A new model of pre-B acute lymphoblastic leukemia chemically induced in rats

Assessing the potential leukemogenic effects of 50 Hz magnetic fields and their harmonics using an animal leukemia model

To answer the still unresolved question of the possible leukemogenic effects of extremely low frequency magnetic fields (ELF-MFs) and of their harmonics on the incidence of B acute lymphoblastic leukemia in children, we used an animal model to explore the possible co-initiating or co-promoting effects of ELF-MFs on the development of leukemia. We used a rat model in which B acute lymphoblastic leukemia is chemically induced by a nitrosurea derivative. From the onset of the chemical treatment, the animals were also exposed to ELF-MFs (100 microT, sinusoidal 50 Hz MFs), with or without harmonics. The experiment was conducted on 280 rats. We compared body weight and survival time, percentage of bone marrow blast cells, cumulative incidence of leukemia and type of leukemia in the unexposed groups and in the groups exposed to 50 Hz MFs, with and without harmonics. The results showed no significant differences between exposed and unexposed rats for any of these parameters (p > 0.05). Significant changes in the leukemia type obtained after gamma-irradiation of the leukemia model, showed its sensitivity to a physical agent. Our results do not support the hypothesis that ELF-MFs, with or without harmonics, affect the development of B acute lymphoblastic leukemia in children.

A novel nude mice model of human extranodal nasal type NK/T-cell lymphoma

A novel nude mice model of human extranodal nasal type NK/T-cell lymphoma was established by subcutaneously implanting the sample taken from the patient with secondary extranodal nasal type NK/T-cell lymphoma of the stomach into the right axillary region of a BALB/c (nu/nu) nude mouse. This model had been successfully transplanted in vivo for thirty-two generations with a stable growth cycle. The survival rates of both resuscitation and transplantation were 100%. Histologically, the tumor cells were medium to large size and arranged in sheets, with a little mesenchyma, and disseminated almost in all passages of the lymphoma-bearing nude mice. Immunologically, the tumor cells were positive for CD56, cytoplasmic CD3, granzyme B or TIA-1 and LMP1, sometimes for CD8 but negative for surface CD3, CD7, CD20 and CD1a. EBER1/2 was found. No T-cell receptor gamma gene rearrangement was detected in the transplanted tumors. Furthermore, both human sequencing-tagged sites SY14 and Y chromosome were detected by PCR or fluorescent in situ hybridization, respectively, in the transplanted tumor. The transplanted tumor in this novel nude mice model maintained the essential features of human extranodal nasal type NK/T-cell lymphoma, and it would be an ideal tool in vivo for further research of the tumor.