[en] The proliferative response to mitogenic stimulation by splenocytes can be augmented by exposing mice to whole-body, chronic, intermittent low doses of ionizing radiation, referred to here as low-dose irradiation. The purpose of this study was to identify the cell(s) in the spleen which is responsive to the proliferation-augmenting effect of low-dose irradiation, i.e., the cellular target. C57BL/6 mice were subjected to low-dose irradiation or to sham irradiation. Three days after the last exposure, spleens were removed, separated into cell fractions which were nonadherent and adherent to plastic surfaces and reconstituted in various combinations, and their proliferative responses to various mitogens were determined. Highly purified T cells were also used in place of the nonadherent cell fraction in the reconstitution studies. THe target cells were shown to be T cells. The target T cells of low-dose-irradiated mice possessed elevated constitutive levels of HSP070 mRNA and HSP-72, and they responded to T-cell receptor-specific anti-CD3 stimulation by producing more HSP-70 mRNA and HSP-72 and by proliferating more extensively than T cells of sham-irradiated mice. 30 refs., 3 figs., 1 tab

[en] The effect of exposure to tritiated water on Plaque-forming cell (PFC) in spleen of BALB/c mice were studied with the liquid-phase monolayer plaque-forming cell technique. After 3 days exposure with i.p. injected tritiated water at a constant dose rate, the PFCs were inhabited exponentially at a dose range from 0.047 to 1.270 Gy. When the dose reached 1.270 Gy, approximately 99% of the PFCs were killed. There was a similar effect of exposure to the tritiated water on the spleen weight and spleen cell number

No abstract available

No abstract available

[en] The kinetics of post-irradiation haemopoietic tissue recovery was studied by evaluating quantitatively the results from histologic studies of the kinetics of endogenous erythroid spleen colony counts in subserial sections of spleens from mice irradiated with 5, 7 or 9 Gy of ⁶⁰Co γ-rays at intervals of 4, 6, 8, and 10 days following irradiation. Emphasis was put on the individual types of colony-forming cells and on time intervals at which these cells enter into action. Large numbers of rapidly maturing microscopic erythroid colonies appeared between 8 and 10 days after irradiation. From this finding we conclude that in addition to colony-forming cells giving rise to macroscopic colonies, large numbers of already differentiated progenitor cells - the products of the first regeneration wave with a peak approximately 6 days following irradiation -participate in the second wave of regeneration which is typically manifested from day 10 after irradiation. (author). 4 tabs., 23 refs

[en] A case report is presented of a 60 year old man whose prolympocytic leukemia responded to lymphocytapheresis (one procedure) and Splenic irradiation (1 Gy 3 times a week, total dose 10 Gy.) A fast and stable clinical and analytic response was obtained during 12 months. (UK)

[en] The mechanism of splenic incorporation of ⁶⁷Ga in chronic myelocytic leukemia (CML) was evaluated. Nine cases (82%) out of 11 chronic cases of CML, ⁶⁷Ga was incorporated more heavily in spleen more than in bone marrow or in liver. These findings correlated with splenic extramedullary erythropoiesis on ferrokinetic measurements. No splenic images were obtained in 5(62.5%) out of 8 cases with blastic crisis, and in 3 cases (37.5%), splenic uptake was demonstrated, of which uptake was lower than hepatic or bone marrow accumulation. Cellular uptake of ⁶⁷Ga into mononuclear and polymorphonuclear cell fraction in patients with CML was investigated by Ficoll-Hypaque gradient separation. Forty-eight hours after the injection, mononuclear cell fraction which contained CML immature cells had 10.3 times higher radioactivity than polymorphonuclear fraction. Splenic higher radioactivity in chronic phase of CML which mainly depended upon the CML immature cells might suggest splenic extramedullary hematopoiesis. ⁶⁷Ga scintiscan would be useful to detect the splenic extramedullary hematopoiesis without performing splenic biopsy nor ferrokinetic body surface counting measurements. (author)

No abstract available

[en] Spleen cells from untreated young male and female C57BL/6 and C58 mice and of male C3H/He mice showed cytotoxic activity in vitro against BALB/c x-radiation-induced leukemia RL male 1 cells by ⁵¹Cr-releasing lymphocyte-mediated cytotoxicity (LMC) tests, but old mice of these strains lacked LMC activity. In contrast, spleen cells from male and female AKR, BALB/c, and DBA/2 mice, and from female C3H/He mice had no appreciable LMC activity. The proportion of active cells in spleens from young (C57BL/6 x BALB/c)F₁ or reciprocal hybrid mice was higher in females than in males. The specificity of the LMC reaction of RL male 1 cells, determined by LMC inhibition assays, was somewhat different from that of previously reported serologic X.1 tests. Thus the antigen detected by LMC has been tentatively designated X.1'. The main effector cells in this system were uncharacterized cells not adherent to glass surfaces or nylon--wool columns. These findings in RL male 1 leukemia extend the evidence for the presence of naturally occurring LMC. With the single unexplained exception of strain C3H/He, the LMC activity against RL male 1 cells, exhibited by untreated mice of various strains, corresponded with a previous classification of mouse strains immunologically as X.1 responders or as X.1 nonresponders according to their ability to reject X.1-positive leukemia cells. (auth)

[en] The present work extends our previous results on the radiosensitivity of the helper cell function. Two helper cell subpopulations, 1 radiosensitive and the other radioresistant, have been demonstrated in the spleen of mice at different times after priming with HRBC. The radiosensitive subpopulation increases with the increasing time interval between carrier-priming and irradiation. The 2 cell subpopulations have been further characterized by different nylon adherence properties: radioresistant helper cells adhere to nylon wool, whereas radiosensitive cells pass through. The 2 cell subpopulations were separated by x-irradiation and nylon wool filtration, and their helper activity was assessed separately or after recombination. The results favor the notion that 2 functionally independent helper T cells, as characterized by different radiosensitivity and nylon adherence, participate synergistically in the helper activity of primed spleen cells