Enhancement of protective action of radioprotector; Mogucnosti potenciranja zastitnog dejstva radioprotektora WR-2721

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Dobric, S; Milovanovic, S [Vojnotehnicki Institut, Belgrade (Yugoslavia)

1996-12-31

The efficacy of radioprotector WR-2721 (300 mg/kg ip, 20 min before irradiation), alone or in combination with an extract of Ginkgo biloba (Tebonin{sup R}) (17.5 mg/kg ip, 20 min before, and then 1 hr and 24 hr after irradiation), an extract of thymus (Thymolip{sup R}) (10 mg/kg sc, 24 hr before and 15 min after irradiation), herbal mitogen agrostemin (0.1 mg/kg ip. 24 before and immediately after irradiation) and calcium antagonist verapamil (1 mg/kg ip, immediately before irradiation), was studied in adult male Wistar rats irradiated by 9 Gy and 12 Gy of X-rays. It was established that above mentioned compounds, except wr-2721, failed to protect irradiated animals. Given in combination with WR-2721 only agrostemin and verapamil enhanced the efficacy of the protector. The combination with verapamil was more effective providing protection even in supralethal irradiated rats. (author) 7 refs. 2 tabs.

Effect of the radioprotector WR 2721 on the response of metastatic Lewis lung carcinoma colonies to alkylating agents

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Wist, E.A.

1985-01-01

WR 2721 protected ''artificial'' lung metastases of Lewis lung carcinoma against the cytotoxic effects of cyclophosphamide and melphalan. When mice were pretreated with WR 2721 30 min before exposure to the alkylating agents a significant increase in the number of lung metastases could be observed. This protection of micrometastases had a significant impact on survival in the case of cyclophosphamide treatment, but not in the case of melphalan treatment. The degree of protection at a standard dose of WR 2721 was dose dependent. (orig.)

Interaction of cultured mammalian cells with WR-2721 and its thiol, WR-1065: implications for mechanisms of radioprotection

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Purdie, J.W.; Inhaber, E.R.; Schneider, H.; Labelle, J.L.

1983-01-01

An isothermal microcalorimeter was used to measure changes in heat flow when radioprotective drugs were added to cultured mammalian cells. The heat produced when WR-2721 was added continued for at least 90 min. WR-2721 was dephosphorylated by the cells to thiol (WR-1065) which oxidizes to disulphide. In the microcalorimeter, thiols give an immediate burst of heat due to this oxidation. A biological oxygen monitor revealed that WR-1065 and cysteamine rapidly consumed all the oxygen in culture medium. (10mM WR-1065 deoxygenated medium in 2 min.). Rapid consumption of oxygen by radioprotective thiols indicates that they will not co-exist with oxygen for long in cells. This has two important implications with respect to mechanisms of radioprotection: (1) oxygen in tissues will be consumed rapidly and could results in local hypoxia; and, (2) at modest doses of protective agents the thiol will be consumed in oxic cells and hence very little will be available for reactions such as hydrogen donation. The results indicate that anoxia is probably the principle mechanism of protection by aminothiols in mammals and aerated cells. (author)

Effects of area postrema lesions on taste aversions produced by treatment with WR-2721 in the rat

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Rabin, B.M.; Hunt, W.A.; Lee, J.

1986-01-01

The conditioned taste aversion procedure was used to further assess some behavioral effects of treatment with the putative radioprotectant WR-2721 and the role of the area postrema in mediating the behavioral effects of treatment. Treatment with 40, 150 or 300 mg/kg WR-2721 produced dose-dependent changes in sucrose intake in both control rats and rats with area postrema lesions. The effectiveness of the lesion in disrupting the acquisition of an aversion varied as a function of the dose administered, with the lesions producing the greatest disruption of aversion learning at the lowest dose and little disruption at the highest dose tested. At all dose levels, sucrose intake was greater for the rats with area postrema lesions than for the sham-operated control rats. Treatment with WR-2721 also produced significant decreases in total fluid intake, particularly at the higher dose levels. The results are discussed as indicating that treatment with WR-2721 produces highly toxic effects on behavior and that the use of the compound as a radioprotectant for radiotherapy requires additional assessment of its effects on brain function and behavior

Protective effect of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on irradiation-induced inhibition of intestinal transport function

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Chen, T.S.; Ando, M.

1983-01-01

The purpose of this study was to investigate the protective effect of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on whole-body irradiation-induced inhibition of intestinal transport function. The jejunal transport of fluid and sugars was studied in male Swiss-Webster mice before and 3 days after whole-body irradiation (1000 rads). The rates of glucose and water transport were decreased by 86 and 70%, respectively, in irradiated animals. However, the rate of transport of 3-O-methyl-D-glucose (3MG) was not affected. In mice receiving WR-2721 (500 mg/kg, ip) 15 to 30 min prior to whole-body irradiation, net water flux was unaffected and the rate of D-glucose transport was decreased only 8%. WR-2721 administered alone (500 mg/kg, ip) had no effect on either D-glucose transport or net water flux across the jejunal mucosa. The results suggest that WR-2721 protects against irradiation-induced inhibition of some intestinal transport functions

Cisplatin neuropathy. Risk factors, prognosis, and protection by WR-2721

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Mollman, J.E.; Glover, D.J.; Hogan, W.M.; Furman, R.E.

1988-01-01

A prospective study of patients receiving cis-diaminedichloroplatin II (DDP) was carried out to determine if risk factors could be identified related to the patient's living habits or past medical history that would predict in which patients DDP neuropathy might develop. Sixty-nine patients receiving six different combinations of chemotherapeutic agents, including DDP were examined. Twenty-eight of these patients received DDP in combination with the radioprotective agent S-2-(3-aminopropylamino)-ethylphosporothioic acid (WR 2721). No risk factors were identified relating to personal habits or past medical history of the patients. However, patients receiving DDP (40 mg/m2) on 5 consecutive days had a significantly higher incidence of neuropathy. Patients receiving DDP in combination with WR 2721 had a significantly lower incidence of neuropathy, and the mean dose at onset was significantly higher than the mean dose at onset of neuropathy for all other groups. In addition, five of six patients who were available for long-term follow-up demonstrated nearly complete reversal of the signs and symptoms of neuropathy

Improved HPLC assay for S-2-(3-aminopropylamino)ethyl phosphorothioate (WR-2721) in plasma

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Swynnerton, N.F.; McGovern, E.P.; Nino, J.A.; Mangold, D.J.

1984-01-01

An HPLC assay is presented for the detection and quantitation of the radioprotective drug S-2-(3-aminopropylamino)ethyl phosphorothioate (WR-2721, ethiofos) present in plasma. Improved selectivity and a 40-fold increase in sensitivity have been demonstrated over the method previously reported by this laboratory. Using precolumn derivatization with fluorescamine and S-3-(4-aminobutylamino)propyl phosphorothioate (WR-80855, a homolog of WR-2721) as the internal standard, drug levels of 0.05 to 1000 μg/mL were determined with excellent precision. Detector response was linear over the entire range. The assay uses 150 μL of plasma and requires a total chromatography time of about 50 minutes. The method was found suitable for pharmacokinetic studies in a preliminary experiment with a beagle dog in which no interferences due to plasma constituents or drug metabolites were observed

Radioprotection of mouse skin by WR-2721: the critical influence of oxygen tension

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Denekamp, J.; Michael, B.D.; Rojas, A.; Stewart, F.A.

1982-01-01

The epidermal clone assay has been used to study the radioprotective effect of WR-2721 on mouse skin under different conditions of oxygenation and under anoxia. The skin has shown a progressive decrease in sensitivity as the inspired gas has changed from 100% oxygen towards 0% oxygen. Compared with mice breathning 100% oxygen, those breathing air are partially protected. The inspired oxygen concentration to give half the full oxygen effect is 10-12%. The radioprotecton observed with 400 mg/kg WR-2721 is markedly dependent on the ambient oxygen concentration. The protection factor is 1.1 or less in mice breathing 5%, 1% or 0% oxygen. Protection is maximal (1.95) in air and in 50% oxygen and diminishes to 1.6 at higher oxygen tensions

Topical or systemic 16,16 dm prostaglandin E2 or WR-2721 (WR-1065) protects mice from alopecia after fractionated irradiation

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Geng, L.; Malkinson, F.D.; Hanson, W.R.

1992-01-01

Previous studies in mice demonstrated that systemic or topical 16,16 dm PGE 2 protected against single dose radiation-induced hair loss. The authors have now investigated prostaglandin, or WR-2721, protection against murine alopecia produced by varying doses and schedules of fractionated radiation. In some studies with the radioprotectors given systematically, WR-2721 afforded slightly greater radioprotection than 16,16 dm PGE 2 . The two compounds were essentially equally radioprotective in the topical application studies. Since both systemic and topical applications of the agents tested enhanced hair regrowth following radiation, the authors conclude that clinical use of these compounds may provide some protection of hair follicles, and perhaps other tissues, lying within a radiation therapy field. (author)

Dose and time relationships of the radioprotector WR-2721 on locomotor activity in mice

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Landauer, M.R.; Davis, H.D.; Dominitz, J.A.; Weiss, J.F.

1987-01-01

The effects of the radioprotector S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on locomotor activity were evaluated in CD2F1 male mice. Separate groups of animals (N = 10/group) received an IP injection of vehicle, 25, 50, 100, 200, or 400 mg/kg of WR-2721 immediately before testing. Horizontal and vertical activity were measured using a Digiscan automated animal activity monitor. The latency to onset and duration of action of each dose of the radioprotector were recorded. For both behavioral measures, a significant reduction was observed in activity at doses of 200 and 400 mg/kg. A dose of 200 mg/kg had a 12- to 14-min latency to onset and significantly reduced behavioral activity for 3 hr. Mice injected with 400 mg/kg exhibited locomotor deficits within 8-10 min and were affected for up to 9 hr. The ED50 for horizontal and vertical activities at 1 hr postinjection were determined to be 271 and 105 mg/kg, respectively. The results demonstrate that significant reductions in locomotor activity are exhibited at doses of 200 mg/kg or more and that vertical activity was more sensitive to the disruptive effects of WR-2721 than was horizontal activity

Protein binding of N-2-mercaptoethyl-1,3-diaminopropane via mixed disulfide formation after oral administration of WR 2721

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Tabachnik, N.F.; Blackburn, P.; Peterson, C.M.; Cerami, A.

1982-02-01

Earlier studies have shown that WR 2721 (H2N-(CH2)3-NH(CH2)2SPO3H2) is converted to its free thiol form, N-2-mercaptoethyl-1,3-diaminopropane (MDP), at the acidic pH of the stomach. MDP is a radioprotective compound and a mucolytic agent capable of decreasing sputum viscosity in the lungs of patients with cystic fibrosis. Conversion of WR 2721 and MDP to the corresponding sulfonic acid (MDP-SO3H) permits quantitative determination of these compounds in physiological fluids by use of an automatic amino acid analyzer. After oral administration of WR 2721 to human patients and rabbits it is converted to MDP and the free thiol form of the drug associates with plasma proteins by mixed disulfide linkage. The plasma proteins serve as a depot and reservoir of MDP for potential exchange at the tissues. When incubated with whole sputum or with purified mucin solutions in vitro, MDP decreased the viscosity of these solutions by reduction of the accessible disulfide bonds of the mucin molecule and was subsequently found in mixed disulfide association with the mucin molecule. The association of MDP with proteins via mixed disulfide linkage has important implications for the development of optimal dose regimens for administration of WR 2721 to patients.

Protein binding of N-2-mercaptoethyl-1,3-diaminopropane via mixed disulfide formation after oral administration of WR 2721

International Nuclear Information System (INIS)

Tabachnik, N.F.; Blackburn, P.; Peterson, C.M.; Cerami, A.

1982-01-01

Earlier studies have shown that WR 2721 [H2N-(CH2)3-NH(CH2)2SPO3H2] is converted to its free thiol form, N-2-mercaptoethyl-1,3-diaminopropane (MDP), at the acidic pH of the stomach. MDP is a radioprotective compound and a mucolytic agent capable of decreasing sputum viscosity in the lungs of patients with cystic fibrosis. Conversion of WR 2721 and MDP to the corresponding sulfonic acid (MDP-SO3H) permits quantitative determination of these compounds in physiological fluids by use of an automatic amino acid analyzer. After oral administration of WR 2721 to human patients and rabbits it is converted to MDP and the free thiol form of the drug associates with plasma proteins by mixed disulfide linkage. The plasma proteins serve as a depot and reservoir of MDP for potential exchange at the tissues. When incubated with whole sputum or with purified mucin solutions in vitro, MDP decreased the viscosity of these solutions by reduction of the accessible disulfide bonds of the mucin molecule and was subsequently found in mixed disulfide association with the mucin molecule. The association of MDP with proteins via mixed disulfide linkage has important implications for the development of optimal dose regimens for administration of WR 2721 to patients

Topical or systemic 16,16 dm prostaglandin E sub 2 or WR-2721 (WR-1065) protects mice from alopecia after fractionated irradiation

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Geng, L.; Malkinson, F.D. (Rush-Presbyterian-St. Luke' s Medical Center, Chicago, IL (United States)); Hanson, W.R. (Hines VA Medical Center, IL (United States))

1992-04-01

Previous studies in mice demonstrated that systemic or topical 16,16 dm PGE{sub 2} protected against single dose radiation-induced hair loss. The authors have now investigated prostaglandin, or WR-2721, protection against murine alopecia produced by varying doses and schedules of fractionated radiation. In some studies with the radioprotectors given systematically, WR-2721 afforded slightly greater radioprotection than 16,16 dm PGE{sub 2}. The two compounds were essentially equally radioprotective in the topical application studies. Since both systemic and topical applications of the agents tested enhanced hair regrowth following radiation, the authors conclude that clinical use of these compounds may provide some protection of hair follicles, and perhaps other tissues, lying within a radiation therapy field. (author).

Protection against the clastogenic effect of CIS-PLATINUM by WR-2721, ATP and Vitamin C

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Rupova, I.; Yagova, A.

1993-01-01

The mutagenic effect of antineoplastic drug Cis-Platinum has been assessed by the frequency of micronuclei in polychromatic erythrocytes (PE) in the mouse bone marrow at time intervals of 24, 48 and 73 h. The maximal clastogenic effect of 2 mg/kg of Cis-Platinum has been found at 24 h interval after treatment (3.6%). The protection against mutagenic activity of Cis-Platinum has been studied by pretreatment of the mice with the thiophosphate compound WR-2721, adenosine triphosphate (ATP) and Vitamin C alone or in combinations at the time of maximal response. The radioprotector WR-2721 exerts a high anti-mutagenic activity when applied prior to Cis-Platinum (2.2%; p 0.05). (author)

Survival of bone marrow-engrafted mice subsequent to protection from lethal radiation by WR 2721

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Kinnamon, K.E.; Ketterling, L.L.; Ledney, G.D.; Lorenz, G.B.; Mioduszewski, R.J.; Stampfli, H.F.

1980-01-01

For the first time data are presented for animals treated with bone marrow cells after lethal radiation exposure while protected with WR 2721 (the single radioprotective chemical compound with the highest known dose reduction factor). The LD 50 30 (lethal dose to 50% in 30 days) for mice exposed to whole-body 60 Co radiation was elevated from 824 +- 8 rad in unprotected and untreated mice to (a) 1181 +- 33 rad in animals which received syngeneic bone marrow cells after exposure; (b) 1342 +- 27 rad in animals which received WR 2721 before radiation exposure; and (c) 1608 +- 33 rad in animals receiving both the radioprotective agent before exposure and bone marrow engraftment after exposure

Amifostine (WR-2721, a cytoprotective agent during high-dose cyclophosphamide treatment of non-Hodgkin's lymphomas: a phase II study

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C.A. De Souza

2000-07-01

Full Text Available Clinical trials indicate that amifostine may confer protection on various normal tissues without attenuating anti-tumor response. When administered prior to chemotherapy or radiotherapy, it may provide a broad spectrum of cytoprotection including against alkylating drugs. The mechanism of protection resides in the metabolism at normal tissue site by membrane-bound alkaline phosphatase. Toxicity of this drug is moderate with hypotension, nausea and vomiting, and hypocalcemia being observed. We report a phase II study using amifostine as a protective drug against high-dose cyclophosphamide (HDCY (7 g/m2, used to mobilize peripheral blood progenitor cells (PBPC and to reduce tumor burden. We enrolled 29 patients, 22 (75.9% affected by aggressive and 7 (24.1% by indolent non-Hodgkin's lymphoma (NHL, who were submitted to 58 infusions of amifostine and compared them with a historical group (33 patients affected by aggressive NHL and treated with VACOP-B followed by HDCY. The most important results in favor of amifostine were the reduction of intensity of cardiac, pulmonary and hepatic toxicity, and a significant reduction of frequency and severity of mucositis (P = 0.04. None of the 29 patients died in the protected group, while in the historical group 2/33 patients died because of cardiac or pulmonary toxicity and 2 patients stopped therapy due to toxicity. Amifostine did not prevent the aplastic phase following HDCY. PBPC collection and hematological recovery were adequate in both groups. The number of CFU-GM (colony-forming units-granulocyte/macrophage colonies and mononuclear cells in the apheresis products was significantly higher in the amifostine group (P = 0.02 and 0.01, respectively. Side effects were mild and easily controlled. We conclude that amifostine protection should be useful in HDCY to protect normal tissues, with acceptable side effects.

Analysis of S-35 labeled WR-2721 and its metabolites in biological fluids

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Anderson, K.W.; Krohn, K.A.; Grunbaum, Z.; Phillips, R.B.; Mahler, P.A.; Menard, T.W.; Spence, A.M.; Rasey, J.S.

1984-01-01

Studies with WR-2721 and related compounds have been hindered by the lack of a suitable assay for the drug and its major metabolites. A chromatographic method which requires no derivation for the separation and detection of WR-2721, the free thiol, its symmetrical disulfide and other mixed disulfides has been developed. The procedure involves ion-pairing for separation of ionizable compounds by causing polar molecules to become more lipophilic and hence separable using reverse phase HPLC. Detection is based upon liquid scintillation counting of S-35 incorporated during the synthesis of the parent compound. This method requires no pre-column preparation of samples and, by detecting the S-35 label, eliminates the chance that a coeluting species could interfere with detection, as might occur with post-column derivatization. This analytical technique employing radiotracers can be used to study radioprotective mechanisms by time dependent measurements of the tissue distribution and chemical form of labeled drug. Such chemical information can then be correlated with biological measures of radiation protection

Toxicity studies on the radioprotective agent WR-2721 in CDF1 mice and beagle dogs

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Palmer, T.E.; Glaza, S.M.; Dickie, B.C.; Weltman, R.H.; Greenspun, K.S.

1985-01-01

WR-2721, S-2-(3-aminopropylamino)ethylphosphorothioic acid, is used extensively to protect normal cells during the irradiation of neoplastic cells. Dose levels for human radiotherapy are based on results obtained from laboratory animal lethality and toxicity studies. WR-2721 was administered intravenously to CDF1 mice and beagle dogs. Single dose lethality studies in mice showed the average 1/10 of the lethal dose, the median lethal dose and 9/10 the lethal dose to be 508 (1523 mg/m2), 589 (1766 mg/m2), and 682 mg/kg (2047 mg/m2), respectively. The lethal dose for female mice was lower than that for males. The 1/10 lethal dose in mice was slightly toxic to dogs; 1/10 of that dose was nontoxic. The lethal dose for dogs (6000 mg/m2) was higher than that for mice (2000 mg/m2). Clinical signs of toxicosis in the single-dose mouse toxicity study were evident in the 1st week following treatment and declined during the recovery period; signs of toxicosis were transient in dogs. Acute drug-induced pathologic changes included elevated BUN and SGOT levels, lymphoid necrosis, and renal tubular degeneration in mice. These changes were evident in the 1st week following treatment, but had dissipated by study termination. Generalized vascular changes (congestion, hemorrhage, and edema) and renal tubular degeneration occurred in treated dogs that had died or were killed moribund 7 days postinjection. These findings indicate sex-dependent and interspecies variation in the toxicity of WR-2721 with acute, but reversible, pathologic changes

Clinical experiences with a chemical radioprotector in tumor radiotherapy: WR-2721

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Tanaka, Y.

1984-01-01

Since cysteine was found to protect lethally irradiated rats, sulfhydryl compounds that provide protection of laboratory animals against lethal doses of ionizing radiations have also been given much attention. The SH compounds have been the most extensively investigated, and β-aminoethylisothiouronium (AET) and cysteamine have been selected as being representative of those drugs that are highly protective. However, clinical application is limited, as the toxicity of these compounds is high. In a series of experiments to reevaluate radioprotective agents with low toxicity, the authors found that 2-mercaptopropionylglycine (MPG) and adrenochrome monoguangylhydrazone methanesulfonate (AMM) have a potent radioprotector effect in a dose far below their toxic doses in both mice and humans. Recently, the development of effective thiophosphate derivatives of cysteamine, namely WR-2721 [S-2-(3-amino-propylaminoethyl)phosphorothioate] by the U.S. Army Medical Research and Development Commands, led to a reevaluation of these compounds and their potential in radiotherapy. Initial investigations indicated that WR-2721 provided a considerable degree of radioprotection to normal tissues. This compound provided excellent protection for normal tissues (DMF = 2-2.5) but little protection for the transplanted tumor. Thus this drug may have a differential protection in vivo and may be useful for improving the therapeutic ratio in cancer radiotherapy. The results of animal and chemical experiments in Japan are summarized herein

Chemical protection against gastrointestinal radiation injury in mice by WR 2822, WR 2823, or WR 109342 after 4 MeV x ray or fission neutron irradiation

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Connor, A.M.; Sigdestad, C.P.

1982-01-01

Three compounds were tested for their radioprotective properties against the effects of 4 MeV X rays or fission neutron irradiation. The endpoints tested were lethality, intestinal crypt survival, and DNA synthesizing cellularity. Two of the compounds tested; S-2(4-aminobutylamino) ethylphosphorothioc acid (WR 2822) and the aminopentylamino derivative (WR 109342). All drugs were administered via intraperitoneal injections at their approximately maximum tolerated dose. WR 2822 was shown to have a slight protective effect against X rays and neutrons. The dose modification factor (DMF) for gastrointestinal death (LD/sub 50(6)/) was 1.23 for X rays and 1.51 for neutrons. The assay for intestinal crypt survival produced DMF's of 1.44 (X rays) and 1.4 (neutrons). WR 2823 also showed a protective action in these assays. The DMF for LD/sub 50(6)/ was 1.32 (X rays) and 1.42 (neutrons). WR 109342 was found to be extremely toxic and had no significant protective effects. All three drugs were more toxic and demonstrated less protection in most of these assays than the benchmark radioprotective agent WR 2721, although WR 2822 protected against lethal effects of fission neutrons almost as well as WR 2721. Both WR 2822 and WR 2823 produced greater protection in the crypt survival assays for fission neutron irradiation than WR 2721

Phase I trials of WR2721 in combination with radiation therapy and with the alkylating agents cyclophosphamide and cis-platinum

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Kligerman, M.M.; Blumberg, A.L.; Glick, J.H.; Nelson, D.F.; Glover, D.; Yuhas, J.M.; Amols, H.I.; Goodman, R.L.

Three phase I trials of the radioprotector S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR2721) have accessed 60 patients. Study 1 is devised to determine the maximum tolerated dose (MTD) of a single dose of the protector 15 to 30 minutes before a single radiation treatment of a size used routinely in palliative management. Study 2 plans to determine the MTD for up to 15 daily doses of the drug over 3 weeks during palliative radiotherapy. Also, the multipe-dose study will establish the MTD before palliative irradiation for fewer than five fractions a week. Study 3 uses the existing single-dose MTD determined in Study 1 as pretreatment 15 to 30 minutes before cyclophosphamide or cis-platinum. Toxic symptoms include emesis, hypotension, hypertension, somnolence, and sneezing. Only one serious episode of hypotension, considered idiosyncratic, and one instance of moderate to severe vomiting have occurred. Forty-one patients have been entered in Study 1 and a dose of 600 mg/m2 has been reached. The next step is to proceed to the planned highest level of 740 mg/m2. Of five patients in the multiple-dose study, one has been given, without toxicity, WR2721 at the level of 100 mg/m2 for 15 fractions over 3 weeks. Fourteen patients are accessed to the alkylating agent study. Using protector doses of 450 mg/m2, a cyclophosphamide level of 1500 mg/m2 has been accomplished. However, two of three patients who received 450 mg/m2 of WR2721 before 120 mg/m2 of cis-platinum have shown moderate elevation of the serum creatinine, both of which returned to normal.

Phase I trials of WR2721 in combination with radiation therapy and with the alkylating agents cyclophosphamide and cis-platinum

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Kligerman, M.M.; Blumberg, A.L.; Glick, J.H.; Nelson, D.F.; Glover, D.; Yuhas, J.M.; Amols, H.I.; Goodman, R.L.

1981-01-01

Three phase I trials of the radioprotector S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR2721) have accessed 60 patients. Study 1 is devised to determine the maximum tolerated dose (MTD) of a single dose of the protector 15 to 30 minutes before a single radiation treatment of a size used routinely in palliative management. Study 2 plans to determine the MTD for up to 15 daily doses of the drug over 3 weeks during palliative radiotherapy. Also, the multipe-dose study will establish the MTD before palliative irradiation for fewer than five fractions a week. Study 3 uses the existing single-dose MTD determined in Study 1 as pretreatment 15 to 30 minutes before cyclophosphamide or cis-platinum. Toxic symptoms include emesis, hypotension, hypertension, somnolence, and sneezing. Only one serious episode of hypotension, considered idiosyncratic, and one instance of moderate to severe vomiting have occurred. Forty-one patients have been entered in Study 1 and a dose of 600 mg/m2 has been reached. The next step is to proceed to the planned highest level of 740 mg/m2. Of five patients in the multiple-dose study, one has been given, without toxicity, WR2721 at the level of 100 mg/m2 for 15 fractions over 3 weeks. Fourteen patients are accessed to the alkylating agent study. Using protector doses of 450 mg/m2, a cyclophosphamide level of 1500 mg/m2 has been accomplished. However, two of three patients who received 450 mg/m2 of WR2721 before 120 mg/m2 of cis-platinum have shown moderate elevation of the serum creatinine, both of which returned to normal

Reduction of radiation effects by chemical protector (WR-2721)

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Lee, C.H.; Kim, Y.K.; Yun, T.K.; Koh, J.H.

1985-01-01

As a part studies on effect of radiation, the present report was carried out to evaluate the changes of leukocytes, lymphocytes percent of leukocytes and several organs in swiss webster (NIH-GP) mice by radiation protective agents prior to γ-ray exposure. The whole body irradiation after administration of a radiation protective agents was done in dose level of 25,50,100 and 300 rads by a single exposure of γ-ray delivered from 60 Co, source tele-irradiation unit at a dose rate of 100 rad/min. Mice of each experimental group were whole body γ-irradiated in plastic cage with special producted rotating machine. The radiation protective agent was employed WR-2721 and the amounts injected intraperitoneally were 400mg/kg of body weight. The leukocytes were counted with hemocytometer. Differential count of leukocytes was done with 200 cells every smear and lymphocyte percent of leukocyte were determined in relative proportion only. All major organ were examined grossly and weighted. After fixation with formalin solution, histo-pathological preparations were made for microscopical study. (Author)

Investigations with beagles about toxicity and radioprotective effect of the chemical radioprotection substance WR 2721

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Wagner, M.; Sedlmeier, H.; Wustrow, T.; Messerschmidt, O.

1980-01-01

The toxicity of the chemical radioprotection substance WR 2721 (S-2-(3-aminopropylamino)ethyl-thiophosphate) was examined in 25 beagles. The study showed that the toxicity of the substance increases as the dose gets higher. Between the doses 200 and 250 mg/kg of body weight, the increase of toxicity was significantly greater than could be expected on the basis of the dose difference. Until a dose of 200 mg/kg, the authors found no side effects which would have disturbed vital functions, but higher doses led to marked symptoms of intoxication. (orig.) [de

The radioprotector WR-2721 reduces neutron-induced mutations at the hypoxanthine-guanine phosphoribosyl transferase locus in mouse splenocytes when administered prior to or following irradiation

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Grdina, D.J.; Basic, I.

1992-01-01

An in vitro T-lymphocyte cloning technique has been applied to study the effects of JANUS fission-spectrum neutron irradiation and the radioprotector S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721) on the subsequent development of somatic mutations at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in hybrid B6CF1 male mice. In control studies performed to establish an in vitro cloning technique, the mutant frequencies of splenic T-lymphocytes, as a result of exposure to a 100 cGy dose of neutrons, increased with time from a control level of 9 x 10 -7 to a maximum value of 1.7 x 10 -5 at 56 days following irradiation. Between 56 and 150 days after irradiation, mutant frequencies were observed to plateau and remain stable. All subsequent determinations were performed at 56 days following the experimental treatment of animals. WR-2721 at a dose of 400 mg/kg was effective in protecting against the induction of hprt mutants (i.e. a mutant frequency reduction factor, MFRF) following the largest dose of neutrons used (i.e. 150 cGy). The antimutagenic effectiveness of WR-2721 administered 30 min prior to irradiation was unaffected, even when the dose was reduced to 200 mg/kg. These findings confirm our earlier report using the radioprotector N-(2-mercaptoethyl)-1,2-diaminopropane (WR-1065) under in vitro conditions, and demonstrate that these agents can be used as effective antimutagens even when they are administered up to 3 h following radiation exposure. (Author)

Radioprotective effects of Sipunculus nudus L. polysaccharide combined with WR-2721, rhIL-11 and rhG-CSF on radiation-injured mice

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Jiang Shuqi; Shen Xianrong; Liu Yuming; He Ying; Jiang Dingwen; Chen Wei

2015-01-01

This study investigated the radioprotective effect of Sipunculus nudus L. polysaccharide (SNP) in combination with WR-2721, rhIL-11 and rhG-CSF on irradiated mice. A total of 70 Imprinting Control Region (ICR) mice were divided into seven groups: the control group, the model group and five administration groups. All groups, except the control group, were exposed to a 5 Gy 60 Co γ-ray beam. Blood parameters [including white blood cell (WBC), red blood cell (RBC) and platelet counts and hemoglobin level] were assessed three days before irradiation, and the on the 3rd, 7th and 14th days after irradiation. Spleen, thymus and testicular indices, DNA contents of bone marrow cells, bone marrow nucleated cells, sperm counts, superoxide dismutase (SOD), malondialdehyde (MDA), testosterone and estradiol levels in the serum were assessed on the 14th day after irradiation. The combined administration of SNP, WR-2721, rhIL-11 and rhG-CSF exerted synergistic recovery effects on peripheral blood WBC, RBC and platelet counts and hemoglobin levels in irradiated mice, and synergistic promotion effects on spleen, thymus, testicle, bone marrow nucleated cells and sperm counts in irradiated mice. The synergistic administration increased the serum SOD activities and serum testosterone content of irradiated mice, but synergy decreased the content of serum MDA and estradiol in irradiated mice. These results suggest that the combined administration of SNP, WR-2721, rhIL-11 and rhG-CSF should increase the efficacy of these drugs for acute radiation sickness, protect immunity, hematopoiesis and the reproductive organs of irradiated-damaged mice, and improve oxidation resistance in the body. (author)

Protective effect of amifostine on dental health after radiotherapy of the head and neck

International Nuclear Information System (INIS)

Rudat, Volker; Meyer, Jens; Momm, Felix; Bendel, Martin; Henke, Michael; Strnad, Vratislav; Groetz, Knut; Schulte, Andreas

2000-01-01

Purpose: The cytoprotective agent amifostine has been shown to reduce the radiation-induced acute and chronic xerostomia in head and neck cancer patients. The purpose of this study was to evaluate whether or not amifostine also reduces the incidence of dental caries associated with the radiation-induced xerostomia. Methods and Materials: The dental status before and 1 year after radiotherapy was retrospectively compared in 35 unselected patients treated as part of the prospective randomized and multicenter open-label Phase III study (WR-38) at the University Hospitals of Heidelberg, Freiburg, and Erlangen. The WR-38 study compared radiotherapy in head and neck cancer with and without concomitant administration of amifostine. Results: Patient and treatment characteristics (particularly the radiation dose and percentage of parotids included in the treatment volume) were equally distributed between the patients who received (n = 17) or did not receive (n = 18) amifostine. Fifteen patients of the amifostine group showed no deterioration of the dental status 1 year after radiotherapy as compared to 7 patients who did not receive the cytoprotector (p = 0.015, two-tailed Fisher exact test). Conclusion: Our data suggest a protective effect of amifostine on the dental health after radiotherapy of the head and neck. The dental status should be used as a primary endpoint in future studies on amifostine.

Protection against radiation-induced mutations at the hprt locus by spermine and N,N double-prime-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278). WR-33278 and spermine protect against mutation induction

International Nuclear Information System (INIS)

Grdina, D.J.; Shigematsu, N.; Schwartz, J.L.

1994-01-01

The polyamine spermine and the disulfide N,N double-prime-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278) are structurally similar agents capable of binding to DNA. WR-33278 is the disulfide moiety of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). Because of their reported structural and functional similarities, it was of interest to characterize and compare their radioprotective properties using the endpoints of cell survival and mutation induction at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in Chinese hamster AA8 cells. In order to facilitate both the uptake of WR-33278 into cells and the direct comparison between the protective properties of WR-33278 and spermine, these agents (at concentrations of 0.01 mM and 0.001 mM) were electroporated into cells. The exposure of cells to both electroporation and irradiation gave rise to enhanced cell killing and mutation induction, with the sequence of irradiation followed 3 h later by electroporation being the more toxic protocol. Enhanced cell survival was observed following electroporation of 0.01 mM of spermine and WR-33278 30 min prior to irradiation; protection factors (PF) of 1.3 and 1.8, respectively. Neither agent was protective at a concentration of 0.001 mM. Protection against radiation-induced hprt mutations was observed for both spermine and WR-33278 under all experimental conditions tested. These data suggest that the properties of radioprotection and chemoprevention exhibited by the phosphorothioate (WR-2721) and associated aminothiol (WR-1065) and disulfide (WR-33278) metabolites may be mediated via endogenous spermine-like polyamine processes. Such a mechanism would have important implications with respect to the design and development of new generation drugs for use in radioprotection and chemoprevention

Novel Formulation Strategy to Improve the Feasibility of Amifostine Administration.

Science.gov (United States)

Ranganathan, Kavitha; Simon, Eric; Lynn, Jeremy; Snider, Alicia; Zhang, Yu; Nelson, Noah; Donneys, Alexis; Rodriguez, Jose; Buchman, Lauren; Reyna, Dawn; Lipka, Elke; Buchman, Steven R

2018-03-19

Amifostine (AMF), a radioprotectant, is FDA-approved for intravenous administration in cancer patients receiving radiation therapy (XRT). Unfortunately, it remains clinically underutilized due to adverse side effects. The purpose of this study is to define the pharmacokinetic profile of an oral AMF formulation potentially capable of reducing side effects and increasing clinical feasibility. Calvarial osteoblasts were radiated under three conditions: no drug, AMF, and WR-1065 (active metabolite). Osteogenic potential of cells was measured using alkaline phosphatase staining. Next, rats were given AMF intravenously or directly into the jejunum, and pharmacokinetic profiles were evaluated. Finally, rats were given AMF orally or subcutaneously, and blood samples were analyzed for pharmacokinetics. WR-1065 preserved osteogenic potential of calvarial osteoblasts after XRT to a greater degree than AMF. Direct jejunal AMF administration incurred a systemic bioavailability of 61.5%. Subcutaneously administrated AMF yielded higher systemic levels, a more rapid peak exposure (0.438 vs. 0.875 h), and greater total systemic exposure of WR-1065 (116,756 vs. 16,874 ng*hr/ml) compared to orally administered AMF. Orally administered AMF achieves a similar systemic bioavailability and decreased peak plasma level of WR-1065 compared to intravenously administered AMF, suggesting oral AMF formulations maintain radioprotective efficacy without causing onerous side effects, and are clinically feasible.

HPLC assay for 2-(3-aminopropylamino)ethanethiol (WR-1065) in plasma

International Nuclear Information System (INIS)

McGovern, E.P.; Swynnerton, N.F.; Steele, P.D.; Mangold, D.J.

1984-01-01

A high pressure liquid chromatography (HPLC) plasma assay for WR-1065 is described which is both precise and accurate throughout the concentration range from 1 to 500 μg/mL of plasma. The analyte is separated by HPLC and detected with a thiol specific electrochemical transducer cell. The detector response is linear over the ranges 1 to 10 μg/mL, 10 to 100 μg/mL, and 100 to 500 μg/mL. The absolute retention times for WR-1065 and WT-1729 are 9 and 12 minutes, respectively. The assay uses 100 μL of plasma and requires a total chromatography cycle time of 40 minutes. The method has been found suitable for the determination of WR-1065 in plasma from a beagle dog after i.v. administration of S-2-(3-aminopropylamino)ethyl phosphorothioate (WR-2721)

Effect of an aminothiol (WR-1065) on radiation-induced mutagenesis and cytotoxicity in two repair-deficient mammalian cell lines

International Nuclear Information System (INIS)

Grdina, D.J.; Nagy, B.; Meechan, P.J.

1991-01-01

WR-2721 and its free thiol WR-1065 have been found to effectively protect against radiation- and/or chemotherapy-induced mutagenesis, transformation and carcinogenesis. With respect to the antimutagenic effect, WR-1065 significantly reduced the frequency of HGPRT mutants even when it was administered up to three hours following exposure of cells to radiation. The mechanisms of action most often attributed to these agents include their ability to scavenge free radicals, enter into chemical repair processes through the donation of hydrogen atoms, and induce intracellular hypoxia by means of auto-oxidative processes. Although evidence exists for each of these processes, none is sufficiently satisfactory to account for the post-irradiation protection of WR-1065 against mutation induction in mammalian cells. The most elegant work describing the role of aminothiols on cellular enzymatic repair processes has focused on well-characterized repair-proficient and -deficient bacterial and yeast cell systems. Protection against radiation-induced cytotoxicity by the aminothiol cysteamine was absent in E. coli cell lines that were characterized as having genetically defective repair systems. Until recently, such studies could not be effectively performed with mammalian cells. However, with the isolation and characterization of rodent cell lines deficient in their ability to repair DNA damage, it is now possible to investigate the role of cell-mediated repair systems on aminothiol radioprotection. Specifically, the authors have investigated the effects of WR-1065 on radiation-induced mutagenesis and cytotoxicity in cell lines EM9 and xrs-5, which are defective in DNA single-strand break (SSB) and double-strand break (DSB) rejoining, respectively. Corresponding parental repair-proficient cell lines, AA8 and K1, were also studied for comparative purposes. 26 refs., 5 figs., 2 tabs

Alteration of radiation-induced hematotoxicity by amifostine

International Nuclear Information System (INIS)

Momm, Felix; Bechtold, Christine; Rudat, Volker; Strnad, Vratislav; Tsekos, Alexander; Fischer, Karin; Henke, Michael

2001-01-01

Purpose: To investigate whether amifostine can reduce radiation hematotoxicity. Patients and Methods: Seventy-three patients undergoing radiotherapy for squamous cell carcinoma of the head and neck at the university clinics of Freiburg, Heidelberg, and Erlangen were evaluated. All received 60 Gy (50-70 Gy) at 5x2 Gy fractions per week employing standard techniques. Thirty-five were randomized to receive 200 mg/m 2 amifostine i.v. 30 min before radiation; 38 served as control patients. Blood counts (total n=501) were determined before, during, and while completing radiotherapy. Changes of leukocyte, platelet, and hemoglobin levels were determined and compared using the t test. Results: The blood hemoglobin level and the platelet count were not affected by irradiation, for either the amifostine-treated or control patients. Similarly, the leukocyte counts of amifostine-treated patients did not change during irradiation. However, control patients experienced a decrease in leukocyte count from 8.1 x 10 3 /mm 3 to 5.8x10 3 /mm 3 (difference: 2.3x10 3 /mm 3 ). This seems to be line specific: Whereas amifostine does not affect lymphocyte count, a radiation-induced decrease of neutrophil granulocytes seems to be prevented. Conclusion: Amifostine protects from radiation hematotoxicity, particularly affecting the granulocytopoiesis. These data confirm results from our former study

A pilot study of topical intrarectal application of amifostine for prevention of late radiation rectal injury

International Nuclear Information System (INIS)

Ben-Josef, Edgar; Han, Sue; Tobi, Martin; Shaw, Leslie M.; Bonner, Heather S.; Vargas, Barbara J.; Prokop, Sharon; Stamos, Beth; Kelly, Laura; Biggar, Sandra; Kaplan, Irving

2002-01-01

Purpose: Clinical symptomatic late injury to the rectal wall occurs in about one-third of patients with prostate cancer treated with external beam irradiation. Reducing the physical dose to the anterior rectal wall without a similar reduction in the posterior peripheral zone is difficult because of the proximity of the prostate to the anterior rectal wall. On the basis of our previous observations in an animal model that intrarectal application of amifostine resulted in very high concentrations of amifostine and its active metabolite WR-1065 in the rectal wall, a Phase I dose-escalation clinical trial was undertaken. Methods and Materials: Twenty-nine patients with localized prostate cancer were accrued. Eligibility criteria included histologically confirmed adenocarcinoma, Karnofsky performance status ≥70, and no pelvic lymphadenopathy or distant metastases. The total dose to the prostate was 70.2 Gy in 20 patients and 73.8 Gy in 9 patients. Therapy was delivered using a 4-field technique with three-dimensional conformal planning. Amifostine was administered intrarectally as an aqueous solution 30 min before irradiation on the first 15 days of therapy. Amifostine was escalated in cohorts from 500 to 2500 mg. Proctoscopy was performed before therapy and at 9 months after completion. Most patients underwent repeat proctoscopy at 18 months. On Days 1 and 10 of radiotherapy, serum samples were collected for pharmacokinetic studies. The clinical symptoms (Radiation Therapy Oncology Group scale) and a proctoscopy score were assessed during follow-up. Results: All patients completed therapy with no amifostine-related toxicity at any dose level. The application was feasible and well tolerated. No substantial systemic absorption occurred. With a median follow-up of 26 months, 9 patients (33%) developed rectal bleeding (8 Grade 1, 1 Grade 2). At 9 months, 16 and 3 patients developed Grade 1 and Grade 2 telangiectasia, respectively. This was mostly confined to the anterior

12 CFR 272.1 - Authority.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Authority. 272.1 Section 272.1 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) FEDERAL OPEN MARKET COMMITTEE RULES OF PROCEDURE § 272.1 Authority. This part is issued by the Federal Open Market Committee (the Committee) pursuant to the...

