Different instability of nuclear DNA at acid hydrolysis in cancerous and noncancerous cells as revealed by fluorescent staining with acridine orange

Hexaphenyl-1,3-butadiene derivative: a novel “turn-on” rapid fluorescent probe for intraoperative pathological diagnosis of hepatocellular carcinoma

The staining method based on AIE-active ZZ-HPB-NC can simple distinguish the hepatocellular carcinoma from liver noncancerous tissue, which overcomes the drawbacks of the poor anti-interference ability of the authoritative clinical H&E technique.

Determination of red cells, nucleic acid-containing cells and platelets (RNP Determination) by a crossover analysis of emission DNA/RNA light

We developed a new flow cytometry analysis method using a crossover analysis of emission light from intracellular DNA/RNA. Both the RNA and the DNA content in each cell were new parameters obtained by fluorescence analysis using acridine orange supravital stain. With this method, two-dimensional diagrams produced by cellular RNA concentration (CRc) and cellular DNA concentration (CDc) enabled clear separation of red cells and platelets, and the diagram (RNP Diagram) also distinguished fluorescently stained blood cells and small particles derived from background dust of the reagent. This study assessed the capability of RNP Determination concerning reticulocyte count and accurate platelet count obtained by the ratio of red cells and platelets. The distance of each event between red cell distribution and platelet distribution was sufficiently large on the diagram, and the two regions did not overlap. Both reticulocyte count and platelet count showed excellent correlation with those obtained by their respective reference methods. In conclusion, this new assay, using RNP Determination, demonstrated great potential for detecting abnormalities of red cells and platelets.

Microfluorocytometric detection of nuclear DNA damage to cancer cells in squamous cell carcinoma after hyperthermia

An 84-year-old woman had a squamous cell carcinoma on her left thigh. Before operation, half of the tumor mass was irradiated with a microwave at 43 degrees C for an hour. After the hyperthermia, the tumor mass was removed, and the DNA instability was investigated by microfluorocytometric measurement of the cells stained with pararosaniline-Feulgen after hydrolysis with 2N HCl at 30 degrees C. The kinetic parameters k1, which is the rate constant for the generation of an apurinic acid, k2, which is the rate constant for the depolymerization of the apurinic acid and which reflects the degree of DNA instability for acid hydrolysis, and y0, which is the theoretical value of the single-stranded DNA present initially and reflects the degree of DNA damage, were determined by a computer fitting of the Bateman function to the hydrolysis curve plotting of the fluorescence intensity of the pararosaniline-Feulgen staining the apurinic acid against the different hydrolysis times. The parameter values y0 and k2 of the cells treated by hyperthermia were much higher than those of the cells treated without hyperthermia. It is our conclusion that this microfluorometric detection would be valuable as an evaluation method for a cancer therapy, although more data from other cancers and treatments will be needed.

A histological and flow cytometric study of dog brain endothelial cell injuries in delayed radiation necrosis

The pathogenesis of delayed cerebral radiation necrosis was studied histologically and biochemically in 25 dogs with special attention to vascular endothelial cell injuries. The dogs were sacrificed 3 to 30 months after irradiation with a single dose of 15 Gy to the head. Brain specimens were appropriately fixed for light and electron microscopic studies, and capillary endothelial cells were isolated for flow cytometric study. The endothelial cells were stained with acridine orange, then the cell ratios in the reproductive phase (S + G2 + M) were investigated with flow cytometry. Thereafter, Feulgen hydrolysis and computer analysis of the hydrolysis curves were performed to examine the qualitative changes in deoxyribonucleic acid (DNA) of endothelial cells after irradiation. Under light microscopy, spongy degeneration with small cell infiltration was observed, especially in the frontal white matter, at 6 months after irradiation. At 9 months, necrotic foci appeared and developed until 15 months after irradiation. Blood vessels around the necrotic area showed luminal narrowing with endothelial hyperplasia and proliferation. At 30 months, no fresh necrotic lesions were observed. Under electron microscopy, endothelial cells of capillaries and small vessels around the necrotic area showed an increase of pinocytosis, and in the nuclei there was an increase of infoldings and euchromatin. The cell ratios in the reproductive phase were 14.5% to 23.3% (maximum at 9 months) in the irradiated group compared to 6.4% in the control group. The rate constant of apurinic acid production, a parameter correlating with DNA transcriptional activity, was minimum at 3 months and maximum at 9 months after irradiation. The data suggest that impairment of the microcirculation plays an important role in the pathogenesis of delayed radiation necrosis, and that the time of necrosis occurrence closely correlates with the cell cycle of vascular endothelial cells.

Rapid in vitro transformation system for liver epithelial cells by iron chelate, Fe-NTA

We have previously found toxic effects of iron chelate, Fe-NTA on cultured normal rat liver epithelial cells (RL34). In the present study, when RL34 cells were exposed to 50 micrograms/ml iron of Fe-NTA for 15 days, besides the expected cytolytic effects in most cells, the appearance of resistant cells was observed. The resistant cells showed drastic morphological transformation, grew in soft agar, and induced hepatocellular carcinomas when transplanted into syngeneic newborn rats in a short period of time. Since DNA instability in the transformed cells was ascertained by differential AO staining, it is suggested that DNA damage by Fe-NTA is of a critical importance for extremely rapid neoplastic transformation of normal epithelial cells.