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PubMedDate not supplied

[Does ionizing radiation induce an adaptive response in mouse L5178Y lymphoma cells?].

Growth kinetics of LY-S and LY-R cells (radiosensitive and radioresistant sublines of murine lymphoma L5178Y) has been investigated after beta-irradiation at cumulative doses of 1.5 to 20 cGy and dose rates of 0.8-10 mGy/h. It has been found that after 48 h culture in a complete medium the number of cells differed 5 times, whereas after X- and gamma-irradiation, Do values differed 1.62 times. Using the growth rate as the end point in evaluating the combined effect of beta-irradiation (10 cGy) and subsequent X-irradiation with lethal doses, we observed an increased relative cell number, in comparison to that after X-irradiation alone (an "adaptive response", using this criterion), in LY-S cells irradiated with a dose of 2 Gy. In contrast, when reproductive death of LY-S and LY-R cells the end-point analyzed, the lethal effect of consecutive beta- and X-irradiation in LY-S cells was higher than that expected for X-radiation alone (the synergistic effect).

Animals↗
PubMed2004

Accurate dose calibrator activity measurement of 90Y-ibritumomab tiuxetan.

UNLABELLED: This investigation examined the accuracy of dose calibrator activity measurement of the beta-emitting radiopharmaceutical (90)Y-ibritumomab tiuxetan. METHODS: Five different facilities independently measured (90)Y in a 10-mL syringe geometry with 30 dose calibrator models from 3 different manufacturers. The activities ranged from 81.4 MBq (2.2 mCi) to 1,406 MBq (38 mCi) over the volume range of 3-9 mL. RESULTS: The mean dial settings for (90)Y measurement were 375, 51 x 10, and 897 x 100 for Atomlab, CRC, and Mark V dose calibrators, respectively. The maximum volume dependence was 0.28%/mL. CONCLUSION: This study demonstrated that when measuring all volumes of (90)Y-ibritumomab tiuxetan activity prescriptions, only a single dial setting for a given manufacturer's dose calibrator is required for accurate measurements. Volume corrections are not necessary. For best accuracy, an individually determined dial value should be used.

Antibodies, Monoclonal↗
PubMed2004

[Analysis of curative result for keloid with integrated methods].

OBJECTIVE: To study the curative effects of keloid by operation combined with postoperative beta radiation and silicone gel sheeting. METHODS: From 1996 to 2002, 598 patients with keloid (243 males, 355 females, aging 15-55 years with an average of 28.6 years) were treated by integrated therapy. Their disease courses were from 6 months to 6 years. The keloid area ranged from 1.0 cm x 1.5 cm-8.0 cm x 15 cm. First, keloid was removed by operation, and then the wounds were sutured directly (group suture) or covered with skin graft (group graft). In group suture, the operational sites were managed by beta ray radiotherapy 24-48 hours after operation. The total doses of radiation were 12-15 Gy, 5 times 1 week (group suture A) and 10 times 2 weeks (group suture B). Radiotherapy was not taken until stitches were taken out in group graft, and then the same methods were adopted as group suture B. After radiotherapy, silicone gel sheeting was used in 325 cases for 3-6 months. RESULTS: All patients were followed up for 12-18 months. (1) The overall efficacy was 91.3% in group suture A (n = 196), and 95.8% in group suture B (n = 383), respectively. There was significant difference between the two groups (P < 0.01). (2) Radiotherapy was of no effect in 6 cases of group graft (n = 19). (3) Silicone gel sheeting had effectiveness in 185 cases. Silicone gel sheeting had no obvious effect on the overall efficacy, but it could improve the quality of texture and color of skin. CONCLUSION: By use of integrated methods to treat keloid, if the wound can be sutured directly, skin grafting should not be adopted. The results in group suture B are better than those in group suture A; silicone gel sheeting should be used as possible.

Adolescent↗
PubMed2004

The "edge effect" after implantation of beta-emitting (55Co) stents with high initial activity.

The aim of this study was to evaluate the incidence and the cause of "edge restenosis" after implantation of high activity 41.1 microCi +/- 1.2 microCi = 1520 kBq +/- 44 kBq, beta-emitting (55Co) stents. Proton bombarding in cyclotron has brought the radioactivity. Intravascular ultrasound (IVUS) investigation has been completed in 10 patients. The angiographies performed at 6 month revealed restenosis >50% in 5 cases (50%). The analysis of edges (5 mm distally and proximally to the last stent struts) showed no significant changes in TVV (187.3 +/- 62.60 mm3 and 176.9 +/- 53.5 mm3) but PMV increase significantly (i.e. neointimal proliferation) from 61.9 +/- 31.2 mm3 to 82.2 +/- 43.4 mm3 (p<0.04) and was the major contributor (from 66%) to lumen volume loss (125.4 +/- 40.7 mm3 and 94.7 +/- 22.2 mm3, p<0.02). In conclusion, neither statistically significant positive nor negative remodelling at the "stent edges", were present. Statistically significant increase in plaque +/- media volume (i.e. neointimal hyperplasia) and reduction in lumen volume were found. The cause of "edge restenosis" was especially (from 66%) due to increase in plaque +/- media volume (i.e. neointimal hyperplasia). Probably, main reason for "edge effect"/neointimal hyperplasia was in this trial sharp fall-off in radiation at the edges of the stents.

Aged↗
PubMedDate not supplied

[Influence of beta-radiation on human erythrocyte surface potential under eicosanoid metabolism inhibition].

The aim of the research consisted in the study of influence of beta-radiation on response of erythrocyte surface potential to inhibitors of eicosanoid metabolism enzymes (cyclo-, lipoxygenase and phospholipase A2). It was shown, that inhibitors of phospholipase A2 (quinacrine, 10-100 microM), cyclooxygenase (aspirin, 10-100 microM) and cyclo- and lipoxygenase (BW755c, 1-100 microM) lowered electrophoretic mobility (EPM) of erythrocytes by 20-30%. An analogous effect can be exerted by beta-radiation. Nonradioactive leucine in the studied concentrations cannot simulate EPM erythrocytes. Response of cellular EPM to these inhibitors depended on their concentration in the incubation medium. Addition of 14C to the incubation medium changed response of EPM of cells to inhibitors of cyclo- and lipoxygenase but not to quinacrine. However beta-radiation fully abolished the stimulative action of nonspecific activator of phospholipase A2 (Ca-independent), H2O2, on cellular EPM. Under these conditions beta-radiation enhanced EPM response to aspirin only at concentration of 100 microM. The EPM response to BW755c is reduced by irradiation at all concentrations with the exception of equal-effective one (10 microM). Data obtained evidence for modification of eicosanoid metabolism by beta-radiation, probably, as a result of phospholipase A2 inhibition, as evident from elimination by radiation of stimulated action of hydrogen peroxide on EPM. The radiation action can also affect the cyclooxygenase lipoxygenase activity ratio, this activity being mediated by cellular membrane signaling systems.

Beta Particles↗