Changes in the tumorigenic and metastatic properties of tumor cells treated with quercetin or 5-azacytidine

The effect of quercetin, a flavonoid derivative, on the transplantability (tumorigenicity) and metastatic behavior of mouse tumor cells was studied. BMT-11 c1-9 fibrosarcoma cells were treated in vitro with quercetin, and after cloning by limiting dilution, cell suspensions of each clone were injected subcutaneously (s.c.) into syngeneic C57BL/6 mice at a dose of 2 X 10(5) cells per mouse. Out of 17 clones examined, 8 were nontumorigenic in normal mice ("regressor" clones), whereas these clones were able to grow in immunosuppressed (600-rad-irradiated) mice. Furthermore, 1 out of 9 tumorigenic clones metastasized spontaneously to the lungs despite the very low metastatic potential of the parent BMT-11 c1-9 cells. In contrast, all 15 clones selected from the untreated parental line grew progressively in normal mice with no evidence of metastases. The appearance of both regressor and metastatic clones was also observed after treatment with a DNA hypomethylating agent, 5-azacytidine. These altered phenotypes resulting from treatment with both chemicals, however, were not necessarily stable if maintained in culture for several months. The data suggest that quercetin may be a useful new material for obtaining regressor or metastatic clones from parental tumor lines.     

Changes in circulating blood volume following isoflurane or sevoflurane anesthesia

Changes of circulating blood volume (CB volume) measured by the dual indicator dilution method were observed in 33 chronically instrumented mongrel dogs following either alpha-chloralose-urethane (C group), additive isoflurane (I group) or sevoflurane anesthesia (S group). These anesthetic groups were each divided into two subgroups with regard to respiratory care, namely Cp, Ip and Sp for those with intermittent positive pressure ventilation (six animals per subgroups), and Cs, Is and Ss for those with spontaneous breathing (five animals per subgroups).The CB volume under positive pressure ventilation remained unchanged in the Ip and Sp groups at both 0.5 and 1.0 MAC, and in the Cp group. The CB volume remained essentially unchanged in the Cs and Is groups at both 0.5 or 1.0 MAC, but the plasma volume tended to increase slightly in the Is group at 1.0 MAC.In the Ss group under spontaneous breathing, however, the CB volume increased from 84.4 ± 7.0 to 91.4 ± 7.7 at 0.5 MAC, and to 91.4 ± 10.2ml·kg^–1 at 1.0 MAC (0.01 P 0.05). These increases were caused by an increase in the plasma volume.The above data suggests that a concomitant increase in the venous pressure associated with an increase in the intrathoracic pressure produced by positive pressure ventilation would attenuate changes in the CB volume during sevoflurane anesthesia.(Hamada H, Takaori M, Kimura K, et al.: Changes in circulating Blood volume following isoflurane or sevoflurane anesthesia. J Anesth 7: 316–324, 1993)     

Early detection of the no-reflow phenomenon in reperfused acute myocardial infarction using technetium-99m tetrofosmin imaging

Evaluation of myocardial perfusion in the early stage of acute myocardial infarction (MI) is clinically important for adjunctive therapies to minimize infarct size. To determine the role of early scintigraphic detection of impaired myocardial reperfusion after primary coronary angioplasty (PTCA) in patients with acute MI, semiquantitative technetium-99m tetrofosmin single-photon emission tomographic (SPET) imaging was performed before primary PTCA (before; area at risk), 60 min after PTCA (after) and at 1 month (1 M; final infarct) in 35 patients with acute MI. The left ventricle was divided into 13 segments and the defect score was calculated as the sum of the perfusion defect of each segment, from 3 (complete defect) to 0 (normal perfusion). A significant myocardial perfusion change after PTCA was defined as a change in the defect score (before minus after PTCA) of >/=4. The echocardiographic asynergic score was defined as the number of asynergic (severe hypokinetic or akinetic) segments corresponding to the analogous segments on SPET images, and recovery of wall motion was calculated as absolute change in the asynergic score (before PTCA minus 1 M). Among the 35 patients, 15 (43%) had a change in the defect score of <4 (no reflow: group 1) while 20 had a change in the defect score of >/=4 (reflow: group 2). There were no significant differences between the two groups with respect to the time between admission to PTCA, revascularization time, collateral grade or Thrombolysis in Myocardial Infarction (TIMI) flow grade before PTCA. Despite the lack of a difference in area at risk between the two groups (group 1 = 12.8+/-4.3 and group 2 = 15.1+/-4.7), final infarct size in group 1 was significantly larger compared with that in group 2 (8.1+/-4.3 vs 4.9+/-3.0, P<0.001). Recovery of wall motion was significantly smaller in group 1 than in group 2 (4.3+/-1.7 to 3.5+/-1.5 vs 4. 1+/-2.1 to 1.6+/-1.6, P<0.001). In conclusion, a small change (<4) in defect score (scintigraphic no-reflow phenomenon) after primary PTCA indicates persisting impaired myocardial perfusion or irreversible cellular damage just after PTCA which is associated with poor recovery of wall motion, as compared with that observed in cases of reflow (>/=4 in defect score).     

Adjuvant immunotherapy using fibroblasts genetically engineered to secrete interleukin 12 prevents recurrence after surgical resection of established tumors in a murine adenocarcinoma model

BACKGROUND: To explore effective therapeutic strategy against cancer of the gastrointestinal tract, tumor vaccination using fibroblasts secreting interleukin-12 (IL-12) was developed as an adjuvant therapy against murine tumor after surgical resection. METHODS: Initially, IL-12 was genetically engineered into fibroblasts (IL-12/3T3 cells), and then we evaluated in vivo and in vitro antitumor effects. In the vaccination model, irradiated C-26 tumor mass was reinoculated intradermally with IL-12/3T3 cells in mice as a tumor vaccine to examine how much it suppresses tumor recurrence. RESULTS: IL-12/3T3 cells producing 7.2 ng/10(6) cells/24 h murine IL-12 in vitro exerted dose-dependent potent tumor suppression when coinoculated with C-26 cells in vivo. Specific immunity was also acquired in 63% of mice in vivo. In the vaccination model, protective immunity was developed in 70% of mice that were inoculated with irradiated tumor mass and IL-12/3T3 cells. In addition, local recurrence was not observed in vaccinated mice, although 44% of control mice had recurrence. CONCLUSIONS: Coinoculation of genetically engineered fibroblasts secreting IL-12 with irradiated tumor mass was proved to be an effective tumor vaccine. This system of vaccination is easily applicable to clinical situations, particularly to human gastrointestinal tract cancers.