1. The susceptibility of mice to the lethal effect of preparations containing the oxygen-labile hemolysin (streptolysin O) of group A hemolytic streptococci has been studied. Injection of a single sublethal dose of the streptococcal preparation causes the development of resistance to the effect of a lethal dose injected subsequently. 2. Resistance is demonstrable 3 to 6 hours after the injectio...

Haploid cells of Saccharomyces cerevisiae were treated with different DNA damaging agents at various doses. A study of the progeny of individual such cells (by pedigree analyses up to the third generation) allowed the assignment of lethal events to distinct post treatment generations. By microscopically inspecting those cells which were not able to form visible colonies we could discriminate be...

Background: In some areas of Ramsar, a city in northern Iran, residents receive a much higher annual radiation exposure than is permitted for radiation workers. Induction of adaptive response in residents of Ramsar has been reported previously. In this study induction of such a response in short term exposure to high background levels of gamma radiation is investigated. Materials and M...

Genetic variation is needed for developing new superior varieties in plant breeding. of chili plants could be increased by inducing mutation with gamma rays irradiation. The aim this study was to determine radiosensitivity two local pepper calculating the lethal dose values at LD20 and LD50. Chili (Capsicum frutescens L.) seeds origin from Tulungagung Ponorogo were irradiated cobalt-60 doses of...

The mouse, dog, and monkey toxicity data on 30 drugs was retrospectively analyzed in comparison with the actual clinical dose schedules used in man. Animal dose schedules were converted to the human schedule and comparisons were made of the human dose versus the large animal toxic dose low, toxic dose high, and lethal dose, the lethal doses for 10% and 90% of normal mice, and the optimal dose i...

Abstract We have reevaluated recent studies of the effects on Earth by cosmic rays (CRs) from nearby supernovae (SNe) at 100 and 50 pc, in diffusive transport CR case, here including an early-time suppression lower energies neglected previous works. Inclusion this leads to overall fluxes early times, atmospheric ionization, smaller resulting ozone depletion, sea-level muon radiation doses. Diff...

High-dose therapy with autologous hematopoietic progenitor cell support is effective treatment for patients with a variety of high-risk malignancies. Accelerating of marrow recovery from near-lethal or lethal toxicity with hematopoietic cell support improves the safety and cost effectiveness of the high-dose regimens. Peripheral blood progenitor cells will soon replace marrow as the major sourc...

Alkylating agent-sensitive and -resistant L1210 leukemia cell lines were used to determine the tumor response to dose levels of drugs that exceeded conventional doses up to a factor of 10. Since those dose levels were lethal to the host mice, tumor response was based on the results of in vivo bioassays of spleen and/or tumor from drug-treated and control mice. When mice bearing about 10(8) drug...

Differentiation factor (D factor), also called leukemia inhibitory factor (LIF), is a glycoprotein that has been increasingly recognized to possess a wide range of physiological activities. We examined the possibility that the administration of D factor may confer beneficial effects and enhance host resistance against lethal endotoxemia. A single intravenous dose of recombinant human D factor c...