Bone and parathyroid inhibitory effects of S-2(3-aminopropylamino)ethylphosphorothioic acid. Studies in experimental animals and cultured bone cells

International Nuclear Information System (INIS)

Attie, M.F.; Fallon, M.D.; Spar, B.; Wolf, J.S.; Slatopolsky, E.; Goldfarb, S.

1985-01-01

S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR 2721) is a radio- and chemoprotective agent which produces hypocalcemia in humans. Intravenous injection of 30 mg/kg WR 2721 in rats and 15 mg/kg in dogs lowers serum calcium by 19 and 25%, respectively. Hypocalcemia in dogs is associated with a fall in serum immunoreactive parathyroid hormone (PTH), which suggests that the mechanism of its hypocalcemic effect is acute hypoparathyroidism. Despite this effect on PTH, in eight chronically parathyroidectomized rats on a low phosphate diet, WR 2721 reduced serum calcium from 9.4 to 7.7 mg/dl at 3 h. Furthermore, in dogs rendered hypercalcemic by continuous infusion of PTH, WR 2721 reduced serum calcium from 11.0 to 10.6 mg/dl. To determine whether WR 2721 causes hypocalcemia by enhancing the exit of calcium from the circulation or inhibiting its entry, the drug was infused 3 h after administration of 45 Ca to rats. WR 2721 did not significantly increase the rate of disappearance of 45 Ca from the circulation even though serum calcium fell by 19%. In incubations with fetal rat long bone labeled in utero with 45 Ca, 10(-3) M WR 2721 inhibited PTH-stimulated, but not base-line release of 45 Ca. Bone resorption by primary culture of chick osteoclasts was inhibited by WR 2721 at concentrations as low as 10(-4) M in the absence of hormonal stimulation. These studies suggest that WR 2721 lowers serum calcium predominantly by blocking calcium release from bone. This acute hypocalcemic effect is at least in part independent of its effect on the parathyroid glands, and is most likely a direct effect of the agent on bone resorption

The Effect of Amifostine on Submandibular Gland Histology after Radiation

Directory of Open Access Journals (Sweden)

Jacqueline C. Junn

2012-01-01

Full Text Available Background. The purpose of this study was to assess the effects of amifostine on submandibular gland histology in patients receiving chemoradiation therapy. Methods. We conducted a retrospective submandibular gland histologic slide review of HNSCC patients receiving chemoradiation for head and neck squamous cell carcinoma with three different levels of amifostine exposure. We used six scoring parameters: fatty replacement, lobular architecture degeneration, interstitial fibrosis, ductal degeneration, acinar degeneration, and inflammatory component presence. Results. Differences in gender, tumor stage, amifostine dose, age, number of days after neck dissection, and smoking history (pack years exposure were not significant between the three groups, although there was a difference between groups in the primary subsite (P=0.006. The nonparametric Cuzick's test for histologic parameters with varied amifostine treatment showed no significance among the three groups. Conclusions. Although patients did not receive a full dose of amifostine due to side effects, varying doses of amifostine had no apparent evident cytoprotective effects in three groups of cancer patients treated with primary chemoradiation.

Amifostine - a radioprotector in locally advanced head and neck tumors

Energy Technology Data Exchange (ETDEWEB)

Schoenekaes, K.G.; Wagner, W. [Paracelsus-Strahlenklinik, Osnabrueck (Germany); Prott, F.J. [Muenster Univ. (Germany). Inst. fuer Strahlenonkologie

1999-11-01

Purpose: There are some preliminary informations about the beneficial use of amifostine in avoiding side effects in patients with head and neck tumors who underwent radiotherapy. Patients and method: Amifostine was given as daily intravenous application (500 mg) 10 to 15 minutes prior to radiotherapy in 20 patients. The results were compared with another collective of patients which was similar. Results: According to the WHO score mucositis became manifest in 10 patients (Grade I) and 4 patients (Grade II) in the amifostine group vs 9 patients (Grade II), 6 patients (Grade III) and 1 patient (Grade IV) in the control group. Xerostomia has been seen in 15 patients (Grade I) and 5 patients (Grade II) after administration of amifostine. Without the drug 2 patients suffered from xerostomia (Grade I), 8 patients (Grade II) and 8 patients (Grade III), respectively. Administering amifostine had been feasible and non problematic. Only a small rate of toxic side effects like nausea (11%) or emesis (4%) was documented. Conclusions: Amifostine is an effective radioprotector decreasing acute and late side effects in patients with head and neck tumors. (orig.) [German] Zielsetzung: Bisher gibt es nur wenige Informationen ueber den Nutzen von Amifostin bezueglich der Verminderung oder Vermeidung von Nebenwirkungen einer Radiatio bei Patienten mit Tumoren im HNO-Trakt. Patienten und Methode: Amifostin wurde als intravenoese Kurzinfusion mit einer Dosis von 500 mg zehn bis 15 Minuten vor der Bestrahlung bei 20 Patienten appliziert. Die unter Radiatio aufgetretenen Nebenwirkungen wurden nach WHO bzw. nach dem Oral Assessment Guide nach Eilers ausgewertet und mit einem entsprechenden historischen Kollektiv der Klinik verglichen. Ergebnisse: In der Amifostin-Gruppe wurde bei zehn Patienten eine Mukositis Grad I und bei vier Patienten eine Mukositis Grad II nach WHO beobachtet. Grad-III- und Grad-IV-Nebenwirkungen traten nicht auf. In der Kontrollgruppe waren dagegen bei neun

Amifostine - a radioprotector in locally advanced head and neck tumors

International Nuclear Information System (INIS)

Schoenekaes, K.G.; Wagner, W.; Prott, F.J.

1999-01-01

Purpose: There are some preliminary informations about the beneficial use of amifostine in avoiding side effects in patients with head and neck tumors who underwent radiotherapy. Patients and method: Amifostine was given as daily intravenous application (500 mg) 10 to 15 minutes prior to radiotherapy in 20 patients. The results were compared with another collective of patients which was similar. Results: According to the WHO score mucositis became manifest in 10 patients (Grade I) and 4 patients (Grade II) in the amifostine group vs 9 patients (Grade II), 6 patients (Grade III) and 1 patient (Grade IV) in the control group. Xerostomia has been seen in 15 patients (Grade I) and 5 patients (Grade II) after administration of amifostine. Without the drug 2 patients suffered from xerostomia (Grade I), 8 patients (Grade II) and 8 patients (Grade III), respectively. Administering amifostine had been feasible and non problematic. Only a small rate of toxic side effects like nausea (11%) or emesis (4%) was documented. Conclusions: Amifostine is an effective radioprotector decreasing acute and late side effects in patients with head and neck tumors. (orig.) [de

Supportive use of amifostine in patients with head and neck tumors undergoing radio-chemotherapy. Is it possible to limit the duration of the application of amifostine?

International Nuclear Information System (INIS)

Peters, K.; Muecke, R.; Hamann, D.; Ziegler, P.G.; Fietkau, R.

1999-01-01

Background: Amifostine is a new cancer-supporting agent to protect normal tissue in patients receiving radio-chemotherapy. The main question of our study is whether the application of amifostine can be limited on the duration of chemotherapy in patients with advanced head and neck tumors undergoing radio-chemotherapy. Patients and methods: In a randomized study 14 patients were treated with amifostine (500 mg, day 1 to 5 and 29 to 33) during concurrent radio-chemotherapy with carboplatin (70 mg/m 2 , day 1 to 5 and 29 to 33), 14 patients were treated without amifostine. The analyzed parameters were dermatitis, mucositis, skin temperature, white blood and platelet count, creatinine and scintigram of salivary glands. Median survival of the amifostine group was 19 months, of the control group 10 months. Results: There were no relevant differences in all analyzed parameters between both arms of the study. Conclusion: Our form of amifostine application is probably not able to obtain a relevant reduction of the toxicity of radio-chemotherapy. (orig.) [de

40 CFR 27.21 - Discovery.

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2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Discovery. 27.21 Section 27.21... Discovery. (a) The following types of discovery are authorized: (1) Requests for production of documents for..., discovery is available only as ordered by the presiding officer. The presiding officer shall regulate the...

Inhibition of topoisomerase IIα activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

International Nuclear Information System (INIS)

Grdina, D.J.

1993-06-01

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector and antimutagenic agent when it is administered 30 min prior to radiation exposure to Chinese hamster ovary Kl cells at a concentration of 4 mM. Under these exposure conditions, topoisomerase (topo) I and II activities and associated protein contents were measured in the K1 cell line using the DNA relaxation assay, the P4 unknotting assay, and immunoblotting, respectively. WR-1065 was ineffective in modifying topo I activity, but it did reduce topo IIa activity by an average of 50 percent. The magnitude of topo IIa protein content, however, was not affected by these exposure conditions. Cell cycle effects were monitored by the method of flow cytometry. Exposure of cells to 4 mM WR-1065 for a period of up to 6 h resulted in a buildup of cells in the G2 compartment. However, in contrast to topo II inhibitors used in chemotherapy, WR-1065 is an effective radioprotector agent capable of protecting against both radiation-induced cell lethality and mutagenesis. One of several mechanisms of radiation protection attributed to aminothiol compounds such as WR-1065 has been their ability to affect endogenous enzymatic reactions involved in DNA synthesis, repair, and cell cycle progression. These results are consistent with such a proposed mechanism and demonstrate in particular a modifying effect by 2-[(aminopropyl)amino]ethanethiol on type II topoisomerase, which is involved in DNA synthesis

Effects of amifostine on radiation-induced apoptosis in mouse ovary

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Lee, Kyoung Hee; Yoon Yong Dal [Hanyang Univ., Seoul (Korea, Republic of)

2002-07-01

The present study was designed to assess the radioprotective effects of amifostine on ovarian follicles. Three week-old female mice with or without pretreatment of amifostine were irradiated with 6.42 Gy of {gamma} -ray. Ovaries were collected 0 and 6h after irradiation. DNA fragmentation pattern and expression of genes and activity of proteins related with apoptosis were investigated by means of RT-PCR and Western blot. Proliferation of granulosa cells was reduced and incidence rate of follicular atresia was increased in ovarian follicles in {gamma} -ray irradiated mice compared to those in control or amifostine-treated group. DNA fragmentation was increased in time-dependent manner in granulosa cells of all irradiated groups. However, no difference between amifostine pre-treated group and irradiated groups was found and the expression of p53 as tumor suppressor gene and Bax as one of pro-apoptotic Bcl-2 family was increased in irradiated mice ovaries. PARP as DNA damage sensor was cleaved and its upstream regulator, Caspase-3 was activated. Fas (CD95), one of membrane bound receptor which initiated apoptosis pathway was expressed by {gamma} -ray. Pretreatment of amifostine before irradiation, however, inhibited the expression of p53 and Bax, the cleavage of PARP and the activation of Caspase-3. In conclusion, amifostine has an inhibitory effect on gonadal cell apoptosis induced by {gamma} -ray irradiation, through lowering the expression of apoptotic signaling peptide and the activation of DNA repair enzymes.

Inhibition of topoisomerase II{alpha} activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

Energy Technology Data Exchange (ETDEWEB)

Grdina, D.J. [Argonne National Lab., IL (United States)]|[Chicago Univ., IL (United States). Dept. of Radiation and Cellular Oncology; Constantinou, A. [Illinois Univ., Chicago, IL (United States). Specialized Cancer Center; Shigematsu, N.; Murley, J.S. [Argonne National Lab., IL (United States)

1993-06-01

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector and antimutagenic agent when it is administered 30 min prior to radiation exposure to Chinese hamster ovary Kl cells at a concentration of 4 mM. Under these exposure conditions, topoisomerase (topo) I and II activities and associated protein contents were measured in the K1 cell line using the DNA relaxation assay, the P4 unknotting assay, and immunoblotting, respectively. WR-1065 was ineffective in modifying topo I activity, but it did reduce topo IIa activity by an average of 50 percent. The magnitude of topo IIa protein content, however, was not affected by these exposure conditions. Cell cycle effects were monitored by the method of flow cytometry. Exposure of cells to 4 mM WR-1065 for a period of up to 6 h resulted in a buildup of cells in the G2 compartment. However, in contrast to topo II inhibitors used in chemotherapy, WR-1065 is an effective radioprotector agent capable of protecting against both radiation-induced cell lethality and mutagenesis. One of several mechanisms of radiation protection attributed to aminothiol compounds such as WR-1065 has been their ability to affect endogenous enzymatic reactions involved in DNA synthesis, repair, and cell cycle progression. These results are consistent with such a proposed mechanism and demonstrate in particular a modifying effect by 2-[(aminopropyl)amino]ethanethiol on type II topoisomerase, which is involved in DNA synthesis.

Protection by S-2-(3-aminopropylamino)ethylphosphorothioic acid against radiation- and cyclophosphamide-induced attenuation in antitumor resistance

International Nuclear Information System (INIS)

Milas, L.; McBride, W.H.; Hunter, N.; Ito, H.

1984-01-01

Studies were performed to investigate whether S-2-(3-amino-propylamino)ethylphosphorothioic acid (WR-2721) can protect antitumor immune rejection responses against the damaging effects of whole-body irradiation (WBI) and cyclophosphamide (CY). The ability of WR-2721 to protect against WBI -induced decreased radioresponse of solitary tumors was also investigated. All experiments were performed with an immunogenic fibrosarcoma syngeneic to C3Hf/ Kam mice. WR-2721 was given i.p. at a dose of 400 mg/kg 30 min before WBI with gamma-rays or CY injection. WBI with 650 rads reduced the number of tumor cells needed for tumor take in 50% of animals from 5.1 X 10(4) cells in normal mice to 2.0 X 10(2). WR-2721 given before WBI almost entirely abolished the effect of WBI : the number of tumor cells needed for tumor take in 50% of animals was 1.4 X 10(4). Treatment of mice with WBI or CY increased the number of tumor nodules in the lung generated by fibrosarcoma cells injected i.v. 5 days later, in a linear dose response. WR-2721 greatly reduced this metastasis enhancement effect of WBI and CY with protection factors of 2.5 for WBI and 1.8 for CY. Fibrosarcomas of 8 mm in diameter exhibited a decreased radiocurability when growing in WBI mice: the dose of irradiation yielding local tumor control in 50% of animals in these mice was 5950 compared to a dose of irradiation yielding local tumor control in 50% of animals of 4160 rads in normal mice. WR-2721 given before WBI inhibited this effect of WBI : the dose of irradiation yielding local tumor control in 50% of animals was 5210 rads. The proportion of macrophages in tumors growing in WBI mice was significantly reduced, but not when WR-2721 was first given. WR-2721 greatly reduced the damaging effects of WBI and CY on natural killer cell activity

A Phase II trial of subcutaneous amifostine and radiation therapy in patients with head-and-neck cancer

International Nuclear Information System (INIS)

Anne, Pramila Rani; Machtay, Mitchell; Rosenthal, David I.; Brizel, David M.; Morrison, William H.; Irwin, David H.; Chougule, Prakash B.; Estopinal, Noel C.; Berson, Anthony; Curran, Walter J.

2007-01-01

Purpose: Intravenous amifostine 200 mg/m 2 reduces xerostomia in head-and-neck cancer patients. This Phase II study evaluated subcutaneous (s.c.) amifostine in a similar patient population. Patients and Methods: Patients received amifostine 500 mg, administered as two 250-mg s.c. injections 60 min before once-daily radiation for head-and-neck cancer (50-70 Gy in 5-7 weeks). The primary endpoint was the incidence of ≥Grade 2 acute xerostomia. Results: Fifty-four patients received s.c. amifostine and radiotherapy. The incidence of ≥Grade 2 acute xerostomia was 56% (95% CI, 43-69%) and the incidence of ≥Grade 2 late xerostomia at 1 year was 45% (95% CI, 29-61%). The incidence of acute xerostomia was lower than reported previously with no amifostine in a controlled study; rates of acute xerostomia were similar between s.c. and i.v. amifostine in the two studies. The rate of late xerostomia with s.c. amifostine was intermediate between rates for i.v. amifostine and no amifostine, and not statistically significantly different from either historical control. Grades 1-2 nausea and emesis were the most common amifostine-related adverse events. Grade 3 amifostine-related adverse events reported by >1 patient included: dehydration (11%); rash (6%); and weight decrease, mucositis, dyspnea, and allergic reaction (each 4%). Seven patients (13%) had serious cutaneous adverse events outside the injection site. One-year rates of locoregional control, progression-free survival, and overall survival were 78%, 75%, and 85%, respectively. Conclusions: Subcutaneous amifostine provides a well-tolerated yet simpler alternative to i.v. amifostine for reducing acute xerostomia in head-and-neck cancer patients

40 CFR 52.2721 - Classification of regions.

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2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Classification of regions. 52.2721 Section 52.2721 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide...

7 CFR 27.21 - Preparation of samples of cotton.

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2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Preparation of samples of cotton. 27.21 Section 27.21... REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Inspection and Samples § 27.21 Preparation of samples of cotton. The samples from each bale shall be prepared as specified in this section...

Stabilization of glucocorticoid receptors in isolated rat hepatocytes by radioprotectants

International Nuclear Information System (INIS)

Karle, J.M.; Ridder, W.E.; Wright, N.; Olmeda, R.; Nielsen, C.J.

1986-01-01

Previous work has shown that glucocorticoid receptors in rat liver homogenate can be stabilized by the addition of MoO 4 plus the sulfhydryl-containing compounds dithiothreitol and WR 1065. The latter is the dephosphorylated, principal metabolite of the radioprotectant WR 2721 (or S-2-(3-aminopropylamino)ethanesphosphorothioic acid). The current work results from applying this knowledge to intact rat hepatocytes. Cells were isolated by collagenase perfusion and incubated in supplemented minimum essential medium at 37 0 C with various concentrations of WR 2721, WR 1065, or vehicle. Samples of these cell suspensions were analyzed at various times for steroid binding capacity by incubating homogenates (27,000 x g supernates) with 50 nM 3 H-triamcinolone acetonide in the presence or absence of excess unlabelled dexamethasone. Concentrations of 10 mM WR 2721 provided marked preservation of the binding capacity (>85% of the initial value at 5 hours) compared to control at 60% of the binding capacity. WR 1065 at 10 mM provided no such protection. This is consistent with the observation that WR 1065 does not pass cell membranes. The authors propose that supplying reducing equivalents to intracellular components such as the glucocorticoid receptor may be one mechanism of the radioprotection afforded by WR 2721

Residual chromosomal damage after radiochemotherapy with and without amifostine detected by 24-color FISH

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Kuechler, A.; Wendt, T.G.; Dreidax, M.; Liehr, T.; Claussen, U.; Pigorsch, S.U.; Dunst, J.

2003-01-01

Background: Amifostine is a radioprotective drug applied to reduce acute radiation toxicity during a course of conventionally fractionated radiotherapy. In the present study, amifostine was used in patients undergoing adjuvant radiochemotherapy for rectal cancer. It was described previously that additional application of amifostine led to less acute skin and bowel toxicity. The present study was aimed to determine whether amifostine has an influence on the amount of residual chromosomal damage. Material and Methods: Peripheral lymphocytes of twelve rectal cancer patients who had undergone postoperative radiochemotherapy 2-3 years ago were investigated for residual chromosomal damage using 24-color fluorescence in situ hybridization (24-color FISH). All twelve patients had received a total dose of 55.8 Gy in conventional fractionation of 1.8 Gy and a 120-h continuous infusion of 5-fluorouracil (5-FU) chemotherapy (1,000 mg/m 2 per day) in the 1st and 5th week of irradiation. Seven out of twelve patients had been given additional amifostine on chemotherapy days (500 mg total dose as short i.v. infusion immediately prior to the daily radiation fraction). Cultivation of lymphocytes and 24-color FISH were performed according to standard protocols. 100 metaphases per patient were analyzed for chromosomal aberrations in a blind study. Results: Analysis of the average number of breaks per mitosis (B/M) revealed an increased amount of residual chromosomal damage in the group treated with amifostine (0.65 B/M [0.32-0.97]) as well as in those treated without amifostine (0.76 B/M [0.31-1.25]). Also the average number of cells containing aberrations per 100 analyzed metaphases was similar (with amifostine: 22.1 [13-32] vs. 24.4 [13-35] without amifostine). The aberration types, occurring as simple translocations, reciprocal translocations, breaks, dicentrics, inversions, rings and complex chromosomal rearrangements, did not show any specific accumulation in one or the other

Amifostine is a potent radioprotector of salivary glands in radioiodine therapy. Structural and ultrastructural findings

International Nuclear Information System (INIS)

Kutta, H.; Kampen, U.; Sagowski, C.; Brenner, W.; Bohuslavizki, K.H.; Paulsen, F.

2005-01-01

Background and purpose: salivary gland impairment following high-dose radioiodine treatment is well recognized. Since differentiated thyroid cancer has a good prognosis, reduction of long-term side effects is important. This study investigates the radioprotective effects of amifostine in salivary glands of rabbits receiving high-dose radioiodine therapy so as to obtain deeper insight in changes on the cellular and ultrastructural level. Material and methods: a total of 20 rabbits were investigated. High-dose radioiodine therapy applying 1 GBq 131 I was performed in 16 animals. Eight of these 16 animals received 200 mg/m 2 body surface amifostine prior to high-dose radioiodine therapy. Four additional rabbits served as controls, two receiving amifostine, the other two no treatment at all. Subsequently, salivary glands (submandibular and parotid glands, respectively) of all animals were examined by light and transmission electron microscopy. Results: parenchymal damage of both parotid and submandibular glands, specially acinar structures comprising cell organelles and nuclei, of animals pretreated with amifostine was much less pronounced than in animals without amifostine pretreatment. Conclusion: the results indicate that parenchymal damage in salivary glands induced by high-dose radioiodine therapy can significantly be reduced by amifostine. Therefore, amifostine therapy may increase quality of life in patients with differentiated thyroid cancer after radioiodine treatment. (orig.)

Cellular thiol levels and aerobic radiosensitization by BSO

International Nuclear Information System (INIS)

Varnes, M.E.; Biaglow, J.E.; Roizin-Towle, L.; Hall, E.J.

1984-01-01

It has been previously shown that pretreatment of A549 human lung carcinoma cells and V79 cells with BSO results in enhancement of the aerobic radiation response. The authors and others have found that addition of either N-acetylcysteine (NAC) or the radioprotector WR-2721 to BSO-treated cells, just prior to irradiation, results in a return to control levels of aerobic sensitivity. NAC and WR-2721 have no effect on the aerobic response of control cells. Reversal of the BSO effect appears unrelated to intracellular thiol levels, since neither NAC nor WR-2721 replenish NPSH within the time that the reversal of the radiation effect is observed. In addition, NAC and WR-2721 must be present during irradiation in order to reverse the BSO sensitization. The authors are continuing to investigate the phenomenon of BSO-induced aerobic sensitization and its reversal, with particular emphasis on the role of membrane thiols and pyridine nucleotide reducing species in radiation response

Interaction between synthetic lecithin and various sulfur-containing radioprotectors

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Rix-Montel, M.A.; Kranck, H.; Vasilescu, D.

1981-01-01

Interaction of the synthetic lecithin dipalmitoylphosphatidylcholine (DPPC) smectic mesophases with sulfur-containing radioprotectors was investigated by means of spectrophotometric and dielectric measurements. Electrical conductivity behavior indicated in all cases that an electrostatic interaction occurs between DPPC and the antiradiation drugs. This interaction is very strong in the case of the WR 2721 molecule. Thermal transitions of DPPC studied by spectrophotometry and conductivity Arrhenius diagrams showed that although the radio-protectors investigated (except WR 2721) delete the pretransition of the lipid phase, the principal transition is not modified. The observed electrostatic interactions are discussed with regard to ionized sites of the phosphatidylcholine lipid head and those of the radioprotectors. The special cases of WR 2721 and its metabolite, WR 1065, are examined

Advances in radioprotection through the use of combined agent regimens

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Weiss, J F; Kumar, K S; Walden, T L; Neta, R; Landauer, M R; Clark, E P [Armed Forces Radiobiology Research Inst., Bethesda, MD (USA)

1990-04-01

Improved radioprotection and reduced lethal toxicity of the phosphorothioate WR 2721 was observed after administration with metals (selenium, zinc or copper). A number of receptor-mediated protectors and other biological compounds, including endotoxin, eicosanoids and cytokines, have at least an additive effect when administered with thiol protectors. Eicosanoids and other bioactive lipids must be administered before exposure, whereas some immunomodulators have activity when administered either before or after exposure, e.g. interleukin administered simultaneously with WR 2721 before or after irradiation enhances the efficacy of WR 2721. The most effective single or combinations of protectors result in a decrement in locomotor activity (index of behavioural toxicity). Recent evidence indicates that caffeine mitigates toxicity of an effective dose of phosphorothioate WR 3689 without altering its efficacy. (UK).

Prophylactic use of amifostine to prevent radiochemotherapy-induced mucositis and xerostomia in head-and-neck cancer

International Nuclear Information System (INIS)

Antonadou, Dosia; Pepelassi, Marizenia; Synodinou, Maria; Puglisi, Maria; Throuvalas, Nicolas

2002-01-01

Purpose: To determine the prophylactic properties of amifostine against acute and late toxicities from radiochemotherapy in patients with head-and-neck cancer. Methods and Materials: Fifty patients were randomized to receive conventional radiotherapy (RT) (2-Gy fractions, 5 days weekly, to a total of 60-74 Gy, depending on the tumor localization and TNM classification) and carboplatin (90 mg/m 2 infusion once per week before RT). Amifostine (300 mg/m 2 ) was administered in the study group only 15-30 min before RT for 6-7.5 weeks. The primary study end point was the grading of acute and late nonhematologic toxicities (mucositis, dysphagia, xerostomia) induced by radiochemotherapy. Secondary end points included treatment duration, hematologic toxicity, and clinical outcome. Results: The treatment duration was significantly shorter in the amifostine-treated group (p=0.013), because treatment interruptions were more frequent in the control group. Acute toxicities (mucositis and dysphagia) were less severe in the amifostine-treated group. By Week 3, all in the control group experienced Grade 2 mucositis compared with only 9% in the amifostine-treated group (p<0.0001). By Week 5, 52.2% of the patients in the control group experienced Grade 4 mucositis compared with 4.5% in the amifostine-treated group (p=0.0006). Similar results were obtained for dysphagia. At 3 months of follow-up, only 27% of patients in the study group experienced Grade 2 xerostomia compared with 73.9% in the control group (p=0.0001). Eighteen months after cessation of therapy, the proportion of patients with Grade 2 xerostomia was 4.5% vs. 30.4% for each respective treatment group (p=0.047). Cytoprotection with amifostine did not affect treatment outcome, with 90.9% complete responses in the amifostine-treated group compared with 78.3% in the control group (p=0.414). Conclusion: Amifostine was effective in reducing mucositis and dysphagia resulting from radiochemotherapy in patients with head

Protection against radiation-induced mutations at the hprt locus by spermine and N,N double-prime-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278)

International Nuclear Information System (INIS)

Grdina, D.J.; Schwartz, J.L.; Shigematsu, N.

1993-06-01

The polyamine spermine and the disulfide NN double-prime-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278) are structurally similar agents capable of binding to DNA. WR-33278 is the disulfide moiety of the clinically studied radioprotective agent (WR-2721). Because of their structural similarities, it was of interest to characterize and compare their radioprotective properties using the endpoints of cell survival and mutation induction at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in Chinese hamster AA8 cells. In order to facilitate both the uptake of VM-33278 into cells and the direct comparison between the protective properties of WR-33278 and spermine, these agents were electroporated into cells. Electroporation alone reduced cell survival to 75% but had no effect on hprt mutation frequency. The electroporation of either spermine or WR-33278 at concentrations greater than 0.01 mM was extremely toxic. The exposure of cells to both electroporation and irradiation gave rise to enhanced cell killing and mutation induction. Cell survival values at a radiation dose of 750 cGy were enhanced by factors of 1.3 and 1.8 following electroporation of 0.01 mM of spermine and WR-33278, respectively, 30 min prior to irradiation. Neither agent was protective at a concentration of 0.001 mM. Protection against radiation-induced hprt mutations was observed for both spermine and WR-33278 under all experimental conditions tested

Radiochemotherapy With Cetuximab, Cisplatin, and Amifostine for Locally Advanced Head and Neck Cancer: A Feasibility Study

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Koukourakis, Michael I.; Tsoutsou, Pelagia G.; Karpouzis, Antonios; Tsiarkatsi, Maria; Karapantzos, Ilias; Daniilidis, Vassilios; Kouskoukis, Constantinos

2010-01-01

Purpose: Radiotherapy (RT) combined with cisplatin or cetuximab is the standard of care for patients with locally advanced head/neck cancer (LA-HNC). The feasibility of radiochemotherapy with cisplatin and cetuximab, supported with amifostine, was herein investigated. Methods and Materials: Forty-three patients with LA-HNC were recruited. Conformal hypofractionated/accelerated RT with amifostine cytoprotection (2.7 Gy/fraction, 21 fractions in 4 weeks) was combined with cisplatin (30 mg/m 2 /week) and cetuximab (standard weekly regimen) therapy. The dose of amifostine was individualized according to tolerance. Results: A high daily amifostine dose (750-1,000 mg) was tolerated by 41.8% of patients, and a standard dose (500 mg) was tolerated by 34.9% of patients. A high amifostine dose was linked to reduced RT delays (p = 0.0003). Grade 3 to 4 (3-4) mucositis occurred in 7/43 (16.2%) patients, and fungal infections occurred in 18/43 (41.8%) patients. Radiation dermatitis was not aggravated. Interruption of cetuximab due to acneiform rash was necessary in 23.3% of patients, while amifostine-related fever and rash were not observed. Severe late radiation sequelae consisted of laryngeal edema (9% laryngeal cases) and cervical strictures (33% of hypopharyngeal cases). Good salivary function was preserved in 6/11 (54.5%) nasopharyngeal cancer patients. The complete response rate was 68.5%, reaching 77.2% in patients with minor radiotherapy delays. The 24-month local control and survival rates were 72.3% and 91%, respectively (median follow-up was 13 months.). Conclusions: In this feasibility study, weekly administration of cisplatin and cetuximab was safely combined with accelerated RT, supported with amifostine, at the cost of a high incidence of acneiform rash but a reduced incidence of amifostine-related fever/rash. A high daily dose of amifostine allows completion of therapy with minor delays.

A New Orally Active, Aminothiol Radioprotector-Free of Nausea and Hypotension Side Effects at Its Highest Radioprotective Doses

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Soref, Cheryl M. [ProCertus BioPharm, Inc., Madison, WI (United States); Hacker, Timothy A. [Department of Medicine, Cardiovascular Physiology Core, University of Wisconsin-Madison, Madison, WI (United States); Fahl, William E., E-mail: fahl@oncology.wisc.edu [ProCertus BioPharm, Inc., Madison, WI (United States); McArdle Laboratory for Cancer Research, University of Wisconsin Carbone Cancer Center, Madison, WI (United States)

2012-04-01

Purpose: A new aminothiol, PrC-210, was tested for orally conferred radioprotection (rats, mice; 9.0 Gy whole-body, which was otherwise lethal to 100% of the animals) and presence of the debilitating side effects (nausea/vomiting, hypotension/fainting) that restrict use of the current aminothiol, amifostine (Ethyol, WR-2721). Methods and Materials: PrC-210 in water was administered to rats and mice at times before irradiation, and percent-survival was recorded for 60 days. Subcutaneous (SC) amifostine (positive control) or SC PrC-210 was administered to ferrets (Mustela putorius furo) and retching/emesis responses were recorded. Intraperitoneal amifostine (positive control) or PrC-210 was administered to arterial cannulated rats to score drug-induced hypotension. Results: Oral PrC-210 conferred 100% survival in rat and mouse models against an otherwise 100% lethal whole-body radiation dose (9.0 Gy). Oral PrC-210, administered by gavage 30-90 min before irradiation, conferred a broad window of radioprotection. The comparison of PrC-210 and amifostine side effects was striking because there was no retching or emesis in 10 ferrets treated with PrC-210 and no induced hypotension in arterial cannulated rats treated with PrC-210. The tested PrC-210 doses were the ferret and rat equivalent doses of the 0.5 maximum tolerated dose (MTD) PrC-210 dose in mice. The human equivalent of this mouse 0.5 MTD PrC-210 dose would likely be the highest PrC-210 dose used in humans. By comparison, the mouse 0.5 MTD amifostine dose, 400 {mu}g/g body weight (equivalent to the human amifostine dose of 910 mg/m{sup 2}), when tested at equivalent ferret and rat doses in the above models produced 100% retching/vomiting in ferrets and 100% incidence of significant, progressive hypotension in rats. Conclusions: The PrC-210 aminothiol, with no detectable nausea/vomiting or hypotension side effects in these preclinical models, is a logical candidate for human drug development to use in healthy

Pre-Treatment with Amifostine Protects against Cyclophosphamide-Induced Disruption of Taste in Mice

Science.gov (United States)

Mukherjee, Nabanita; Carroll, Brittany L.; Spees, Jeffrey L.; Delay, Eugene R.

2013-01-01

Cyclophosphamide (CYP), a commonly prescribed chemotherapy drug, has multiple adverse side effects including alteration of taste. The effects on taste are a cause of concern for patients as changes in taste are often associated with loss of appetite, malnutrition, poor recovery and reduced quality of life. Amifostine is a cytoprotective agent that was previously shown to be effective in preventing chemotherapy-induced mucositis and nephrotoxicity. Here we determined its ability to protect against chemotherapy-induced damage to taste buds using a mouse model of CYP injury. We conducted detection threshold tests to measure changes in sucrose taste sensitivity and found that administration of amifostine 30 mins prior to CYP injection protected against CYP-induced loss in taste sensitivity. Morphological studies showed that pre-treatment with amifostine prevented CYP-induced reduction in the number of fungiform taste papillae and increased the number of taste buds. Immunohistochemical assays for markers of the cell cycle showed that amifostine administration prevented CYP-induced inhibition of cell proliferation and also protected against loss of mature taste cells after CYP exposure. Our results indicate that treatment of cancer patients with amifostine prior to chemotherapy may improve their sensitivity for taste stimuli and protect the taste system from the detrimental effects of chemotherapy. PMID:23626702

Pre-treatment with amifostine protects against cyclophosphamide-induced disruption of taste in mice.

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Nabanita Mukherjee

Full Text Available Cyclophosphamide (CYP, a commonly prescribed chemotherapy drug, has multiple adverse side effects including alteration of taste. The effects on taste are a cause of concern for patients as changes in taste are often associated with loss of appetite, malnutrition, poor recovery and reduced quality of life. Amifostine is a cytoprotective agent that was previously shown to be effective in preventing chemotherapy-induced mucositis and nephrotoxicity. Here we determined its ability to protect against chemotherapy-induced damage to taste buds using a mouse model of CYP injury. We conducted detection threshold tests to measure changes in sucrose taste sensitivity and found that administration of amifostine 30 mins prior to CYP injection protected against CYP-induced loss in taste sensitivity. Morphological studies showed that pre-treatment with amifostine prevented CYP-induced reduction in the number of fungiform taste papillae and increased the number of taste buds. Immunohistochemical assays for markers of the cell cycle showed that amifostine administration prevented CYP-induced inhibition of cell proliferation and also protected against loss of mature taste cells after CYP exposure. Our results indicate that treatment of cancer patients with amifostine prior to chemotherapy may improve their sensitivity for taste stimuli and protect the taste system from the detrimental effects of chemotherapy.

Amifostine reduces the seminiferous epithelium damage in doxorubicin-treated prepubertal rats without improving the fertility status

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Miraglia Sandra M

2010-01-01

Full Text Available Abstract Background Amifostine is an efficient cytoprotector against toxicity caused by some chemotherapeutic drugs. Doxorubicin, a potent anticancer anthracycline, is known to produce spermatogenic damage even in low doses. Although some studies have suggested that amifostine does not confer protection to doxorubicin-induced testicular damage, schedules and age of treatment have different approach depending on the protocol. Thus, we proposed to investigate the potential cytoprotective action of amifostine against the damage provoked by doxorubicin to prepubertal rat testes (30-day-old by assessing some macro and microscopic morphometric parameters 15, 30 and 60 days after the treatment; for fertility evaluation, quantitative analyses of sperm parameters and reproductive competence in the adult phase were also carried out. Methods Thirty-day-old male rats were distributed into four groups: Doxorubicin (5 mg/kg, Amifostine (400 mg/kg, Amifostine/Doxorubicin (amifostine 15 minutes before doxorubicin and Sham Control (0.9% saline solution. "Standard One Way Anova" parametric and "Anova on Ranks" non-parametric tests were applied according to the behavior of the obtained data; significant differences were considered when p Results The rats killed 30 and 60 days after doxorubicin treatment showed diminution of seminiferous epithelium height and reduction on the frequency of tubular sections containing at least one type of differentiated spermatogonia; reduction of sperm concentration and motility and an increase of sperm anomalous forms where observed in doxorubicin-treated animals. All these parameters were improved in the Amifostine/Doxorubicin group only when compared to Doxorubicin group. Such reduction, however, still remained below the values obtained from the Sham Control group. Nevertheless, the reproductive competence of doxorubicin-treated rats was not improved by amifostine pre-administration. Conclusions These results suggest that

Inhibition of topoisomerase II activity in repair-proficient CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

International Nuclear Information System (INIS)

Grdina, D.J.; Constantinou, A.; Shigematsu, N.

1992-09-01

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector under in vitro conditions when it is administered 30 min prior to radiation exposure at a concentration of 4 mM to repair-proficient Chinese hamster ovary Kl cells (i.e., a dose modification factor of 1.4). In contrast, the DNA double-strand break, repair-deficient Chinese hamster ovary xrs-5 cell line is not protected under these conditions (i.e., a dose modification factor of 1.0). Topoisomerase (topo) I and II activities and protein contents were measured in both Kl and xrs-5 cell lines and were found to be similar in magnitude. Neither exposure to radiation, to WR-1065, or to both affected these variables in xrs-5 cells. WR 1065 was effective, however, in reducing topo 11 activity by a factor of 2 in the repair-proficient Kl cell line. Topo II protein content, however, was not affected by these exposure conditions. One of several mechanisms of radiation protection attributed to aminothiol compounds has been their ability to affect enzymatic reactions involved in DNA synthesis, repair, and cell cycle progression. These results demonstrate a modifying effect by 2-[(aminopropyl)amino]ethanethiol on a specific nuclear enzyme (i.e., type H topoisomerase), which is involved in DNA synthesis. These results also suggest that differences do exist between the topo 11 enzymes isolated from the parent repair-proficient Kl and the DNA double-strand break, repair-deficient xrs-5 mutant cell lines

Inhibition of topoisomerase II activity in repair-proficient CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

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Grdina, D.J.; Constantinou, A.; Shigematsu, N.

1992-09-01

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector under in vitro conditions when it is administered 30 min prior to radiation exposure at a concentration of 4 mM to repair-proficient Chinese hamster ovary Kl cells (i.e., a dose modification factor of 1.4). In contrast, the DNA double-strand break, repair-deficient Chinese hamster ovary xrs-5 cell line is not protected under these conditions (i.e., a dose modification factor of 1.0). Topoisomerase (topo) I and II activities and protein contents were measured in both Kl and xrs-5 cell lines and were found to be similar in magnitude. Neither exposure to radiation, to WR-1065, or to both affected these variables in xrs-5 cells. WR 1065 was effective, however, in reducing topo 11 activity by a factor of 2 in the repair-proficient Kl cell line. Topo II protein content, however, was not affected by these exposure conditions. One of several mechanisms of radiation protection attributed to aminothiol compounds has been their ability to affect enzymatic reactions involved in DNA synthesis, repair, and cell cycle progression. These results demonstrate a modifying effect by 2-[(aminopropyl)amino]ethanethiol on a specific nuclear enzyme (i.e., type H topoisomerase), which is involved in DNA synthesis. These results also suggest that differences do exist between the topo 11 enzymes isolated from the parent repair-proficient Kl and the DNA double-strand break, repair-deficient xrs-5 mutant cell lines.

