Oxidative dna damage of lymphocytes in peripheral blood and ascites in cancer patients

BACKGROUND

Patients with malignant ascites (ma) usually experience poor quality of life, and treatment of this symptom remains a challenge. Oxidative stress, which can cause oxidative damage to dna, plays a pivotal role in carcinogenesis; however, the relationship between oxidative stress and dna damage to tumour-associated lymphocytes (tals) in ma is unclear.

METHODS

We measured the total antioxidant capacity (tac) of plasma and ma supernatant in 31 cancer patients with ma, and we used a comet assay to assess dna damage to both peripheral blood mononuclear cells (pbmcs) and tals. Measurements in age- and sex-matched healthy volunteers were used as controls.

RESULTS

The tac of plasma was remarkably lower in cancer patients (9.73 ± 1.96 U/mL) than in healthy control subjects (11.31 ± 1.50 U/mL, p < 0.001). The tac of ma supernatant (6.34 ± 1.57 U/mL) was significantly lower than that of plasma in cancer patients (7.42 ± 1.36 U/mL, p < 0.001). The comet percentage of pbmcs was higher in cancer patients (17.26% ± 6.04%) than in healthy control subjects (9.44% ± 4.47%, p < 0.01). In cancer patients, the comet percentage of tals (36.14% ± 17.85%) was significantly higher than that of pbmcs (17.26% ± 6.04%, p < 0.001). In cancer patients with ma, negative correlations were observed between plasma tac and dna damage to pbmcs (r = -0.505, p = 0.004) and between the tac of ma supernatant and the comet percentage of tals (r = -0.588, p = 0.001).

CONCLUSIONS

Results indicate the presence of significant oxidative damage to the dna of lymphocytes in peripheral blood and ascites from patients with ma, being especially higher in the cells from ascites. The lower tac of ma supernatant may be related to a higher degree of dna damage to tals. The present study suggests that an oxidant-antioxidant imbalance may be one of the mechanisms leading to the dna damage detected in peripheral blood and local tals in patients with ma, which may provide a novel approach to the treatment of ma.

Successful allogeneic bone marrow transplantation (BMT) by injection of bone marrow cells via portal vein: stromal cells as BMT-facilitating cells

We examined the importance of the coadministration of bone marrow (BM) stromal cells with BM cells via the portal vein. A significant increase in the number of day-14 colony-forming unit-spleen (CFU-S) was observed in the recipient mice injected with hemopoietic stem cells (HSCs) along with donor BM stromal cells obtained after three to four weeks of culture. Histological examination revealed that hematopoietic colonies composed of both donor hemopoietic cells and stromal cells coexist in the liver of these mice. However, when donor HSCs plus BM stromal cells were administered i.v., neither the stimulatory effects on CFU-S formation nor the hemopoietic colonies in the recipient liver were observed. These findings suggest that the interaction of HSCs with stromal cells in the liver is the first crucial step for successful engraftment of allogeneic HSCs. It is likely that donor stromal cells and HSCs trapped in the liver migrate into the recipient BM and spleen, where they form CFU-BM and CFU-S, respectively.

The decomposition and aggregation of rat lens protein induced by selenite in vitro and in vivo

A single subcutaneous injection of sodium selenite at the dose of 20 mumol/kg body weight induced bilateral nuclear cataracts in suckling rats. This selenite-induced cataract incidence can be increased by pretreating animals with a glutathione synthesis inhibitor. Sodium dodecyl sulfate polyacrylamide electrophoresis of urea-soluble proteins from selenite-induced cataractous lenses showed the appearance of high molecular weight aggregates and decomposed products of lens proteins. These products were found in association with the emergence of a 45 K band. Incubation of water-soluble lens proteins with selenite in vitro produced changes similar to those demonstrated in selenite-induced cataractous lenses. Furthermore, selenite induced the gradual development of opalescence and the oxidation of sulfhydryl in the lens protein solution. Therefore, we presume that the oxidation of lens protein sulfhydryl by selenite is associated with both aggregate formation and the decomposition of lens proteins, and that these changes may provide a partial explanation for the mechanism of selenite cataract.

Detection of Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, in dialysis fluid of patients with uremia

In order to estimate the exposure levels of mutagenic and carcinogenic heterocyclic amines in humans, we developed a high-performance liquid chromatography method to detect 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in dialysis fluid of patients with uremia. Using this methods, dialysis fluid of 12 patients who had received hemodialysis treatment or continuous ambulatory peritoneal dialysis was examined. Trp-P-1 was detected in dialysate of all uremic patients (727 +/- 282 pmoles, n = 12). In patients who had been treated with continuous ambulatory peritoneal dialysis, the average amount of Trp-P-1 found in whole dialysate (6 l) per day was 710 +/- 203 pmoles (mean +/- S.D., n = 8). Moreover, Trp-P-2 could be detected in 5 out of 12 patients (206 +/- 85 pmoles, n = 5). These results indicate that patients with uremia are actually exposed to carcinogenic tryptophan pyrolysis products. The average exposure level of Trp-P-1 in uremic patients apparently exceeded 710 pmoles (150 ng) per day.