition and distribution of lipids, proteins, mucus and collagens in normal and malignant tissue. Unsupervised hierarchical cluster analysis shows two unsupervised distinct clusters that were assigned to normal and adenocarcinomatous in accordance with conventional histopathological examination. The spectral images allowed good correlation between pseudo-color Raman and histopathological features.

[Effects on myointimal proliferation of an antisense oligonucleotide directed against c-myb: specificity of action and consequences on vasoreactivity]. / Effets sur la prolifération myo-intimale d'un oligonucléotide antisens dirigé contre le c-myb: spécificité d'action et conséquences sur la vasoréactivité.

Several reports have shown that an antisense oligonucleotide directed against c-myb (AS 18) inhibits the proliferation of smooth muscle cell. The aims of this study were to confirm the specificity of a new c-myb antisens and to evaluate changes in vasoreactivity following treatment with a c-myb antisense. Five groups of rats were constituted. All underwent desendothelialisation of the abdominal aorta. A solution containing pluronic gel, or one of the following oligonucleotides: AS 18, 15 mere antisense directed against c-myb, an aleatory 4G sequence containing 4 consecutive guanosines, a 15 mere antisense mismatch (n = 11), was applied around the aorta. After 21 days, the thickness and mean surface areas of the media and intima were calculated. Four groups of rats were constituted for the reactivity study: control (A), desendothelialisation (B), desendothelialisation + application of AS 18 (C), and application of AS 18 alone (D). One ring per aorta was sampled at the 21st day and analysed in an organ chamber. The following results were obtained: the thickness and average surface areas of the intima were smaller (p < 0.05) in the 4G and AS 18 groups; in group B, none of the 8 segments responded to acetylcholine; in group C, 6 out of 8 segments responded. The contraction study showed no difference between groups A and D or between B and C. The mode of action of AS 18 antisense of c-myb is non specific but due to the presence of 4 consecutive guanosines in the oligonucleotide. Oligonucleotide with this sequence inhibits myo-intimal hyperplasia and improves endothelium-dependent relaxation in this model without affecting the contraction.

[Effects of an anti-c-myb antisense oligonucleotide on myo-intimal proliferation. Specificity of action and consequences on vasoreactivity]. / Effets sur la prolifération myo-intimale d'un oligonucléotide antisens dirigé contre le c-myb. Spécificité d' action et conséquences sur la vasoréactivité.

Several reports have shown that an 18-mere antisense oligonucleotide directed against c-myb (AS 18) inhibits the proliferation of smooth muscle. The aims of this study were to confirm the specificity of a new anti-c-myb antisense and to evaluate changes in vasoreactivity following treatment with a c-myb antisense. Five groups of rats. All underwent desendothelialisation of the abdominal aorta. A solution containing pluronic gel, or one of the following oligonucleotides: AS 18, 15 mere antisense directed against c-myb, an aleatory 4G sequence containing 4 consecutive guanosines, a 15 mere antisense mismatch (n = 11), was applied around the aorta. After 21 days, the thickness and mean surface areas of the media and intima were calculated. Four groups of rats were constituted for the vasoreactivity study: control (A), desendothelialisation (B), desendothelialisation + application of AS 18 (C) and application of AS 18 alone (D). One ring per aorta was sampled at the 21st day and analysed in an organ chamber. The following results were obtained: the thickness and average surface areas of the intima were smaller (p < 0.05) in the 4G and AS 18-groups; in group B, none of the 8 segments responded to acetylcholine; in group C, 6 out of 8 segments responded. The contraction study showed no differences between groups A and D or between groups B and C. The authors conclude that the mode of action of AS 18 antisense of c-myb is non-specific but due to the presence of 4 consecutive guanosines in the oligonucleotide. Oligonucleotide with this sequence inhibits myo-intimal hyperplasia and improves endothelium-dependent relaxation in this model without affecting the contraction.

[Effect of antisense oligonucleotides on myo-intimal hyperplasia in a model of abdominal aortic injury in the rat]. / Action des oligonucléotides antisens sur l'hyperplasie myo-intimale dans un modèle de traumatisme d'aorte abdominale de rat.

Restenosis at a rate > 30% at 6 months is the major complication of both coronary and peripheral arterial angioplasty. Restenosis is mainly due to proliferation of smooth muscle cells, extracellular matrix and collagen which form a neointima. The proto-oncogene c-myb is a gene with an immediate response which has been implicated in the proliferation and alteration of the phenotype of smooth muscle cells. The antisenses are molecules of single-helix DNA the sequence of which is inverse to that of messenger RNA of the target proto-oncogene. They therefore have the possibility of forming a double helix with the messenger RNA and of preventing its translation. The antisenses of c-myb have already been successfully tested in in vitro and in vivo models of neointimal proliferation. The aim of this study was to demonstrate the efficacy of c-myb antisenses on the proliferation of smooth muscle cells in a model of abdominal aortic injury in the rat. Thirty-five male Wistar rats with an average weight of 350 grams were operated. Smooth muscle cell proliferation was obtained by desendothelialisation of the abdominal aorta from the level of the left renal vein to the aortic bifurcation. Using a randomised, double-blind protocol, 17 rats were given 500 microliters of pluronic gel (control group), 9 a sense oligonucleotide of c-myb in 500 microliters of pluronic gel (sense group) and 9 a c-myb antisense oligonucleide in 500 microliters of pluronic gel (antisense group). Two rats were given fluorescinlabelled antisenses; one was sacrificed 4 hours and the other 24 hours later.(ABSTRACT TRUNCATED AT 250 WORDS)