Effect of amifostine on patient assessed clinical benefit in irradiated head and neck cancer

International Nuclear Information System (INIS)

Wasserman, Todd; Mackowiak, John I.; Brizel, David M.; Oster, Wolfgang; Zhang, Jianliang; Peeples, Patricia J.; Sauer, Rolf

2000-01-01

Purpose: To determine if head and neck (H/N) cancer patients receiving daily amifostine during radiation therapy (RT) experienced clinical benefit (improvement in their ability to carry out normal functions with reduced discomfort) compared to nonamifostine treated patients. Methods and Materials: This was an open-label, multi-institutional randomized trial in 303 H/N cancer patients treated with RT +amifostine. Clinical benefit was measured using an 8-item validated Patient Benefit Questionnaire (PBQ) during and up to 11 months after RT. Results: 301 patients completed one or more PBQ assessments. Amifostine patients had significantly better PBQ scores (p < 0.05) than controls. The improvement in PBQ scores was most significant during chronic xerostomia. Conclusions: Amifostine use results in improved Patient Benefit Questionnaire (PBQ) scores, which is indicative of improved oral toxicity related outcomes and improved clinical benefit. Less oral toxicity should lead to preservation of late dental and oral health, and improvements in activities such as diet, nutrition, and sleep

Animal experimental studies on the modification of radiogenic mucositis enoralis through amifostin

International Nuclear Information System (INIS)

Fleischer, G.; Doerr, W.

2004-01-01

The purpose of the present study was to quantify the protective effect of amifostin administered intravenously and subcutaneously in conjunction with one-time irradiation and fractionated irradiation regimes. Ulceration of the mouse lingual mucous membrane equivalent to RTOG/EORTC stage III confluent mucositis served as a clinically relevant parameter. In summary it can be said that the mucoprotective effect of amifostin is clearly dependent on when it is given. It is only effective when administered at the start of fractionated irradiation. It has no effect when administered at a later time, possibly even masking the effect of earlier doses. Amifostin administered subcutaneously, a mode which has been associated with markedly fewer side-effects in clinical studies, and after a suitably adapted time interval following irradiation is just as effective as when it is injected intravenously [de

Cytoprotection with amifostine in radiotherapy or combined radio-chemotherapy of head and neck cancer; Zytoprotektion mit Amifostin in der Strahlentherapie bzw. Strahlen-/Chemotherapie von Kopf-Hals-Tumoren

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Altmann, S.; Hoffmanns, H. [Krankenhaus Maria-Hilf, Moenchengladbach (Germany). Strahlentherapie und Radiologische Onkologie

1999-11-01

Background: A considerable amount of experimental and clinical data prove the cytoprotective effect of amifostine on normal tissue exposed to different types of antineoplastic treatments. The present study examines its influence on the short-term toxicity of either radiotherapy alone or combined radio-chemotherapy in patients with advanced head and neck cancer. Patients and methods: Twenty-three patients with advanced head and neck cancer, mainly Stage III and IV, were treated with preoperative radiation (n=1), pre- as well as postoperative radiotherapy (n=5), postoperative radiation (n=9) or combined postoperative radio-chemotherapy (n=6). Before each radiation application a total dose of 500 mg amifostine was administered intravenously over 15 minutes. The documentation of this unselected patient group was compared retrospectively to a historical control group comprising 17 patients. Results: In 15 patients (65%) of the amifostine group, therapy induced side effects such as mucositis and dermatitis of WHO Grade {<=}2 were detected, requiring interruptions of the radiotherapy (mean: 6.5, maximum 17 days). No mucosa or dermatologic toxicity of WHO Grade 3 or 4 was observed in this group. Significantly more acute toxicity was detected in the historical control group. Stomatitis or epitheliolysis of WHO Grade 3 occurred in 7 patients (41%). The side effects induced by the antineoplastic therapy caused an interruption of treatment in 15 patients (88%) (mean: 16, maximum 40 days; p=0.0016). Conclusion: The application of amifostine before each radiation treatment seems to result in a distinct reduction of short-term toxicity of radiotherapy or combined radio-chemotherapy in patients with head and neck cancer, allowing for a better adherence to the planned radiation time schedule. (orig.) [German] Hintergrund: Zahlreiche experimentelle und klinische Daten belegen die zytoprotektive Wirkung von Amifostin auf gesundes Gewebe bei Anwendung verschiedener antineoplastischer

The rat acute-phase protein {alpha}{sub 2}-macroglobulin plays a central role in amifostine-mediated radioprotection

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Mirjana, Mihailovic; Goran, Poznanovic; Nevena, Grdovic; Melita, Vidakovic; Svetlana, Dinic; Ilijana, Grigorov; Desanka, Bogojevic, E-mail: mista@ibiss.bg.ac.r [Department of Molecular Biology, Institute for Biological Research ' Sinisa Stankovic' , University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade (Serbia)

2010-09-15

Previously we reported that elevated circulating concentrations of the acute-phase (AP) protein {alpha}{sub 2}-macroglobulin ({alpha}{sub 2}M), either as typically occurring in pregnant female rats or after administration to male rats, provides radioprotection, displayed as 100% survival of experimental animals exposed to total-body irradiation with 6.7 Gy (LD{sub 50/30}) x-rays, that is as effective as that afforded by the synthetic radioprotector amifostine. The finding that amifostine administration induces a 45-fold increase in {alpha}{sub 2}M in the circulation led us to hypothesise that {alpha}{sub 2}M assumes an essential role in both natural and amifostine-mediated radioprotection in the rat. In the present work we examined the activation of cytoprotective mechanisms in rat hepatocytes after the exogenous administration of {alpha}{sub 2}M and amifostine. Our results showed that the IL6/JAK/STAT3 hepatoprotective signal pathway, described in a variety of liver-injury models, upregulated the {alpha}{sub 2}M gene in amifostine-pretreated animals. In both {alpha}{sub 2}M- and amifostine-pretreated rats we observed the activation of the Akt signalling pathways that mediate cellular survival. At the cellular level this was reflected as a significant reduction of irradiation-induced DNA damage that allowed for the rapid and complete restoration of liver mass and ultimately at the level of the whole organism the complete restoration of body weight. We conclude that the selective upregulation of {alpha}{sub 2}M plays a central role in amifostine-provided radioprotection.

The potentiation of the radioprotective efficacy of two medical countermeasures, gamma-tocotrienol and amifostine, by a combination prophylactic modality

International Nuclear Information System (INIS)

Singh, Vijay K.; Fatanmi, Oluseyi O.; Wise, Stephen Y.; Newman, Victoria L.; Romaine, Patricia L.P.; Seed, Thomas M.

2016-01-01

This study was designed to evaluate the possible potentiation of survival protection afforded by relatively low-dose amifostine prophylaxis against total body irradiation in combination with a protective, less toxic agent, gamma-tocotrienol (GT3). Mice were administered amifostine and/or GT3, then exposed to 9.2 Gy 60 Co γ-irradiation and monitored for survival for 30 days. To investigate cytokine stimulation, mice were administered amifostine or GT3; serum samples were collected and analyzed for cytokines. Survival studies show single treatments of GT3 or amifostine significantly improved survival, compared to the vehicle, and combination treatments resulted in significantly higher survival compared to single treatments. In vivo studies with GT3 confirmed prior work indicating GT3 induces granulocyte colony-stimulating factor (G-CSF). This approach, the prophylactic combination of amifostine and GT3, which act through different mechanisms, shows promise and should be investigated further as a potential countermeasure for acute radiation syndrome. (authors)

14 CFR 272.1 - Purpose.

Science.gov (United States)

2010-01-01

... and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS ESSENTIAL AIR SERVICE TO THE FREELY ASSOCIATED STATES § 272.1 Purpose. Paragraph 5 of Article IX... Transportation (Department), as successor to the Civil Aeronautics Board (Board), to guarantee essential air...

Intrarectal amifostine suspension may protect against acute proctitis during radiation therapy for prostate cancer: A pilot study

International Nuclear Information System (INIS)

Singh, Anurag K.; Menard, Cynthia; Guion, Peter; Simone, Nicole L.; Smith, Sharon; Crouse, Nancy Sears; Godette, Denise J.; Cooley-Zgela, Theresa; Sciuto, Linda C.; Coleman, Jonathan; Pinto, Peter; Albert, Paul S.; Camphausen, Kevin; Coleman, C. Norman

2006-01-01

Purpose: Our goal was to test the ability of intrarectal amifostine to limit symptoms of radiation proctitis. Methods and Materials: The first 18 patients received 1 g of intrarectal amifostine suspension placed 30-45 min before each radiation treatment. The following 12 patients received 2 g of amifostine. Total dose prescribed ranged from 66 to 76 Gy. All patients were treated with three-dimensional conformal radiation therapy. The suspension remained intrarectal during treatment and was expelled after treatment. For gastrointestinal symptoms, during treatment and follow-up, all patients had a Radiation Therapy Oncology Group (RTOG) grade recorded. Results: Median follow-up was 18 months (range, 6-24 months). With 2 g vs. 1 g amifostine, there was a nearly significant decrease in RTOG Grade 2 acute rectal toxicity. Seven weeks after the start of radiation therapy, the incidence of Grade 2 toxicity was 33% in the 1-g group (6/18) compared with 0% (0/12) in the 2-g group (p = 0.06). No Grade 3 toxicity or greater occurred in this study. Conclusion: This trial suggests greater rectal radioprotection from acute effects with 2 g vs. 1 g amifostine suspension. Further studies should be conducted in populations at higher risk for developing symptomatic acute and late proctitis

In vitro evaluation of some latent radioprotective compounds

International Nuclear Information System (INIS)

Vos, O.; Budke, L.; Grant, G.A.

1976-01-01

In tissue culture, protection against X-irradiation by a number of cysteamine derivatives was studied and the results were compared with data obtained in mice. Compounds with a covered SH group, like WR 638, cysteamine phosphate, WR 2721, and AE 48527, showed practically no protection when dissolved in tissue-culture medium, but developed a protective activity when dissolved in rat blood. Thiol measurements demonstrated that in rat blood the compounds were partly hydrolysed to thiols. C511 was also hydrolysed in culture medium and was slightly less effective than cysteamine in culture medium. Cysteamine phosphate was hydrolysed more easily than cysteamine sulphate and the protective activity in rat blood was better. WR 2721 was also partly hydrolysed in rat blood. The in vitro protection of this compound was disappointing when compared with results in vivo. Its SH form (WR 1065) also showed less protection than expected from in vivo experiments. Thus, the little protection by WR 2721 in vitro in rat blood was not only due to its incomplete conversion into its thiol. Longer incubation times and the use of rat blood as a solvent brought the protective activity of WR 1065 almost up to the level of cysteamine. This may indicate that WR 1065 penetrates the cells poorly. WR 1065 was the only compound which was studied whose protective activity in vitro was improved appreciably by dissolving it in rat plasma. (author)

In vitro evaluation of some latent radioprotective compounds

International Nuclear Information System (INIS)

Vos, O.; Grant, G.A.; Budke, L.

1976-08-01

Protection against X-irradiation by a number of cysteamine derivatives was studied in tissue culture and the results were compared with data obtained in mice. Compounds with a covered SH group like WR 638, cysteamine phosphate, WR 2721 and AE 48527, showed practically no protection when dissolved in tissue culture medium, but developed a protective activity when dissolved in rat blood. Thiol measurements demonstrated that in rat blood the compounds were partly hydrolysed to thiols. C511 was also hydrolysed in culture medium and was slightly less effective than cysteamine in culture medium. Cysteamine phosphate was hydrolysed more easily than cysteamine sulphate and concordantly the protective activity in rat blood was better. WR 2721 was also partly hydrolysed in rat blood. The in vitro protection of this compound was disappointing when compared with results in vivo. Its SH form (WR 1065) also showed less protection than expected from in vivo experiments. Thus the little protection by WR 2721 in vitro in rat blood is not only due to its incomplete conversion into its thiol. Longer incubation times and the use of rat blood as a solvent brought the protective activity of WR 1065 up to almost the level of cysteamine. This may indicate that WR 1065 is poorly penetrating into the cells. WR 1065 was the only compound studied whose protective activity in vitro was improved appreciably by dissolving it in rat plasma

Radioprotection of salivary glands by S-2-(3-aminopropylamino)-ethylphosphorothioic (amifostine) obtained in a rabbit animal model

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Bohuslavizki, Karl H; Klutmann, Susanne; Jenicke, Lars; Brenner, Winfried; Feyerabend, Bernd; Henze, Eberhard; Clausen, Malte

1999-08-01

Background: Impairment of salivary gland function following high-dose radioiodine treatment (HDRIT) is a well-recognized side effect of the treatment. Because differentiated thyroid cancer has an excellent prognosis, reduction of long-term side-effects is mandatory. Therefore, the aim of this study was to investigate the radioprotective effect of amifostine in a rabbit animal model. Methods: Salivary gland scintigraphy was performed in a total of 16 New Zealand White rabbits. Uptake of {sup 99m}Tc-pertechnetate was calculated in percentage of injected activity as a quantitative measure of both salivary gland and thyroid function. Reproducibility of salivary gland scintigraphy was evaluated in one rabbit without any intervention. Fifteen rabbits were studied prior to and up to 6 months after high-dose radioiodine treatment applying 2 GBq {sup 131}I. Ten animals received 200 mg/kg amifostine prior to high-dose radioiodine therapy, and 5 served as controls. Salivary glands were examined histopathologically. Results: Variation coefficient of parenchymal function was less than 3.8% in salivary glands. Prior to HDRIT, thyroid uptake was 0.417 {+-} 0.373% and 0.421 {+-} 0.241% in control and amifostine-treated rabbits, respectively. Four weeks after HDRIT, complete ablation of the thyroid was achieved in both groups. Prior to HDRIT, uptake of {sup 99m}Tc-pertechnetate in salivary glands of five control rabbits was not significantly different from ten amifostine-treated rabbits. In control rabbits 6 months after HDRIT, parenchymal function was reduced significantly (p < 0.0001) by 75.3 {+-} 5.3% and 53.6 {+-} 17.4% in parotid and submandibular glands, respectively. In contrast, in amifostine-treated rabbits, parenchymal function was reduced by 10.6 {+-} 3.4% and 6.5 {+-} 4.3% (p > 0.05) in parotid and submandibular glands, respectively. Histopathologically, marked lipomatosis was observed in control animals but was negligible in amifostine-treated animals. Conclusion

Acute toxicity of postoperative radiochemotherapy with amifostine vs radiochemotherapy alone in head and neck cancer patients. Preliminary results of a randomized trial; Nebenwirkungen einer postoperativen Radiochemotherapie mit Amifostin versus alleiniger Radiochemotherapie bei Kopf-Hals-Tumoren. Vorlaeufige Ergebnisse einer prospektiv randomisierten Untersuchung

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Vacha, P; Marx, M; Engel, A; Richter, E; Feyerabend, T [Medizinische Univ. Luebeck (Germany). Klinik fuer Strahlentherapie und Nuklearmedizin

1999-11-01

Purpose: Experimental and clinical data suggest a reduction of radiation-induced acute toxicity by amifostine. We investigated this issue in a randomized trial comparing radiochemotherapy (RCT) versus radiochemotherapy and amifostine (RCT+A) in patients with head and neck cancer. Patients and methods: Forty-seven patients with pharyngeal or laryngeal cancer (T{sub 1-2}N{sub 1-2}G{sub 3},T{sub 3-4}N{sub 0-2}G{sub 1-3}) were randomized to receive RCT alone (21 patients) or RCT+A (21 patients). Patients were irradiated up to 60 Gy (R{sub 0}) or 70 Gy (R{sub 1/2}). Chemotherapy consisted of 70 mg/m{sup 2} carboplatin and was administered over 5 days in the 1st and 5th week of the radiotherapy course. 250 mg amifostine were applied daily just before each radiotherapy session. Acute toxicity was evaluated according to the Common Toxicity Criteria (CTC). As for xerostomia no patients with laryngeal cancer were assessed because in these cases only small volumes of the salivary glands were within the treatment volume. To evaluate the overall toxicity a summarized CTC score of all observed side effects was calculated. Results: Forty-two patients were evaluable. Clinical characteristics (age, sex, Karnofsky index, tumor-staging) were well balanced in both treatment groups. Amifostine provided reduction in xerostomia and mucositis. Conclusions: According to our preliminary results amifostine has a radioprotective effect on salivary glands. Mucositis can be reduced during radiochemotherapy. At this point of patient accrual the difference between both groups are statistically not significant. To improve the radioprotective effects of amifostine in clinical practice the application of a higher dose (>250 mg) seems to be necessary. (orig.) [German] Ziel: Diese Untersuchung soll die Frage beantworten, ob bei der postoperativen Radiochemotherapie von Patienten mit HNO-Tumoren eine zusaetzliche Amifostin-Medikation Ausmass und Haeufigkeit akuter Strahlenreaktionen vermindert

Radioprotection of salivary glands by S-2-(3-aminopropylamino)-ethylphosphorothioic (amifostine) obtained in a rabbit animal model

International Nuclear Information System (INIS)

Bohuslavizki, Karl H.; Klutmann, Susanne; Jenicke, Lars; Brenner, Winfried; Feyerabend, Bernd; Henze, Eberhard; Clausen, Malte

1999-01-01

Background: Impairment of salivary gland function following high-dose radioiodine treatment (HDRIT) is a well-recognized side effect of the treatment. Because differentiated thyroid cancer has an excellent prognosis, reduction of long-term side-effects is mandatory. Therefore, the aim of this study was to investigate the radioprotective effect of amifostine in a rabbit animal model. Methods: Salivary gland scintigraphy was performed in a total of 16 New Zealand White rabbits. Uptake of 99m Tc-pertechnetate was calculated in percentage of injected activity as a quantitative measure of both salivary gland and thyroid function. Reproducibility of salivary gland scintigraphy was evaluated in one rabbit without any intervention. Fifteen rabbits were studied prior to and up to 6 months after high-dose radioiodine treatment applying 2 GBq 131 I. Ten animals received 200 mg/kg amifostine prior to high-dose radioiodine therapy, and 5 served as controls. Salivary glands were examined histopathologically. Results: Variation coefficient of parenchymal function was less than 3.8% in salivary glands. Prior to HDRIT, thyroid uptake was 0.417 ± 0.373% and 0.421 ± 0.241% in control and amifostine-treated rabbits, respectively. Four weeks after HDRIT, complete ablation of the thyroid was achieved in both groups. Prior to HDRIT, uptake of 99m Tc-pertechnetate in salivary glands of five control rabbits was not significantly different from ten amifostine-treated rabbits. In control rabbits 6 months after HDRIT, parenchymal function was reduced significantly (p 0.05) in parotid and submandibular glands, respectively. Histopathologically, marked lipomatosis was observed in control animals but was negligible in amifostine-treated animals. Conclusion: Parenchymal damage in salivary glands induced by high-dose radioiodine treatment can be significantly reduced by amifostine in this rabbit animal model. This corresponds to data obtained in patients with differentiated thyroid cancer

Randomized phase III trial of postoperative radiochemotherapy {+-} amifostine in head and neck cancer. Is there evidence for radioprotection?

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Vacha, P; Fehlauer, F; Mahlmann, B; Marx, M; Richter, E [Dept. of Radiation Oncology and Nuclear Medicine, Univ. of Luebeck (Germany); Hinke, A [WiSP Research Inst., Langenfeld (Germany); Sommer, K [Dept. of Head and Neck Surgery, Univ. of Luebeck (Germany); Feyerabend, T [Practice for Radiation Therapy Bonn-Rhein-Sieg, Bonn (Germany)

2003-06-01

Purpose: Experimental and clincial data suggest a reduction of radiation-induced acute toxicity by amifostine (A). We investigated this issue in a randomized trial comparing radiochemotherapy (RT + CT) versus radiochemotherapy plus amifostine (RC + CT + A) in patients with head and neck cancer. Patients and Methods: 56 patients with oro-/hypopharynx or larynx cancer (T1-2 N1-2 G3, T3-4 N0-2 G1-3) were randomized to received RC + CT alone or RC + CT + A. Patients were irradiated up to 60 Gy (R0) or 70 Gy (R1/2) and received chemotherapy (70 mg/m{sup 2} carboplatin, day 1-5 week 1 and 5 of radiotherapy). 250 mg amifostine were applied daily before each radiotherapy session. Acute toxicity was evaluated according to the common toxicity criteria (CTC). As for acute xerostomia, patients with laryngeal cancer were excluded from evaluation. Results: 50 patients were evaluable (25 patients in the RC + CT, 25 patients in the RC + CT + A group). Clinical characteristics were well balanced in both treatment groups. Amifostine provided reduction in acute xerostomia and mucositis but had no obvious influence on Karnofsky performance status, body weight, cutaneous side effects, and alopecia. The differences between both groups were statistically significant for acute xerostomia and nonsignificant, but with a trend for mucositis. Conclusions: According to our results, there is a radioprotective effect on salivary glands and a potential effect on oral mucosa by amifostine in postoperative radiotherapy combined with carboplatin. To improve the radio- and chemoprotective effects of amifostine in clinical practice, the application of a higher dose (> 250 mg) seems to be necessary. (orig.)

Daily amifostine given concomitantly to chemoradiation in head and neck cancer. A pilot study

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Trog, D.; Bank, P.; Wendt, T.G. [Friedrich-Schiller Univ., Jena (Germany). Dept. of Radiation Oncology; Koscielny, S.; Beleites, E. [Friedrich-Schiller Univ., Jena (Germany). Dept. of Ear Nose Throat Diseases

1999-09-01

Background: In patients with loco-regionally advanced head and neck cancer conventionally fractionated radiotherapy alone results in poor loco-regional control and survival rates. Treatment intensification by simultaneous administration of cytotoxic drugs produces higher acute morbidity. Therefore chemical radioprotection of normal tissues may be of clinical benefit. Patients and Methods: In a pilot study patients with advanced nonresectable head neck cancer treated with conventionally fractionated radical radiotherapy (60 to 66 Gy total doses) and concomitantly given 5-fluorouracil as protracted venous infusion, 250 mg/sqm/24 h over the entire treatment period were given amifostine 300 mg absolutely before each fraction. Acute treatment related mobidity was scored according to CTC classification and loco-regional control and survival rates were estimated. Comparison was made with a historical control group of identical chemoradiation but without amifostine application. Results: Chemoradiation induced oral mucositis was delayed and showed significant lower degrees at all 10 Gy increments (p<0.05) except 60 Gy and over (p>0.05). No significant toxicity was recorded with respect to blood pressure, serum calcium, potassium, hematologic parameters, emesis, nausea or body weight loss. Progression free survival and overall survival probability at 2 years were not statistically different in both cohorts. Conclusion: Amifostine given before each fraction of radiotherapy over 6 weeks has no cumulative toxicity, was well tolerated and may reduce treatment induced oral mucositis. No tumor protective effect was observed. (orig.) [German] Hintergrund: Bei Patienten mit lokoregionaer fortgeschrittenen Karzinomen im Kopf-Hals-Bereich fuehrt die alleinige konventionell fraktionierte Radiotherapie zu unuenstigen lokoregionaeren Tumorkontrollraten und Ueberlebensraten. Die Therapieintensivierung durch simultane Radiochemotherapie fuehrt zu gesteigerter Akutmorbiditaet. Die chemische

Behavioral toxicity of selected radioprotectors

Science.gov (United States)

Landauer, M. R.; Davis, H. D.; Kumar, K. S.; Weiss, J. F.

1992-10-01

Effective radioprotection with minimal behavioral disruption is essential for the selection of protective agents to be used in manned spaceflight. This overview summarizes the studies on the behavioral toxicity of selected radioprotectors classified as phosphorothioates (WR-2721, WR-3689), bioactive lipids (16, 16 dimethylprostaglandin E2(DiPGE2), platelet activating factor (PAF), leukotriene C4), and immunomodulators (glucan, synthetic trehalose dicorynomycolate, and interleukin-1). Behavioral toxicity was examined in laboratory mice using a locomotor activity test. For all compounds tested, there was a dose-dependent decrease in locomotor behavior that paralleled the dose-dependent increase in radioprotection. While combinations of radioprotective compounds (DiPGE2 plus WR-2721) increased radioprotection, they also decreased locomotor activity. The central nervous system stimulant, caffeine, was able to mitigate the locomotor decrement produced by WR-3689 or PAF.

Randomized phase III trial of postoperative radiochemotherapy ± amifostine in head and neck cancer. Is there evidence for radioprotection?

International Nuclear Information System (INIS)

Vacha, P.; Fehlauer, F.; Mahlmann, B.; Marx, M.; Richter, E.; Hinke, A.; Sommer, K.; Feyerabend, T.

2003-01-01

Purpose: Experimental and clincial data suggest a reduction of radiation-induced acute toxicity by amifostine (A). We investigated this issue in a randomized trial comparing radiochemotherapy (RT + CT) versus radiochemotherapy plus amifostine (RC + CT + A) in patients with head and neck cancer. Patients and Methods: 56 patients with oro-/hypopharynx or larynx cancer (T1-2 N1-2 G3, T3-4 N0-2 G1-3) were randomized to received RC + CT alone or RC + CT + A. Patients were irradiated up to 60 Gy (R0) or 70 Gy (R1/2) and received chemotherapy (70 mg/m 2 carboplatin, day 1-5 week 1 and 5 of radiotherapy). 250 mg amifostine were applied daily before each radiotherapy session. Acute toxicity was evaluated according to the common toxicity criteria (CTC). As for acute xerostomia, patients with laryngeal cancer were excluded from evaluation. Results: 50 patients were evaluable (25 patients in the RC + CT, 25 patients in the RC + CT + A group). Clinical characteristics were well balanced in both treatment groups. Amifostine provided reduction in acute xerostomia and mucositis but had no obvious influence on Karnofsky performance status, body weight, cutaneous side effects, and alopecia. The differences between both groups were statistically significant for acute xerostomia and nonsignificant, but with a trend for mucositis. Conclusions: According to our results, there is a radioprotective effect on salivary glands and a potential effect on oral mucosa by amifostine in postoperative radiotherapy combined with carboplatin. To improve the radio- and chemoprotective effects of amifostine in clinical practice, the application of a higher dose (> 250 mg) seems to be necessary. (orig.)

The histopathological comparison of L-carnitine with amifostine for protective efficacy on radiation-induced acute small intestinal toxicity

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Murat Caloglu

2012-01-01

Full Text Available Background: The aim of the study was to compare the protective efficacy of l-carnitine (LC to amifostine on radiation-induced acute small intestine damage. Materials and Methods: Thirty, 4-week-old Wistar albino rats were randomly assigned to four groups - Group 1: control (CONT, n = 6, Group 2: irradiation alone (RT, n = 8, Group 3: amifostine plus irradiation (AMI+RT, n = 8, and Group 4: l-Carnitine plus irradiation (LC+RT, n = 8. The rats in all groups were irradiated individually with a single dose of 20 Gy to the total abdomen, except those in CONT. LC (300 mg/kg or amifostine (200 mg/kg was used 30 min before irradiation. Histopathological analysis of small intestine was carried out after euthanasia. Results: Pretreatment with amifostine reduced the radiation-induced acute degenerative damage (P = 0.009 compared to the RT group. Pretreatment with LC did not obtain any significant difference compared to the RT group. The vascular damage significantly reduced in both of the AMI+RT (P = 0.003 and LC+RT group (P = 0.029 compared to the RT group. The overall damage score was significantly lower in the AMI+RT group than the RT group (P = 0.009. There was not any significant difference between the LC+RT and RT group. Conclusions: Amifostine has a marked radioprotective effect against all histopathological changes on small intestinal tissue while LC has limited effects which are mainly on vascular structure.

Cytoprotection with amifostine in the simultaneous radio-chemotherapy of recurrent head and neck cancer; Zytoprotection mit Amifostin im Rahmen der Radiochemotherapie bei vorbestrahlten Kopf-Hals-Karzinomen

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Buentzel, J.; Weinaug, R.; Kuettner, K. [Zentralklinikum gGmbH Suedthueringen, Suhl (Germany). Klinik fuer Hals-Nasen-Ohren-Heilkunde, Plastische Operationen; Glatzel, M.; Froehlich, D. [Zentralklinikum gGmbH Suedthueringen, Suhl (Germany). Klinik fuer Strahlentherapie; Schuth, J. [Essex Pharma, Muenchen (Germany)

1999-11-01

Purpose: The radiotherapeutic possibilities are limited for patients with a recurrent or second head and neck cancer if the patient was already irradiated in the first therapy. In the presented study we investigated the changes of this situation due to the usage of amifostine in the case of re-irradiation (simultaneous radio-chemotherapy). Patients and methods: Between 1995 and 1997 we treated 14 patients with a recurrent or second malignancy of the head and neck region by a simultaneous radio-chemotherapy (20x1.5 Gy, Carboplatin 70 mg/m{sup 2} BSA on days 1 to 5 and 16 to 20, 500 mg amifostine prior to every carboplatin infusion). Six out of 14 patients got an additional brachytherapy (10 to 15 Gy) to increase the local dose because of a residual tomor. In 4 cases the treatment was an adjunctive one, following the surgical tumor debulking. Results: We have seen 3 complete remissions (21.4%), and 8 partial remissions (57.1%). The median time of observation in 13 months now. Three out of 14 patients died, 2 because of the tumor. Hematological toxicities: Side effects Grade 2 WHO were seen only in 1 patient. Acute non-hematological toxicities: Mucositis Grade 0/1 in 7 patients, mucositis Grade 2 in 7 patients, dysphagia Grade 0/1 in 9 patients, dysphagia Grade 2 in 5 patients, xerostomia Grade 1 in 9 patients, xerostomia Grade 2 in 3 patients. We registrated only 1 serious late toxicity due to radio-chemotherapy: 4 months after brachytherapy a patient (with laryngectomy) developed a submental fistula. Conclusion: These first results suggest that the usage of amifostine offers new potential ways for re-irradiation of patients with recurrent or second malignancies in the head neck region. (orig.) [German] Ziel: Bei einem Rezidiv- oder Zweitkarzinom im Kopf-Hals-Bereich sind die radiotherapeutischen Moeglichkeiten bei bereits vorbestrahlten Patienten sehr begrenzt. Inwieweit die Integration des selektiven Zytoprotektivums Amifostin in eine nochmalige Radiochemotherapie

Changes in spermatid population of mice following radiation exposure in the presence of a Thiophosphate

International Nuclear Information System (INIS)

Jaimala, H.; Bhartiya, C.

1987-01-01

Adult Swiss albino mice were exposed to 3, 6 and 8 Gy of 60 Co gamma rays in three separate groups after i.p. injection of a thiophosphate compound (WR-2721) in aqueous solution. Another group of animals was irradiated similary without WR-2721 pretreatment for comparative study. Animals from both groups were killed at various post-irradiation intervals. Testes were removed, fixed in the Bouins's fluid, paraffin section were cut and stained with PAS-haematoxylin. Number of spermatids was counted from the transverse section of testes and corrected for errors. Spermatid population was found to decrease continuously up to day 28 after exposure at all the intervalls and dose levels studied in both the drug treated (experimental) and non-drug treated (control) animals. Experimental testes showed significantly higher spermatid population than their respective controls at all the dose levels and intervals studied. Higher spermatid population observed in the experimental groups may be attributed to the radioprotective effect of WR-2721. The degree of protection was higher at 8 Gy than at 3 and 6 Gy

AFRRI (Armed Forces Radiobiology Research Institute) reports, April, May, June 1987. Technical report

Energy Technology Data Exchange (ETDEWEB)

1987-07-01

This document is a collection of reprinted technical reports. Partial contents include: Effect of ionizing radiation on prostaglandins and gastric secretion in rhesus monkeys; Characterization of rat prothymocyte with monoclonal antibodies recognizing rat lymphocyte membrane antigenic determinants; Effects of subdiaphragmatic vagotomy on the acquisition of a radiation-induced condition taste aversion; Ethanol-induced taste aversions; Lack of involvement of acetaldehyde and the area postrema; Dose and time relationships of the radioprotector WR-2721 on locomotor activity in mice; Purification and analysis of rat hematopoietic stem cells by flow cytometry, Plasma histamine and catecholamine levels during hypotension induced by morphine and compound 48/80; Effects of ionizing radiation on hippocampal excitability, Tumor necrosis factor/cachectin is a less-potent inducer of serum amyloid A synthesis than interleukin 1, Protection of mice against fission-neutron irradiation by WR-2721 or WR-151327, Induction of colony-stimulating factor in vivo by recombinant interleukin 1 a and recombinant tumor necrosis factor alpha; 16,16-Dimethyl prostaglandin E2 increases survival in mice following irradiation, Selenium pretreatment enhances the radioprotective effect and reduces the lethal toxicity of WR-2721; Rat phantom depth dose studies in electron, x-ray, gamma-ray, and reactor-radiation fields; Wall attenuation and scatter characteristics of ionization chambers at Armed Forces Radiobiology Research Institute.

Amifostine protects rat kidneys during peptide receptor radionuclide therapy with [177Lu-DOTA0,Tyr3]octreotate

International Nuclear Information System (INIS)

Rolleman, Edgar J.; Forrer, Flavio; Bernard, Bert; Bijster, Magda; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de; Vermeij, Marcel

2007-01-01

In peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues, the kidneys are the major dose-limiting organs, because of tubular reabsorption and retention of radioactivity. Preventing renal uptake or toxicity will allow for higher tumour radiation doses. We tested the cytoprotective drug amifostine, which selectively protects healthy tissue during chemo- and radiotherapy, for its renoprotective capacities after PRRT with high-dose [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate. Male Lewis rats were injected with 278 or 555 MBq [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate to create renal damage and were followed up for 130 days. For renoprotection, rats received either amifostine or co-injection with lysine. Kidneys, blood and urine were collected for toxicity measurements. At 130 days after PRRT, a single-photon emission computed tomography (SPECT) scan was performed to quantify tubular uptake of 99m Tc-dimercaptosuccinic acid (DMSA), a measure of tubular function. Treatment with 555 MBq [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate resulted in body weight loss, elevated creatinine and proteinuria. Amifostine and lysine treatment significantly prevented this rise in creatinine and the level of proteinuria, but did not improve the histological damage. In contrast, after 278 MBq [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate, creatinine values were slightly, but not significantly, elevated compared with the control rats. Proteinuria and histological damage were different from controls and were significantly improved by amifostine treatment. Quantification of 99m Tc-DMSA SPECT scintigrams at 130 days after [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate therapy correlated well with 1/creatinine (r 2 = 0.772, p 177 Lu-DOTA 0 ,Tyr 3 ]octreotate. Besides lysine, amifostine might be used in clinical PRRT as well as to maximise anti-tumour efficacy. (orig.)

Chemical inhibition of host toxicity as a means of overcoming tumor resistance

International Nuclear Information System (INIS)

Yuhas, J.M.; Pardini, M.C.; Children's Hospital of Philadelphia, PA)

1983-01-01

Largely because we have accumulated so much information on WR-2721 in the past decade, we know that this drug is not a universal panacea which will solve all the problems which confront us. However, in those instances where it would appear applicable, clinical testing would appear appropriate. Thanks largely to the efforts of M.M. Kligerman, these studies have been initiated. In those instances where WR-2721 would appear inappropriate or not of sufficient activity, the information we have already accumulated should point the way to the development of qualitatively and/or quantitatively superior drugs which selectively inhibit host toxicity

Assessment of the radioprotective effects of amifostine and melatonin on human lymphocytes irradiated with gamma-rays in vitro

International Nuclear Information System (INIS)

Kopjar, N.; Miocic, S.; Ramic, S.; Milic, M.; Viculin, T.

2005-01-01

Radioprotective effects of amifostine and melatonin on human peripheral blood irradiated with g-rays were investigated using the micronucleus (MN) assay and the analysis of sister chromatid exchanges (SCE). Duplicate blood samples were pre-treated with amifostine (7.7 mM), melatonin (2 mM) and their combination for 30 minutes. Negative controls were also included. After treatment with radioprotectors, one blood sample from each experimental group was exposed to g-rays from a 6 0C o source. The radiation dose absorbed was 2 Gy. Pre-treated irradiated blood samples showed a decrease in the total number of MN and in the number of cells with more than one MN. Moreover, they also showed significantly lower mean SCE values. Our results indicate that amifostine, melatonin and their combination in vitro have radioprotective effects on g-irradiated human peripheral blood lymphocytes, with no significant genotoxicity. Therefore, it may be reasonable to use them in combination, adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. Before employment, this combination should be extensively tested in vitro and in vivo, using the same and other biomarkers for different radiation dose and concentration ranges of both radioprotectors.(author)

Comparison of the protective roles of L-carnitine and amifostine against radiation-induced acute ovarian damage by histopathological and biochemical methods

Directory of Open Access Journals (Sweden)

Vuslat Yurut-Caloglu

2015-01-01

Full Text Available Purpose: The aim of this study was to compare the radioprotective efficacies of L-carnitine (LC and amifostine against radiation-induced acute ovarian damage. Materials and Methods: Forty-five, 3-month-old Wistar albino rats were randomly assigned to six groups. Control (CONT, n = 7; irradiation alone RT: radiation therapy (RT, n = 8; amifostine plus irradiation (AMI + RT, n = 8; LC plus irradiation (LC + RT, n = 8; LC and sham irradiation (LC, n = 7; and amifostine and sham irradiation (AMI, n = 7. The rats in the AMI + RT, LC + RT and RT groups were irradiated with a single dose of 20 Gy to the whole abdomen. LC (300 mg/kg and amifostine (200 mg/kg was given intraperitoneally 30 min before irradiation. Five days after irradiation, both antral follicles and corpus luteum in the right ovaries were counted, and tissue levels of malondialdehyde (MDA and advanced oxidation protein product (AOPP were measured. Results: Irradiation significantly decreased antral follicles and corpus luteum (P: 0.005 and P 0.05. The level of MDA and AOPP significantly increased after irradiation (P = 0.001 and P 0.005. The levels of both MDA and AOPP were also similar when LC + RT is compared with AMI + RT group (P > 0.005. Conclusions: L-carnitine and amifostine have a noteworthy and similar radioprotective effect against radiation-induced acute ovarian toxicity.

Effects of WR1065 on 6-hydroxydopamine-induced motor imbalance: Possible involvement of oxidative stress and inflammatory cytokines.

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Kheradmand, Afshin; Nayebi, Alireza M; Jorjani, Masoumeh; Khalifeh, Solmaz; Haddadi, Rasool

2016-08-03

Over production of reactive oxygen species (ROS) is postulated to be the main contributor in degeneration of nigrostriatal dopaminergic neurons. In this study we investigated the effects of WR1065, a free radical scavenger, on motor imbalance, oxidative stress parameters and inflammatory cytokines in CSF and brain of hemi-parkinsonian rats. Lesion of dopaminergic neurons was done by unilateral infusion of 6-hydroxydopamine into the central region of the substentia nigra pars compacta (SNc) to induce hemi-parkinsonism and motor imbalance in rats. WR1065 (20, 40 and 80μg/2μl/rat) was administered three days before 6-OHDA administration. After three weeks behavioral study was performed and then brain and CSF samples were collected to assess tumor necrosis factor (TNFα), interlukin (IL-1β), reduced glutathione (GSH), and malondialdehyde (MDA). WR1065 pre-treatment in rats before receiving 6-OHDA, improved significantly motor impairment and caused reduction of MDA and inflammatory cytokines TNFα and IL-1β levels, while GSH level significantly increased when compared with lesioned rats. Our study indicated that WR1065 could improve 6-OHDA-induced motor imbalance. Furthermore, it decreased lipid peroxidation and inflammatory cytokines and restored the level of GSH up to normal range. We suggest that WR1065 can be proposed as a potential neuroprotective agent in motor impairments of PD. However to prove this hypothesis more clinical trial studies should be done. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Radiotherapy alone, versus radiotherapy with amifostine 3 times weekly, versus radiotherapy with amifostine 5 times weekly: A prospective randomized study in squamous cell head and neck cancer

NARCIS (Netherlands)

Jellema, Anke Petra; Slotman, Ben J.; Muller, Martin J.; Leemans, C. Rene; Smeele, Ludi E.; Hoekman, Klaas; Aaronson, Neil K.; Langendijk, Johannes A.

2006-01-01

BACKGROUND: The main objective of this study was to investigate whether nondaily intravenous administration of amifostine was as effective as daily intravenous administration with regard to the reduction of the incidence of Grade 2 or greater xerostomia in patients with head and neck cancer.

WR 120bb and WR 120bc: a pair of WN9h stars with possibly interacting circumstellar shells

Science.gov (United States)

Burgemeister, S.; Gvaramadze, V. V.; Stringfellow, G. S.; Kniazev, A. Y.; Todt, H.; Hamann, W.-R.

2013-03-01

Two optically obscured Wolf-Rayet (WR) stars have been recently discovered by means of their infrared (IR) circumstellar shells, which show signatures of interaction with each other. Following the systematics of the WR star catalogues, these stars obtain the names WR 120bb and WR 120bc. In this paper, we present and analyse new near-IR, J-, H- and K-band spectra using the Potsdam Wolf-Rayet model atmosphere code. For that purpose, the atomic data base of the code has been extended in order to include all significant lines in the near-IR bands. The spectra of both stars are classified as WN9h. As their spectra are very similar the parameters that we obtained by the spectral analyses hardly differ. Despite their late spectral subtype, we found relatively high stellar temperatures of 63 kK. The wind composition is dominated by helium, while hydrogen is depleted to 25 per cent by mass. Because of their location in the Scutum-Centaurus Arm, WR 120bb and WR 120bc appear highly reddened, A_{K_s} ≈ 2 mag. We adopt a common distance of 5.8 kpc to both stars, which complies with the typical absolute K-band magnitude for the WN9h subtype of -6.5 mag, is consistent with their observed extinction based on comparison with other massive stars in the region, and allows for the possibility that their shells are interacting with each other. This leads to luminosities of log ({textit {L}/L}_{odot }) = 5.66 and 5.54 for WR 120bb and WR 120bc, with large uncertainties due to the adopted distance. The values of the luminosities of WR 120bb and WR 120bc imply that the immediate precursors of both stars were red supergiants (RSG). This implies in turn that the circumstellar shells associated with WR 120bb and WR 120bc were formed by interaction between the WR wind and the dense material shed during the preceding RSG phase.

