9,062 research outputs found

    The Effect of Irradiating a Transplanted Solid Sarcoma on the Subsequent Development of Metastases

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    A slowly growing solid sarcoma was implanted subcutaneously on the anterior chest wall of mice. On reaching a predetermined size the tumours were locally irradiated using 240 kV x-rays with single doses of 0, 2000 or 5000 rad. The mice were sacrificed 12 weeks after irradiation and examined for lung metastases, which were found to be less frequent in those mice whose implanted tumours had received the most irradiation

    Effect of the nitroimidazole Ro 03-8799 on the activity of chemotherapeutic agents against a murine tumour in vivo.

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    The effect of the 2-nitroimidazole Ro 03-8799 (8799) on the activity of 11 chemotherapeutic agents against the anaplastic MT tumour in mice has been determined by soft agar cloning. The 8799, whilst producing little cytotoxicity by itself, potentiated the cytotoxic actions of the alkylating agents melphalan and cyclophosphamide, and the nitrosoureas BCNU, CCNU and MeCCNU. This potentiation was influenced by the time interval between the administration of 8799 and the chemotherapeutic agents, and also by the site of tumour implantation. However, 8799 did not potentiate the cytotoxicities of the compounds CBDCA, cisplatin, adriamycin, vincristine, 5-fluorouracil and bleomycin. A review is included of the reported in vivo effects of nitroimidazoles on the chemotherapeutic agents investigated here

    Effects of P-wave Annihilation on the Angular Power Spectrum of Extragalactic Gamma-rays from Dark Matter Annihilation

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    We present a formalism for estimating the angular power spectrum of extragalactic gamma-rays produced by dark matter annihilating with any general velocity-dependent cross section. The relevant density and velocity distribution of dark matter is modeled as an ensemble of smooth, universal, rigid, disjoint, spherical halos with distribution and universal properties constrained by simulation data. We apply this formalism to theories of dark matter with p-wave annihilation, for which the relative-velocity-weighted annihilation cross section is \sigma v=a+bv^2. We determine that this significantly increases the gamma-ray power if b/a >> 10^6. The effect of p-wave annihilation on the angular power spectrum is very similar for the sample of particle physics models we explored, suggesting that the important effect for a given b/a is largely determined by the cosmic dark matter distribution. If the dark matter relic from strong p-wave theories is thermally produced, the intensities of annihilation gamma-rays are strongly p-wave suppressed, making them difficult to observe. If an angular power spectrum consistent with a strong p-wave were to be observed, it would likely indicate non-thermal production of dark matter in the early Universe.Comment: 20 pages, 3 figure

    The effect of low-dose pre-operative X-irradiation of implanted mouse mammary carcinomas on local recurrence and metastasis.

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    Pre-operative X-irradiation of s.c. implanted first-generation mammary tumours in C3H mice, using either 500 rad or two fractions of 350 rad, produced no improvement in the success of surgery in causing local control or in reduction of distant metastases. The metastasis rate was just significantly higher after the two-fraction treatment of the implanted tumour than after surgical removal alone. The results are in agreement with previously published results on carcinomas and a sarcoma but contrast with those for murine lymphomas

    Further investigations of the effects of the hypoxic-cell radiosensitizer, Ro-07-0582, on local control of a mouse tumour.

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    The tumour used, designated MT1, is a more radiosensitive form of the anaplastic MT tumour previously described. No explanation for the increased radiosensitivity was found, but it was shown not to be due to infection or to a change in immunological status, growth rate or histology. The sensitivity has remained constant throughout the present work. No cytotoxicity in the tumour was observed when 1 mg/g body weight of Ro-07-0582 was injected immediately after a single dose of X-rays; indeed a small protective effect was seen. A radiosensitization enhancement of 1-5 was achieved with a relatively low drug dose of Ro-07-0582 in a 5F/4d fractionated regime. The interval between the injection of a low dose of Ro-07-0582 and the start of irradiation was found to be critical, the optimum interval being 45-60 min. The subsequent incidence of distant metastases was not increased by the use of Ro-07-0582 at the time of "primary" tumour irradiation

    Modest radiosensitization of solid tumours in C3H mice by the hypoxic cell radiosensitizer NDPP.

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    The x-ray dose required to cure half the mice bearing first generation transplanted mammary carcinomata 150 days after irradiation was determined. NDPP proved to be a relatively poor radiosensitizer in mice, for although a maximum enhancement ratio of 1-3 was obtained when x-rays produced from a 1-4 MeVp electron accelerator were given between 10 and 17 min after the administration of NDPP, this was at a drug concentration sufficient to cause marked kidney abnormalities in 5-10% of the mice

    cis-6-Methoxycarbonyl-2,10-dioxa-1-phosphabicyclo[4.4.0]decane 1-Oxide

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    The crystal structure of the title compound, C9H1505P, is described. The molecule consists of two cis-fused six-membered rings, both in the chair conformation.
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