X-ray Sensitivity of E. Coli as Modified by Oxygen Tension

Hollaender, Alexander; Stapleton, G. E.; Martin, Frances L.

doi:10.1038/167103a0

Cited by 130 publications

(33 citation statements)

References 10 publications

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“…In 1951 Hollaender et al published their study on the radiosensitivity of aerobically and anaerobically cultured Escherichia coli [5]. Their study helped form the foundation of current thinking on tumor hypoxia and its effect on radiotherapy.…”

Section: Understanding the Impact Of Anemiamentioning

confidence: 99%

Radiotherapy-Associated Anemia: The Scope of the Problem

Harrison

2000

The Oncologist

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The impact of anemia on cancer patients undergoing chemotherapy is well established, but only recently has the prevalence of anemia in patients receiving radiotherapy received much attention. Many cancer patients present with anemia prior to radiotherapy, and even more experience anemia or a worsening of anemia at some point during treatment. However, the problem of anemia is often ignored because patients may experience only functional anemia, defined as a hemoglobin level less than 12 g/dl. Unless physiologic anemia (hemoglobin = 8 g/dl) is discovered, efforts to correct anemia are often not made. Because hemoglobin levels <12 g/dl seem to be associated with tumor hypoxia and poorer outcomes of radiotherapy in a number of patient populations, ignoring even modest anemia can result in decreased locoregional control, overall survival, and quality of life (QOL). Because increasing hemoglobin levels 1-2 g/dl is usually easily accomplished, there exists the potential for improving outcomes by paying greater attention to this problem. This article focuses on the prevalence of anemia, particularly functional anemia, and discusses the impact of anemia on locoregional control, overall survival, and QOL. INTRODUCTIONContinuing advances in oncology care, including new radiotherapy technologies and recent developments with multimodal therapies, have significantly improved clinical outcomes and quality of life (QOL) for many patients with cancer. However, the prevalence and impact of cancer-associated anemia is not widely appreciated. Emerging data demonstrate that cancer-related anemia is unexpectedly common in cancer patients receiving radiotherapy and/or chemotherapy and that even modest anemia (hemoglobin <12 g/dl) substantially impairs QOL. In addition, a growing body of literature suggests that hemoglobin concentrations of less than 12-13 g/dl during cancer therapy are associated with reduced local tumor control and decreased survival [1,2]. Although anemia of this magnitude can be easily managed, it is often overlooked or considered clinically insignificant. However, restoration of normal hemoglobin concentrations in patients undergoing radiotherapy has the potential to improve local tumor control and survival and produce sizable improvements in patient QOL.

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Section: Understanding the Impact Of Anemiamentioning

confidence: 99%

Radiotherapy-Associated Anemia: The Scope of the Problem

Harrison

2000

The Oncologist

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“…Therefore, catalase and peroxidase (EC 1.11.1.7) in the cell play an important role in protecting cells from active oxygen molecules. HOL-LAENDER et al (25) did not find a protective effect of SOD against r-ray irradiation. However, the results described in this study show that the scavenger inside cells slightly increase the survival of i-ray irradiated cells (Fig.…”

Section: Discussionmentioning

confidence: 99%

Escherichia coli cell inactivation by superoxide anion and hydrogen peroxide.

Nishida

Takagi

Yano

1981

J. Gen. Appl. Microbiol.

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The effect of superoxidc anion (02-) on killing of cells was studied. E. coli was killed by a non-enzymatical 02--generating system, i.e. a phenazine methosulfate (PMS)-NADH system. Both polA and recA repairdeficient mutants were more sensitive to 02 _ than wild type cells. Furthermore, using the polA mutant strain, it was clearly shown that incubation in growing medium increased survival, indicating the involvement of a rec-dependent repair system. It was concluded that the direct cause of cell death induced by 02 was DNA damage. When a scavenger of the active oxygen, such as superoxide dismutase (SOD) or catalase, was present in the reaction buffer during 02 _ treatment, the survival of cells increased. Of especial note, cells were completely protected by addition of catalase. It was suggested that H2O2 produced from 02-and H2O was a molecule more toxic to E. coli cells than the 02-itself in this system. When SOD and catalase were induced inside cells by adding methylviologen in the medium, a protective effect against 02-appeared. Cells treated with methyl-viologen were also resistant, although slightly, to aerobic Y-ray irradiation, suggesting that the scavenger of active oxygen in cells was partly responsible for protection against f-ray irradiation. It is deduced that 02-and/or H2O2 generated in cells may be one of the causes of cell damage by aerobic C -ray irradiation.The presence of oxygen during irradiation with ,-rays or X-rays enhances the lethality to living organisms. Such a phenomenon, called the oxygen effect, has been suggested to be caused by the active oxygen molecules such as 02-, OH', H2O2, 102, which are known to be generated in H2O when irradiated under the aerobical condition. There are many reports which indicate that the active oxygen molecules play toxic roles in biological systems (1-3). Concerning the cause of the oxygen effect, however, it is unclear which species of the active oxygen molecule is responsible for the enhancement of the cell damage. Involvement of 02_ 477

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“…curves were compared and the obtained oxygen enhancement ratio, OER, i.e., Do value of the deoxygenated cells divided by D" value of the control cells, was about 2.6, 3.60 Gy/ 1.35 Gy, as first shown by Hollaender et al (1951).…”

Section: Resultsmentioning

confidence: 99%

“…The chamber was closed air-tightly and the saturatedly humidified NZ gas (95% NZ +S% C02), (3) was flowed into the chamber (2). Deoxygenated drug solution (4) can be measured by syringe (5) and poured on the cells (1). N2 gas was further flowed prior to x-irradiation.…”

Section: Methodsmentioning

confidence: 99%