Radioprotective effect of amifostine on parotid gland functioning is region dependent

NARCIS (Netherlands)

Konings, AWT; Faber, H; Vissink, A; Coppes, RP

2005-01-01

Purpose: To investigation the protective ability of amifostine during partial irradiation of the rat parotid gland. Methods and Materials: Single-dose X-ray irradiation was performed by use of collimators with conformal radiation portals for either the 100% volume (15 Gy) or the 50% cranial/caudal

Acceptance test report 2721-Z upgrades

International Nuclear Information System (INIS)

Keck, R.D.

1998-01-01

This test procedure provides instructions for acceptance testing of modifications to the 2721-Z diesel-generator system made by Project C-189. The modifications include (1) replacing the generator NUMA-LOGIC controller with connection to the PFP distributed control system (DCS), (2) replacing ATSI with a breaker switching scheme for 2736-ZB backup power and (3) providing a method for generator load and system testing

Acute toxicity of postoperative radiochemotherapy with amifostine vs radiochemotherapy alone in head and neck cancer patients. Preliminary results of a randomized trial

International Nuclear Information System (INIS)

Vacha, P.; Marx, M.; Engel, A.; Richter, E.; Feyerabend, T.

1999-01-01

Purpose: Experimental and clinical data suggest a reduction of radiation-induced acute toxicity by amifostine. We investigated this issue in a randomized trial comparing radiochemotherapy (RCT) versus radiochemotherapy and amifostine (RCT+A) in patients with head and neck cancer. Patients and methods: Forty-seven patients with pharyngeal or laryngeal cancer (T 1-2 N 1-2 G 3 ,T 3-4 N 0-2 G 1-3 ) were randomized to receive RCT alone (21 patients) or RCT+A (21 patients). Patients were irradiated up to 60 Gy (R 0 ) or 70 Gy (R 1/2 ). Chemotherapy consisted of 70 mg/m 2 carboplatin and was administered over 5 days in the 1st and 5th week of the radiotherapy course. 250 mg amifostine were applied daily just before each radiotherapy session. Acute toxicity was evaluated according to the Common Toxicity Criteria (CTC). As for xerostomia no patients with laryngeal cancer were assessed because in these cases only small volumes of the salivary glands were within the treatment volume. To evaluate the overall toxicity a summarized CTC score of all observed side effects was calculated. Results: Forty-two patients were evaluable. Clinical characteristics (age, sex, Karnofsky index, tumor-staging) were well balanced in both treatment groups. Amifostine provided reduction in xerostomia and mucositis. Conclusions: According to our preliminary results amifostine has a radioprotective effect on salivary glands. Mucositis can be reduced during radiochemotherapy. At this point of patient accrual the difference between both groups are statistically not significant. To improve the radioprotective effects of amifostine in clinical practice the application of a higher dose (>250 mg) seems to be necessary. (orig.) [de

Amifostine protects rat kidneys during peptide receptor radionuclide therapy with [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate

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Rolleman, Edgar J.; Forrer, Flavio; Bernard, Bert; Bijster, Magda; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Vermeij, Marcel [Erasmus MC, Department of Pathology, Rotterdam (Netherlands)

2007-05-15

In peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues, the kidneys are the major dose-limiting organs, because of tubular reabsorption and retention of radioactivity. Preventing renal uptake or toxicity will allow for higher tumour radiation doses. We tested the cytoprotective drug amifostine, which selectively protects healthy tissue during chemo- and radiotherapy, for its renoprotective capacities after PRRT with high-dose [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate. Male Lewis rats were injected with 278 or 555 MBq [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate to create renal damage and were followed up for 130 days. For renoprotection, rats received either amifostine or co-injection with lysine. Kidneys, blood and urine were collected for toxicity measurements. At 130 days after PRRT, a single-photon emission computed tomography (SPECT) scan was performed to quantify tubular uptake of {sup 99m}Tc-dimercaptosuccinic acid (DMSA), a measure of tubular function. Treatment with 555 MBq [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate resulted in body weight loss, elevated creatinine and proteinuria. Amifostine and lysine treatment significantly prevented this rise in creatinine and the level of proteinuria, but did not improve the histological damage. In contrast, after 278 MBq [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate, creatinine values were slightly, but not significantly, elevated compared with the control rats. Proteinuria and histological damage were different from controls and were significantly improved by amifostine treatment. Quantification of {sup 99m}Tc-DMSA SPECT scintigrams at 130 days after [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate therapy correlated well with 1/creatinine (r {sup 2} = 0.772, p < 0.001). Amifostine and lysine effectively decreased functional renal damage caused by high-dose [{sup 177}Lu-DOTA{sup 0},Tyr{sup 3}]octreotate. Besides lysine, amifostine might be used in clinical PRRT as well

Phase II multicenter randomized study of amifostine for prevention of acute radiation rectal toxicity: Topical intrarectal versus subcutaneous application

International Nuclear Information System (INIS)

Kouloulias, Vassilis E.; Kouvaris, John R.; Pissakas, George; Mallas, Elias; Antypas, Christos; Kokakis, John D.; Matsopoulos, George; Michopoulos, Spyros; Mystakidou, Kyriaki; Vlahos, Lambros J.

2005-01-01

Purpose: To investigate the cytoprotective effect of subcutaneous vs. intrarectal administration of amifostine against acute radiation toxicity. Methods and materials: Patients were randomized to receive amifostine either intrarectally (Group A, n = 27) or a 500-mg flat dose subcutaneously (Group B, n = 26) before irradiation. Therapy was delivered using a four-field technique with three-dimensional conformal planning. In Group A, 1,500 mg of amifostine was administered intrarectally as an aqueous solution in 40 mL of enema. Two different toxicity scales were used: the European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group (RTOG) rectal and urologic toxicity criteria and the Subjective-RectoSigmoid scale based on the endoscopic terminology of the World Organization for Digestive Endoscopy. Objective measurements with rectosigmoidoscopy were performed at baseline and 1-2 days after radiotherapy completion. The area under the curve for the time course of mucositis (RTOG criteria) during irradiation represented the mucositis index. Results: Intrarectal amifostine was feasible and well tolerated without any systemic or local side effects. According to the RTOG toxicity scale, Group A had superior results with a significantly lower incidence of Grades I-II rectal radiation morbidity (11% vs. 42%, p 0.04) but inferior results concerning urinary toxicity (48% vs. 15%, p 0.03). The mean rectal mucositis index and Subjective-RectoSigmoid score were significantly lower in Group A (0.44 vs. 2.45 [p = 0.015] and 3.9 vs. 6.0 [p = 0.01], respectively), and the mean urinary mucositis index was lower in Group B (2.39 vs. 0.34, p < 0.028). Conclusions: Intrarectal administration of amifostine (1,500 mg) seemed to have a cytoprotective efficacy in acute radiation rectal mucositis but was inferior to subcutaneous administration in terms of urinary toxicity. Additional randomized studies are needed for definitive decisions concerning the

Daily amifostine given concomitantly to chemoradiation in head and neck cancer. A pilot study

International Nuclear Information System (INIS)

Trog, D.; Bank, P.; Wendt, T.G.; Koscielny, S.; Beleites, E.

1999-01-01

Background: In patients with loco-regionally advanced head and neck cancer conventionally fractionated radiotherapy alone results in poor loco-regional control and survival rates. Treatment intensification by simultaneous administration of cytotoxic drugs produces higher acute morbidity. Therefore chemical radioprotection of normal tissues may be of clinical benefit. Patients and Methods: In a pilot study patients with advanced nonresectable head neck cancer treated with conventionally fractionated radical radiotherapy (60 to 66 Gy total doses) and concomitantly given 5-fluorouracil as protracted venous infusion, 250 mg/sqm/24 h over the entire treatment period were given amifostine 300 mg absolutely before each fraction. Acute treatment related mobidity was scored according to CTC classification and loco-regional control and survival rates were estimated. Comparison was made with a historical control group of identical chemoradiation but without amifostine application. Results: Chemoradiation induced oral mucositis was delayed and showed significant lower degrees at all 10 Gy increments (p 0.05). No significant toxicity was recorded with respect to blood pressure, serum calcium, potassium, hematologic parameters, emesis, nausea or body weight loss. Progression free survival and overall survival probability at 2 years were not statistically different in both cohorts. Conclusion: Amifostine given before each fraction of radiotherapy over 6 weeks has no cumulative toxicity, was well tolerated and may reduce treatment induced oral mucositis. No tumor protective effect was observed. (orig.) [de

The potential influence of cell protectors for dose escalation in cancer therapy: an analysis of amifostine

International Nuclear Information System (INIS)

McCumber, Linda M.

2004-01-01

The attempt to increase the therapeutic ratio in an effort to improve survival or quality of life is the goal of modern cancer therapy. It is commonly accepted that local and systemic tumor control would increase if the dose intensity of antineoplastic drugs, radiation therapy, or the combination were increased. Radiation dose escalation using intensity-modulated radiation therapy (IMRT), accelerated or hypofractionated radiation schemes, and multidrug chemotherapy regimens are being used to try to increase tumor kill while inflicting minimal injury to normal tissue. Modern chemoradiation techniques have led to improved local regional control and increased cure rates, but the potentially severe and debilitating adverse effects of the therapies prevent them from reaching the ultimate goal of curing the disease while leaving the patient with a good quality of life. Cell protectants such as amifostine function by reducing the effects of therapy on normal cells while maintaining tumor sensitivity to the therapy. In various studies, amifostine has been analyzed and appears to be a potentially powerful adjuvant to current cancer therapy. Administering amifostine may allow dose escalation with less or equal risk to surrounding normal tissues. This could improve therapeutic efficacy, survival, and quality of life for cancer patients

Effect of Amifostine on Response Rates in Locally Advanced Non-Small-Cell Lung Cancer Patients Treated on Randomized Controlled Trials: A Meta-Analysis

International Nuclear Information System (INIS)

Mell, Loren K.; Malik, Renuka; Komaki, Ritsuko; Movsas, Benjamin; Swann, R. Suzanne; Langer, Corey; Antonadou, Dosia; Koukourakis, Michael; Mundt, Arno J.

2007-01-01

Purpose: Amifostine can reduce the cytotoxic effects of chemotherapy and radiotherapy in patients with locally advanced non-small-cell lung cancer, but concerns remain regarding its possible tumor-protective effects. Studies with sufficient statistical power to address this question are lacking. Methods and Materials: We performed a meta-analysis of all published clinical trials involving locally advanced non-small-cell lung cancer patients treated with radiotherapy with or without chemotherapy, who had been randomized to treatment with amifostine vs. no amifostine or placebo. Random effects estimates of the relative risk of overall, partial, and complete response were obtained. Results: Seven randomized trials involving 601 patients were identified. Response rate data were available for six studies (552 patients). The pooled relative risk (RR) estimate was 1.07 (95% confidence interval, 0.97-1.18; p = 0.18), 1.21 (95% confidence interval, 0.83-1.78; p = 0.33), and 0.99 (95% confidence interval, 0.78-1.26; p = 0.95) for overall, complete, and partial response, respectively (a RR >1 indicates improvement in response with amifostine compared with the control arm). The results were similar after sensitivity analyses. No evidence was found of treatment effect heterogeneity across the studies. Conclusions: Amifostine has no effect on tumor response in patients with locally advanced non-small-cell lung cancer treated with radiotherapy with or without chemotherapy

Amifostine Analog, DRDE-30, Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice

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Aastha Arora

2018-04-01

Full Text Available Bleomycin (BLM is an effective curative option in the management of several malignancies including pleural effusions; but pulmonary toxicity, comprising of pneumonitis and fibrosis, poses challenge in its use as a front-line chemotherapeutic. Although Amifostine has been found to protect lungs from the toxic effects of radiation and BLM, its application is limited due to associated toxicity and unfavorable route of administration. Therefore, there is a need for selective, potent, and safe anti-fibrotic drugs. The current study was undertaken to assess the protective effects of DRDE-30, an analog of Amifostine, on BLM-induced lung injury in C57BL/6 mice. Whole body micro- computed tomography (CT was used to non-invasively observe tissue damage, while broncheo-alveolar lavage fluid (BALF and lung tissues were assessed for oxidative damage, inflammation and fibrosis. Changes in the lung density revealed by micro-CT suggested protection against BLM-induced lung injury by DRDE-30, which correlated well with changes in lung morphology and histopathology. DRDE-30 significantly blunted BLM-induced oxidative stress, inflammation and fibrosis in the lungs evidenced by reduced oxidative damage, endothelial barrier dysfunction, Myeloperoxidase (MPO activity, pro-inflammatory cytokine release and protection of tissue architecture, that could be linked to enhanced anti-oxidant defense system and suppression of redox-sensitive pro-inflammatory signaling cascades. DRDE-30 decreased the BLM-induced augmentation in BALF TGF-β and lung hydroxyproline levels, as well as reduced the expression of the mesenchymal marker α-smooth muscle actin (α-SMA, suggesting the suppression of epithelial to mesenchymal transition (EMT as one of its anti-fibrotic effects. The results demonstrate that the Amifostine analog, DRDE-30, ameliorates the oxidative injury and lung fibrosis induced by BLM and strengthen its potential use as an adjuvant in alleviating the side effects of

Influence of intravenous amifostine on xerostomia, tumor control, and survival after radiotherapy for head-and- neck cancer: 2-year follow-up of a prospective, randomized, phase III trial

International Nuclear Information System (INIS)

Wasserman, Todd H.; Brizel, David M.; Henke, Michael; Monnier, Alain; Eschwege, Francois; Sauer, Rolf; Strnad, Vratislav

2005-01-01

Purpose: To evaluate chronic xerostomia and tumor control 18 and 24 months after initial treatment with amifostine in a randomized controlled trial of patients with head-and-neck cancer; at 12 months after radiotherapy (RT), amifostine had been shown to reduce xerostomia without changing tumor control. Methods and Materials: Adults with head-and-neck cancer who underwent once-daily RT for 5-7 weeks (total dose, 50-70 Gy) received either open-label amifostine (200 mg/m 2 i.v.) 15-30 min before each fraction of radiation (n = 150) or RT alone (control; n = 153). Results: Amifostine administration was associated with a reduced incidence of Grade ≥2 xerostomia over 2 years of follow-up (p = 0.002), an increase in the proportion of patients with meaningful (>0.1 g) unstimulated saliva production at 24 months (p = 0.011), and reduced mouth dryness scores on a patient benefit questionnaire at 24 months (p < 0.001). Locoregional control rate, progression-free survival, and overall survival were not significantly different between the amifostine group and the control group. Conclusions: Amifostine administration during head-and-neck RT reduces the severity and duration of xerostomia 2 years after treatment and does not seem to compromise locoregional control rates, progression-free survival, or overall survival

Efficacy and Safety of Subcutaneous Amifostine in Minimizing Radiation-Induced Toxicities in Patients Receiving Combined-Modality Treatment for Squamous Cell Carcinoma of the Head and Neck

International Nuclear Information System (INIS)

Law, Amy; Kennedy, Thomas; Pellitteri, Phillip; Wood, Craig; Christie, Douglas; Yumen, Omar

2007-01-01

Purpose: To report long-term data from a prospective trial of subcutaneous (s.c.) amifostine in patients who received chemoradiotherapy for squamous cell carcinoma of the head and neck (SCCHN). Methods and Materials: Patients ≥18 years of age with previously untreated Stage III/IV SCCHN received fractionated radiotherapy, 1.8-2.0 Gy/day, 5 days per week, to a total dose of 70-72 Gy, plus weekly paclitaxel (40 mg/m 2 ) and carboplatin (100 mg/m 2 ) administered intravenously (i.v.) for 6 weeks. All patients received 500 mg s.c. amifostine 30-60 min before radiotherapy with antihistamine and antiemetic prophylaxis. Results: Twenty patients were evaluable (median age, 55 years). The incidence of Grade 2 xerostomia was 42% and 29% at 12 and 18 months, respectively; there were no reports of Grade ≥3 xerostomia. Grade ≥3 mucositis occurred in 30% of patients, with median time to resolution of 12.5 weeks (range, 5-17 weeks). Survival estimates at 1 and 2 years were 95% and 71%, respectively. All patients experienced Grade 2 weight loss; 7 patients (35%) experienced Grade ≤2 nausea/vomiting. There were no reports of Grade ≥3 amifostine-related adverse events. Conclusions: Subcutaneous amifostine was well tolerated by patients receiving chemoradiotherapy for SCCHN, with lower rates of nausea/vomiting than reported in trials with i.v. amifostine. Xerostomia and mucositis rates were similar to those reported in trials with i.v. amifostine

A phase II randomized study of topical intrarectal administration of amifostine for the prevention of acute radiation-induced rectal toxicity

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Kouloulias, V.E. [Dept. of Radiation Oncology, Aretaieion Univ. Hospital, Univ. of Athens Medical School, Athens (Greece); Dept. of Electrical and Computer Engineering, National Technical Univ. of Athens, Athens (Greece); Center of Radiation Oncology, YGEIA Diagnostic and Therapeutic Center of Athens, Athens (Greece); Kouvaris, J.R.; Kokakis, J.D.; Antypas, C.; Mallas, E.; Vosdoganis, S.P.; Vlahos, L.J. [Dept. of Radiation Oncology, Aretaieion Univ. Hospital, Univ. of Athens Medical School, Athens (Greece); Pissakas, G. [Radiotherapy Dept., Agios Savvas Anticancer Hospital, Athens (Greece); Matsopoulos, G. [Dept. of Electrical and Computer Engineering, National Technical Univ. of Athens, Athens (Greece); Michopoulos, S. [Gastroenterology Unit, Alexandra General Hospital, Athens (Greece); Kostakopoulos, A. [Urology Dept., Sismanoglio Hospital, Univ. of Athens Medical School, Athens (Greece)

2004-09-01

Purpose: to investigate the cytoprotective effect of intrarectal amifostine administration on acute radiation-induced rectal toxicity. Patients and methods: 67 patients with T1b-2 NO MO prostate cancer were randomized to receive amifostine intrarectally (group A, n - 33) or not (group B, n = 34) before irradiation. Therapy was delivered using a four-field technique with three-dimensional conformal planning. In group A, 1,500 mg amifostine was administered intrarectally as an aqueous solution in a 40-ml enema. Two different toxicity scales were used: EORTC/RTOG rectal and urologic toxicity criteria along with a Subjective-RectoSigmoid (S-RS) scale based on the endoscopic terminology of the World Organization for Digestive Endoscopy. Objective measurements with rectosigmoidoscopy were performed at baseline and 1-2 days after the completion of radiotherapy. The area under curve for the time course of mucositis (RTOG criteria) during irradiation represented the mucositis index (MI). Results: intrarectal amifostine was feasible and well tolerated without any systemic or local side effects. According to the RTOG toxicity scale, five out of 33 patients showed grade 1 mucositis in group A versus 15 out of 34 patients with grade 1/2 in group B (p = 0.026). Mean rectal MI was 0.3 {+-} 0.1 in group A versus 2.2 {+-} 0.4 in group B (p < 0.001), while S-RS score was 3.9 {+-} 0.5 in group A versus 6.3 {+-} 0.7 in group B (p < 0.001). The incidence of urinary toxicity was the same in both groups. Conclusion: intrarectal administration of amifostine seems to have a cytoprotective efficacy in acute radiation-induced rectal mucositis. Further randomized studies are needed for definitive therapeutic decisions. (orig.)

Radioprotection: mechanism and radioprotective agents including honeybee venom

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Varanda, E.A.; Tavares, D.C. [UNESP, Araraquara, SP (Brazil). Escola de Ciencias Farmaceuticas. Dept. de Ciencias Biologicas

1998-07-01

Since 1949, a great deal of research has been carried on the radioprotective action of chemical substances. These substances have shown to reduce mortality when administered to animals prior to exposure to a lethal dose of radiation. This fact is of considerable importance since it permits reduction of radiation-induced damage and provides prophylactic treatment for the damaging effects produced by radiotherapy. The following radioprotection mechanisms were proposed: free radical scavenger, repair by hydrogen donation to target molecules formation of mixed disulfides, delay of cellular division and induction of hypoxia in the tissues. Radioprotective agents have been divided into four major groups: the thiol compounds, other sulfur compounds, pharmacological agents (anesthetic drugs, analgesics, tranquilizers, etc.) and other radioprotective agents (WR-1065, WR-2721, vitamins C and E, glutathione, etc.). Several studies revealed the radioprotective action of Apis mellifera honeybee venom as well as that of its components mellitin and histamine. Radioprotective activity of bee venom involves mainly the stimulation of the hematopoietic system. In addition, release of histamine and reduction in oxygen tension also contribute to the radioprotective action of bee venom. (author)

Radioprotection: mechanism and radioprotective agents including honeybee venom

International Nuclear Information System (INIS)

Varanda, E.A.; Tavares, D.C.

1998-01-01

Since 1949, a great deal of research has been carried on the radioprotective action of chemical substances. These substances have shown to reduce mortality when administered to animals prior to exposure to a lethal dose of radiation. This fact is of considerable importance since it permits reduction of radiation-induced damage and provides prophylactic treatment for the damaging effects produced by radiotherapy. The following radioprotection mechanisms were proposed: free radical scavenger, repair by hydrogen donation to target molecules formation of mixed disulfides, delay of cellular division and induction of hypoxia in the tissues. Radioprotective agents have been divided into four major groups: the thiol compounds, other sulfur compounds, pharmacological agents (anesthetic drugs, analgesics, tranquilizers, etc.) and other radioprotective agents (WR-1065, WR-2721, vitamins C and E, glutathione, etc.). Several studies revealed the radioprotective action of Apis mellifera honeybee venom as well as that of its components mellitin and histamine. Radioprotective activity of bee venom involves mainly the stimulation of the hematopoietic system. In addition, release of histamine and reduction in oxygen tension also contribute to the radioprotective action of bee venom. (author)

Effects of insulin-like growth factor-1 (IGF-1) and amifostine in spinal cord reirradiation

International Nuclear Information System (INIS)

Nieder, C.; Andratschke, N.; Price, R.E.; Rivera, B.; Ang, K. Kian

2005-01-01

Purpose: To test whether insulin-like growth factor-1 (IGF-1) and amifostine modulate the reirradiation tolerance of rat cervical spinal cord. Initial experiments by the authors' group suggested that administration of each agent alone significantly increased the median latent time to radiation myelopathy (RM) in previously unirradiated animals but did not change the dose-response relationship. Because of different modes of action, a follow-up study was undertaken to test the combined treatment. Material and Methods: The cervical spinal cord of 51 adult Fisher F-344 rats received a single fraction of 16 Gy, which corresponds to approximately 75% of the median paresis dose (ED 50 ), followed 5 months later by a second radiation dose, which ranged from 17 to 21 Gy. The study animals received a single intrathecal injection of 0.3 mg amifostine into the cisterna magna 30-60 min before reirradiation plus three subcutaneous doses of IGF-1 (700 μg) starting from 24 h before to 24 h after reirradiation. Control animals received saline injections via the same routes. Animals were followed until RM developed or until 12 months from reirradiation. Histopathologic examinations were performed post mortem. Results: No animals showed any neurologic abnormalities before reirradiation. RM occurred in controls versus treated rats after a mean latency of 218 versus 314 days (19 Gy; p=0.11) and 104 versus 186 days (21 Gy; p=0.002) from second dose (Figure 1). ED 50 was 18.2 versus 19.4 Gy (p=0.15; Figure 2). Treatment with IGF-1 and amifostine did not significantly influence the rates of tumor induction or intercurrent death. Conclusion: IGF-1 and amifostine significantly reduced RM rates after 21 Gy. The shift of the dose-response curve suggests an increase of the ED 50 for single-dose treatment by approximately 7%. Thus, brief therapeutic intervention might slightly decrease radiation-induced neurotoxicity in a retreatment situation. (orig.)

Effects of insulin-like growth factor-1 (IGF-1) and amifostine in spinal cord reirradiation

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Nieder, C.; Andratschke, N. [TU Muenchen (Germany). Dept. of Radiation Oncology; Price, R.E.; Rivera, B. [University of Texas M.D. Anderson Cancer Center, Houston, TX (United States). Dept. of Veterinary Medicine and Surgery; Ang, K. Kian [University of Texas M.D. Anderson Cancer Center, Houston, TX (United States). Dept. of Radiation Oncology

2005-11-01

Purpose: To test whether insulin-like growth factor-1 (IGF-1) and amifostine modulate the reirradiation tolerance of rat cervical spinal cord. Initial experiments by the authors' group suggested that administration of each agent alone significantly increased the median latent time to radiation myelopathy (RM) in previously unirradiated animals but did not change the dose-response relationship. Because of different modes of action, a follow-up study was undertaken to test the combined treatment. Material and Methods: The cervical spinal cord of 51 adult Fisher F-344 rats received a single fraction of 16 Gy, which corresponds to approximately 75% of the median paresis dose (ED{sub 50}), followed 5 months later by a second radiation dose, which ranged from 17 to 21 Gy. The study animals received a single intrathecal injection of 0.3 mg amifostine into the cisterna magna 30-60 min before reirradiation plus three subcutaneous doses of IGF-1 (700 {mu}g) starting from 24 h before to 24 h after reirradiation. Control animals received saline injections via the same routes. Animals were followed until RM developed or until 12 months from reirradiation. Histopathologic examinations were performed post mortem. Results: No animals showed any neurologic abnormalities before reirradiation. RM occurred in controls versus treated rats after a mean latency of 218 versus 314 days (19 Gy; p=0.11) and 104 versus 186 days (21 Gy; p=0.002) from second dose (Figure 1). ED{sub 50} was 18.2 versus 19.4 Gy (p=0.15; Figure 2). Treatment with IGF-1 and amifostine did not significantly influence the rates of tumor induction or intercurrent death. Conclusion: IGF-1 and amifostine significantly reduced RM rates after 21 Gy. The shift of the dose-response curve suggests an increase of the ED{sub 50} for single-dose treatment by approximately 7%. Thus, brief therapeutic intervention might slightly decrease radiation-induced neurotoxicity in a retreatment situation. (orig.)

Creating an enabling environment for WR&R implementation.

Science.gov (United States)

Stathatou, P-M; Kampragou, E; Grigoropoulou, H; Assimacopoulos, D; Karavitis, C; Gironás, J

2017-09-01

Reclaimed water is receiving growing attention worldwide as an effective solution for alleviating the growing water scarcity in many areas. Despite the various benefits associated with reclaimed water, water recycling and reuse (WR&R) practices are not widely applied around the world. This is mostly due to complex and inadequate local legal and institutional frameworks and socio-economic structures, which pose barriers to wider WR&R implementation. An integrated approach is therefore needed while planning the implementation of WR&R schemes, considering all the potential barriers, and aiming to develop favourable conditions for enhancing reclaimed water use. This paper proposes a comprehensive methodology supporting the development of an enabling environment for WR&R implementation. The political, economic, social, technical, legal and institutional factors that may influence positively (drivers) or negatively (barriers) WR&R implementation in the regional water systems are identified, through the mapping of local stakeholder perceptions. The identified barriers are further analysed, following a Cross-Impact/System analysis, to recognize the most significant barriers inhibiting system transition, and to prioritize the enabling instruments and arrangements that are needed to boost WR&R implementation. The proposed methodology was applied in the Copiapó River Basin in Chile, which faces severe water scarcity. Through the analysis, it was observed that barriers outweigh drivers for the implementation of WR&R schemes in the Copiapó River Basin, while the key barriers which could be useful for policy formulation towards an enabling environment in the area concern the unclear legal framework regarding the ownership of treated wastewater, the lack of environmental policies focusing on pollution control, the limited integration of reclaimed water use in current land use and development policies, the limited public awareness on WR&R, and the limited availability of

Continuous brightening of IGR J17473-2721

DEFF Research Database (Denmark)

Baldovin Saavedra, C.; Chenevez, Jérôme; Kuulkers, E.

2008-01-01

Renewed accretion activity has been reported by Swift/XRT (ATel #1459), XTE/PCA (ATel #1460) and INTEGRAL/IBIS/ISGRI (ATel #1461) from the RXTE transient IGR J17473-2721 (= XTE J1747-274; ATels #467, #498) after the detection of an X-ray burst by SuperAGILE (ATel #1445). From the on-going Galactic...... bulge monitoring program (see ATels #1385, #1461) we report that the transient continues to brighten as seen with IBIS/ISGRI and JEM-X....

Hard X-ray activity of IGR J17473-2721

DEFF Research Database (Denmark)

Kuulkers, E.; Shaw, S.; Beckmann, V.

2008-01-01

Persistent X-ray activity has been reported by Swift/XRT (ATel #1459) and RXTE/PCA (ATel #1460) from the transient IGR J17473-2721 (= XTE J1747-274; ATels #467, #498) after the detection of an X-ray burst by SuperAGILE (ATel #1445). We report the detection of persistent activity at 18-100 keV wit...

High throughput assay for evaluation of reactive carbonyl scavenging capacity.

Science.gov (United States)

Vidal, N; Cavaille, J P; Graziani, F; Robin, M; Ouari, O; Pietri, S; Stocker, P

2014-01-01

Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

High throughput assay for evaluation of reactive carbonyl scavenging capacity

Directory of Open Access Journals (Sweden)

N. Vidal

2014-01-01

Full Text Available Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

Effect of amifostine on sperm DNA fragmentation and testes after radioiodine treatment

Directory of Open Access Journals (Sweden)

Sen Cigdem Cebi

2017-12-01

Full Text Available Introduction: Radioactive iodine (RAI is commonly used for the treatment of hyperthyroidism caused by Graves’ disease or thyroid nodules. However, information available on the impact of RAI therapy on male gonadal function is scarce. This study aimed to determine any possible damage to testicular tissue and sperm quality caused by RAI therapy, and the radioprotective effect of amifostine against such damage.

Radioprotective effects of CBLB502 on γ-radiated Rhesus monkey

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Xing SHEN

2015-06-01

Full Text Available Objective　A Rhesus monkey model was employed to study the radioprotective effects of a Toll-like receptor 5 agonist, CBLB502, against 7.0Gy whole-body irradiation of 60Co gamma-rays. Methods　Thirty animals were assigned to a placebo treatment group, a WR-2721 positive control group, and three CBLB502 treatment groups (n=6 animals/group. Each animal was irradiated with 7.0Gy 60Co γ and given CBLB502 at 2.5, 10 and 40μg/kg, respectively in treatment groups, or WR-2721 at 30mg/kg, or physiological saline 0.3ml/kg for the placebo treatment group. The treatment was given once by intramuscular injection 30 min before irradiation. All irradiated animals received symptomatic treatment based on same guidelines. General observation, peripheral blood tests, hemopoietic progenitor cell colony-counting, and histopathological examination were performed. Results　We found that 10 or 40μg/kg CBLB502 treatment resulted in 100% survival, while the survival rate was 33% in placebo treatment group. Hematopoietic recovery in the WR-2721 treatment group was marginally superior to the irradiation control group. Nadirs of peripheral white cell and platelet counts of animals treated with 40μg/kg of CBLB502 were significantly higher than those of the placebo treatment group (P<0.05. CBLB502 at 40μg/kg also gave a shortened duration of low platelet count, earlier recovery time, reduced the amount of blood transfusion and damage to the bone marrow and intestine. Conclusion　All Rhesus monkeys irradiated with 7.0Gy 60Co γ-rays would suffer from severe acute radiation sickness of hematopoietic system. CBLB502 at 40μg/kg is radioprotective in this model and a single intramuscular injection of CBLB502 in a dose of 40μg/kg 30min before irradiation gives better radioprotective effects than WR-2721. DOI: 10.11855/j.issn.0577-7402.2015.04.07

Preventive effect of two-component chemical radioprotector and variability in its application

International Nuclear Information System (INIS)

Lambov, V.; Metodiev, S.

1993-01-01

The purpose of the study is to evaluate the radioprotective efficiency of two-component radioprotective schema consisting of the chemically synthesized radioprotector WR-2721 (OK-79) and a new glycoside pigment obtained from melanoidine CL. The application of melanoidine 7-21 days before WR-2721 significantly increases the radioprotective efficiency of the chemically obtained product and enhances the 30-day survival of hybrid mice treated with 15 Gy whole body gamma irradiation. The effect of potentiated radioprotection is not observed when the interval between the application of the two agents is reduced to 24 h. It is suggested that the observed enhancement of the radioprotective efficiency in the two-component schema is due to the antioxidant and immuno modulating properties of the pigment product, observed and described in our previous investigations. (author)

Cytoprotection with amifostine in the simultaneous radio-chemotherapy of recurrent head and neck cancer

International Nuclear Information System (INIS)

Buentzel, J.; Weinaug, R.; Kuettner, K.

1999-01-01

Purpose: The radiotherapeutic possibilities are limited for patients with a recurrent or second head and neck cancer if the patient was already irradiated in the first therapy. In the presented study we investigated the changes of this situation due to the usage of amifostine in the case of re-irradiation (simultaneous radio-chemotherapy). Patients and methods: Between 1995 and 1997 we treated 14 patients with a recurrent or second malignancy of the head and neck region by a simultaneous radio-chemotherapy (20x1.5 Gy, Carboplatin 70 mg/m 2 BSA on days 1 to 5 and 16 to 20, 500 mg amifostine prior to every carboplatin infusion). Six out of 14 patients got an additional brachytherapy (10 to 15 Gy) to increase the local dose because of a residual tumor. In 4 cases the treatment was an adjunctive one, following the surgical tumor debulking. Results: We have seen 3 complete remissions (21.4%), and 8 partial remissions (57.1%). The median time of observation in 13 months now. Three out of 14 patients died, 2 because of the tumor. Hematological toxicities: Side effects Grade 2 WHO were seen only in 1 patient. Acute non-hematological toxicities: Mucositis Grade 0/1 in 7 patients, mucositis Grade 2 in 7 patients, dysphagia Grade 0/1 in 9 patients, dysphagia Grade 2 in 5 patients, xerostomia Grade 1 in 9 patients, xerostomia Grade 2 in 3 patients. We registrated only 1 serious late toxicity due to radio-chemotherapy: 4 months after brachytherapy a patient (with laryngectomy) developed a submental fistula. Conclusion: These first results suggest that the usage of amifostine offers new potential ways for re-irradiation of patients with recurrent or second malignancies in the head neck region. (orig.) [de

Kilohertz QPOs, spectral state transitions and the distance to the neutron star X-ray transient IGR J17473-2721

DEFF Research Database (Denmark)

Altamirano, D.; Galloway, D.; Chenevez, Jérôme

2008-01-01

We report on RXTE monitoring observations of the transient X-ray binary IGR J17473-2721 since the beginning of its latest outburst on March 26th, 2008 (see ATEL #1445, #1459, #1460, #1461 and #1468). IGR J17473-2721 reached a maximum unabsorbed flux of ~1.30E-8 ergs cm-2 s-1 (2-10 keV, assuming n...

DF-1, A Nontoxic Carbon Fullerene Based Antioxidant, is Effective as a Biomedical Countermeasure Against Radiation

Science.gov (United States)

Theriot, Corey A.; Casey, Rachael; Conyers, Jodie; Wu, Honglu

2010-01-01

A long-term goal of radiation research is the mitigation of inherent risks of radiation exposure. Thus the study and development of safe agents, whether biomedical or dietary, that act as effective radioprotectors is an important step in accomplishing this long-term goal. Some of the most effective agents to date have been aminothiols and their derivatives. Unfortunately, most of these agents have side effects such as nausea, vomiting, hypotension, weakness, and fatigability. For example, nausea and emesis occur in most patients treated with WR-2721 (Amifostine), requiring the use of effective antiemetics, with hypotension being the dose-limiting side effect in patients treated. Clearly, the need for a radioprotector that is both effective and safe still exists. Development of biocompatible nano-materials for radioprotection is a promising emerging technology that could be exploited to address the need to minimize biological effects when exposure is unavoidable. Testing free radical scavenging nanoparticles for potential use in radioprotection is exciting and highly relevant. Initial investigations presented here demonstrate the ability of a particular functionalized carbon fullerene nanoparticle, (DF-1), to act as an effective radioprotector. DF-1 was first identified as the most promising candidate in a screen of several functionalized carbon fullerenes based on lack of toxicity and antioxidant therapeutic potential against oxidative injuries (i.e. organ reperfusion and ionizing radiation). Subsequently, DF-1 has been shown to reduce chromosome aberration yield and cell death, as well as overall ROS levels in human lymphocytes and fibroblasts after exposure to gamma radiation and energetic protons while demonstrating no associated toxicity. The dose-reducing factor of DF-1 at LD50 is nearly 2.0 for gamma radiation. In addition, DF-1 treatment also significantly prevented cell cycle arrest after exposure. Finally, DF-1 markedly attenuated COX2 upregulation in cell

Radioprotective effect of low doses of 2-(1-naphthylmethyl)-2-imidazoline alone or associated with phosphorothioates

International Nuclear Information System (INIS)

Laval, J.D.; Roman, V.; Fatome, M.; Laduranty, J.; Miginiac, L.; Lion, C.; Sentenac-Roumanou, H.

1993-01-01

In the mouse, the intraperitoneal injection of 2-(1-naphthylmethyl)-2-imidazoline has a radioprotective effect even at low doses. Its association with S-[2-(3-aminopropyl)aminoethyl] phosphorothioate (WR 2721) or S-[3-(3-methylaminopropyl)-aminopropyl]phosphorothioate (WR 151327) at low doses led to an enhancement of their respective radioprotective activities without any apparent side effects. These results strengthen the interest of this non-sulphur compound as a radioprotector

Pinwheel Nebula around WR 98a.

Science.gov (United States)

Monnier; Tuthill; Danchi

1999-11-10

We present the first near-infrared images of the dusty Wolf-Rayet star WR 98a. Aperture-masking interferometry has been utilized to recover images at the diffraction limit of the Keck I telescope, less, similar50 mas at 2.2 µm. Multiepoch observations spanning about 1 yr have resolved the dust shell into a "pinwheel" nebula, the second example of a new class of dust shell first discovered around WR 104 by Tuthill, Monnier, & Danchi. Interpreting the collimated dust outflow in terms of an interacting winds model, the binary orbital parameters and apparent wind speed are derived: a period of 565+/-50 days, a viewing angle of 35&j0;+/-6 degrees from the pole, and a wind speed of 99+/-23 mas yr-1. This period is consistent with a possible approximately 588 day periodicity in the infrared light curve, linking the photometric variation to the binary orbit. Important implications for binary stellar evolution are discussed by identifying WR 104 and WR 98a as members of a class of massive, short-period binaries whose orbits were circularized during a previous red supergiant phase. The current component separation in each system is similar to the diameter of a red supergiant, which indicates that the supergiant phase was likely terminated by Roche lobe overflow, leading to the present Wolf-Rayet stage.

A dust shell around the early-type Wolf-Ryate star WR 19

International Nuclear Information System (INIS)

Williams, P.M.; Hucht, K.A. van der; Bouchet, P.

1990-01-01

Infrared photometry of the WC4-type Wolf-Rayet star WR 19 (LS 3) in 1988-90 shows evidence for an expanding dust shell in its wind, similar to those observed from late-type WR stars like WR 48a (WC8), WR 140 (WC7+04) and WR 137 (WC7+). This demonstrates that dust formation by Wolf-Rayet stars is not restricted to later WC subtypes and is more common than hitherto supposed. (author)

A Literature Review on the Mechanism of Action of Sulphur and Nitrogen Mustard

Science.gov (United States)

1989-07-01

for years is also poeqible (Aasted et al, 1987; Colardyn et al, 1986). Severely poisoned individuals exhibit bone marrow depression and may die from...MMS does not produce the enhanced depression of DNA synthesis in sensitive cells, compared to resistant cells, produced by sulphur mustard and...Compound MATD 1 Protection (mg/mouse) index 2 WR-3689 15 159 WR-2721 15 44 Aminoethylcysteine 80 27 N- acetylcysteine 8 26 Glutathione 60 22 Cysteine 8

Evaluation of the efficacy of zoledronic acid and amifostine on radiation induced bone loss in mice

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Wook; Lee, Sueum; Kang, Sohi; Moon, Cahng Jong; Kim, Jong Choon; Kim, Sung Ho [College of Veterinary Medicine, Chonnam National University, Gwangju (Korea, Republic of); Jung, Uhee; Jo, Sung Kee [Advanced Radiation Technology Institute, Jeungeup (Korea, Republic of); Jang, Jong Sik [College of Ecology and Environmental Science, Kyungpook National University, Sangju (Korea, Republic of)

2016-09-15

This study investigated the effects of zoledronic acid (ZA) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham control and three irradiated groups (3 Gy, gamma ray). The irradiated mice were treated for 12 weeks with vehicle, amifostine (intraperitoneal injection), or ZA (subcutaneous injection). Grip strength, uterus weight, and serum alkaline phosphatase (ALP), and tartrate-resistant acid phosphatase (TRAP) levels were measured. Tibiae were analyzed using micro-computed tomography. Treatment of ZA (100 μg·kg{sup -1}·week{sup -1}) significantly preserved trabecular bone volume, trabecular thickness, trabecular number, trabecular separation, bone mineral density of proximal tibia metaphysic, and cortical bone volume, but did not alter the uterus weight of the mice. The administration of ZA for 12 weeks lowered serum ALP and TRAP levels in irradiated mice, suggesting that ZA can reduce the bone turnover rate in mice. No differences were apparent between the amifostine-treated group and the irradiation control group. The results indicate that ZA can prevent radiation-induced bone loss in mice.

