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Volume 34 (1993)
- Issue 4 Pages 269-
- Issue 3 Pages 195-
- Issue 2 Pages 141-
- Issue 1 Pages 1-
Volume 34, Issue 2
Displaying 1-5 of 5 articles from this issue
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ATTILA TAKÁTS, VU HOA BINH, KATALIN OFFENMÜLLER, KATALIN B ...1993 Volume 34 Issue 2 Pages 141-147
Published: June 15, 1993
Released on J-STAGE: May 24, 2006
JOURNAL FREE ACCESSA dose dependent but not parallel decreases were observed both in SH content and catalytic activity of “free” catalytic subunit after irradiation (0-3200 Gy), while SH groups of membrane-associated adenylate cyclase were insensitive (under 3200 Gy). An initial “radioactivation” of membrane-associated enzyme was found under 800 Gy, then an inhibition above 1600 Gy.
The SH alkylating agent, N-ethylmaleimide resulted in a complete inactivation, both of membrane associated form of adenylate cyclase and “free” catalytic subunit with similar inactivation profiles. These data indicate that in the radiosensitivity or “radioprotection” of adenylate cyclase, its membrane association/ integration might play a more important role than the SH groups themselves.View full abstractDownload PDF (285K) -
CHIDORI MURAISO, JOHN S. MUDGETT, HIROMICHI MATSUDAIRA, GARY F. STRNIS ...1993 Volume 34 Issue 2 Pages 148-156
Published: June 15, 1993
Released on J-STAGE: May 24, 2006
JOURNAL FREE ACCESSA shuttle vector system was developed to quantitate and analyze ionizing radiation-induced mutation in mammalian host cells, COS-1 and CV-1. The shuttle vector pSV2-lacY, which was constructed to detect both point mutations and deletions, was irradiated in vitro with 60Co gamma rays before introduction into unirradiated host cells. The plasmid was then isolated and reintroduced into HB101 (lacY-) bacterial host cells for identification of mutated lacY marker genes. Gamma-irradiation produced a decrease of the survival (recovery) and an increase of mutation of the shuttle vector. The mutated shuttle vector molecules were examined for structural changes by means of restriction endonuclease digestion and agarose gel electrophoresis. A dose dependent increase was observed in the percentages of gross alteration events of total mutations in mammalian host. This system will be useful for studies of ionizing radiation-induced mutagenesis.View full abstractDownload PDF (375K) -
YOSHIHISA KUBOTA, HIROSHI SATO, CHIHIRO KOSHIMOTO, SENTARO TAKAHASHI1993 Volume 34 Issue 2 Pages 157-163
Published: June 15, 1993
Released on J-STAGE: May 24, 2006
JOURNAL FREE ACCESSCross-placental transfer of 239Pu from the mother to fetus was studied in C3H mice. The activity of 239Pu in the conceptus was measured 24 hrs after the intravenous injection of 239Pu citrate on days 10.5 to 16.5 of gestation. More 239Pu was transferred to the conceptus when the plutonium was administered in the later stages of gestation; 0.12% of the injected dose per conceptus on day 10.5 and 1.3% on day 16.5. In all the gestational stages examined, the yolk sac and decidua contained more than 89% of the total activity distributed in the conceptus. The concentration of 239Pu in the yolk sac was about two orders of magnitude greater than that in the fetus. The 239Pu concentration in the maternal liver decreased with the gestational stage. In the early gestational stages the concentration in the maternal liver was greater than that in the yolk sac; but, this relationship was reversed in the later stages.View full abstractDownload PDF (339K) -
YOSHIFUMI TORII, MIKIO SHIKITA, HIROSHI SAITO, NORIO MATSUKI1993 Volume 34 Issue 2 Pages 164-170
Published: June 15, 1993
Released on J-STAGE: May 24, 2006
JOURNAL FREE ACCESSX-irradiation-induced emesis was investigated in Suncus murinus, a house musk shrew. Whole body X-irradiation caused emesis, and the calculated ED50 value that induced emesis in 50% of animals was 429 cGy. At the irradiation dose of 800 cGy all the animals vomited 10.0±2.4 times with a latency of 20.0±2.9 min. The emetogenic effect of X-irradiation was dependent on the part of the body exposed. Abdominal X-irradiation at 1000 cGy caused emesis in all animals studied, whereas the same dose to the head had no emetogenic effect. We investigated several prophylactic methods against X-irradiation-induced emesis. Surgical vagotomy completely inhibited the emesis induced by 800 cGy X-irradiation. Emesis was also prevented by the subcutaneous administration of tropisetron (ICS 205-930, a selective serotonergic 5-HT3 receptor antagonist) with an ID50 value of 29 μg/kg. These results suggest that (1) suncus is a useful experimental animal for the study of radiation-induced emesis and the development of prophylactic drugs, (2) serotonin plays an important role in X-irradiation-induced emesis, and (3) X-irradiation-induced emesis is very similar to that caused by cancer chemotherapeutic agents.View full abstractDownload PDF (305K) -
SENTARO TAKAHASHI, CHIHIRO KOSHIMOTO, YOSHIHISA KUBOTA1993 Volume 34 Issue 2 Pages 171-176
Published: June 15, 1993
Released on J-STAGE: May 24, 2006
JOURNAL FREE ACCESSThe effect of γ-irradiation on a major nutritional function of the yolk sac (the uptake and digestion of macromolecular materials) was studied in rat visceral yolk sacs cultured in vitro being used 125I-labeled bovine serum albumin (RISA) as the tracer protein. The uptake of RISA (per g wet weight) by rat yolk sacs irradiated with doses of 5-80 Gy was essentially the same as that in the unirradiated control yolk sacs. There were no significant differences in yolk sac uptake of RISA with respect to the radiation doses or to culture period up to 18 hours after irradiation. External γ-irradiation with 10-80 Gy doses also had no effect on the extracellular release of 125I from yolk sacs which had been taken it up as RISA. The ratios of the activity in ultrafiltrates of the medium to the total activity in the medium were slightly higher at doses of 40 and 80 Gy.View full abstractDownload PDF (253K)
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