Prevention of radiochemotherapy-induced toxicity with amifostine in patients with malignant orbital tumors involving the lacrimal gland: a pilot study

International Nuclear Information System (INIS)

Goldblum, David; Ghadjar, Pirus; Curschmann, Juergen; Greiner, Richard; Aebersold, Daniel

2008-01-01

To use amifostine concurrently with radiochemotherapy (CT-RT) or radiotherapy (RT) alone in order to prevent dry eye syndrome in patients with malignancies located in the fronto-orbital region. Five patients (2 males, 3 females) with diagnosed malignancies (Non-Hodgkin B-cell Lymphoma, neuroendocrine carcinoma) involving the lacrimal gland, in which either combined CT-RT or local RT were indicated, were prophylactically treated with amifostine (500 mg sc). Single RT fraction dose, total dose and treatment duration were individually adjusted to the patient's need. Acute and late adverse effects were recorded using the RTOG score. Subjective and objective dry eye assessment was performed for the post-treatment control of lacrimal gland function. All patients have completed CT-RT or RT as indicated. The median total duration of RT was 29 days (range, 23 – 39 days) and the median total RT dose was 40 Gy (range, 36 – 60 Gy). Median lacrimal gland exposure was 35.9 Gy (range, 16.8 – 42.6 Gy). Very good partial or complete tumor remission was achieved in all patients. The treatment was well tolerated without major toxic reactions. Post-treatment control did not reveal in any patient either subjective or objective signs of a dry eye syndrome. The addition of amifostine to RT/CT-RT of patients with tumors localized in orbital region was found to be associated with absence of dry eye syndrome

Amifostine as radioprotective agent for the rectal mucosa during irradiation of pelvic tumors. A phase II randomized study using various toxicity scales and rectosigmoidoscopy

Energy Technology Data Exchange (ETDEWEB)

Kouvaris, J.; Antypas, C.; Kokakis, J.; Vlahos, L. [Radiology-Radiotherapy Dept., National Technical Univ. of Athens (Greece); Kouloulias, V. [Radiology-Radiotherapy Dept., National Technical Univ. of Athens (Greece); Dept. of Electrical and Computer Engineering, Inst. of Communication and Computer Systems, National Technical Univ. of Athens (Greece); Malas, E. [Endoscopy-Gastroenterology Unit, Dept. of Surgical Oncology, Aretaieion Univ. Hospital, Athens (Greece); Michopoulos, S. [Dept. of Gastroenterology, Alexandra General Hospital of Athens (Greece); Matsopoulos, G. [Dept. of Electrical and Computer Engineering, Inst. of Communication and Computer Systems, National Technical Univ. of Athens (Greece)

2003-03-01

Aim: To evaluate the cytoprotective effect of amifostine against radiation-induced acute toxicity to the rectal mucosa. Patients and Methods: 36 patients irradiated for prostate or gynecologic cancer were randomized to receive amifostine (n = 18, group A) or not (n = 18, group B). The radiation-induced acute rectal toxicity was evaluated by using three different toxicity scales: WHO scale, EORTC/RTOG toxicity criteria, and a modified toxicity scale based on the LENT-SOMA grading scale and the endoscopic terminology of the World Organization for Digestive Endoscopy. The objective measurements were coming from flexible rectosigmoidoscopy performed at baseline and 1-2 days after completion of the radiotherapy schedule. Anterior-posterior fields were used in the gynecologic patients while 3-D conformal 4-field technique was applied in the prostate cancer patients. The area under the curve (AUC) for dose-volume histograms (DVHs) of the rectum was also assessed during a 3-D treatment planning schedule, and no significant differences were assessed between the two groups, indicating a homogeneous dose-volume effect. Results: Amifostine was well tolerated. No grade 2 or higher WHO and EORTC/RTOG acute toxicity was noted in group A, while acute rectal toxicity ({>=} grade 1) was observed in 16/18 patients of group B versus 2/18 of group A (p < 0.001). The onset as well as the duration of acute rectal toxicity were significantly improved in group A (p = 0.002). Rectosigmoidoscopy revealed more severe rectal mucositis in noncytoprotected patients (group B), and modified LENT-SOMA overall mucositis grading score was significantly lower in group A (p = 0.003). Conclusion: Amifostine seems to have a significant cytoprotective efficacy in acute radiation-induced rectal mucositis in terms of symptomatic and objective endpoints. (orig.)

Amifostine as radioprotective agent for the rectal mucosa during irradiation of pelvic tumors. A phase II randomized study using various toxicity scales and rectosigmoidoscopy

International Nuclear Information System (INIS)

Kouvaris, J.; Antypas, C.; Kokakis, J.; Vlahos, L.; Kouloulias, V.; Malas, E.; Michopoulos, S.; Matsopoulos, G.

2003-01-01

Aim: To evaluate the cytoprotective effect of amifostine against radiation-induced acute toxicity to the rectal mucosa. Patients and Methods: 36 patients irradiated for prostate or gynecologic cancer were randomized to receive amifostine (n = 18, group A) or not (n = 18, group B). The radiation-induced acute rectal toxicity was evaluated by using three different toxicity scales: WHO scale, EORTC/RTOG toxicity criteria, and a modified toxicity scale based on the LENT-SOMA grading scale and the endoscopic terminology of the World Organization for Digestive Endoscopy. The objective measurements were coming from flexible rectosigmoidoscopy performed at baseline and 1-2 days after completion of the radiotherapy schedule. Anterior-posterior fields were used in the gynecologic patients while 3-D conformal 4-field technique was applied in the prostate cancer patients. The area under the curve (AUC) for dose-volume histograms (DVHs) of the rectum was also assessed during a 3-D treatment planning schedule, and no significant differences were assessed between the two groups, indicating a homogeneous dose-volume effect. Results: Amifostine was well tolerated. No grade 2 or higher WHO and EORTC/RTOG acute toxicity was noted in group A, while acute rectal toxicity (≥ grade 1) was observed in 16/18 patients of group B versus 2/18 of group A (p < 0.001). The onset as well as the duration of acute rectal toxicity were significantly improved in group A (p = 0.002). Rectosigmoidoscopy revealed more severe rectal mucositis in noncytoprotected patients (group B), and modified LENT-SOMA overall mucositis grading score was significantly lower in group A (p = 0.003). Conclusion: Amifostine seems to have a significant cytoprotective efficacy in acute radiation-induced rectal mucositis in terms of symptomatic and objective endpoints. (orig.)

WR stars with ring nebulae

International Nuclear Information System (INIS)

Tutukov, A.

1982-01-01

It is shown that most of usually apparently single nitrogen WR stars with ring emission nebulae around them (WN + Neb) are a probable product of the evolution of a massive close binary with initial masses of components exceeding approximately 20 solar masses. (Auth.)

Examination of the effect of ovarian radiation injury induced by hysterosalpingography on ovarian proliferating cell nuclear antigen and the radioprotective effect of amifostine: an experimental study

Directory of Open Access Journals (Sweden)

Can B

2018-05-01

Full Text Available Behzat Can,1 Remzi Atilgan,1 Sehmus Pala,1 Tuncay Kuloğlu,2 Sule Kiray,3 Nevin Ilhan4 1Department of Obstetrics and Gynecology, Firat University School of Medicine, Elazig, Turkey; 2Department of Histology and Embryology, Firat University School of Medicine, Elazig, Turkey; 3Department of Obstetrics and Gynecology, Maltepe University School of Medicine, Istanbul, Turkey; 4Department of Biochemistry, Firat University School of Medicine, Elazig, Turkey Aim: The aim of this study was to examine the effect of amifostine on cellular injury in the ovarian tissue induced by hysterosalpingography (HSG.Methods: In total, forty 4-month old female Wistar Albino rats were assigned into 8 groups. Each group contained 5 rats. Group 1 (G1: rats were decapitated without any procedure. Group 2 (G2: rats were decapitated after 3 hours of total body irradiation. Group 3 (G3: rats were decapitated 3 hours after HSG procedure. Group 4 (G4: rats were decapitated 3 hours after HSG procedure performed 30 min after receiving amifostine 200 mg/kg intraperitoneally. Group 5 (G5: rats were decapitated after 1 month without any procedure. Group 6 (G6: rats were decapitated after 1 month of total body irradiation. Group 7 (G7: rats were decapitated 1 month after HSG procedure. Group 8 (G8: rats were decapitated 1 month after HSG procedure performed 30 min after receiving amifostine 200 mg/kg intraperitoneally. After rats were decapitated under general anesthesia in all groups, blood samples were obtained and bilateral ovaries were removed. One of the ovaries was placed in 10% formaldehyde solution for histological germinal epithelial degeneration, apoptosis and proliferating cell nuclear antigen scoring. The other ovary and blood sera were stored at –80°C. TNF-α, total antioxidant status, total oxidant status, and malondialdehyde levels were studied in tissue samples and anti-mullerian hormone levels in blood samples.Results: At the end of the first month, there was

Phase-resolved XMM-Newton and swift observations of WR 25

Energy Technology Data Exchange (ETDEWEB)

Pandey, J. C.; Pandey, S. B.; Karmakar, Subhajeet, E-mail: jeewan@aries.res.in [Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 002 (India)

2014-06-10

We present an analysis of long-term X-ray and optical observations of the Wolf-Rayet binary, WR 25. Using archival data from observations with the XMM-Newton and the Swift observatories, spanning over ∼10 yr, we show that WR 25 is a periodic variable in X-rays with a period of 208 ± 3 days. X-ray light curves in the 0.5-10.0 keV energy band show phase-locked variability, where the flux increased by a factor of ∼2 from minimum to maximum, being maximum near periastron passage. The light curve in the soft energy band (0.5-2.0 keV) shows two minima indicating the presence of two eclipses. However, the light curve in the hard energy band (2.0-10.0 keV) shows only one minimum during the apastron passage. The X-ray spectra of WR 25 were explained by a two-temperature plasma model. Both the cool and the hot plasmas were constant at 0.628 ± 0.008 and 2.75 ± 0.06 keV throughout an orbital cycle, where the cooler plasma could be due to small scale shocks in a radiation-driven outflow and the high temperature plasma could be due to the collision of winds. The column density varied with the orbital phase and was found to be maximum after the periastron passage, when the WN star is in front of the O star. The abundances of WR 25 were found to be non-solar. Optical V-band data of WR 25 also show the phase-locked variability, being at maximum near periastron passage. The results based on the present analysis indicate that WR 25 is a colliding wind binary where the presence of soft X-rays is attributed to individual components; however, hard X-rays are due to the collision of winds.

Scavenger

DEFF Research Database (Denmark)

2009-01-01

Scavenger is one of the cyber foraging frameworks developed in the Locusts project. It has been released as open source software at http://code.google.com/p/scavenger-cf/......Scavenger is one of the cyber foraging frameworks developed in the Locusts project. It has been released as open source software at http://code.google.com/p/scavenger-cf/...

Effects of an Amifostine analogue on radiation induced lung inflammation and fibrosis

International Nuclear Information System (INIS)

Arora, Aastha; Bhuria, Vikas; Soni, Ravi; Singh, Saurabh; Hazari, Puja Panwar; Bhatt, Anant Narayan; Dwarakanath, B.S.; Pathak, Uma; Mathur, Shweta; Sandhir, Rajat

2014-01-01

Radiation-induced pulmonary toxicity causes significant morbidity and mortality in patients irradiated for thoracic malignancies as well as in victims of accidental radiation exposure. We have recently established the efficacy of an analogue of Amifostine (DRDE-30) in reducing the mortality of whole body irradiated mice. The widely used radioprotector Amifostine has been found to reduce the incidence of radiation induced pneumonitis during radiation therapy for non small cell lung carcinoma. In the present study, we investigated the potential of DRDE-30 in ameliorating the radiation induced lung damage. Intra-peritoneal administration of DRDE-30 at 220 mg/kg b.wt 30 min. prior to 13.5 Gy thoracic radiation enhanced the 24-month survival of C57BL/6 mice to 80% compared to 0% with radiation alone. Reduced protein content and cell number in the broncheo-alveolar lavage fluid suggested reduction in radiation induced vascular permeability in DRDE-30 treated mice. Higher levels of MnSOD and Catalase observed under these conditions indicated that strengthening of the anti-oxidant defense system by DRDE-30 could also contribute to the protection against radiation induced lung damage. Reduced levels of p-p38 observed under these conditions suggested down-regulation of the p38/MAP kinase pathway as one of the plausible mechanisms underlying anti-inflammatory effects of DRDE-30, while lower levels of Vimentin seen, indicated inhibition of epithelial to mesenchymal transition revealing its anti-fibrotic effect as well. Structural analysis with X-ray CT indicated comparable lung architecture in control and drug treated mice in terms of reduced opacity, which correlated well with the lung morphology (H and E staining) and reduced collagen deposition (trichrome staining). These results demonstrate the potential of DRDE-30 in reducing radiation induced pulmonary toxicity by attenuating the inflammatory and fibrotic responses. (author)

WR-1065 and radioprotection of vascular endothelial cells. I. Cell proliferation, DNA synthesis and damage

International Nuclear Information System (INIS)

Rubin, D.B.; Drab, E.A.; Kang, H.J.; Baumann, F.E.; Blazek, E.R.

1996-01-01

Normal tissue toxicity limits radiation therapy and could depend on the extent of damage to the vascular endothelium. Aminothiols such as WR-1065 [N-(2-mercaptoethyl)-1,3-diaminopropane] provide radioprotection for normal tissues, but little is known about how the aminothiols specifically affect the endothelium. Bovine aortic endothelial cells in culture were exposed to WR-1065 for 2 h before irradiation ( 137 Cs γ rays, 1 Gy/min). Alone, WR-1065 demonstrated an antiproliferative effect that was related to dose (0.5-4 mM) and was evident by lowered counts of adherent cells 48 h after exposure. WR-1065 was clearly radioprotective when assessed by colony formation and incorporation of [ 3 H]thymidine. However, when the number of adherent cells was evaluated, radioprotection appeared to be slight and evident only in logarithmically growing cells. WR-1065 at 2 mM suppressed single-strand DNA breaks after 3 Gy by 22% and double-strand breaks after 9 Gy by 47%. Also in the irradiated cells, WR-1065 more than doubled the rate of progression of cells from G 1 to S phase. WR-1065 pretreatment elevated cellular glutathione (GSH) content more than twofold. Although pretreatment with buthionine sulfoximine inhibited the elevation of GSH, the radioprotective impact of WR-1065 on total DNA strand breaks and colony formation was unaffected. These results suggest that WR-1065 may enable tissue recovery from irradiation by promoting the replication of endothelial cells, possibly by mechanisms independent of GSH. 46 refs., 6 figs., 2 tabs

The various scenarios leading to WR stars: Their relative importance and the role of mixing

International Nuclear Information System (INIS)

Maeder, A.

1982-01-01

Over the last 40 years WR stars have been associated with almost all possible evolutionary stages. The author lists 7 scenarios which may be considered as most relevant in view of recent surface abundance determinations. He then considers the importance of mass loss in WR formation and discusses properties of binary WR which suggest that formation is dependent on metallicity and thus galactic location. The role of internal mixing in WR formation is also considered. Mass loss on the MS is shown only to be able to explain a minute fraction of the observed WR stars, whereas internal mixing by shear instability has, for all stellar masses, a larger effect on MS evolution than mass loss. (Auth./C.F.)

Regiones H II alrededor de estrellas WR

Science.gov (United States)

Giménez Benitez, S.; Niemela, V.

En base a observaciones espectroscópicas en el rango óptico, obtenidas en el CASLEO, se estudian las condiciones físicas de tres regiones H II alrededor de estrellas WR: N76 en el entorno de Ab7, en la Nube Menor de Magallanes, N79 alrededor de Br 2, en la Nube Mayor de Magallanes y G2.4+1.4 alrededor de WR 102, en nuestra Galaxia. Estas regiones presentan una alta ionización. Se observa la línea nebular de HeII en 4686 Å . Utilizando líneas nebulares de diagnóstico, se derivan los valores de la densidad y la temperatura electrónica, así como también las abundancias de algunos de los elementos químicos nebulares.

Retention of 241Am and 239Pu in the rat as influenced by Triton WR 1339

International Nuclear Information System (INIS)

Gruner, R.; Siedel, A.

1976-01-01

A lysosomotropic agent, the non-ionic detergent Triton WR 1339 (a poly-oxyethylene ether of formaldehyde polymers of octylphenol) is known to be stored in rat liver lysosomes. The results of a study made to determine whether Triton WR 1339 exerts an influence on the metabolic fate of monomeric 239 Pu and 241 Am in the rat as well as on the removal of these nuclides by DTPA, since Triton WR 1339 and transuranic elements share the same deposition site, are reported. The influence of Triton WR 1339 on the 241 Am content (per cent of 241 Am dose) of rat organs (skeleton, liver, kidneys) at different times after Triton WR 1339 injection, the influence of the time of Triton WR 1339 injection on the 241 Am content (per cent of 241 Am dose) of the same rat organs, and the influence of Triton WR 1339 Zn-DTPA and the combination of them on the retention of monomeric 239 Pu in the same rat organs (per cent of 239 Pu dose), are shown in tabular form. The mechanism whereby Triton WR 1339 appears to shorten the biological half-life of 239 Pu and 241 Am in rat liver is discussed. (U.K.)

Impairment of blood lipids pattern in gamma irradiated albino mice and prophylactic role of thiols and W R-2721

Energy Technology Data Exchange (ETDEWEB)

EL-dighidy, E A.M.; El-Kady, M H.R. [National Centre for Radiation Research and Technology, Atomic Energy Authority, Cairo, (Egypt)

1987-12-31

The present work aims to investigate the effect of shot doses of whole body gamma irradiation at the levels, 6, 7.5, 11, 25 and 15 Gy, on the blood lipids pattern in male swiss albino mice. This has been manifested by the levels of total lipids, triglycerides, phospholipids and cholesterol. The radioprotective capacities of two sulfhydryl compounds: thiols and W R-2721, against impairment in blood lipids pattern, have been evaluated in mice received the higher shot radiation dose-level at 15 Gy. Significant increases in the levels of blood total lipid, phospholipids, triglycerides and cholesterol have been recorded on the third day post exposure under the experiment conditions, the data indicated more efficient protection of blood lipid pattern exerted by W R-2721 than in case of thiols. 2 figs., 2 tabs.

Impairment of blood lipids pattern in gamma irradiated albino mice and prophylactic role of thiols and W R-2721

International Nuclear Information System (INIS)

EL-dighidy, E.A.M.; El-Kady, M.H.R.

1986-01-01

The present work aims to investigate the effect of shot doses of whole body gamma irradiation at the levels, 6, 7.5, 11, 25 and 15 Gy, on the blood lipids pattern in male swiss albino mice. This has been manifested by the levels of total lipids, triglycerides, phospholipids and cholesterol. The radioprotective capacities of two sulfhydryl compounds: thiols and W R-2721, against impairment in blood lipids pattern, have been evaluated in mice received the higher shot radiation dose-level at 15 Gy. Significant increases in the levels of blood total lipid, phospholipids, triglycerides and cholesterol have been recorded on the third day post exposure under the experiment conditions, the data indicated more efficient protection of blood lipid pattern exerted by W R-2721 than in case of thiols. 2 figs., 2 tabs

WR 110: A SINGLE WOLF-RAYET STAR WITH COROTATING INTERACTION REGIONS IN ITS WIND?

International Nuclear Information System (INIS)

Chene, A.-N.; Moffat, A. F. J.; Fahed, R.; St-louis, N.; Muntean, V.; Chevrotiere, A. De La; Cameron, C.; Matthews, J. M.; Gamen, R. C.; Lefevre, L.; Rowe, J. F.; Guenther, D. B.; Kuschnig, R.; Weiss, W. W.; Rucinski, S. M.; Sasselov, D.

2011-01-01

A 30 day contiguous photometric run with the Microvariability and Oscillations of STars (MOST) satellite on the WN5-6b star WR 110 (HD 165688) reveals a fundamental periodicity of P = 4.08 ± 0.55 days along with a number of harmonics at periods P/n, with n ∼ 2, 3, 4, 5, and 6, and a few other possible stray periodicities and/or stochastic variability on timescales longer than about a day. Spectroscopic radial velocity studies fail to reveal any plausible companion with a period in this range. Therefore, we conjecture that the observed light-curve cusps of amplitude ∼0.01 mag that recur at a 4.08 day timescale may arise in the inner parts, or at the base, of a corotating interaction region (CIR) seen in emission as it rotates around with the star at constant angular velocity. The hard X-ray component seen in WR 110 could then be a result of a high velocity component of the CIR shock interacting with the ambient wind at several stellar radii. Given that most hot, luminous stars showing CIRs have two CIR arms, it is possible that either the fundamental period is 8.2 days or, more likely in the case of WR 110, there is indeed a second weaker CIR arm for P = 4.08 days, that occurs ∼two-thirds of a rotation period after the main CIR. If this interpretation is correct, WR 110 therefore joins the ranks with three other single WR stars, all WN, with confirmed CIR rotation periods (WR 1, WR 6, and WR 134), albeit with WR 110 having by far the lowest amplitude photometric modulation. This illustrates the power of being able to secure intense, continuous high-precision photometry from space-based platforms such as MOST. It also opens the door to revealing low-amplitude photometric variations in other WN stars, where previous attempts have failed. If all WN stars have CIRs at some level, this could be important for revealing sources of magnetism or pulsation in addition to rotation periods.

X-ray observations of the colliding wind binary WR 25

Science.gov (United States)

Arora, Bharti; Pandey, Jeewan Chandra

2018-04-01

Using the archival data obtained from Chandra and Suzaku spanning over '8 years, we present an analysis of a WN6h+O4f Wolf-Rayet binary, WR 25. The X-ray light curves folded over a period of '208 d in the 0.3 - 10.0 keV energy band showed phase-locked variability where the count rates were found to be maximum near the periastron passage. The X-ray spectra of WR 25 were well explained by a two-temperature plasma model with temperatures of 0.64 ± 0.01 and 2.96 ± 0.05 keV and are consistent with previous results. The orbital phase dependent local hydrogen column density was found to be maximum just after the periastron passage, when the WN type star is in front of the O star. The hard (2.0 - 10.0 keV) X-ray luminosity was linearly dependent on the inverse of binary separation which confirms that WR 25 is a colliding wind binary.

WR 148: identifying the companion of an extreme runaway massive binary*

Science.gov (United States)

Munoz, Melissa; Moffat, Anthony F. J.; Hill, Grant M.; Shenar, Tomer; Richardson, Noel D.; Pablo, Herbert; St-Louis, Nicole; Ramiaramanantsoa, Tahina

2017-05-01

WR 148 (HD 197406) is an extreme runaway system considered to be a potential candidate for a short-period (4.3173 d) rare WR + compact object binary. Provided with new high-resolution, high signal-to-noise spectra from the Keck observatory, we determine the orbital parameters for both the primary WR and the secondary, yielding respective projected orbital velocity amplitudes of 88.1 ± 3.8 km s-1 and 79.2 ± 3.1 km s-1 and implying a mass ratio of 1.1 ± 0.1. We then apply the shift-and-add technique to disentangle the spectra and obtain spectra compatible with a WN7ha and an O4-6 star. Considering an orbital inclination of ˜67°, derived from previous polarimetry observations, the system's total mass would be a mere 2-3M_{⊙}, an unprecedented result for a putative massive binary system. However, a system comprising a 37 M_{⊙} secondary (typical mass of an O5V star) and a 33 M_{⊙} primary (given the mass ratio) would infer an inclination of ˜18°. We therefore reconsider the previous methods of deriving the orbital inclination based on time-dependent polarimetry and photometry. While the polarimetric results are inconclusive requiring better data, the photometric results favour low inclinations. Finally, we compute WR 148's space velocity and retrace the runaway's trajectory back to the Galactic plane (GP). With an ejection velocity of 198 ± 27 km s-1 and a travel time of 4.7 ± 0.8 Myr to reach its current location, WR 148 was most likely ejected via dynamical interactions in a young cluster.

A Chandra grating observation of the dusty Wolf-Rayet star WR 48a

Energy Technology Data Exchange (ETDEWEB)

Zhekov, Svetozar A. [Space Research and Technology Institute, Akad. G. Bonchev Str., bl.1, Sofia 1113 (Bulgaria); Gagné, Marc [Department of Geology and Astronomy, West Chester University, West Chester, PA 19383 (United States); Skinner, Stephen L., E-mail: szhekov@space.bas.bg, E-mail: mgagne@wcupa.edu, E-mail: stephen.skinner@colorado.edu [CASA, University of Colorado, Boulder, CO 80309 (United States)

2014-04-10

We present results of a Chandra High-Energy Transmission Grating (HETG) observation of the carbon-rich Wolf-Rayet (WR) star WR 48a. These are the first high-resolution spectra of this object in X-ray. Blueshifted centroids of the spectral lines of ∼ – 360 km s{sup –1} and line widths of 1000-1500 km s{sup –1} (FWHM) were deduced from the analysis of the line profiles of strong emission lines. The forbidden line of Si XIII is strong and not suppressed, indicating that the rarified 10-30 MK plasma forms far from strong sources of far-ultraviolet emission, most likely in a wind collision zone. Global spectral modeling showed that the X-ray spectrum of WR 48a suffered higher absorption in the 2012 October Chandra observation compared with a previous 2008 January XMM-Newton observation. The emission measure of the hot plasma in WR 48a decreased by a factor ∼3 over the same period of time. The most likely physical picture that emerges from the analysis of the available X-ray data is that of colliding stellar winds in a wide binary system with an elliptical orbit. We propose that the unseen secondary star in the system is another WR star or perhaps a luminous blue variable.

AFRRI Reports October - December 1990

Science.gov (United States)

1991-01-01

alterations in the steady state rates could produce ation, long-term GM-CFC- depressions could place significant alterations in peripheral leukocyte con- the...days, demonstrate depressed stem cell levels. Depending and accelerated outflow -rates- of postmitotic PMNs on the extent of injury, the initial...sulfhydryl compounds such as WR-2721, cysteamine, N- acetylcysteine , and diethyldithiocarbamate (Landauer et al., 1988c). Similar effects have been

A Numerical Procedure for Analysis of W/R Contact Using Explicit Finite Element Methods

NARCIS (Netherlands)

Ma, Y.; Markine, V.L.

2015-01-01

Since no effective experimental approaches have been proposed to assess wheel and rail (W/R) contact performance till now, numerical computational analysis is known as an alternative to approximately simulate the W/R interaction. In this paper, one numerical procedure is proposed on the basis of

Biological activities of Umbilicaria crustulosa (Ach. frey acetone extract

Directory of Open Access Journals (Sweden)

Zlatanović Ivana

2017-01-01

Full Text Available This paper reports for the first time the effect of an acetone extract of Umbilicaria crustulosa on the micronucleus distribution of human lymphocytes, and on the cholinesterase activity and antioxidant activity by the cupric ion reducing antioxidant capacity (CUPRAC method. Additionally, the total phenolic compounds (TPC and the antioxidant properties were estimated via DPPH, ABTS and TRP assays. Moreover, the antibacterial activity against two Gram-positive and three Gram-negative bacteria were determined. Acetone extract of U. crustulosa at concentration of 1 and 2 μg mL-1 decreased a frequency of micronuclei (MN by 10.8 and 16.8 %, respectively, acting more or slightly less than the synthetic protector amifostine (AMF, WR-2721, 11.4 %, at concentration of 1 μg mL-1. The tested extract did not inhibit cholinesterase activity nor did it exhibit activity toward the examined bacteria. The extract reduced the concentration of DPPH and ABTS radicals by 88.7 and 96.2 %, respectively. Values for total reducing power (TRP and cupric reducing capacity (CUPRAC were 0.6197±0.0166 μg ascorbic acid equivalents (AAE per mg of dry extract, and 19.7641±1.6546 μg trolox equivalents (TE per mg of dry extract, respectively. The total phenol content was 350.4188 ±14.587 μg gallic acid equivalents (GAE per mg of dry extract. The results of the present study showed that U. crustulosa acetone extract is a promising candidate for in vivo experiments considering its antioxidant activity and protective effect on human lymphocytes. [Projekat Ministarstva nauke Republike Srbije, br. 172047

WR 143: A Wolf-Rayet Binary

OpenAIRE

Varricatt, Watson P.; Ashok, Nagarhalli M.

2005-01-01

Near infrared spectroscopy and photometry of the Wolf-Rayet Star WR 143 (HD 195177) were obtained in the $JHK$ photometric bands. High resolution spectra observed in the J and H bands exhibit narrow 1.083-micron He I line and the H I Pa Beta and the Brackett series lines in emission superposed on the broad emission line spectrum of the Wolf-Rayet star, giving strong indications of the presence of a companion. From the narrow emission lines observed, the companion is identified to be an early-...

The Role of Flavonoids as Potential Radioprotectors

International Nuclear Information System (INIS)

Benkovic, V.; Djikic, D.; Horvat Knezevic, A.; Lisicic, D.; Orsolic, N.; Kopjar, N.

2011-01-01

Investigations for effective and non toxic compounds with radioprotection capability led to increasing interest in naturally occurring antioxidants since most of known chemical radioprotectors (AET, WR2721, WR 1065, etc.) express toxic side effects that limit their use in medical practice. Among the promissing compounds there are flavonoids, whosentioxidant activity is based on ability of direct free radicals scavenging or stabilizing the reactive oxygen species (ROS) by interacting with the reactive compound of the radical. Because of the high reactivity of the hydroxyl substituents of flavonoids, radicals are made inactive. Flavonoids can also increase the function of the endogenous antioxidant enzyme systems: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and gluthation. Antioxidant effects may be also a combined result of radical scavenging and interaction with enzyme functions. Flavonoids induce activities of the immune system as well. Increased hematopoietic activity could account for the improved hematopoietic tolerance to radiotherapy. In this study we evaluated radioprotective effects of selected flavonoids (caffeic acid, chrysin, naringin and quercetin) administered to mice prior to whole-body irradiation with γ-rays (absorbed dose was 9 Gy). The survival analysis and alkaline comet assay on white blood cells were employed both on irradiated and non-irradiated animals. Blood samples were taken 30 min. after irradiation. Appropriate negative and positive control groups (administered chemical radioprotector AET, S-(2-Aminoethyl) isothiouronium bromide hydrobromide, i. p. at a dose of 281 mg kg -1 body weight) were also selected and handled in the same manner. We observed statistically significant difference in surviving time of mice pre-treated with test components and the most effective radioprotector was quercetin. Tested flavonoids were not genotoxic to non-irradiated mice and offered good

The WR-1 corrosion test facility

International Nuclear Information System (INIS)

Murphy, E.V.; Simmons, G.R.

1978-07-01

This report describes a new Corrosion Test Facility which has recently been installed in the WR-1 organic-cooled research reactor. The irradiation facility is a single insert, installed in a reactor site, which can deliver a fast neutron flux density of 2.65 x 10 17 neutrons/(m 2 .s) to specimens under irradiation. A self-contained controlled-chemistry cooling water circuit removes the gamma- and neutron-heat generated in the insert and specimens. Specimen temperatures typically vary from 245 deg C to 280 deg C across the insert core region. (author)

Hypolipidemic action of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice

Directory of Open Access Journals (Sweden)

Micheli Stéfani Zarzecki

2014-01-01

Full Text Available Chrysin (5,7-dihydroxyflavone is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts. The objective of this study was to investigate the hypolipidemic properties of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice. Triton WR-1339 was administered intraperitoneally (400 mg/kg to overnight-fasted mice to develop acute hyperlipidemia. Chrysin was administered orally (10 mg/kg 30 min before Triton WR-1339. At 24 h after Triton WR-1339 injection, blood samples were collected to measure plasma lipid levels. The hepatic thiobarbituric acid reactive substances (TBARS, carbonyl content, non-protein sulfhydryl (NPSH and ascorbic acid (AA levels, as well as catalase (CAT and superoxide dismutase (SOD activity were recorded. Chrysin administration significantly decreased total cholesterol levels. In addition, it partially decreased non-high density lipoprotein-cholesterol and triglycerides levels in plasma of hyperlipidaemic mice. In addition chrysin administration prevented the increase on TBARS levels and prevented the decrease in SOD activity induced by Triton WR-1339. These findings indicated that chrysin was able to decrease plasma lipids concentration and that its antioxidant properties was, at least in part, involved in the hypolipidaemic action of chrysin.

Why herbals as radioprotectors?

International Nuclear Information System (INIS)

Naruka, Kavita

2012-01-01

Increasing use of ionizing radiations for diagnostic as well as therapeutic purposes has drawn the attention of many radiobiologists towards the side effects of such exposures. Therefore, it is desirable that the response of the various tissues to radiation exposure be modified to facilitate the beneficial uses of radiations. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Work on the development of chemicals to protect biological system from radiation damage was initiated nearly six decades ago with cysteine. Thereafter, several chemical compounds have been screened for their radioprotective efficacy. Among the chemical radioprotectors, S-2(3- amino-propylamino) ethyl phosphorothioic acid (WR-2721) or amifostine is the most thoroughly investigated radioprotective drug. It is a derivative of cysteamine, which produces more radioprotection to normal tissues than tumor tissues. It offers more than twice the protection observed with other members of the same phosphorothioate series. Therefore, it has been recommended for cancer patients to reduce the side effects of radiotherapy and chemotherapy. But the drug has many drawbacks that it is toxic at maximum effective dose, ineffective by oral administration, unable to provide post irradiation protection and costly. No ideal, safe, synthetic radioprotector are available to date. So the search for alternative radioprotectors has been going on, which are nontoxic, orally effective and cheap. A number of medicinal plants evaluated for their radioprotective ability, which have shown protective effects against the deleterious effects of ionizing radiations. The plants and natural products are usually non-toxic, can be orally administered, inexpensive and act through multiple mechanisms due to presence of many chemicals. Therefore, development of radioprotectors from natural sources

Spectral Identification of New Galactic cLBV and WR Stars

Science.gov (United States)

Stringfellow, G. S.; Gvaramadze, V. V.; Beletsky, Y.; Kniazev, A. Y.

2012-12-01

We have undertaken a near-IR spectral survey of stars associated with compact nebulae recently revealed by the Spitzer and WISE imaging surveys. These circumstellar nebulae, produced by massive evolved stars, display a variety of symmetries and shapes and are often only evident at mid-IR wavelengths. Stars associated with ˜50 of these nebulae have been observed. We also obtained recent spectra of previously confirmed (known) luminous blue variables (LBVs) and candidate LBVs (cLBVs). The spectral similarity of the stars observed when compared directly to known LBVs and Wolf-Rayet (WR) stars indicate many are newly identified cLBVs, with a few being newly discovered WR stars, mostly of WN8-9h spectral type. These results suggest that a large population of previously unidentified cLBVs and related transitional stars reside in the Galaxy and confirm that circumstellar nebulae are inherent to most (c)LBVs.

Peroxynitrite scavenging by flavonids.

NARCIS (Netherlands)

Haenen, G.R.M.M.; Paquay, J.B.G.; Korthouwer, R.E.M.; Bast, A.

1997-01-01

The peroxynitrite scavenging activity of a series of structurally related flavonoids was tested. It was found that flavonoids are excellent scavengers of peroxynitrite. Compared to the known peroxynitrite scavenger ebselen, the most active flavonoids proved to be 10 times more effective. Indications

REVEALING THE ASYMMETRY OF THE WIND OF THE VARIABLE WOLF-RAYET STAR WR1 (HD 4004) THROUGH SPECTROPOLARIZATION

Energy Technology Data Exchange (ETDEWEB)

St-Louis, N., E-mail: stlouis@astro.umontreal.ca [Département de physique and Centre de Recherche en Astrophysique du Québec (CRAQ), Université de Montréal, C.P. 6128, Succ. Centre Ville, Montréal, QC H3C 3J7 (Canada)

2013-11-01

In this paper, high quality spectropolarimetric observations of the Wolf-Rayet (WR) star WR1 (HD 4004) obtained with ESPaDOnS at the Canada-France-Hawaii Telescope are presented. All major emission lines present in the spectrum show depolarization in the relative Stokes parameters Q/I and U/I. From the behavior of the amount of line depolarization as a function of line strength, the intrinsic continuum light polarization of WR1 is estimated to be P/I = 0.443% ± 0.028% with an angle of θ = –26.°2. Although such a level of polarization could in principle be caused by a wind flattened by fast rotation, the scenario in which it is a consequence of the presence of corotating interaction regions (CIRs) in the wind is preferred. This is supported by previous photometric and spectroscopic observations showing periodic variations with a period of 16.9 days. This is now the third WR star thought to exhibit CIRs in its wind that is found to have line depolarization. Previous authors have found a strong correlation between line depolarization and the presence of an ejected nebula, which they interpret as a sign that the star has relatively recently reached the WR phase since the nebula are thought to dissipate very fast. In cases where the presence of CIRs in the wind is favored to explain the depolarization across spectral lines, the above-mentioned correlation may indicate that those massive stars have only very recently transited from the previous evolutionary phase to the WR phase.

Protective effect of WR-2823 in irradiated mice

International Nuclear Information System (INIS)

Milovanovicj, A.; Tanasijevicj, D.; Cvetkovicj, M.; Cjosicj, M.; Chizmicj, Z.

1987-01-01

A chemical compound named WR-2823 has been synthetised. The acute toxicity after IP application has been investigated and LD 50 estimated. The protective ability of the radioprotector has been investigated in mice with gamma rays of 60 Co, or at the origin of 252 Cf. High protective potency in mice, treated with lethal doses of gamma rays and neutrons have been estimated. (author) 8 refs.; 1 tab

A NEAR-INFRARED SURVEY OF THE INNER GALACTIC PLANE FOR WOLF-RAYET STARS. I. METHODS AND FIRST RESULTS: 41 NEW WR STARS

International Nuclear Information System (INIS)

Shara, Michael M.; Gerke, Jill; Zurek, David; Moffat, Anthony F. J.; Doyon, Rene; Villar-Sbaffi, Alfredo; Stanonik, Kathryn; Artigau, Etienne; Drissen, Laurent

2009-01-01

The discovery of new Wolf-Rayet (WR) stars in our Galaxy via large-scale narrowband optical surveys has been severely limited by dust extinction. Recent improvements in infrared technology have made narrowband-broadband imaging surveys viable again. We report a new J, K, and narrowband imaging survey of 300 deg 2 of the plane of the Galaxy, spanning 150 degrees in Galactic longitude and reaching 1 degree above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 within a few degrees of the Galactic center. Thousands of emission line candidates have been detected. In spectrographic follow-ups of 173 WR star candidates we have discovered 41 new WR stars, 15 of type WN and 26 of type WC. Star subtype assignments have been confirmed with K-band spectra, and distances approximated using the method of spectroscopic parallax. A few of the new WR stars are among the most distant known in our Galaxy. The distribution of these new WR stars is seen to follow that of previously known WR stars along the spiral arms of the Galaxy. Tentative radial velocities were also measured for most of the new WR stars.

A NEAR-INFRARED SURVEY OF THE INNER GALACTIC PLANE FOR WOLF-RAYET STARS. II. GOING FAINTER: 71 MORE NEW W-R STARS

Energy Technology Data Exchange (ETDEWEB)

Shara, Michael M.; Faherty, Jacqueline K.; Zurek, David [American Museum of Natural History, 79th Street and Central Park West, New York, NY 10024-5192 (United States); Moffat, Anthony F. J.; Doyon, Rene [Departement de Physique, Universite de Montreal, CP 6128, Succ. C-V, Montreal, QC, H3C 3J7 (Canada); Gerke, Jill [Department of Astronomy, Ohio State University, Columbus, OH 43210-1173 (United States); Artigau, Etienne; Drissen, Laurent, E-mail: mshara@amnh.org, E-mail: jfaherty@amnh.org, E-mail: dzurek@amnh.org, E-mail: moffat@astro.umontreal.ca, E-mail: doyon@astro.umontreal.ca, E-mail: gerke@astronomy.ohio-state.edu, E-mail: artigau@astro.umontreal.ca, E-mail: ldrissen@phy.ulaval.ca [Departement de Physique, Universite Laval, Pavillon Vachon, Quebec City, QC, G1K 7P4 (Canada)

2012-06-15

We are continuing a J, K and narrowband imaging survey of 300 deg{sup 2} of the plane of the Galaxy, searching for new Wolf-Rayet (W-R) stars. Our survey spans 150 Degree-Sign in Galactic longitude and reaches 1 Degree-Sign above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 (due to severe crowding) within a few degrees of the Galactic center. Thousands of emission-line candidates have been detected. In spectrographic follow-ups of 146 relatively bright W-R star candidates, we have re-examined 11 previously known WC and WN stars and discovered 71 new W-R stars, 17 of type WN and 54 of type WC. Our latest image analysis pipeline now picks out W-R stars with a 57% success rate. Star subtype assignments have been confirmed with the K-band spectra and distances approximated using the method of spectroscopic parallax. Some of the new W-R stars are among the most distant known in our Galaxy. The distribution of these new W-R stars is beginning to trace the locations of massive stars along the distant spiral arms of the Milky Way.

A NEAR-INFRARED SURVEY OF THE INNER GALACTIC PLANE FOR WOLF-RAYET STARS. II. GOING FAINTER: 71 MORE NEW W-R STARS

International Nuclear Information System (INIS)

Shara, Michael M.; Faherty, Jacqueline K.; Zurek, David; Moffat, Anthony F. J.; Doyon, René; Gerke, Jill; Artigau, Etienne; Drissen, Laurent

2012-01-01

We are continuing a J, K and narrowband imaging survey of 300 deg 2 of the plane of the Galaxy, searching for new Wolf-Rayet (W-R) stars. Our survey spans 150° in Galactic longitude and reaches 1° above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 (due to severe crowding) within a few degrees of the Galactic center. Thousands of emission-line candidates have been detected. In spectrographic follow-ups of 146 relatively bright W-R star candidates, we have re-examined 11 previously known WC and WN stars and discovered 71 new W-R stars, 17 of type WN and 54 of type WC. Our latest image analysis pipeline now picks out W-R stars with a 57% success rate. Star subtype assignments have been confirmed with the K-band spectra and distances approximated using the method of spectroscopic parallax. Some of the new W-R stars are among the most distant known in our Galaxy. The distribution of these new W-R stars is beginning to trace the locations of massive stars along the distant spiral arms of the Milky Way.

Phase I North Central Cancer Treatment Group Trial-N9923 of escalating doses of twice-daily thoracic radiation therapy with amifostine and with alternating chemotherapy in limited stage small-cell lung cancer

International Nuclear Information System (INIS)

Garces, Yolanda I.; Okuno, Scott H.; Schild, Steven E.; Mandrekar, Sumithra J.; Bot, Brian M.; Martens, John M.; Wender, Donald B.; Soori, Gamini S.; Moore, Dennis F.; Kozelsky, Timothy F.; Jett, James R.

2007-01-01

Purpose: The primary goal was to identify the maximum tolerable dose (MTD) of thoracic radiation therapy (TRT) that can be given with chemotherapy and amifostine for patients with limited-stage small-cell lung cancer (LSCLC). Methods and Materials: Treatment began with two cycles of topotecan (1 mg/m 2 ) Days 1 to 5 and paclitaxel (175 mg/m 2 ) Day 5 (every 3 weeks) given before and after TRT. The TRT began at 6 weeks. The TRT was given in 120 cGy fractions b.i.d. and the dose escalation (from 4,800 cGy, dose level 1, to 6,600 cGy, dose level 4) followed the standard 'cohorts of 3' design. The etoposide (E) (50 mg/day) and cisplatin (C) (3 mg/m 2 ) were given i.v. before the morning TRT and amifostine (500 mg/day) was given before the afternoon RT. This was followed by prophylactic cranial irradiation (PCI). The dose-limiting toxicities (DLTs) were defined as Grade ≥4 hematologic, febrile neutropenia, esophagitis, or other nonhematologic toxicity, Grade ≥3 dyspnea, or Grade ≥2 pneumonitis. Results: Fifteen patients were evaluable for the Phase I portion of the trial. No DLTs were seen at dose levels 1 and 2. Two patients on dose level 4 experienced DLTs: 1 patient had a Grade 4 pneumonitis, dyspnea, fatigue, hypokalemia, and anorexia, and 1 patient had a Grade 5 hypoxia attributable to TRT. One of 6 patients on dose level 3 had a DLT, Grade 3 esophagitis. The Grade ≥3 toxicities seen in at least 10% of patients during TRT were esophagitis (53%), leukopenia (33%), dehydration (20%), neutropenia (13%), and fatigue (13%). The median survival was 14.5 months. Conclusion: The MTD of b.i.d. TRT was 6000 cGy (120 cGy b.i.d.) with EP and amifostine

PROBING WOLF–RAYET WINDS: CHANDRA/HETG X-RAY SPECTRA OF WR 6

Energy Technology Data Exchange (ETDEWEB)

Huenemoerder, David P.; Schulz, N. S. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Hamann, W.-R.; Oskinova, L.; Shenar, T. [Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States); Nichols, J. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 34, Cambridge, MA 02138 (United States); Pollock, A. M. T., E-mail: dph@space.mit.edu, E-mail: ken.gayley@gmail.com, E-mail: wrh@astro.physik.uni-potsdam.de, E-mail: lida@astro.physik.uni-potsdam.de, E-mail: shtomer@astro.physik.uni-potsdam.de, E-mail: ignace@mail.etsu.edu, E-mail: jnichols@cfa.harvard.edu [European Space Agency, ESAC, Apartado 78, E-28691 Villanueva de la Cañada (Spain)

2015-12-10

With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines whose profiles show that the X-rays originate from a uniformly expanding spherical wind of high X-ray-continuum optical depth. The presence of strong helium-like forbidden lines places the source of X-ray emission at tens to hundreds of stellar radii from the photosphere. Variability was present in X-rays and simultaneous optical photometry, but neither were correlated with the known period of the system or with each other. An enhanced abundance of sodium revealed nuclear-processed material, a quantity related to the evolutionary state of the star. The characterization of the extent and nature of the hot plasma in WR 6 will help to pave the way to a more fundamental theoretical understanding of the winds and evolution of massive stars.

Puzzling thermonuclear burst behaviour from the transient low-mass X-ray binary IGR J17473-2721

DEFF Research Database (Denmark)

Chenevez, Jérôme

2010-01-01

We investigate the thermonuclear bursting behaviour of IGR J17473-2721, an X-ray transient that in 2008 underwent a six month long outburst, starting (unusually) with an X-ray burst. We detected a total of 57 thermonuclear bursts throughout the outburst with AGILE, Swift, RXTE, and INTEGRAL...... it dropped (at a persistent flux corresponding to 15%of m˙ Edd) a few days before the outburst peak, after which bursts were not detected for a month. As the persistent emission subsequently decreased, the bursting activity resumed at a much lower rate than during the outburst rise. This hysteresis may arise...... produced a similar quenching of burst activity....

LM1-64: a Newly Reported Lmc-Pn with WR Nucleus

Science.gov (United States)

Pena, M.; Olguin, L.; Ruiz, M. T.; Torres-Peimbert, S.

1993-05-01

The object LM1-64 was reported by Lindsay & Mullan (1963, Irish Astron. J., 5, 51) as a probable PN in the LMC. Optical and UV spectra taken by us confirm that suggestion. LM1-64 is a high excitation planetary nebulae which shows evidence of having a WC central star. Broad stellar emission at lambda 4650 is detected in the optical spectrum obtained with the CTIO 4m telescope, in 1989. A UV spectrum in the range from 1200 Angstroms to 2000 Angstroms was obtained with IUE in 1990. We have measured all the emission line fluxes available and determined values for the physical conditions and chemical abundances of the nebular ionized gas. The derived values are T(OIII) = 14000K, log He/H = 11.05, log C/H = 9.48, log O/H = 8.55 and log Ne/H = 7.94. LM1-64 shows a large C enhancement in the envelope as result of the central star activity, while He, O and Ne are comparable to the average values reported for the LMC-PNe (Monk, Barlow & Clegg, 1988, MNRAS, 234, 583). We have estimated the He II Zanstra temperature of the central star to be ~ 80,000 K. This temperature is much higher than the values reported for the known LMC-PNe with WR nucleus that Monk et al. have classified as W4 to W8. The only other high temperature WR nucleus in a LMC-PN is N66 which recently showed evidence of undergoing a WR episode (Torres-Peimbert, Ruiz, Peimbert & Pe\\ na, 1993, IAU Symp. 155, eds. A. Acker & R. Weinberger, in press).

Organobasierter Sauerstoff-Scavenger/-Indikator

OpenAIRE

Langowski, H.C.; Wanner, T.

2007-01-01

WO 2007059901 A1 UPAB: 20070911 NOVELTY - Oxygen scavenger/indicator which contains at least one substance having combined scavenging and indicating functions for oxygen which is capable of absorbing oxygen under the effect of moisture in alkaline conditions, and at least one alkaline compound. The indicator effect is caused by a change in at least one physical property of the substance having combined scavenging and indicating function for oxygen, the change being initiated by the presence o...

Botanical Scavenger Hunt

Science.gov (United States)

Walker-Livingston, Wendy

2009-01-01

Why not combine the use of technology with the excitement of a scavenger hunt that moves middle-level students out into the "wilds" of their school campus to classify plants? In the lesson plan described here, students embark on a botanical scavenger hunt and then document their findings using a digital camera. This project was designed to allow…

Response to the Letter to the Editor of Crop Science from Donald R. Davis regarding our research article published in Crop Science (2011: 51:2721-2727)

Science.gov (United States)

This letter serves as a response to the Letter to the Editor submitted by Donald R. Davis regarding our research article entitled “Mineral Concentration of Broccoli Florets in Relation to Year of Cultivar Release” published in Crop Science (2011, 51:2721-2727). In our manuscript, we clearly stated ...

[Sensitivity of BALB/c and WR strain mice to the immunodepressive action of cyclophosphamide and thiophosphamide].

Science.gov (United States)

Ir, K N; Telegin, L Iu; Pevnitskiĭ, L A; Malashenko, A M

1984-05-01

Experiments were made on BALB/cJ YSto and WR/Y mice to study the immunosuppressant action of cyclophosphamide (CP) and thiophosphamide (thiotepa) in vivo. WR mice were found to be significantly more sensitive to the immunosuppressant action of thiotepa than BALB/c mice and to have similar sensitivity to the action of CP. BALB/c mice appeared highly resistant to the action of both the drugs. Based on the data obtained and those reported in the literature a possible parallelism is suggested between the mutagenic and immunosuppressant action of CP and thiotepa.

Neutrino jets from high-mass WR gauge bosons in TeV-scale left-right symmetric models

Science.gov (United States)

Mitra, Manimala; Ruiz, Richard; Scott, Darren J.; Spannowsky, Michael

2016-11-01

We reexamine the discovery potential at hadron colliders of high-mass right-handed (RH) gauge bosons WR—an inherent ingredient of left-right symmetric models (LRSM). We focus on the regime where the WR is very heavy compared to the heavy Majorana neutrino N , and we investigate an alternative signature for WR→N decays. The produced neutrinos are highly boosted in this mass regime. Subsequently, their decays via off-shell WR bosons to jets, i.e., N →ℓ±jj, are highly collimated, forming a single neutrino jet (jN). The final-state collider signature is then ℓ±jN, instead of the widely studied ℓ±ℓ±j j . Present search strategies are not sensitive to this hierarchical mass regime due to the breakdown of the collider signature definition. We take into account QCD corrections beyond next-to-leading order (NLO) that are important for high-mass Drell-Yan processes at the 13 TeV Large Hadron Collider (LHC). For the first time, we evaluate WR production at NLO with threshold resummation at next-to-next-to-leading logarithm (NNLL) matched to the threshold-improved parton distributions. With these improvements, we find that a WR of mass MWR=3 (4 )[5 ] TeV and mass ratio of (mN/MWR)discovered with a 5 - 6 σ statistical significance at 13 TeV after 10 (100 )[2000 ] fb-1 of data. Extending the analysis to the hypothetical 100 TeV Very Large Hadron Collider (VLHC), 5 σ can be obtained for WR masses up to MW R=15 (30 ) with approximately 100 fb-1 (10 ab-1 ). Conversely, with 0.9 (10 )[150 ] fb-1 of 13 TeV data, MWR<3 (4 )[5 ] TeV and (mN/MWR)<0.1 can be excluded at 95% C.L.; with 100 fb-1 (2.5 ab-1 ) of 100 TeV data, MW R<22 (33 ) TeV can be excluded.

Peroxynitrite scavenging activity of herb extracts.

Science.gov (United States)

Choi, Hye Rhi; Choi, Jae Sue; Han, Yong Nam; Bae, Song Ja; Chung, Hae Young

2002-06-01

Peroxynitrite (ONOO(-)) is a cytotoxicant with strong oxidizing properties toward various cellular constituents, including sulphydryls, lipids, amino acids and nucleotides and can cause cell death, lipid peroxidation, carcinogenesis and aging. The aim of this study was to characterize ONOO(-) scavenging constituents from herbs. Twenty-eight herbs were screened for their ONOO(-) scavenging activities with the use of a fluorometric method. The potency of scavenging activity following the addition of authentic ONOO(-) was in the following order: witch hazel bark > rosemary > jasmine tea > sage > slippery elm > black walnut leaf > Queen Anne's lace > Linden flower. The extracts exhibited dose-dependent ONOO(-) scavenging activities. We found that witch hazel (Hamamelis virginiana L.) bark showed the strongest effect for scavenging ONOO(-) of the 28 herbs. Hamamelitannin, the major active component of witch hazel bark, was shown to have a strong ability to scavenge ONOO(-). It is suggested that hamamelitannin might be developed as an effective peroxynitrite scavenger for the prevention of ONOO(-) involved diseases. Copyright 2002 John Wiley & Sons, Ltd.

Detached dust shell around Wolf-Rayet star WR60-6 in the young stellar cluster VVV CL036

Energy Technology Data Exchange (ETDEWEB)

Borissova, J.; Amigo, P.; Kurtev, R. [Departamento de Física y Astronomía, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030 (Chile); Kumar, M. S. N. [Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Chené, A.-N. [Gemini Observatory, Northern Operations Center, 670 North A' ohoku Place Hilo, HI 96720 (United States); Minniti, D., E-mail: jura.borissova@uv.cl [Pontificia Universidad Católica de Chile, Facultad de Física, Departamento de Astronomía y Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile)

2014-01-01

The discovery of a detached dust shell around the Wolf-Rayet (WR) star WR60-6 in the young stellar cluster VVV CL036 is reported. This shell is uncovered through the Spitzer-MIPS 24 μm image, where it appears brightest, and it is invisible at shorter wavelengths. Using new APEX observations and other data available from the literature, we have estimated some of the shell parameters: the inner and outer radii of 0.15 and 0.90 pc, respectively; the overall systemic velocity of the molecular {sup 12}CO(3 → 2) emission of –45.7 ± 2.3 km s{sup –1}; an expansion velocity of the gas of 16.3 ± 1 km s{sup –1}; the dust temperature and opacity of 122 ± 12 K and 1.04, respectively; and an age of 2.8 × 10{sup 4} yr. The WR star displays some cyclic variability. The mass computed for the WR60-6 nebula indicates that the material was probably ejected during its previous stages of evolution. In addition, we have identified a bright spot very close to the shell, which can be associated with the Midcourse Space Experiment source G312.13+00.20.

[Clinical case of the month. Mild hemolytic disease of the newborn due to an anti-Wr(a) antibody].

Science.gov (United States)

Keutgens, A; Monfort, M; Wagemans, D; Van Cauwenberge, J-R; Gérard, C

2012-01-01

A Caucasian woman, with a A+ CCD.ee K neg erythrocyte phenotype and no history of blood transfusion, delivered a first child who developed mild anemia. The direct antiglobulin test performed on the newborn red blood cells belonging to the A+ CCD.ee K neg group, was strongly positive for IgG. During the pregnancy and after the delivery, the woman had a negative irregular antibody screening test, using standard red blood cells. However, at birth, using a collection of thawed red blood cells with rare phenotypes (private antigens), the lab showed an antibody anti-Wr(a) in the maternal serum. The activity of the maternal antibody, with a titer of 16, was completely inhibited by dithiothreitol, indicating the nature IgM of the circulating antibody. The presence of the antigen Wr(a) on the surface of the newborn and its biological father red blood cells was confirmed. The concentration of IgG anti-Wr(a) on baby erythrocytes was demonstrated by the presence of the antibody anti-Wr(a) in the eluate. This case illustrates the difficulties to detect antibodies against private antigens on baby erythrocytes, responsible of hemolytic diseases of newborn. Indeed, standard red blood cell panels used for irregular antibodies screening test do not express generally those private antigens.

Scavenging and recombination kinetics in a radiation spur: The successive ordered scavenging events

Science.gov (United States)

Al-Samra, Eyad H.; Green, Nicholas J. B.

2018-03-01

This study describes stochastic models to investigate the successive ordered scavenging events in a spur of four radicals, a model system based on a radiation spur. Three simulation models have been developed to obtain the probabilities of the ordered scavenging events: (i) a Monte Carlo random flight (RF) model, (ii) hybrid simulations in which the reaction rate coefficient is used to generate scavenging times for the radicals and (iii) the independent reaction times (IRT) method. The results of these simulations are found to be in agreement with one another. In addition, a detailed master equation treatment is also presented, and used to extract simulated rate coefficients of the ordered scavenging reactions from the RF simulations. These rate coefficients are transient, the rate coefficients obtained for subsequent reactions are effectively equal, and in reasonable agreement with the simple correction for competition effects that has recently been proposed.

76 FR 10899 - Decision To Evaluate a Petition To Designate a Class of Employees From the W.R. Grace and Company...

Science.gov (United States)

2011-02-28

... Employees From the W.R. Grace and Company in Curtis, MD, To Be Included in the Special Exposure Cohort... evaluate a petition to designate a class of employees from the W.R. Grace and Company in Curtis, Maryland... Compensation Program Act of 2000. The initial proposed definition for the class being evaluated, subject to...

2-[(aminopropyl)amino]ethanethiol (WR1065) is anti-neoplastic and anti-mutagenic when given during 60Coγ-ray irradiation

International Nuclear Information System (INIS)

Hill, C.K.; Nagy, B.; Peraino, C.; Grdina, D.

1986-01-01

The effect of 2[(aminopropyl)amino]ethanethiol (WR1065) has been studied on the induction of neoplastic transformation using 10T1/2 cells and on mutation of the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus using Chinese hamster V79 cells. The first observations that treatment of 10T1/2 cells with 1 mM WR1065 for a total of 35 min during irradiation with 60 C γ-rays significantly reduces the incidence of neoplastic transformation while having no effect on cell viability are reported. In a similar experiment with V79 cells in which 4mM WR1065 was used, a significant reduction in mutation frequency at the HGPRT locus and significant protection against cell killing was found. These results suggest that WR1965 acts to modulate both acute damage and sub-lethal processes that lead to mutation and neoplastic transformation. Beyond the purely mechanistic approach of these studies, the potential application of these agents to minimizing the long-term neoplastic effects of radiation or chemotherapeutic agents currently in use for treating potentially curable cancer patients should be further investigated. (author)

21 CFR 868.5590 - Scavenging mask.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scavenging mask. 868.5590 Section 868.5590 Food... DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5590 Scavenging mask. (a) Identification. A scavenging mask is a device positioned over a patient's nose to deliver anesthetic or analgesic gases to the...

Lung autophagic response following exposure of mice to whole body irradiation, with and without amifostine

International Nuclear Information System (INIS)

Zois, Christos E.; Giatromanolaki, Alexandra; Kainulainen, Heikki; Botaitis, Sotirios; Torvinen, Sira; Simopoulos, Constantinos; Kortsaris, Alexandros; Sivridis, Efthimios; Koukourakis, Michael I.

2011-01-01

Research highlights: → We investigated the effect 6 Gy of WBI on the autophagic machinery of normal mouse lung. → Irradiation induces dysfunction of the autophagic machinery in normal lung, characterized by decreased transcription of the LC3A/Beclin-1 mRNA and accumulation of the LC3A, and p62 proteins. → The membrane bound LC3A-II protein levels increased in the cytosolic fraction (not in the pellet), contrasting the patterns noted after starvation-induced autophagy. → Administration of amifostine, reversed all the LC3A and p62 findings, suggesting protection of the normal autophagic function. -- Abstract: Purpose: The effect of ionizing irradiation on the autophagic response of normal tissues is largely unexplored. Abnormal autophagic function may interfere the protein quality control leading to cell degeneration and dysfunction. This study investigates its effect on the autophagic machinery of normal mouse lung. Methods and materials: Mice were exposed to 6 Gy of whole body γ-radiation and sacrificed at various time points. The expression of MAP1LC3A/LC3A/Atg8, beclin-1, p62/sequestosome-1 and of the Bnip3 proteins was analyzed. Results: Following irradiation, the LC3A-I and LC3A-II protein levels increased significantly at 72 h and 7 days. Strikingly, LC3A-II protein was increased (5.6-fold at 7 days; p < 0.001) only in the cytosolic fraction, but remained unchanged in the membrane fraction. The p62 protein, was significantly increased in both supernatant and pellet fraction (p < 0.001), suggesting an autophagosome turnover deregulation. These findings contrast the patterns of starvation-induced autophagy up-regulation. Beclin-1 levels remained unchanged. The Bnip3 protein was significantly increased at 8 h, but it sharply decreased at 72 h (p < 0.05). Administration of amifostine (200 mg/kg), 30 min before irradiation, reversed all the LC3A and p62 findings on blots, suggesting restoration of the normal autophagic function. The LC3A and Beclin1 m

LEW.1WR1 RATS DEVELOP AUTOIMMUNE DIABETES SPONTANEOUSLY AND IN RESPONSE TO ENVIRONMENTAL PERTURBATION

Science.gov (United States)

Mordes, John P.; Leif, Jean H.; Woda, Bruce A.; Flanagan, Joan F.; Greiner, Dale L.; Kislauskis, Edward H.; Tirabassi, Rebecca S.

2005-01-01

We describe a new rat model of autoimmune diabetes that arose in a major histocompatibility complex (MHC) congenic LEW rat. Spontaneous diabetes in LEW.1WR1 rats (RT1u/u/a) occurs with a cumulative frequency of ∼2% at a median age of 59 days. The disease is characterized by hyperglycemia, glycosuria, ketonuria and polyuria. Both sexes are affected, and islets of acutely diabetic rats are devoid of beta cells whereas alpha and delta cell populations are spared. The peripheral lymphoid phenotype is normal, including the fraction of ART2+ regulatory T cells (Tregs). We tested the hypothesis that the expression of diabetes would be increased by immunological perturbation of innate or adaptive immunity. Treatment of young rats with depleting anti-ART2.1 mAb increased the frequency of diabetes to 50%. Treatment with the toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid increased the frequency of diabetes to 100%. All diabetic rats exhibited end-stage islets. The LEW.1WR1 rat is also susceptible to collagen-induced arthritis but is free of spontaneous thyroiditis. The LEW.1WR1 rat provides a new model for studying autoimmune diabetes and arthritis in an animal with a genetic predisposition to both disorders that can be amplified by environmental perturbation. PMID:16123363

Draft genome sequence of the intestinal parasite Blastocystis subtype 4-isolate WR1

NARCIS (Netherlands)

Wawrzyniak, Ivan; Courtine, Damien; Osman, Marwan; Hubans-Pierlot, Christine; Cian, Amandine; Nourrisson, Céline; Chabe, Magali; Poirier, Philippe; Bart, Aldert; Polonais, Valérie; Delgado-Viscogliosi, Pilar; El Alaoui, Hicham; Belkorchia, Abdel; van Gool, Tom; Tan, Kevin S. W.; Ferreira, Stéphanie; Viscogliosi, Eric; Delbac, Frédéric

2015-01-01

(ST1-ST17) described to date. Only the whole genome of a human ST7 isolate was previously sequenced. Here we report the draft genome sequence of Blastocystis ST4-WR1 isolated from a laboratory rodent at Singapore. (C) 2015 The Authors. Published by Elsevier Inc

Radioprotective action of WR-1065 on radiation-induced DNA strand breaks in cultured Chinese hamster ovary cells

International Nuclear Information System (INIS)

Murray, D.; VanAnkeren, S.C.; Milas, L.; Meyn, R.E.

1988-01-01

We have examined the radioprotective effect of WR-1065 on cultured Chinese hamster ovary cells. The effects of the drug on the induction and rejoining of gamma-ray-induced DNA single-strand breaks (SSBs) and double-strand breaks (DSBs) were measured using alkaline (pH 12.1) and neutral (pH 7.0) elution, respectively. Molecular protection factors (PFs) calculated from these data allowed us to determine whether the degree of modification of strand breakage accurately predicted the PFs measured using the biological end point of cell survival. The drug did protect against the induction of both SSBs and DSBs, although to an extent that did not appear to fully account for the degree of radioprotection in terms of cell killing measured under identical conditions. It is therefore unlikely that radioprotection by WR-1065 occurs simply as a consequence of a general lowering of all types of gamma-ray-induced DNA lesions, and it is possible that the drug could differentially protect against the induction of subsets of these DNA lesions. The rate of SSB rejoining was retarded following preirradiation treatment of cells with WR-1065, but there was no effect on DSB rejoining. Postirradiation treatment with WR-1065 also appeared to retard SSB rejoining but without an accompanying effect on either DSB rejoining or cell survival; however, this effect was largely reversed by the addition of catalase and was, therefore, probably a result of H 2 O 2 generated by autoxidation of the drug. Based on these observations, it would appear that the molecular actions of aminothiol radioprotective compounds that lead to reduced cell killing are much more complex than previously thought

Amifostine Protection Against Mitomycin-induced Chromosomal Breakage in Fanconi Anaemia Lymphocytes

Directory of Open Access Journals (Sweden)

Miriam T. P. Lopes

2008-08-01

Full Text Available Fanconi anaemia (FA is a rare genetic chromosomal instability syndrome caused by impairment of DNA repair and reactive oxygen species (ROS imbalance. This disease is also related to bone marrow failure and cancer. Treatment of these complications with radiation and alkylating agents may enhance chromosomal breakage. We have evaluated the effect of amifostine (AMF on basal and mitomycin C (MMC-induced chromosomal breakage in FA blood cells using the micronucleus assay. The basal micronuclei count was higher among FA patients than healthy subjects. Pre-treatment with AMF significantly inhibited micronucleation induced by MMC in healthy subjects (23.4 ± 4.0 – MMC vs 12.3 ± 2.9 – AMF →MMC MN/1000CB, p < 0.01, one way ANOVA as well as in FA patients (80.0 ± 5.8 – MMC vs 40.1 ± 5.8 – AMF →MMC MN/1000CB, p < 0.01, ANOVA. Release of ROS by peripheral blood mononuclear cells treated with AMF →MMC and measured by chemoluminometry showed that AMF-protection was statistically higher among FA patients than in healthy individuals. Based on these results we suggest that AMF prevents chromosomal breakage induced by MMC, probably by its antioxidant effect.

Scavenging and recombination kinetics in radiation chemistry.

Science.gov (United States)

Al-Samra, Eyad H; Green, Nicholas J B

2017-08-02

This work describes stochastic models developed to study the competition between radical scavenging and recombination for simple model systems typical of radiation chemistry, where the reactive particles are tightly clustered and reactions are assumed fully diffusion limited. Three models are developed: a Monte Carlo random flights model with a periodic boundary condition for scavengers, Monte Carlo simulations in which the scavenging rate is calculated from the Smoluchowski theory for diffusion-limited reactions and a modification of the independent reaction times method where the scavengers close to the spur are explicitly included and the scavengers further away are treated as a continuum. The results indicate that the Smoluchowski theory makes a systematic overestimate of the scavenging rate when such competition is present. A correction for the Smoluchowski rate constant is suggested, an analytical justification is presented and it is tested against the simulations, and shown to be a substantial improvement.

Zytoprotektion mit Amifostin (Ethyol®) in der Chemotherapie: Meta-Analyse zum pharmakokinetischen Interaktionspotential mit Zytostatika.

Science.gov (United States)

Czejka, Martin; Schüller, Johannes; Kletzl, Heidemarie

2017-08-25

The cytoprotective agent amifostine (AMI) is capable to protect healthy cells (contrary to tumor cells) due to higher activity of alkaline phosphatase at the membrane site of normal cells. In seven clinical trials the influence of AMI on the pharmacokinetics of different cytostatics was investigated. Preadministration of AMI increased Cmax of doxorubicin (+ 44 %, p < 0.06), epirubicin (+ 31 %, P < 0.08), mitomycin C (+ 41 %, p < 0.01) and docetaxel (+ 31 % and + 17 %, not significant). In contrary, the peak concentration of pirarubicin , the tetrahydropyranyl-prodrug of doxorubicin was decreased (- 50 %, P < 0.03), leading to an equal higher concentrationof doxorubicin in the blood . In accordance to the peak concentrations, the AUC'ast was increased by chemoprotection: doxorubicin + 53 % (p < 0.01) and epirubicin + 23 % (not significant), docetaxel + 25 % and + 31 % (not significant). AUC'ast of mitomycin C and paclitaxel seemed to be unaffected by preadministered AMI. A particular inhibition of the protein binding by AMI has been identified as one reason for higher serum concentrations of anthracycline drugs. After cytoprotection, a possible increase of the cytostatic's Serum concentrations should be taken into account for optimal dosage schedules.

THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

International Nuclear Information System (INIS)

Ignace, R.; Gayley, K. G.; Hamann, W.-R.; Oskinova, L. M.; Huenemoerder, D. P.; Pollock, A. M. T.; McFall, M.

2013-01-01

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds

THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

Energy Technology Data Exchange (ETDEWEB)

Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37663 (United States); Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52245 (United States); Hamann, W.-R.; Oskinova, L. M. [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany); Huenemoerder, D. P. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Pollock, A. M. T. [European Space Agency XMM-Newton Science Operations Centre, European Space Astronomy Centre, Apartado 78, Villanueva de la Cañada, E-28691 Madrid (Spain); McFall, M., E-mail: ignace@etsu.edu [Department of Physics, 191 W. Woodruff Avenue, Ohio State University, Columbus, OH 43210 (United States)

2013-09-20

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds.

Dielectric polymer: scavenging energy from human motion

Science.gov (United States)

Jean-Mistral, Claire; Basrour, Skandar; Chaillout, Jean-Jacques

2008-03-01

More and more sensors are embedded in human body for medical applications, for sport. The short lifetime of the batteries, available on the market, reveals a real problem of autonomy of these systems. A promising alternative is to scavenge the ambient energy such as the mechanical one. Up to now, few scavenging structures have operating frequencies compatible with ambient one. And, most of the developed structures are rigid and use vibration as mechanical source. For these reasons, we developed a scavenger that operates in a large frequency spectrum from quasi-static to dynamic range. This generator is fully flexible, light and does not hamper the human motion. Thus, we report in this paper an analytical model for dielectric generator with news electrical and mechanical characterization, and the development of an innovating application: scavenging energy from human motion. The generator is located on the knee and design to scavenge 0.1mJ per scavenging cycle at a frequency of 1Hz, enough to supply a low consumption system and with a poling voltage as low as possible to facilitate the power management. Our first prototype is a membrane with an area of 5*3cm and 31µm in thickness which scavenge 0.1mJ under 170V at constant charge Q.

Electron scavenging in ethylene glycol-water glass at 4 and 77 K: scavenging of trapped vs mobile electrons. [. gamma. -rays, x radiation

Energy Technology Data Exchange (ETDEWEB)

Lin, D P; Kevan, L [Wayne State Univ., Detroit, Mich. (USA). Dept. of Chemistry; Steen, H B

1976-01-01

Electron scavenging efficiencies have been measured at 77 and 4 K in ethylene glycol-water glass for the following scavengers which span a 250-fold range of scavenger efficiencies at 77 K: HCl, NaNO/sub 3/ and K/sub 2/Cr0/sub 4/. The range of scavenging efficiencies decreases to 62 at 4 K with the largest relative change occurring for the less efficient scavengers. These results are suggested to be most consistent with a model in which scavenging occurs by tunneling from shallowly and deeply trapped electrons at 4 and 77 K, respectively.

Draft genome sequence of the intestinal parasite Blastocystis subtype 4-isolate WR1

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Ivan Wawrzyniak

2015-06-01

Full Text Available The intestinal protistan parasite Blastocystis is characterized by an extensive genetic variability with 17 subtypes (ST1–ST17 described to date. Only the whole genome of a human ST7 isolate was previously sequenced. Here we report the draft genome sequence of Blastocystis ST4-WR1 isolated from a laboratory rodent at Singapore.

The effect of 2-[(aminopropyl)amino] ethanethiol (WR 1065) on radiation-induced DNA damage and repair and cell progression in V79 cells

International Nuclear Information System (INIS)

Grdina, D.J.; Nagy, B.

1986-01-01

The radioprotector 2-[(aminopropyl)amino] ethanethiol (WR 1065) was investigated with respect to its ability to affect radiation-induced DNA damage and repair in V79 cells. At a concentration of 4mM, WR 1065 protected against the formation of single strand breaks (SSB), when present during irradiation. The protector appeared, however, to inhibit the subsequent postirradiation repair or rejoining of SSB. While repair was complete within 24h, the protector reduced the rate of repair by a factor of 3. This inhibitory effect on the rate of repair did not correlate with either measured differences in cell survival or mutagenesis. WR 1065 present in the growth medium inhibited the progression of cells through S-phase, and cell-doubling time following a 3h exposure to the protector was increased from 11 to 18h. These data are consistent with the property of thiols to inhibit DNA polymerase activity. It was concluded that, while the presence of WR 1065 during irradiation reduced SSB-DNA damage, its effect on the subsequent rejoining of these breaks could not be correlated with its observed effect on protecting against radiation-induced mutagenesis. (author)

Modification of bone marrow radiosensitivity by medicinal plant extracts

Energy Technology Data Exchange (ETDEWEB)

Ganasoundari, A.; Zare, S. M.; Uma Devi, P. [Department of Radiobiology, Kasturba Medical College, Manipal 576 119 (India)

1997-07-01

Withaferin A (WA), a steroidal lactone, and Plumbagin (Pi), a naphthoquinone, from the roots of Withania somnifera and Plumbage rosea, respectively, have been shows to possess growth inhibitory and radiosensitizing effects on experimental mouse tumours. An aqueous extract of the leaves of Ocimum sanctum (OE) was found to protect mice against radiation lethality. Therefore, the radiomodifying effects of the above plant products on the bone marrow of the adult Swiss mouse was studied. Single doses of WA (30 mg kg{sup -1}) or P1 (5 mg kg{sup -1}) were injected intraperitoneally tip) and OE (10 mg kg{sup -1}) was injected ip once daily for five consecutive days. Administration of extracts was followed by 2 Gy whole body gamma irradiation. Bone marrow stem cell survival was studied by an exogenous spleen colony unit (CFU-S) assay. The effects of WA and P1 were compared with that of cyclophosphamide (CP) and radioprotection by OE was compared with that of WR-2721 (WR). Radiation reduced the CFU-S to less than 50% of normal. WA, CP and P1 significantly enhanced this effect and reduced the CFU-S to almost the same extent (to <20% of normal), although individually WA and P1 were less cytotoxic than CP. These results indicate that radiosensitization by WE and P1 is not tumour specific. OE significantly increased CFU-S compared with radiotherapy (RT) alone. OE + RT gave a higher stem cell survival (p < 0.05) than that produced by WR + RT. While WR alone had a toxic effect, OE treatment showed no such effect, suggesting that the latter may have an advantage over WR in clinical application. (author)

Scavenger receptors in homeostasis and immunity.

Science.gov (United States)

Canton, Johnathan; Neculai, Dante; Grinstein, Sergio

2013-09-01

Scavenger receptors were originally identified by their ability to recognize and to remove modified lipoproteins; however, it is now appreciated that they carry out a striking range of functions, including pathogen clearance, lipid transport, the transport of cargo within the cell and even functioning as taste receptors. The large repertoire of ligands recognized by scavenger receptors and their broad range of functions are not only due to the wide range of receptors that constitute this family but also to their ability to partner with various co-receptors. The ability of individual scavenger receptors to associate with different co-receptors makes their responsiveness extremely versatile. This Review highlights recent insights into the structural features that determine the function of scavenger receptors and the emerging role that these receptors have in immune responses, notably in macrophage polarization and in the pathogenesis of diseases such as atherosclerosis and Alzheimer's disease.

Differential Scavenging Among Pig, Rabbit, and Human Subjects.

Science.gov (United States)

Steadman, Dawnie Wolfe; Dautartas, Angela; Kenyhercz, Michael W; Jantz, Lee M; Mundorff, Amy; Vidoli, Giovanna M

2018-04-12

Different animal species have been used as proxies for human remains in decomposition studies for decades, although few studies have sought to validate their use in research aimed at estimating the postmortem interval. This study examines 45 pig, rabbit, and human subjects placed in three seasonal trials at the Anthropology Research Facility. In an earlier paper, we found that overall decomposition trends did vary between species that could be due to differential insect and scavenger behavior. This study specifically examines if scavenger behavior differs by carrion species. Daily photographs, game camera photographs, written observations, and Total Body Score (TBS) documented scavenging and decomposition changes. Results show that raccoons were the most commonly observed vertebrate scavenger, that scavenging was most extensive in winter, and that certain human subjects were preferred over other humans and all non-human subjects. Finally, scavenging activity greatly reduces the accuracy of postmortem interval estimates based on TBS. © 2018 American Academy of Forensic Sciences.

Boundary scavenging in the Pacific Ocean

International Nuclear Information System (INIS)

Anderson, R.F.; Lao, Y.; Broecker, W.S.; Trumbore, S.E.; Hofmann, H.J.; Wolfli, W.

1990-01-01

Concentrations of U, Th, 231 Pa and 10 Be were measured in Holocene sediments from two cores collected off the west coast of South America, two cores from the East Pacific Rise, two from the equatorial Pacific and one from the south Pacific central gyre. Our results, together with data from 5 cores reported in the literature, show that boundary scavenging plays a major role in the removal of 10 Be from the Pacific Ocean. Deposition rates of 10 Be at three margin sites are more than an order of magnitude greater than at sites of red clay accumulation in the deep central Pacific. Deposition of 231 Pa is 4 to 5-fold greater at the margin sites. The residence time of 10 Be with respect to chemical scavenging, defined as its inventory in the water column divided by its rate of removal to the sediments, varies regionally from >1000 years at the red-clay sites in the deep central Pacific to ∝100 years at the margin sites. Different factors control boundary scavenging of Pa and Be. For example, scavenging of 231 Pa is enhanced by metal-oxide coatings of particles, whereas this seems to have little influence on the scavenging of 10 Be. (orig.)

Aminoquinolone WR6026 as a feasible substitute for gentian violet in Chagas' disease prophylaxis in preserved blood for transfusional purposes

Directory of Open Access Journals (Sweden)

Moraes-Souza Helio

2002-01-01

Full Text Available The search for a colorless, nontoxic and efficient drug to prevent transfusion-associated Chagas' disease (TACD has been underway unsuccessfully since 1953 when gentian violet was preconized and to date is still being used as the only in vitro trypanocidal agent. The recent findings of aminoquinolone "WR6026" as a trypanocidal agent, led the authors to study the metabolism of red cells stored with this compound, the main objective of which was to define its applicability in TACD control. Ten units of human whole blood collected in CPDA-1 were divided into two equal satellite bags. One had "WR6026" (final concentration 62.5µg/mL added and the other was used as a control, both were stored at 4ºC. At baseline, day 7, 14, 21 and 28, samples were taken for the following measurements: adenosine triphosphate (ATP, hemoglobin, electrolytes (sodium and potassium, gases (pO2 and pCO2 and osmotic fragility. The results of tests and control were analyzed through parametric t-student test. The results were similar in both groups throughout the experiment except for the level of ATP on day 14, which presented significantly higher values in the tests when compared with the controls (p = 0.012. It was concluded that WR6026 does not interfere in the preservation and probably the viability of the erythrocytes also until day 28 of storage. Consequently the authors suggest that WR6026 could emerge as a colorless substitute for gentian violet in the control of TACD in endemic areas.

Validation of KENO V.a for criticality safety calculations involving WR-1 fast-neutron fuel arrangements

Energy Technology Data Exchange (ETDEWEB)

Gauld, I. C.

1991-07-15

The KENO V.a criticality safety code, used with the SCALE 27-energy-group ENDF/B-IV-based cross-section library, has been validated for low-enriched uranium carbide (UC) WR-1 fast-neutron (FN) fuel arrangements. Because of a lack of relevant experimental data for UC fuel in the published literature, the validation is based primarily on calculational comparisons with critical experiments for fuel types with a range of enrichments and densities that cover those of the FN UC fuel. The ability of KENO V.a to handle the unique annular pin arrangement of the WR-1 FN fuel bundle was established using a comparison with the MCNP3B code used with a continuous-energy ENDF/B-V-based cross-section library. This report is part of the AECL--10146 report series documenting the validation of the KENO V.a criticality safety code.

Application of radioprotectors in radiation protection

International Nuclear Information System (INIS)

Kljajic, R.R.; Masic, Z.S.

2000-01-01

Application of the ionizing radiation in almost all the fields of human activities enlarged the knowledge of their harming influence on the living beings. At the same time there have been many investigations of different chemical means that could successfully be used in protection from radiation. Until today several hundreds of different chemical compounds have been considered to be a potential chemical radioprotector. Analyzing the results of investigating great number of potential radioprotective compounds, it can be said that those containing sulfur provide the most effective protection. That are aminothiols, aminodisulphides, derivatives of thiourea, thiosulphuric and thiophosphate acid, dithiocarbamates, thiazolines, some of biogen amines and their derivates. Among the investigated compounds there is a certain number that, under some circumstances, has shown a protective effect on the experimental animals. In the work comparative investigation of the protective effect of cistaphosa (WR-638) and gamaphosa (WR-2721) have been researched on the big experimental animals, radiated with a high level of X-radiation. Well protective influence of both radioprotectors has been proven but gamafos showed higher efficiency. (author)

Americans with Disabilities Act Scavenger Hunt

Science.gov (United States)

Ramsey, Ursula

2018-01-01

This article describes a scavenger hunt for Business Law students. Specifically, students compete in this scavenger hunt to identify accessible design features on campus to undergird their study of Title III of the Americans with Disabilities Act (ADA). Title III of the ADA prohibits public accommodations from discriminating on the basis of…

Investigation into Seasonal Scavenging Patterns of Raccoons on Human Decomposition.

Science.gov (United States)

Jeong, Yangseung; Jantz, Lee Meadows; Smith, Jake

2016-03-01

Although raccoons are known as one of the most common scavengers in the U.S., scavenging by these animals has seldom been studied in terms of forensic significance. In this research, the seasonal pattern of raccoon scavenging and its effect on human decomposition was investigated using 178 human cadavers placed at the Anthropological Research Facility (ARF) of the University of Tennessee, Knoxville (UTK) between February 2011 and December 2013. The results reveal that (i) the frequency of scavenging increases during summer, (ii) scavenging occurs relatively immediately and lasts shorter in summer months, and (iii) scavenging influences the decomposition process by hollowing limbs and by disturbing insect activities, both of which eventually increases the chance of mummification on the affected body. This information is expected to help forensic investigators identify raccoon scavenging as well as make a more precise interpretation of the effect of raccoon scavenging on bodies at crime scenes. © 2015 American Academy of Forensic Sciences.

Influence of a radioprotector WR-638 on the lymphoid compartment of the irradiated rat thymus: a flow cytometric analysis

International Nuclear Information System (INIS)

Dragojevic-Simic, V.; Colic, M.; Gasic, S.

1994-01-01

The T cell composition of the thymus of X-ray irradiated (3.5 Gy) Wistar rat protected with WR-638 was analyzed by flow cytometry using monoclonal antibodies directed to the Thy 1.1, CD43, CD2, CD5, CD4, CD8 and class I and II MHC antigens. It was shown that this dose of X-rays caused cyclic changes in thymic cellularity manifested as: primary involution (until day 2), primary regeneration (from days 2 to 14), secondary involution (from days 14 to 21) and secondary regeneration (from days 21 to 30). WR-638 reduced the magnitude of thymocyte depletion in the primary involutive phase of the irradiated thymi. (author)

Shark scavenging behavior in the presence of competition

Directory of Open Access Journals (Sweden)

Shannon P. GERRY, Andrea J. SCOTT

2010-02-01

Full Text Available The distribution of organisms within a community can often be determined by the degree of plasticity or degree of specialization of resource acquisition. Resource acquisition is often based on the morphology of an organism, behavior, or a combination of both. Performance tests of feeding can identify the possible interactions that allow one species to better exploit a prey item. Scavenging behaviors in the presence or absence of a competitor were investigated by quantifying prey selection in a trophic generalist, spiny dogfish Squalus acanthias, and a trophic specialist, smooth-hounds Mustelus canis, in order to determine if each shark scavenged according to its jaw morphology. The diet of dogfish consists of small fishes, squid, ctenophores, and bivalves; they are expected to be nonselective predators. Smooth-hounds primarily feed on crustaceans; therefore, they are predicted to select crabs over other prey types. Prey selection was quantified by ranking each prey item according to the order it was consumed. Dietary shifts were analyzed by comparing the percentage of each prey item selected during solitary versus competitive scavenging. When scavenging alone, dogfish prefer herring and squid, which are easily handled by the cutting dentition of dogfish. Dogfish shift their diet to include a greater number of prey types when scavenging with a competitor. Smooth-hounds scavenge on squid, herring, and shrimp when alone, but increase the number of crabs in the diet when scavenging competitively. Competition causes smooth-hounds to scavenge according to their jaw morphology and locomotor abilities, which enables them to feed on a specialized resource [Current Zoology 56 (1: 100–108 2010].

Colorectal cancer: what's new in 1992. Cancers du colon et du rectum: nouveautes en 1992

Energy Technology Data Exchange (ETDEWEB)

Rivoire, M. (Centre de Lutte Contre le Cancer Leon-Berard, 69 - Lyon (France))

1992-12-01

Five studies presented at the 1992 ASCO meeting are analysed. Kligerman's study was designed to determine if pre-treatment with WR-2721 could p rotect normal tissues from the toxicities induced by radiation therapy (in 100 patients with an advanced rectal cancer). This pre-treatment resulted in a 13% reduction of moderate and severe acute toxicity. No WR-2721 patient experienced moderate or severe late toxicities compared to five in the group without pre-treatment. Minski studied the acute toxicity (during treatment and two weeks after) of combined pelvic radiation therapy, 5-FU and leucovorin when delivered pre-operatively (16 patients) versus post-operatively (25 patients) in patients with rectal cancer. The final report of the inter group study of 5-FU plus levamisole as adjuvant therapy for stage C colon cancer was made by Moertel. With a median follow-up time of 5.5 years, the 5-FU plus levamisole treatment has reduced the recurrence rate by 39%, the cancer related death rate by 32% and the overall death rate by 31%. Most of the recurrences occurred during the first two years. There was a decrease in the liver, great omentum, peritoneum and lung metastases, but there was no modification in loco-regional recurrence rate. Welt presented a phase I/II study of radio-immunotherapy with I [sup 131] monoclonal antibody A33 in patients with advanced colorectal carcinoma. Results were characterized by major hematologic toxicity and minor tumor response rate. Heiss undertook a prospective study to evaluate the influence of homologous blood transfusion on recurrence rate after colorectal cancer surgery. Fifty-eight patients receiving autologous blood transfusion were compared with sixty-two patients receiving homologous transfusion. With a median follow-up of 21 months a higher recurrence rate was found in the homologous group (29.4% versus 16.7%).

Colorectal cancer: what's new in 1992

International Nuclear Information System (INIS)

Rivoire, M.

1992-01-01

Five studies presented at the 1992 ASCO meeting are analysed. Kligerman's study was designed to determine if pre-treatment with WR-2721 could p rotect normal tissues from the toxicities induced by radiation therapy (in 100 patients with an advanced rectal cancer). This pre-treatment resulted in a 13% reduction of moderate and severe acute toxicity. No WR-2721 patient experienced moderate or severe late toxicities compared to five in the group without pre-treatment. Minski studied the acute toxicity (during treatment and two weeks after) of combined pelvic radiation therapy, 5-FU and leucovorin when delivered pre-operatively (16 patients) versus post-operatively (25 patients) in patients with rectal cancer. The final report of the inter group study of 5-FU plus levamisole as adjuvant therapy for stage C colon cancer was made by Moertel. With a median follow-up time of 5.5 years, the 5-FU plus levamisole treatment has reduced the recurrence rate by 39%, the cancer related death rate by 32% and the overall death rate by 31%. Most of the recurrences occurred during the first two years. There was a decrease in the liver, great omentum, peritoneum and lung metastases, but there was no modification in loco-regional recurrence rate. Welt presented a phase I/II study of radio-immunotherapy with I 131 monoclonal antibody A33 in patients with advanced colorectal carcinoma. Results were characterized by major hematologic toxicity and minor tumor response rate. Heiss undertook a prospective study to evaluate the influence of homologous blood transfusion on recurrence rate after colorectal cancer surgery. Fifty-eight patients receiving autologous blood transfusion were compared with sixty-two patients receiving homologous transfusion. With a median follow-up of 21 months a higher recurrence rate was found in the homologous group (29.4% versus 16.7%)

Blood Glutamate Scavenging: Insight into Neuroprotection

Directory of Open Access Journals (Sweden)

Alexander Zlotnik

2012-08-01

Full Text Available Brain insults are characterized by a multitude of complex processes, of which glutamate release plays a major role. Deleterious excess of glutamate in the brain’s extracellular fluids stimulates glutamate receptors, which in turn lead to cell swelling, apoptosis, and neuronal death. These exacerbate neurological outcome. Approaches aimed at antagonizing the astrocytic and glial glutamate receptors have failed to demonstrate clinical benefit. Alternatively, eliminating excess glutamate from brain interstitial fluids by making use of the naturally occurring brain-to-blood glutamate efflux has been shown to be effective in various animal studies. This is facilitated by gradient driven transport across brain capillary endothelial glutamate transporters. Blood glutamate scavengers enhance this naturally occurring mechanism by reducing the blood glutamate concentration, thus increasing the rate at which excess glutamate is cleared. Blood glutamate scavenging is achieved by several mechanisms including: catalyzation of the enzymatic process involved in glutamate metabolism, redistribution of glutamate into tissue, and acute stress response. Regardless of the mechanism involved, decreased blood glutamate concentration is associated with improved neurological outcome. This review focuses on the physiological, mechanistic and clinical roles of blood glutamate scavenging, particularly in the context of acute and chronic CNS injury. We discuss the details of brain-to-blood glutamate efflux, auto-regulation mechanisms of blood glutamate, natural and exogenous blood glutamate scavenging systems, and redistribution of glutamate. We then propose different applied methodologies to reduce blood and brain glutamate concentrations and discuss the neuroprotective role of blood glutamate scavenging.

Carcass Type Affects Local Scavenger Guilds More than Habitat Connectivity.

Science.gov (United States)

Olson, Zachary H; Beasley, James C; Rhodes, Olin E

2016-01-01

Scavengers and decomposers provide an important ecosystem service by removing carrion from the environment. Scavenging and decomposition are known to be temperature-dependent, but less is known about other factors that might affect carrion removal. We conducted an experiment in which we manipulated combinations of patch connectivity and carcass type, and measured responses by local scavenger guilds along with aspects of carcass depletion. We conducted twelve, 1-month trials in which five raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), and domestic rabbit (Oryctolagus spp.) carcasses (180 trials total) were monitored using remote cameras in 21 forest patches in north-central Indiana, USA. Of 143 trials with complete data, we identified fifteen species of vertebrate scavengers divided evenly among mammalian (N = 8) and avian species (N = 7). Fourteen carcasses (9.8%) were completely consumed by invertebrates, vertebrates exhibited scavenging behavior at 125 carcasses (87.4%), and four carcasses (2.8%) remained unexploited. Among vertebrates, mammals scavenged 106 carcasses, birds scavenged 88 carcasses, and mammals and birds scavenged 69 carcasses. Contrary to our expectations, carcass type affected the assemblage of local scavenger guilds more than patch connectivity. However, neither carcass type nor connectivity explained variation in temporal measures of carcass removal. Interestingly, increasing richness of local vertebrate scavenger guilds contributed moderately to rates of carrion removal (≈6% per species increase in richness). We conclude that scavenger-specific differences in carrion utilization exist among carcass types and that reliable delivery of carrion removal as an ecosystem service may depend on robust vertebrate and invertebrate communities acting synergistically.

Carcass Type Affects Local Scavenger Guilds More than Habitat Connectivity.

Directory of Open Access Journals (Sweden)

Zachary H Olson

Full Text Available Scavengers and decomposers provide an important ecosystem service by removing carrion from the environment. Scavenging and decomposition are known to be temperature-dependent, but less is known about other factors that might affect carrion removal. We conducted an experiment in which we manipulated combinations of patch connectivity and carcass type, and measured responses by local scavenger guilds along with aspects of carcass depletion. We conducted twelve, 1-month trials in which five raccoon (Procyon lotor, Virginia opossum (Didelphis virginiana, and domestic rabbit (Oryctolagus spp. carcasses (180 trials total were monitored using remote cameras in 21 forest patches in north-central Indiana, USA. Of 143 trials with complete data, we identified fifteen species of vertebrate scavengers divided evenly among mammalian (N = 8 and avian species (N = 7. Fourteen carcasses (9.8% were completely consumed by invertebrates, vertebrates exhibited scavenging behavior at 125 carcasses (87.4%, and four carcasses (2.8% remained unexploited. Among vertebrates, mammals scavenged 106 carcasses, birds scavenged 88 carcasses, and mammals and birds scavenged 69 carcasses. Contrary to our expectations, carcass type affected the assemblage of local scavenger guilds more than patch connectivity. However, neither carcass type nor connectivity explained variation in temporal measures of carcass removal. Interestingly, increasing richness of local vertebrate scavenger guilds contributed moderately to rates of carrion removal (≈6% per species increase in richness. We conclude that scavenger-specific differences in carrion utilization exist among carcass types and that reliable delivery of carrion removal as an ecosystem service may depend on robust vertebrate and invertebrate communities acting synergistically.

Carcass Type Affects Local Scavenger Guilds More than Habitat Connectivity

Science.gov (United States)

Olson, Zachary H.; Beasley, James C.; Rhodes, Olin E.

2016-01-01

Scavengers and decomposers provide an important ecosystem service by removing carrion from the environment. Scavenging and decomposition are known to be temperature-dependent, but less is known about other factors that might affect carrion removal. We conducted an experiment in which we manipulated combinations of patch connectivity and carcass type, and measured responses by local scavenger guilds along with aspects of carcass depletion. We conducted twelve, 1-month trials in which five raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), and domestic rabbit (Oryctolagus spp.) carcasses (180 trials total) were monitored using remote cameras in 21 forest patches in north-central Indiana, USA. Of 143 trials with complete data, we identified fifteen species of vertebrate scavengers divided evenly among mammalian (N = 8) and avian species (N = 7). Fourteen carcasses (9.8%) were completely consumed by invertebrates, vertebrates exhibited scavenging behavior at 125 carcasses (87.4%), and four carcasses (2.8%) remained unexploited. Among vertebrates, mammals scavenged 106 carcasses, birds scavenged 88 carcasses, and mammals and birds scavenged 69 carcasses. Contrary to our expectations, carcass type affected the assemblage of local scavenger guilds more than patch connectivity. However, neither carcass type nor connectivity explained variation in temporal measures of carcass removal. Interestingly, increasing richness of local vertebrate scavenger guilds contributed moderately to rates of carrion removal (≈6% per species increase in richness). We conclude that scavenger-specific differences in carrion utilization exist among carcass types and that reliable delivery of carrion removal as an ecosystem service may depend on robust vertebrate and invertebrate communities acting synergistically. PMID:26886299

Rain scavenging of radioactive particles

International Nuclear Information System (INIS)

Williams, A.L.

1975-01-01

An assessment is made of the rainout of airborne radioactive particles from a nuclear detonation with emphasis on the microphysical removal processes. For submicron particles the scavenging processes examined are Brownian and turbulent diffusion to cloud droplets. For particles larger than 1 μm radius, nucleation scavenging is examined. For various particle size and radioactivity distributions, it is found that from 27 to 99 percent of the radioactivity is attached to cloud droplets and subject to rapid removal by rain. (U.S.)

The infrared emission features in the spectrum of the Wolf-Rayet star WR 48a

NARCIS (Netherlands)

Chiar, JE; Peeters, E; Tielens, A. G. G. M.

2002-01-01

We present the first detection of unidentified infrared (UIR) emission features at similar to6.4 and 7.9 mum in the spectrum of the dusty WC8 Wolf-Rayet star WR 48a. Based on the H-deficient nature of WC stars, we attribute the emission features to large carbonaceous molecules or amorphous carbon

Radical scavenging activity of crude polysaccharides from Camellia sinensis

Directory of Open Access Journals (Sweden)

Yang Fan

2011-01-01

Full Text Available A preparation of crude polysaccharides (TPS was isolated from Camellia sinensis by precipitation and ultrafiltration. TPS1, TPS2, and TPS3 had molecular weights of 240, 21.4, and 2.46 kDa, respectively. The radical scavenging activities of TPS were evaluated by DPPH free radical, hydroxyl radical and superoxide radical scavenging. These results revealed that TPS exhibited strong radical scavenging activity in a concentration-dependent manner. TPS3 with lowest molecular weight showed a higher radical scavenging activity.

Weight savings in aerospace vehicles through propellant scavenging

Science.gov (United States)

Schneider, Steven J.; Reed, Brian D.

1988-01-01

Vehicle payload benefits of scavenging hydrogen and oxygen propellants are addressed. The approach used is to select a vehicle and a mission and then select a scavenging system for detailed weight analysis. The Shuttle 2 vehicle on a Space Station rendezvous mission was chosen for study. The propellant scavenging system scavenges liquid hydrogen and liquid oxygen from the launch propulsion tankage during orbital maneuvers and stores them in well insulated liquid accumulators for use in a cryogenic auxiliary propulsion system. The fraction of auxiliary propulsion propellant which may be scavenged for propulsive purposes is estimated to be 45.1 percent. The auxiliary propulsion subsystem dry mass, including the proposed scavenging system, an additional 20 percent for secondary structure, an additional 5 percent for electrical service, a 10 percent weight growth margin, and 15.4 percent propellant reserves and residuals is estimated to be 6331 kg. This study shows that the fraction of the on-orbit vehicle mass required by the auxiliary propulsion system of this Shuttle 2 vehicle using this technology is estimated to be 12.0 percent compared to 19.9 percent for a vehicle with an earth-storable bipropellant system. This results in a vehicle with the capability of delivering an additional 7820 kg to the Space Station.

Weight savings in aerospace vehicles through propellant scavenging

Science.gov (United States)

Schneider, Steven J.; Reed, Brian D.

1988-05-01

Vehicle payload benefits of scavenging hydrogen and oxygen propellants are addressed. The approach used is to select a vehicle and a mission and then select a scavenging system for detailed weight analysis. The Shuttle 2 vehicle on a Space Station rendezvous mission was chosen for study. The propellant scavenging system scavenges liquid hydrogen and liquid oxygen from the launch propulsion tankage during orbital maneuvers and stores them in well insulated liquid accumulators for use in a cryogenic auxiliary propulsion system. The fraction of auxiliary propulsion propellant which may be scavenged for propulsive purposes is estimated to be 45.1 percent. The auxiliary propulsion subsystem dry mass, including the proposed scavenging system, an additional 20 percent for secondary structure, an additional 5 percent for electrical service, a 10 percent weight growth margin, and 15.4 percent propellant reserves and residuals is estimated to be 6331 kg. This study shows that the fraction of the on-orbit vehicle mass required by the auxiliary propulsion system of this Shuttle 2 vehicle using this technology is estimated to be 12.0 percent compared to 19.9 percent for a vehicle with an earth-storable bipropellant system. This results in a vehicle with the capability of delivering an additional 7820 kg to the Space Station.

Multiple free-radical scavenging capacity in serum

Science.gov (United States)

Oowada, Shigeru; Endo, Nobuyuki; Kameya, Hiromi; Shimmei, Masashi; Kotake, Yashige

2012-01-01

We have developed a method to determine serum scavenging-capacity profile against multiple free radical species, namely hydroxyl radical, superoxide radical, alkoxyl radical, alkylperoxyl radical, alkyl radical, and singlet oxygen. This method was applied to a cohort of chronic kidney disease patients. Each free radical species was produced with a common experimental procedure; i.e., uv/visible-light photolysis of free-radical precursor/sensitizer. The decrease in free-radical concentration by the presence of serum was quantified with electron spin resonance spin trapping method, from which the scavenging capacity was calculated. There was a significant capacity change in the disease group (n = 45) as compared with the healthy control group (n = 30). The percent values of disease’s scavenging capacity with respect to control group indicated statistically significant differences in all free-radical species except alkylperoxyl radical, i.e., hydroxyl radical, 73 ± 12% (p = 0.001); superoxide radical, 158 ± 50% (p = 0.001); alkoxyl radical, 121 ± 30% (p = 0.005); alkylperoxyl radical, 123 ± 32% (p>0.1); alkyl radical, 26 ± 14% (p = 0.001); and singlet oxygen, 57 ± 18% (p = 0.001). The scavenging capacity profile was illustrated using a radar chart, clearly demonstrating the characteristic change in the disease group. Although the cause of the scavenging capacity change by the disease state is not completely understood, the profile of multiple radical scavenging capacities may become a useful diagnostic tool. PMID:22962529

Free Radical Scavenging Properties of Annona squamosa

Science.gov (United States)

Vikas, Biba; Akhil B, S; P, Remani; Sujathan, K

2017-10-26

Annona squamosa has extensively been used in the traditional and folkloric medicine and found to possess many biological activities. Different solvents, petroleum ether, chloroform, ethyl acetate and methanol extracts of Annona squamosa seeds (ASPE, ASCH, ASEA, ASME) have been used to prepare plant extracts. The present investigations dealt with the free radical scavenging activity of four extracts using various techniques such as total reducing power estimation, total phenolic count, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect, evaluation of ABTS cation decolorisation capacity, FRAP assay, hdroxyl radical scavenging assay, super oxide assay and Nitric oxide radical scavenging assay of the extracts. The results showed that the four extracts of Annona squamosa showed significant reducing power in four extracts. The total phenolic contents in petroleum ether, chloroform, ethyl acetate, methanol extracts and positive control were 0.64±0.17, 0.54±0.27, 0.49±0.24, 0.57±0.22 and 0.66±0.33. The antioxidant capacity by ABTS assay of ASPE, ASCH, ASEA, ASME and positive control, trolox showed 77.75±0.5,73.25±1.7,78.5± 1.2 , 80 ± 0.8 μg/ml and 94.2 ± 0.9 respectively. The (50 % scavenging activity) SA50 of ASPE and ASCH, ASEA and ASME was found to be 34.4 μg/ml, 43.8 μg/ml 34.7 μg/m and 28.8 μg/ml respectively by DPPH assay. The percentage of hydroxyl radical scavenging increased with the increasing concentration of the extracts. ASPE, ASCH, ASEA and ASME showed superoxide radical scavenging activity, as indicated by their values 66 ± 0.5, 68 ± 1 ,63 ± 1 and 70 ± 0.5 μg/ml respectively compared to gallic acid which was 97 ± 0.5 μg/ml. The values for scavenging of nitric oxide for ASPE, ASCH, ASEA and ASME were 91.0 ± 1.0, 66.75 ± 0.5, 71.75 ± 1.1 and 75.75 ± 1.15 μg/ml while value for standard ascorbic acid was 91.0 ± 1.0 μg/ml. The results revealed strong antioxidants in four extracts may lead to the development of potent

Survival of irradiated mice treated with WR-151327, synthetic trehalose dicorynomycolate, or ofloxacin

Science.gov (United States)

Ledney, G. D.; Elliott, T. B.; Landauer, M. R.; Vigneulle, R. M.; Henderson, P. L.; Harding, R. A.; Tom, S. P.

1994-10-01

Spaceflight personnel need treatment options that would enhance survival from radiation and would not disrupt task performance. Doses of prophylactic or therapeutic agents known to induce significant short-term (30-day) survival with minimal behavioral (locomotor) changes were used for 180-day survival studies. In protection studies, groups of mice were treated with the phosphorothioate WR-151327 (200 mg/kg, 25% of the LD10) or the immunomodulator, synthetic trehalose dicorynomycolate (S-TDCM; 8 mg/kg), before lethal irradiation with reactor-generated fission neutrons and γ-rays (n/γ = 1) or 60Co γ-rays. In therapy studies, groups of mice received either S-TDCM, the antimicrobial ofloxacin, or S-TDCM plus ofloxacin after irradiation. For WR-151327 treated-mice, survival at 180 days for n/γ = 1 and γ-irradiated mice was 90% and 92%, respectively; for S-TDCM (protection), 57% and 78%, respectively; for S-TDCM (therapy), 20% and 25%, respectively; for ofloxacin, 38% and 5%, respectively; for S-TDCM combined with ofloxacin, 30% and 30%, respectively; and for saline, 8% and 5%, respectively. Ofloxacin or combined ofloxacin and S-TDCM increased survival from the gram-negative bacterial sepsis that predominated in n/γ = 1) irradiated mice. The efficacies of the treatments depended on radiation quality, treatment agent and its mode of use, and microflora of the host.

To scavenge or not to scavenge: that is the question

Energy Technology Data Exchange (ETDEWEB)

Nowak, Elzbieta; Brzuszkiewicz, Anna [Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States); Dauter, Miroslawa [SAIC-Frederick Inc., Basic Research Program, Argonne National Laboratory, Argonne, IL 60439 (United States); Dauter, Zbigniew, E-mail: dauter@anl.gov [Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States); Rosenbaum, Gerd, E-mail: dauter@anl.gov [Department of Biochemistry, University of Georgia, SER-CAT at the APS, Argonne, IL 60439 (United States); Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States)

2009-09-01

Analysis of a series of diffraction data sets measured from several native as well as nicotinic acid-soaked crystals of trypsin suggests that this potential scavenger does not have any statistically significant effect on the amount of radiation damage incurred in the crystals on X-ray irradiation at 100 K. Analysis of a series of diffraction data sets measured from four native as well as four nicotinic acid-soaked crystals of trypsin at 100 K shows a high variability in radiation-sensitivity among individual crystals for both nicotinic acid-soaked and native crystals. The level of radiation-sensitivity and the extent of its variability is statistically indistinguishable between the two conditions. This suggests that this potential scavenger does not have any statistically significant effect on the amount of radiation damage incurred in the crystals on X-ray irradiation. This is in contrast to previous results [Kauffmann et al. (2006 ▶), Structure, 14, 1099–1105] where only one crystal specimen was used for each condition (native and nicotinic acid-soaked)

Habitat of in vivo transformation influences the levels of free radical scavengers in Clinostomum complanatum: implications for free radical scavenger based vaccines against trematode infections.

Science.gov (United States)

Zafar, Atif; Rizvi, Asim; Ahmad, Irshad; Ahmad, Masood

2014-01-01

Since free radical scavengers of parasite origin like glutathione-S-transferase and superoxide dismutase are being explored as prospective vaccine targets, availability of these molecules within the parasite infecting different hosts as well as different sites of infection is of considerable importance. Using Clinostomum complanatum, as a model helminth parasite, we analysed the effects of habitat of in vivo transformation on free radical scavengers of this trematode parasite. Using three different animal models for in vivo transformation and markedly different sites of infection, progenetic metacercaria of C. complanatum were transformed to adult ovigerous worms. Whole worm homogenates were used to estimate the levels of lipid peroxidation, a marker of oxidative stress and free radical scavengers. Site of in vivo transformation was found to drastically affect the levels of free radical scavengers in this model trematode parasite. It was observed that oxygen availability at the site of infection probably influences levels of free radical scavengers in trematode parasites. This is the first report showing that habitat of in vivo transformation affects levels of free radical scavengers in trematode parasites. Since free radical scavengers are prospective vaccine targets and parasite infection at ectopic sites is common, we propose that infections at different sites, may respond differently to free radical scavenger based vaccines.

Spatial complexity of carcass location influences vertebrate scavenger efficiency and species composition.

Science.gov (United States)

Smith, Joshua B; Laatsch, Lauren J; Beasley, James C

2017-08-31

Scavenging plays an important role in shaping communities through inter- and intra-specific interactions. Although vertebrate scavenger efficiency and species composition is likely influenced by the spatial complexity of environments, heterogeneity in carrion distribution has largely been disregarded in scavenging studies. We tested this hypothesis by experimentally placing juvenile bird carcasses on the ground and in nests in trees to simulate scenarios of nestling bird carrion availability. We used cameras to record scavengers removing carcasses and elapsed time to removal. Carrion placed on the ground was scavenged by a greater diversity of vertebrates and at > 2 times the rate of arboreal carcasses, suggesting arboreal carrion may represent an important resource to invertebrate scavengers, particularly in landscapes with efficient vertebrate scavenging communities. Nonetheless, six vertebrate species scavenged arboreal carcasses. Rat snakes (Elaphe obsolete), which exclusively scavenged from trees, and turkey vultures (Cathartes aura) were the primary scavengers of arboreal carrion, suggesting such resources are potentially an important pathway of nutrient acquisition for some volant and scansorial vertebrates. Our results highlight the intricacy of carrion-derived food web linkages, and how consideration of spatial complexity in carcass distribution (i.e., arboreal) may reveal important pathways of nutrient acquisition by invertebrate and vertebrate scavenging guilds.

UNDERSTANDING THE UNUSUAL X-RAY EMISSION PROPERTIES OF THE MASSIVE, CLOSE BINARY WR 20a: A HIGH ENERGY WINDOW INTO THE STELLAR WIND INITIATION REGION

International Nuclear Information System (INIS)

Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel

2013-01-01

The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit

Understanding the Unusual X-Ray Emission Properties of the Massive, Close Binary WR 20a: A High Energy Window into the Stellar Wind Initiation Region

Science.gov (United States)

Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel

2013-11-01

The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.

UNDERSTANDING THE UNUSUAL X-RAY EMISSION PROPERTIES OF THE MASSIVE, CLOSE BINARY WR 20a: A HIGH ENERGY WINDOW INTO THE STELLAR WIND INITIATION REGION

Energy Technology Data Exchange (ETDEWEB)

Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2013-11-10

The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.

Free Radical Scavenging Activities of Methanol Extract and ...

African Journals Online (AJOL)

Michael Horsfall

fractions were subjected to in vitro antioxidant evaluation using the DPPH free radical scavenging ... The crude extract has IC-50 value for radical scavenging activity of 5μg/mL which was .... effective concentration of the sample that is required.

Free radical scavenging injectable hydrogels for regenerative therapy

Energy Technology Data Exchange (ETDEWEB)

Komeri, Remya [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India); Thankam, Finosh Gnanaprakasam [Dept. of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha NE68178 (United States); Muthu, Jayabalan, E-mail: mjayabalan52@gmail.com [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India)

2017-02-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07 kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. - Graphical abstract: Injectable hydrogel with inherent free radical scavenging property for regenerative tissue engineering application. - Highlights: • Novel injectable hydrogel (PEAX-P) is prepared using D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer

Free radical scavenging injectable hydrogels for regenerative therapy

International Nuclear Information System (INIS)

Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

2017-01-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07 kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. - Graphical abstract: Injectable hydrogel with inherent free radical scavenging property for regenerative tissue engineering application. - Highlights: • Novel injectable hydrogel (PEAX-P) is prepared using D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer

An illicit economy: scavenging and recycling of medical waste.

Science.gov (United States)

Patwary, Masum A; O'Hare, William Thomas; Sarker, M H

2011-11-01

This paper discusses a significant illicit economy, including black and grey aspects, associated with medical waste scavenging and recycling in a megacity, considering hazards to the specific group involved in scavenging as well as hazards to the general population of city dwellers. Data were collected in Dhaka, Bangladesh, using a variety of techniques based on formal representative sampling for fixed populations (such as recycling operatives) and adaptive sampling for roaming populations (such as scavengers). Extremely hazardous items (including date expired medicines, used syringes, knives, blades and saline bags) were scavenged, repackaged and resold to the community. Some HCE employees were also observed to sell hazardous items directly to scavengers, and both employees and scavengers were observed to supply contaminated items to an informal plastics recycling industry. This trade was made possible by the absence of segregation, secure storage and proper disposal of medical waste. Corruption, a lack of accountability and individual responsibility were also found to be contributors. In most cases the individuals involved with these activities did not understand the risks. Although motivation was often for personal gain or in support of substance abuse, participants sometimes felt that they were providing a useful service to the community. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of vulture exclusion on carrion consumption by facultative scavengers.

Science.gov (United States)

Hill, Jacob E; DeVault, Travis L; Beasley, James C; Rhodes, Olin E; Belant, Jerrold L

2018-03-01

Vultures provide an essential ecosystem service through removal of carrion, but globally, many populations are collapsing and several species are threatened with extinction. Widespread declines in vulture populations could increase the availability of carrion to other organisms, but the ways facultative scavengers might respond to this increase have not been thoroughly explored. We aimed to determine whether facultative scavengers increase carrion consumption in the absence of vulture competition and whether they are capable of functionally replacing vultures in the removal of carrion biomass from the landscape. We experimentally excluded 65 rabbit carcasses from vultures during daylight hours and placed an additional 65 carcasses that were accessible to vultures in forested habitat in South Carolina, USA during summer (June-August). We used motion-activated cameras to compare carrion use by facultative scavenging species between the experimental and control carcasses. Scavenging by facultative scavengers did not increase in the absence of competition with vultures. We found no difference in scavenger presence between control carcasses and those from which vultures were excluded. Eighty percent of carcasses from which vultures were excluded were not scavenged by vertebrates, compared to 5% of carcasses that were accessible to vultures. At the end of the 7-day trials, there was a 10.1-fold increase in the number of experimental carcasses that were not fully scavenged compared to controls. Facultative scavengers did not functionally replace vultures during summer in our study. This finding may have been influenced by the time of the year in which the study took place, the duration of the trials, and the spacing of carcass sites. Our results suggest that under the warm and humid conditions of our study, facultative scavengers would not compensate for loss of vultures. Carcasses would persist longer in the environment and consumption of carrion would likely shift from

Radioprotective Agents

Directory of Open Access Journals (Sweden)

Ilker Kelle

2008-01-01

Full Text Available Since1949, a great deal of research has been carried out on the radioprotective activity of various chemical substances. Thiol compounds, compounds which contain –SH radical, different classes of pharmacological agents and other compounds such as vitamine C and WR-2721 have been shown to reduce mortality when administered prior to exposure to a lethal dose of radiation. Recently, honey bee venom as well as that of its components melittin and histamine have shown to be valuable in reduction of radiation-induced damage and also provide prophylactic alternative treatment for serious side effects related with radiotherapy. It has been suggested that the radioprotective activity of bee venom components is related with the stimulation of the hematopoetic system.

Characterization and DPPH Radical Scavenging Activity of Gallic ...

African Journals Online (AJOL)

Characterization and DPPH Radical Scavenging Activity of Gallic Acid-Lecithin Complex. C Liu, C Chen, H Ma, E Yuan, Q Li. Abstract. Purpose: To investigate the physicochemical properties and DPPH radical scavenging activity of gallic acid–lecithin complex. Methods: The complex of gallic acid with lecithin was prepared ...

Radical scavenging propensity of Cu2 +, Fe3 + complexes of flavonoids and in-vivo radical scavenging by Fe3 +-primuletin

Science.gov (United States)

Jabeen, Erum; Janjua, Naveed Kausar; Ahmed, Safeer; Murtaza, Iram; Ali, Tahir; Hameed, Shahid

2017-01-01

Cu2 + and Fe3 + complexes of three flavonoids (morin or mo, quercetin or quer and primuletin or prim) were synthesized with the objective of improving antioxidant capacities of flavonoids. The radical scavenging activities of pure flavonoids and their metal complexes were assayed to monitor their tendencies towards sequestering of radicals at physiological conditions. The scavenger potencies of metal-flavonoid complexes were significantly higher than those of the parent flavonoids. Further, influence of the solvent polarity on the radical capturing by flavonoids and their metal complexes was in favor for the polar solvent. Fe3 +-prim displayed its radical scavenging ability via up gradation of CAT and SOD activities in in-vivo antioxidant assays.

Integrated Analysis of the Scavenging Process in Marine Two-Stroke Diesel Engines

DEFF Research Database (Denmark)

Andersen, Fredrik Herland

Large commercial ships such as container vessels and bulk carriers are propelledby low-speed, uniow scavenged two-stroke diesel engines. An integralin-cylinder process in this type of engine is the scavenging process, where the burned gases from the combustion process are evacuated through...... receiver fora two-stroke diesel engine. Time resolved boundary conditions corresponding to measurements obtained from an operating engine as well as realistic initial conditions are used in the simulations. The CFD model provides a detailed description of the in-cylinder ow from exhaust valve opening (EVO...... in the scavenge and exhaust receivers increase while the scavenge port exposure time, tscav, decrease. Further the scavenging pressure is varied while the engine speed is kept constant. From the perspective of the scavenging process this will resemble a load sweep following a generator curve. The scavenge port...

Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin.

Science.gov (United States)

Dose, Janina; Matsugo, Seiichi; Yokokawa, Haruka; Koshida, Yutaro; Okazaki, Shigetoshi; Seidel, Ulrike; Eggersdorfer, Manfred; Rimbach, Gerald; Esatbeyoglu, Tuba

2016-01-14

Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH) and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health.

Radical Scavenging Efficacy of Thiol Capped Silver Nanoparticles

Indian Academy of Sciences (India)

aSchool of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur 492 010, India. bDepartment of ... of nanosilver in foods, health care and consumer products as antimi- ... of the radical scavenging behavior of thiolated antiox- idants (alone) and ..... case of GSH@AgNPs; DPPH scavenging activity was found to be ...

Multiple free-radical scavenging (MULTIS) capacity in cattle serum.

Science.gov (United States)

Sueishi, Yoshimi; Kamogawa, Erisa; Kimura, Anna; Kitahara, Go; Satoh, Hiroyuki; Asanuma, Taketoshi; Oowada, Shigeru

2017-01-01

Multiple free-radical scavenging (MULTIS) activity in cattle and human sera was evaluated with electron spin resonance spectroscopy. Scavenging rates against six active species, namely hydroxyl radical, superoxide anion, alkoxyl radical, alkylperoxyl radical, methyl radical, and singlet oxygen were quantified. The difference in the electron spin resonance signal intensity in the presence and absence of the serum was converted into the scavenging rates. Comparative MULTIS measurements were made in sera from eight beef cattle, three fetal calves and fifteen healthy human volunteers. Further, we determined the MULTIS value of albumin, the most abundant component in serum. MULTIS values in cattle sera indicated higher scavenging activity against most free radical species tested than human sera. In particular, cattle serum scavenging activities against superoxide and methyl radical were higher than human serum by 2.6 and 3.7 fold, respectively. In cattle serum, albumin appears to play a dominant role in MULTIS activity, but in human serum that is not the case. Previous data indicated that the abundance of uric acid in bovine blood is nearly 80% less than humans; however, this difference does not explain the deviation in MULTIS profile.

Searching for WR stars in I Zw 18 -- The origin of HeII emission

OpenAIRE

de Mello, Duilia; Schaerer, Daniel; Heldmann, Jennifer; Leitherer, Claus

1998-01-01

I Zw 18 is the most metal poor star-forming galaxy known and is an ideal laboratory to probe stellar evolution theory at low metallicities. Using archival HST WFPC2 imaging and FOS spectroscopy we were able to improve previous studies. We constructed a continuum free HeII map, which was used to identify Wolf-Rayet (WR) stars recently found by ground-based spectroscopy and to locate diffuse nebular emission. Most of the HeII emission is associated with the NW stellar cluster, clearly displaced...

Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines.

Science.gov (United States)

Sersen, Frantisek; Gregan, Fridrich; Kotora, Peter; Kmetova, Jarmila; Filo, Juraj; Loos, Dusan; Gregan, Juraj

2017-05-29

Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene)-N'-[2,6-dinitro-4-(trifluoromethyl)]phenylhydrazines. The chemical structures of these compounds were confirmed by 1H-NMR, 13C-NMR, 19F-NMR, IR spectroscopy, LC-MS, and elemental analysis. The prepared compounds were tested for their activity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR), and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) radicals. The free radical scavenging activity expressed as SC50 values of these compounds varied in a wide range, from a strong to no radical scavenging effect. The most effective radical scavengers were hydroxybenzylidene hydrazines containing three hydroxyl groups in the benzylidene part of their molecules. The prepared compounds were also tested for their activity to inhibit photosynthetic electron transport in spinach chloroplasts. IC50 values of these compounds varied in wide range, from an intermediate to no inhibitory effect.

Bergenin Content and Free Radical Scavenging Activity of Bergenia Extracts. .

Science.gov (United States)

Hendrychová, Helena; Martin, Jan; Tůmová, Lenka; Kočevar-Glavač, Nina

2015-07-01

Our research was focused on the evaluation of bergenin content and free radical scavenging activity of extracts prepared from three different species of Bergenia - B. crassifolia (L.) Fritsch., B. ciliata (Haw.) Sternb. and B. x ornata Stein. collected during different seasons. Using an HPLC method, the highest total amount of bergenin was revealed in the leaves of B. x ornata and B. crassifolia (4.9 - 5.1 mg x g(-1)). Free radical scavenging power was determined by two methods--FRAP and NADH. The best free radical scavengers were B. crassifolia (FRAP: 6.7 - 15.9 mg GAE. 100g(-1); NADH: 20.3 - 50.9%) and B. ornata (FRAP: 13.7 - 15.2 mg GAE. 100g(-1); NADH: 29.3 - 31.1%). The lowest content of bergenin and the weakest radical scavenger was B. ciliata (bergenin: 3.1 mg x g(-1); FRAP: 5.5 - 11.0 mg GAE.100g(-1); NADH: 23.2 - 25.6%). The presence of a large percentage of bergenin is responsible for the radical scavenging activity, as shown by the results from the FRAP and NADH assays. Significant, positive correlation was found between bergenin content and radical scavenging activity in both methods.

Identification of Radical Scavengers in Sweet Grass (Hierochloe odorata)

NARCIS (Netherlands)

Pukalskas, A.; Beek, van T.A.; Venskutonis, R.P.; Linssen, J.P.H.; Veldhuizen, van A.; Groot, de Æ.

2002-01-01

Extracts from aerial parts of sweet grass (Hierochloe odorata) were active DPPH free radical scavengers, The active compounds were detected in extract fractions using HPLC with on-line radical scavenging detection. After multistep fractionation of the extract, two new natural products possessing

A Geospatial Scavenger Hunt

Science.gov (United States)

Martinez, Adriana E.; Williams, Nikki A.; Metoyer, Sandra K.; Morris, Jennifer N.; Berhane, Stephen A.

2009-01-01

With the use of technology such as Global Positioning System (GPS) units and Google Earth for a simple-machine scavenger hunt, you will transform a standard identification activity into an exciting learning experience that motivates students, incorporates practical skills in technology, and enhances students' spatial-thinking skills. In the…

Radioprotection by WR-151327 against the late normal tissue damage in mouse hind legs from gamma ray radiation

International Nuclear Information System (INIS)

Matsushita, Satoru; Ando, Koichi; Koike, Sachiko

1994-01-01

To evaluate the protective effect of WR-151327 on late radiation-induced damaged to normal tissues in mice, the right hind legs of mice with or without WR-151327 administration (400 mg/kg) were irradiated with 137 Cs gamma rays. Leg contracture and skin shrinkage assays were performed at 380 days after irradiation. The mice were killed on day 400 postirradiation and histological sections of the legs were made. The thickness of the dermis, epidermis, and skin (dermis plus epidermis) was measured. The muscular area of the legs and the posterior knee angle between the femur and tibia were also measured. The left hind legs were similarly assessed as nonirradiated controls. Group means and standard deviations were calculated and dose-response curves were drawn for every endpoint. Then, the dose modifying factor (DMF) for each endpoint and the correlations among endpoints were determined. Latae damage assayed by leg contracture and skin shrinkage progressed with increasing radiation dose. However, it was reduced by drug treatment. The significant effect was indicated for skin shrinkage by a DMF of 1.8 at 35%. The DMF for leg contracture was 1.3 at 6 mm. In the irradiated legs, epidermal hyperplasia and dermal fibrosis in the skin, muscular atrophy, and extension disturbance of the knee joint were observed. These changes progressed with increasing radiation dose. Skin damage assayed by the present endpoints was also reduced by drug treatment by DMFs of 1.4 to 1.7. However, DMFs for damage to the muscle and knee were not determined because no isoeffect was observed. There were good correlations between leg contracture or skin shrinkage and the other endpoints in both untreated and drug-treated mice. WR-151327 has the potential to protect against radiation-induced late normal tissue damage. 17 refs., 6 figs., 2 tabs

Modeling of an Integrated Electromagnetic Generator for Energy Scavenging

NARCIS (Netherlands)

Lu, J.; Kovalgin, Alexeij Y.; Schmitz, Jurriaan

2007-01-01

The ubiquitous deploying of wireless electronic devices due to pervasive computing results in the idea of Energy Scavenging, i.e., harvesting ambient energy from surroundings of the electronic devices. As an approach to possible practical realization of such an energy scavenger, we aim at the

Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

Science.gov (United States)

Lin, M Y; Yen, C L

1999-08-01

The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

Occurrence and distribution of nitrogen-scavenging bacteria in marine environment

OpenAIRE

Sugahara, Isao; Kimura, Toshio; Hayashi, Koichiro

1987-01-01

The occurrence and distribution nitrogen-scavenging bacteria in the water of coastal and oceanic of Japan were studied during the Seisui-Maru cruises from 1986 to 1987. Nitroben-scavenging bacteria in the water usually occurred at the level of 10-104 cfu/ml.This value was almost comparable to that of aerobic heterotrophic bacteria. It seems that nitrogen-scavenging bacteria play an important role in the efficient uptake of low levels of nitrogenous compounds in marine enviroment.

Energy scavenging sources for biomedical sensors

International Nuclear Information System (INIS)

Romero, E; Warrington, R O; Neuman, M R

2009-01-01

Energy scavenging has increasingly become an interesting option for powering electronic devices because of the almost infinite lifetime and the non-dependence on fuels for energy generation. Moreover, the rise of wireless technologies promises new applications in medical monitoring systems, but these still face limitations due to battery lifetime and size. A trade-off of these two factors has typically governed the size, useful life and capabilities of an autonomous system. Energy generation from sources such as motion, light and temperature gradients has been established as commercially viable alternatives to batteries for human-powered flashlights, solar calculators, radio receivers and thermal-powered wristwatches, among others. Research on energy harvesting from human activities has also addressed the feasibility of powering wearable or implantable systems. Biomedical sensors can take advantage of human-based activities as the energy source for energy scavengers. This review describes the state of the art of energy scavenging technologies for powering sensors and instrumentation of physiological variables. After a short description of the human power and the energy generation limits, the different transduction mechanisms, recent developments and challenges faced are reviewed and discussed. (topical review)

Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines

Directory of Open Access Journals (Sweden)

Frantisek Sersen

2017-05-01

Full Text Available Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene-N′-[2,6-dinitro-4-(trifluoromethyl]phenylhydrazines. The chemical structures of these compounds were confirmed by 1H-NMR, 13C-NMR, 19F-NMR, IR spectroscopy, LC-MS, and elemental analysis. The prepared compounds were tested for their activity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH, galvinoxyl radical (GOR, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS radicals. The free radical scavenging activity expressed as SC50 values of these compounds varied in a wide range, from a strong to no radical scavenging effect. The most effective radical scavengers were hydroxybenzylidene hydrazines containing three hydroxyl groups in the benzylidene part of their molecules. The prepared compounds were also tested for their activity to inhibit photosynthetic electron transport in spinach chloroplasts. IC50 values of these compounds varied in wide range, from an intermediate to no inhibitory effect.

Free radical scavenging injectable hydrogels for regenerative therapy.

Science.gov (United States)

Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

2017-02-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron beam treatment with radical scavengers/enhancers

International Nuclear Information System (INIS)

Gehringer, P.

1994-08-01

E-beam treatment of low level contaminated groundwater is best apt to demonstrate the role of scavengers and enhancers, respectively because groundwater already contains some scavengers as natural solutes. The action of ionizing radiation to water is known to result in the formation of ions, molecular and free radical species. For low level contaminations of groundwater (pollutant concentration aqu - and H are of interest for pollutant decomposition. The pollutants have to compete for the free radical species with the natural solutes. 10 figures are discussed. (author)

New actualistic data on the ecology and energetics of hominin scavenging opportunities.

Science.gov (United States)

Pobiner, Briana L

2015-03-01

For decades, the 'hunting-scavenging debate' has been an important research focus in Plio-Pleistocene hominin behavioral ecology. Here I present new data on potential scavenging opportunities from fresh carnivore kills on a conservancy in central Kenya. This ecosystem is dominated by felids (mainly lions) and has a different carnivore guild than in many earlier studies of scavenging opportunities that took place in areas such as Ngorongoro and Serengeti in Tanzania and Maasai Mara in Kenya, where lions face high levels of inter-specific competition from bone-crunching hyenas. I found that while scavenging opportunities vary among carcasses, most carcasses retained some scavengeable resources. Excluding within-bone resources, even the scavengeable meat on 'defleshed' larger sized prey carcasses is usually substantial enough to meet the total daily caloric requirements of at least one adult male Homo erectus individual. I argue, as others have before me, that scavenging opportunities in a particular ecosystem will vary in part due to carnivore taxon, density and guild composition; prey size, biomass and community structure; and habitat (e.g., vegetation, physiography). We should expect variability in scavenging opportunities in different locales and should focus our research efforts on identifying which variables condition these differences in order to make our findings applicable to the diversity of ecological settings characterizing the past. Published by Elsevier Ltd.

Deer carcass decomposition and potential scavenger exposure to chronic wasting disease

Science.gov (United States)

Jennelle, C.S.; Samuel, M.D.; Nolden, C.A.; Berkley, E.A.

2009-01-01

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy afflicting the Cervidae family in North America, causing neurodegeneration and ultimately death. Although there are no reports of natural cross-species transmission of CWD to noncervids, infected deer carcasses pose a potential risk of CWD exposure for other animals. We placed 40 disease-free white-tailed deer (Odocoileus virginianus) carcasses and 10 gut piles in the CWD-affected area of Wisconsin (USA) from September to April in 2003 through 2005. We used photos from remotely operated cameras to characterize scavenger visitation and relative activity. To evaluate factors driving the rate of carcass removal (decomposition), we used KaplanMeier survival analysis and a generalized linear mixed model. We recorded 14 species of scavenging mammals (6 visiting species) and 14 species of scavenging birds (8 visiting species). Prominent scavengers included American crows (Corvus brachyrhynchos), raccoons (Procyon lotor), and Virginia opossums (Didelphis virginiana). We found no evidence that deer consumed conspecific remains, although they visited gut piles more often than carcasses relative to temporal availability in the environment. Domestic dogs, cats, and cows either scavenged or visited carcass sites, which could lead to human exposure to CWD. Deer carcasses persisted for 18 days to 101 days depending on the season and year, whereas gut piles lasted for 3 days. Habitat did not influence carcass decomposition, but mammalian and avian scavenger activity and higher temperatures were positively associated with faster removal. Infected deer carcasses or gut piles can serve as potential sources of CWD prions to a variety of scavengers. In areas where surveillance for CWD exposure is practical, management agencies should consider strategies for testing primary scavengers of deer carcass material.

Nitric oxide radical scavenging potential of some Elburz medicinal ...

African Journals Online (AJOL)

Some plants scavenge nitric oxide (NO) with high affinity. For this purpose, forty extracts from 26 medicinal plants, growing extensively in Elburz mountains, were evaluated for their NO scavenging activity. Total phenolic and flavonoid contents of these extracts were also measured by Folin Ciocalteu and AlCl3 colorimetric ...

The research progress of several kinds of free radical scavengers

International Nuclear Information System (INIS)

Qian Liren; Huang Yuecheng; Cai Jianming

2009-01-01

Ionization radiation can generate free radicals in biological system, which could induce lipid peroxi-dation, biomacromolecule and biomembrane damage, lost of cell function, cell cycle disturbance, genetic mutation and so on. The scavenging free radicals can protect organism from radiation damage. Many radio-protective agents, such as amylase, hydroxyl-benzene derivatives, hormone, vitamin, have great abilities to protect organism from radiation via scavenging free radicals. In this paper, we mainly review the free radical scavenging effects of several kinds of radio-protective agents. (authors)

Scavenging efficiency and red fox abundance in Mediterranean mountains with and without vultures

Science.gov (United States)

Morales-Reyes, Zebensui; Sánchez-Zapata, José A.; Sebastián-González, Esther; Botella, Francisco; Carrete, Martina; Moleón, Marcos

2017-02-01

Vertebrate scavenging assemblages include two major functional groups: obligate scavengers (i.e., vultures), which depend totally on carrion and are undergoing severe declines around the globe, and facultative scavengers, which exploit carrion opportunistically and are generally ubiquitous. Our goal was to investigate the hypothesis that vultures can indirectly regulate the abundance of mesopredators (i.e., facultative scavengers) through modulating their access to carrion resources. We studied scavenging efficiency and red fox (Vulpes vulpes) abundance in two neighbouring areas of South-eastern Spain where vultures (mainly griffon vultures Gyps fulvus) are present (Cazorla) and absent (Espuña). To do so, we monitored ungulate carcasses consumption during winter and summer, and counted red fox scats along walking transects as a proxy of fox density. Our results confirmed that scavenging efficiency was higher in Cazorla and in carcasses visited by vultures. This resulted in increasing scavenging opportunities for facultative scavengers where vultures were absent. Accordingly, mean red fox abundance was higher in Espuña. These results suggest the existence of a vulture-mediated mesopredator release (i.e., an increase of mesopredator numbers following vulture loss), which could trigger important indirect ecological effects. Also, our study demonstrates that facultative scavengers are hardly able to functionally replace vultures, mainly because the former exploit carrion on a slower time scale.

Precipitation scavenging of aerosol particles

International Nuclear Information System (INIS)

Radke, L.F.; Eltgroth, M.W.; Hobbs, P.V.

1978-01-01

The paper presents the results of precipitation scavenging measurements of particles in the atmosphere and in plumes which were obtained using an airborne measuring system. Attention is given to the so-called 'Greenfield gap' and collection efficiencies for submicron particles

Changes in free-radical scavenging ability of kombucha tea during fermentation.

Science.gov (United States)

Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

2008-07-01

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

The Impact of Flight Hardware Scavenging on Space Logistics

Science.gov (United States)

Oeftering, Richard C.

2011-01-01

For a given fixed launch vehicle capacity the logistics payload delivered to the moon may be only roughly 20 percent of the payload delivered to the International Space Station (ISS). This is compounded by the much lower flight frequency to the moon and thus low availability of spares for maintenance. This implies that lunar hardware is much more scarce and more costly per kilogram than ISS and thus there is much more incentive to preserve hardware. The Constellation Lunar Surface System (LSS) program is considering ways of utilizing hardware scavenged from vehicles including the Altair lunar lander. In general, the hardware will have only had a matter of hours of operation yet there may be years of operational life remaining. By scavenging this hardware the program, in effect, is treating vehicle hardware as part of the payload. Flight hardware may provide logistics spares for system maintenance and reduce the overall logistics footprint. This hardware has a wide array of potential applications including expanding the power infrastructure, and exploiting in-situ resources. Scavenging can also be seen as a way of recovering the value of, literally, billions of dollars worth of hardware that would normally be discarded. Scavenging flight hardware adds operational complexity and steps must be taken to augment the crew s capability with robotics, capabilities embedded in flight hardware itself, and external processes. New embedded technologies are needed to make hardware more serviceable and scavengable. Process technologies are needed to extract hardware, evaluate hardware, reconfigure or repair hardware, and reintegrate it into new applications. This paper also illustrates how scavenging can be used to drive down the cost of the overall program by exploiting the intrinsic value of otherwise discarded flight hardware.

The hypolipidemic activity of Ayurvedic medicine, Arogyavardhini vati in Triton WR-1339-induced hyperlipidemic rats: A comparison with fenofibrate.

Science.gov (United States)

Kumar, Gajendra; Srivastava, Amita; Sharma, Surinder Kumar; Gupta, Yogendra Kumar

2013-07-01

Hyperlipidemia is a major risk factor of coronary heart disease. Currently available hypolipidemic drugs have been associated with number of side effects. Arogyavardhini vati, an Ayurvedic polyherbal formulation has been used for liver disorders. Therefore, present study was designed to evaluate the effect of Arogyavardhini vati in Triton WR-1339-induced hyperlipidemia in rats. Anti-hyperlipidemic activity evaluation of Arogyavardhini vati against Triton WR-1339-induced hyperlipidemia in rats. Overnight fasted male Wistar rats (150-200 g) were randomly divided into normal control group [4% Dimethyl Sulfoxide (DMSO), i.p.], positive control group (Triton WR-1339 in 4% DMSO, 400 mg/kg, i.p.), standard drug treated (fenofibrate 65 mg/kg, p.o. for 7 days after inducing hyperlipidemia) and Arogyavardhini vati treated (50, 100, 200 mg/kg, p.o. for 7 days after inducing hyperlipidemia). Rat doses were calculated by extrapolating the equivalent human dose (therapeutic dose, sub-maximum, and maximum dose). Serum total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein HDL, liver malondialdehyde (MDA), and glutathione (GSH) levels were estimated at end of experiments. Arogyavardhini vati significantly decreased serum cholesterol, triglyceride, LDL, and C-reactive protein (CRP) and significantly increased serum HDL in a dose-dependent manner. Decreased MDA and increased GSH levels in liver were observed at all doses of Arogyavardhini vati (50, 100, 200 mg/kg) and fenofibrate-treated groups when compared with Triton-treated group. Atherogenic Index (AI) level was significantly decreased in fenofibrate and Arogyavardhini vati (200 mg/kg) treated rats when compared with normal control. Arogyavardhini vati, a traditionally used Ayurvedic medicine may be a useful therapy for hypercholesterolemia through reducing oxidative stress (decreasing MDA and increasing GSH) and lipid levels.

Influence of various scavengers of •OH radicals on the radiation sensitivity of yeast and bacteria.

Science.gov (United States)

Múčka, Viliam; Bláha, Pavel; Čuba, Václav; Červenák, Jaroslav

2013-12-01

To quantitatively investigate the influence of various •OH (hydroxyl radical) scavengers on the radiation sensitivity of yeast and bacteria, particularly to define the relationship between the protective effect of a scavenger and its •OH scavenging efficiency. In order to study the protective effect of •OH scavengers we used various concentrations of four scavengers (methanol, potassium formate, ethanol and ascorbic acid) in isotonic salt solutions. These solutions containing live yeast (Saccharomyces cerevisiae) or bacteria (Escherichia coli) were irradiated with (60)Co isotope γ -radiation using two different doses and dose rates. The number of surviving cells was determined prior to and after irradiation both in suspension with and without scavengers. The surviving fractions after irradiation with and without the scavenger were evaluated. The main results of the paper were: The surviving fraction increased approximately linearly within the measured interval with increasing concentration of the scavenger. The same dependences were found for the protecting effect depending on the scavenging efficiency. The slopes of these dependences (k) were found to be characteristic for each scavenger. The k value determined the degree in which the scavenging of •OH radicals participated in the protection of living cells. The protective effects of scavengers at the same scavenging efficiency were different and unique for each scavenger. No simple relation was found between the efficiency of scavenger k and the rate constant kOH of the reactions between scavengers and •OH radicals. Our results suggest that the studied scavengers effectively protected yeast and bacteria against ionizing radiation. Although the scavenging of •OH radicals seems to be important for protection of living cells, it is clearly not the only process on which the protection is based.

Free radical scavenging properties of some wine probes

International Nuclear Information System (INIS)

Stasko, A.; Liptakova, M.; Malik, F.

1999-01-01

There are preliminary results of investigation of scavenging properties of 8 probes of Slovak wines (consisting of one reference, 3 probes of white wine and 4 probes of red wine). According to the literature so far, wine probes contain paramagnetic species (Mn 2+ , characterised with sextet spectrum, and a singlet line around g=2,00). In our probes we observed Mn 2+ signals, but no significant evidence for a single line of free radical was found. We can conclude that Mn 2+ content in the red wines is generally higher than in the white ones. Further, we investigated the scavenging activities of the probes adding solution of dinitropicryl hydrazyl (DPPH-stable radical) to them. Their ability to terminate free radicals resulted in the decrease of the final DPPH concentrations in the probes. The red wines have significantly higher capability to scavenge free radicals than the probes of white wines. (authors)

Scavenging energy from human motion with tubular dielectric polymer

Science.gov (United States)

Jean-Mistral, Claire; Basrour, Skandar

2010-04-01

Scavenging energy from human motion is a challenge to supply low consumption systems for sport or medical applications. A promising solution is to use electroactive polymers and especially dielectric polymers to scavenge mechanical energy during walk. In this paper, we present a tubular dielectric generator which is the first step toward an integration of these structures into textiles. For a 10cm length and under a strain of 100%, the structure is able to scavenge 1.5μJ for a poling voltage of 200V and up to 40μJ for a poling voltage of 1000V. A 30cm length structure is finally compared to our previous planar structure, and the power management module for those structures is discussed.

Forensically significant scavenging guilds in the southwest of Western Australia.

Science.gov (United States)

O'Brien, R Christopher; Forbes, Shari L; Meyer, Jan; Dadour, Ian

2010-05-20

Estimation of time since death is an important factor in forensic investigations and the state of decomposition of a body is a prime basis for such estimations. The rate of decomposition is, however, affected by many environmental factors such as temperature, rainfall, and solar radiation as well as by indoor or outdoor location, covering and the type of surface the body is resting upon. Scavenging has the potential for major impact upon the rate of decomposition of a body, but there is little direct research upon its effect. The information that is available relates almost exclusively to North American and European contexts. The Australian faunal assemblage is unique in that it includes no native large predators or large detrivorous avians. This research investigates the animals that scavenge carcasses in natural outdoor settings in southern Western Australia and the factors which can affect each scavenger's activity. The research was conducted at four locations around Perth, Western Australia with different environmental conditions. Pig carcasses, acting as models for the human body, were positioned in an outdoor environment with no protection from scavengers or other environmental conditions. Twenty-four hour continuous time-lapse video capture was used to observe the pattern of visits of all animals to the carcasses. The time of day, length of feeding, material fed upon, area of feeding, and any movement of the carcass were recorded for each feeding event. Some species were observed to scavenge almost continually throughout the day and night. Insectivores visited the carcasses mostly during bloat and putrefaction; omnivores fed during all stages of decomposition and scavenging by carnivores, rare at any time, was most likely to occur during the early stages of decomposition. Avian species, which were the most prolific visitors to the carcasses in all locations, like reptiles, fed only during daylight hours. Only mammals and amphibians, which were seldom seen

Free radical-scavenging delta-lactones from Boletus calopus.

Science.gov (United States)

Kim, Jin-Woo; Yoo, Ick-Dong; Kim, Won-Gon

2006-12-01

The methanol extracts from the fruiting body of the mushroom Boletus calopus showed free radical-scavenging activity. Bioactivity-guided fractionation of the methanol extracts led to a new hydroxylated calopin named calopin B, along with the known delta-lactones calopin and cyclocalopin A. The structure of the new calopin analogue was elucidated by spectroscopic methods. All compounds showed potent free radical-scavenging activity against superoxide, DPPH, and ABTS radicals with IC (50) values of 1.2 - 5.4 microg/mL.

Scavenger Receptors and Their Potential as Therapeutic Targets in the Treatment of Cardiovascular Disease

Directory of Open Access Journals (Sweden)

Sam L. Stephen

2010-01-01

Full Text Available Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis.

pH-dependent radical scavenging capacity of green tea catechins

NARCIS (Netherlands)

Muzolf, M.; Szymusiak, H.; Gliszczynska-Swiglo, A.; Rietjens, I.M.C.M.; Tyrakowska, B.

2008-01-01

The effect of pH on the radical scavenging capacity of green tea catechins was investigated using experimental as well as theoretical methods. It was shown that the radical scavenging capacity of the catechins, quantified by the TEAC value, increases with increasing pH of the medium. Comparison of

Scavenging Capacities of Some Wines and Wine Phenolic Extracts

Directory of Open Access Journals (Sweden)

Ioannis G. Roussis

2005-01-01

Full Text Available The aim of this study was to assess the ability of different wines – a sweet red, a dry red, a sweet white, and a dry white – to scavenge the stable 1,1’-diphenyl-2-picryl-hydrazyl radical (DPPH. and to determine their phenolic composition. Both red wines contained, apart from anthocyanins, also higher concentration of total phenolics, tartaric esters, and flavonols than the two white wines. All wines exhibited scavenging activity analogous to their total phenolic content. However, their phenolics differed in antiradical potency, which was visible in their EC50 values. The dry red wine, Xinomavro, had a lower EC50 value, indicating the higher antiradical potency of its phenolics. The scavenging capacities of phenolic extracts from Xinomavro red wine on hydroxyl radicals, superoxide radicals, and singlet oxygen were also assessed. Wine total extract was fractionated by extraction, and each of the three fractions was then subfractionated by column chromatography into two subfractions. Wine total extract, and its fractions and subfractions exhibited scavenging capacity on hydroxyl radicals, superoxide radicals, and singlet oxygen, indicating the activity of many wine phenolics. The most active wine extracts towards hydroxyl radicals were characterized by the high peaks of flavanols, anthocyanins and flavonols in their HPLC-DAD chromatograms. The most active extract towards superoxide radicals was rich in flavanols and anthocyanins. The characteristic phenolics of the most active wine extracts towards singlet oxygen were flavanols, flavonols and phenolic acids. The ability of all red wine phenolic extracts to scavenge singlet oxygen, along with hydroxyl and superoxide radicals, emphasizes its health functionality.

Optimum injection dose rate of hydrogen sulfide scavenger for treatment of petroleum crude oil

Directory of Open Access Journals (Sweden)

T.M. Elshiekh

2016-03-01

Full Text Available Hydrogen sulfide H2S scavengers are chemicals that favorably react with hydrogen sulfide gas to eliminate it and produce environmental friendly products. These products depend on the type and composition of the scavenger and the conditions at which the reaction takes place. The scavenger should be widely available and economical for industry acceptance by having a low unit cost. The optimum values of H2S scavenger injection dose rate of scavenging hydrogen sulfide from the multiphase fluid produced at different wells conditions in one of the Petroleum Companies in Egypt were studied. The optimum values of H2S scavenger injection dose rate depend on pipe diameter, pipe length, gas molar mass velocity, inlet H2S concentration and pressure. The optimization results are obtained for different values of these parameters using the software program Lingo. In general, the optimum values of H2S scavenger injection dose rate of the scavenging of hydrogen sulfide are increased by increasing of the pipe diameter and increasing the inlet H2S concentration, and decreased by increasing the pipe length, gas molar mass velocity and pressure.

Trophic facilitation or limitation? Comparative effects of pumas and black bears on the scavenger community.

Science.gov (United States)

Allen, Maximilian L; Elbroch, L Mark; Wilmers, Christopher C; Wittmer, Heiko U

2014-01-01

Scavenging is a widespread behaviour and an important process influencing food webs and ecological communities. Large carnivores facilitate the movement of energy across trophic levels through the scavenging and decomposition of their killed prey, but competition with large carnivores is also likely to constrain acquisition of carrion by scavengers. We used an experimental approach based on motion-triggered video cameras at black-tailed deer (Odocoileus hemionus columbianus) carcasses to measure the comparative influences of two large carnivores in the facilitation and limitation of carrion acquisition by scavengers. We found that pumas (Puma concolor) and black bears (Ursus americanus) had different effects on their ecological communities. Pumas, as a top-level predator, facilitated the consumption of carrion by scavengers, despite significantly reducing their observed sum feeding times (165.7 min ± 21.2 SE at puma kills 264.3 min ± 30.1 SE at control carcasses). In contrast, black bears, as the dominant scavenger in the system, limited consumption of carrion by scavengers as evidenced by the observed reduction of scavenger species richness recorded at carcasses where they were present (mean = 2.33 ± 0.28 SE), compared to where they were absent (mean = 3.28 ± 0.23 SE). Black bears also had large negative effects on scavenger sum feeding times (88.5 min ± 19.8 SE at carcasses where bears were present, 372.3 min ± 50.0 SE at carcasses where bears were absent). In addition, we found that pumas and black bears both increased the nestedness (a higher level of order among species present) of the scavenger community. Our results suggest that scavengers have species-specific adaptions to exploit carrion despite large carnivores, and that large carnivores influence the structure and composition of scavenger communities. The interactions between large carnivores and scavengers should be considered in future studies of food webs and ecological communities.

Effect of superoxide anion scavenger on rat hearts with chronic intermittent hypoxia.

Science.gov (United States)

Pai, Peiying; Lai, Ching Jung; Lin, Ching-Yuang; Liou, Yi-Fan; Huang, Chih-Yang; Lee, Shin-Da

2016-04-15

Only very limited information regarding the protective effects of the superoxide anion scavenger on chronic intermittent hypoxia-induced cardiac apoptosis is available. The purpose of this study is to evaluate the effects of the superoxide anion scavenger on cardiac apoptotic and prosurvival pathways in rats with sleep apnea. Forty-two Sprague-Dawley rats were divided into three groups, rats with normoxic exposure (Control, 21% O2, 1 mo), rats with chronic intermittent hypoxia exposure (Hypoxia, 3-7% O2vs. 21% O2per 40 s cycle, 8 h per day, 1 mo), and rats with pretreatment of the superoxide anion scavenger and chronic intermittent hypoxia exposure (Hypoxia-O2 (-)-Scavenger, MnTMPyP pentachloride, 1 mg/kg ip per day; 3-7% O2vs. 21% O2per 40 s cycle, 8 h per day, 1 mo) at 5-6 mo of age. After 1 mo, the protein levels and apoptotic cells of excised hearts from three groups were measured by Western blotting and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay. The superoxide anion scavenger decreased hypoxia-induced myocardial architecture abnormalities, left ventricular hypertrophy, and TUNEL-positive apoptosis. The superoxide anion scavenger decreased hypoxia-induced Fas ligand, Fas death receptors, Fas-associated death domain (FADD), activated caspase-8, and activated caspase-3 (Fas-dependent apoptotic pathway) as well as Bad, activated caspase-9 and activated caspase-3 (mitochondria-dependent apoptotic pathway), endonuclease G (EndoG), apoptosis-inducing factor (AIF), and TUNEL-positive apoptosis. The superoxide anion scavenger increased IGF-1, IGF-1R, p-PI3k, p-Akt, p-Bad, Bcl-2, and Bcl-xL (survival pathway). Our findings imply that the superoxide anion scavenger might prevent cardiac Fas-mediated and mitochondrial-mediated apoptosis and enhance the IGF-1-related survival pathway in chronic intermittent hypoxia. The superoxide anion scavenger may prevent chronic sleep apnea-enhanced cardiac apoptotic pathways and enhances

Human macrophage scavenger receptors: Primary structure, expression, and localization in atherosclerotic lesions

International Nuclear Information System (INIS)

Matsumoto, Akiyo; Itakura, Hiroshige; Kodama, Tatsuhiko; Naito, Makoto; Takahashi, Kiyoshi; Ikemoto, Shinji; Asaoka, Hitoshi; Hayakawa, Ikuho; Kanamori, Hiroshi; Takaku, Fumimaro; Aburatani, Hiroyuki; Suzuki, Hiroshi; Kobari, Yukage; Miyai, Tatsuya; Cohen, E.H.; Wydro, R.; Housman, D.E.

1990-01-01

Two types of cDNAs for human macrophage scavenger receptors were cloned from a cDNA library derived from the phorbol ester-treated human monocytic cell line THP-1. The type I and type II human scavenger receptors encoded by these cDNAs are homologous (73% and 71% amino acid identity) to their previously characterized bovine counterparts and consist of six domains: cytoplasmic (I), membrane-spanning (II), spacer (III), α-helical coiled-coil (IV), collagen-like (V), and a type-specific C-terminal (VI). The receptor gene is located on human chromosome 8. The human receptors expressed in CHO-K1 cells mediated endocytosis of modified low density lipoproteins. Two mRNAs, 4.0 and 3.2 kilobases, have been detected in human liver, placenta, and brain. Immunohistochemical studies using an anti-peptide antibody which recognizes human scavenger receptors indicated the presence of the scavenger receptors in the macrophages of lipid-rich atherosclerotic lesions, suggesting the involvement of scavenger receptors in atherogenesis

Computational study of the structure-free radical scavenging relationship of procyanidins.

Science.gov (United States)

Mendoza-Wilson, Ana María; Castro-Arredondo, Sergio Ivan; Balandrán-Quintana, René Renato

2014-10-15

Procyanidins (PCs) are effective free radical scavengers, however, their antioxidant ability is variable because they have different degrees of polymerisation, are composed by distinct types of subunits and are very susceptible to changes in conformation. In this work the structure-free radical scavenging relationship of monomers, dimers and trimers of PCs was studied through the hydrogen atom transfer (HAT), sequential proton-loss electron-transfer (SPLET) and single electron transfer followed by proton transfer (SET-PT) mechanisms in aqueous phase, employing the Density Functional Theory (DFT) computational method. The structure-free radical scavenging relationship of PCs showed a very similar behaviour in HAT and SET-PT mechanisms, but very different in the SPLET mechanism. The structural factor that showed more effects on the ability of PCs to scavenge free radicals in aqueous phase was the conformation. Copyright © 2014 Elsevier Ltd. All rights reserved.

The scavenger activities of tea polyphenol and quercetin against oxygen radicals

International Nuclear Information System (INIS)

Fang Ruoying; Cheng Jiwu; Hu Tianxi; Tu Tiecheng; Dong Jirong; Wang Wenfeng; Lin nianyun

1992-01-01

Studies of free radical biology and medicine have shown that carcinogenesis, vascular diseases of heart and brain, radiation injuries, ageing etc are strictly correlated with free radical injury of tissues. Thus, pharmacologists and biologists are focusing attention on searching for scavengers, especially naturally occurring antioxidant of oxidizing free radicals. Previous studies have indicated that phenolic antioxidants have efficient scavenger activities. Utilizing following methods including chemical luminescence, ESR spectroscopy and pulse radiolysis techniques the scavenger activities of tea polyphenols and quercetin against active species of oxygen have been studied

Effect of parenterally administered cystamine and gammaphos (WR-2721) on some biochemical parameters in dog blood serum

International Nuclear Information System (INIS)

Simsa, J.; Tichy, M.; Podzimek, F.; Spelda, S.; Resl, M.; Kuna, P.

1987-01-01

The effects were studied of intravenous and intramuscular administration of radioprotectives cystamine and gammaphos in dogs on the biochemical parameters of the blood serum. The activities were studied of enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine kinase, gamma-glutamyl transpeptidase, lactate dehydrogenase, malate dehydrogenase, sorbitol dehydrogenase and alpha-amylase. The contents were determined of total protein, albumin, bilirubin, urea nitrogen, creatinine, glucose, triglycerides, cholesterol, lipids, calcium, sodium and potassium. Cystamine was shown to be hepatotoxic. The intramuscular administration of gammaphos was found to be more advantageous than of cystamine. Only slight increase was observed in the activities of lactate dehydrogenase, malate dehydrogenase, and alpha-amylase. With cystamine, the changes in all biochemical parameters were most marked. (M.D.). 17 figs., 18 refs

Trophic facilitation or limitation? Comparative effects of pumas and black bears on the scavenger community.

Directory of Open Access Journals (Sweden)

Maximilian L Allen

Full Text Available Scavenging is a widespread behaviour and an important process influencing food webs and ecological communities. Large carnivores facilitate the movement of energy across trophic levels through the scavenging and decomposition of their killed prey, but competition with large carnivores is also likely to constrain acquisition of carrion by scavengers. We used an experimental approach based on motion-triggered video cameras at black-tailed deer (Odocoileus hemionus columbianus carcasses to measure the comparative influences of two large carnivores in the facilitation and limitation of carrion acquisition by scavengers. We found that pumas (Puma concolor and black bears (Ursus americanus had different effects on their ecological communities. Pumas, as a top-level predator, facilitated the consumption of carrion by scavengers, despite significantly reducing their observed sum feeding times (165.7 min ± 21.2 SE at puma kills 264.3 min ± 30.1 SE at control carcasses. In contrast, black bears, as the dominant scavenger in the system, limited consumption of carrion by scavengers as evidenced by the observed reduction of scavenger species richness recorded at carcasses where they were present (mean = 2.33 ± 0.28 SE, compared to where they were absent (mean = 3.28 ± 0.23 SE. Black bears also had large negative effects on scavenger sum feeding times (88.5 min ± 19.8 SE at carcasses where bears were present, 372.3 min ± 50.0 SE at carcasses where bears were absent. In addition, we found that pumas and black bears both increased the nestedness (a higher level of order among species present of the scavenger community. Our results suggest that scavengers have species-specific adaptions to exploit carrion despite large carnivores, and that large carnivores influence the structure and composition of scavenger communities. The interactions between large carnivores and scavengers should be considered in future studies of food webs and ecological communities.

The effects of radioprotective agents on the radiation-induced DNA single strand breaks

International Nuclear Information System (INIS)

Rhiu, Sung Ryul; Ko, Kyung Hwan; Jung, In Yong; Cho, Chul Ku; Kim, Tae Hwan; Park, Woo Wiun; Kim, Sung Ho; Ji, Young Hoon; Kim, Kyung Jung; Bang, Hio Chang; Jung, Young Suk; Choi, Moon Sik

1992-04-01

With the increased use of atomic energy in science, industry, medicine and public power production, the probability of nuclear accidents certainly appears to be on the increase. Therefore, early medical diagnosis and first-aid are needed urgently to establish an efficient treatment. We carried out the studies of radiation protector such as DDC, MEA, WR-2721 and variety of decontaminator with a view to establishing the protective measure and diagnostic standards for safety of worker and neighbors living around the radiation area in case of occurring the accidental contamination. In this experiment, we examined radiation-induced DNA single strand breaks as one of the study on molecular biology of the response of cells to radiation because an understanding of the radiation-induced damage in molecular level would add to our knowledge of radiation protection and treatment. (Author)

Investigations on the influence of aminopropyl-aminoethyl-phosphorothioic acid on the radio-iron utilization after a whole-body irradiation of mice in the sublethal dose range

International Nuclear Information System (INIS)

Moenig, H.; Seiter, I.; Kofler, E.

1975-01-01

The effectiveness of the thiophosphate compound WR 2721 was investigated with regard to the radiosensitivity of X-irradiated female mice in the sublethal dose range of 50 to 150 R using the radioiron test ( 59 Fe). An increase of the radioresistance with regard to the radioiron uptake in young erythrocyte populations was obtained only beyond radiation doses of 75 R. In lower dose ranges the animals treated with thiophoshate became even more radiosensitive. At dose values of 100 R and 150 R dose reduction factors (DRF) of 1.3 and 1.5 respectively were obtained. These factors are considerably smaller than the DRF-values found for the survival rate at LDsub(50/30). A possible mechanism for this result may be due to the different dephosphorylation rate of the thiophosphate in various tissues, as described in literature. (orig.) [de

Mobile vapor recovery and vapor scavenging unit

International Nuclear Information System (INIS)

Stokes, C.A.; Steppe, D.E.

1991-01-01

This patent describes a mobile anti- pollution apparatus, for the recovery of hydrocarbon emissions. It comprises a mobile platform upon which is mounted a vapor recovery unit for recovering vapors including light hydrocarbons, the vapor recovery unit having an inlet and an outlet end, the inlet end adapted for coupling to an external source of hydrocarbon vapor emissions to recover a portion of the vapors including light hydrocarbons emitted therefrom, and the outlet end adapted for connection to a means for conveying unrecovered vapors to a vapor scavenging unit, the vapor scavenging unit comprising an internal combustion engine adapted for utilizing light hydrocarbon in the unrecovered vapors exiting from the vapor recovery unit as supplemental fuel

Scavenging of radionuclides in the marine environment, (1)

International Nuclear Information System (INIS)

Mahara, Yasunori

1989-01-01

It is very important to predict diffusion, scavenging and accumulation of the long lives radionuclides which may be discharged from the reprocessing plant in the marine environment, for the purpose of polishing up methods of the radiation does estimation to the high quality stage. This study reports that distribution and behavior of transuranic elements, which are extremely harmful for the human beings and are discharged probably from the reprocessing plant, are investigated in both the survey of bibliography and the in-situ observation. Results of the field observation on the distribution of transuranic elements in the marine show that plutonium and americium are easily scavenged from the sea water and are accumulated on the sea bottom. Transuranic elements, which are originated from fallout and are discharged from the reprocessing plant, have generally the similar distribution in the marine and the same chemical behavior. This facts suggest that the fallout data which are probably and easily collected in the world are available for fabrication of the scavenging model for transuranic elements discharged from the reprocessing plants. (author)

Scavenger Receptor CD163 and Its Biological Functions

Directory of Open Access Journals (Sweden)

Gabriela Onofre

2009-01-01

Full Text Available CD163 is a member of scavenger receptor super family class B of the first subgroup. It is mapped to the region p13 on chromosome 12. Five different isoforms of CD163 have been described, which differ in the structure of their cytoplasmic domains and putative phosporylation sites. This scavenger receptor is selectively expressed on cells of monocytes and macrophages lineage exclusively. CD163 immunological function is essentially homeostatic. It also has other functions because participates in adhesion to endothelial cells, in tolerance induction and tissues regeneration. Other very important function of CD163 is the clearance of hemoglobin in its cell-free form and participation in anti-inflammation in its soluble form, exhibiting cytokine-like functions. We review the biological functions of CD163 which have been discovered until now. It seems apparent from this review that CD163 scavenger receptor can be used as biomarker in different diseases and as a valuable diagnostic parameter for prognosis of many diseases especially inflammatory disorders and sepsis.

Environment, urban poverty and scavenging: review of relationship and its effectiveness

International Nuclear Information System (INIS)

Chamhuri Siwar; Amzad Hossain; Norshamleeda Chamhuri

2001-01-01

Urban poverty and environment is interrelated to each other. Environmental degradation is a crucial factor for urban poverty and vice-versa. The generation of solid waste all over the world has reached an alarming proportion and constitutes one of the world's greatest sources of environmental degradation (fagan, 1974). Solid waste is one of the three major environmental problems faced by municipalities in Malaysia (World Bank, 1993) which is one of the major cause or contributor to urban poverty. However, urban solid waste consists of two strata such as source of environmental degradation and income generating agents for urban poor scavengers. In Malaysia, full-time and part-time scavengers are recycling 6% of total generated residential solid waste in some selected areas other wise its emitted or disposed to the environment. On the other hand, by doing this work full-time scavengers are earning wages of RM750 per month which is equal to that of the majority of Third world urbanities; part-time scavengers are earning 33% of their daily income. This paper discusses a theoretical framework of the relationship of environment and urban poverty. Policies, issues and some case studies of scavenging as a means of urban poverty reduction and environmental improvements of sustainable urban development are also explored. (Author)

Enhanced protection of PDMS-embedded palladium catalysts by co-embedding of sulphide-scavengers.

Science.gov (United States)

Comandella, Daniele; Ahn, Min Hyung; Kim, Hojeong; Mackenzie, Katrin

2017-12-01

For Pd-containing hydrodechlorination catalysts, coating with poly(dimethyl siloxane) (PDMS) was proposed earlier as promising protection scheme against poisoning. The PDMS coating can effectively repel non-permeating poisons (such as SO 3 2- ) retaining the hydrodechlorination Pd activity. In the present study, the previously achieved protection efficiency was enhanced by incorporation of sulphide scavengers into the polymer. The embedded scavengers were able to bind permeating non-ionic poisons (such as H 2 S) during their passage through PDMS prior to Pd contact which ensured an extended catalyst lifetime. Three scavenger types forming non-permeable sulphur species from H 2 S - alkaline, oxidative or iron-based compounds - were either incorporated into single-layer coats around individual Pd/Al 2 O 3 particles or into a second layer above Pd-containing PDMS films (Pd-PDMS). Hydrodechlorination and hydrogenation were chosen as model reactions, carried out in batch and continuous-flow reactors. Batch tests with all scavenger-containing catalysts showed extended Pd protection compared to scavenger-free catalysts. Solid alkaline compounds (Ca(OH) 2 , NaOH, CaO) and MnO 2 showed the highest instantaneous scavenger efficiencies (retained Pd activity=30-60%), while iron-based catalysts, such as nano zero-valent iron (nZVI) or ferrocene (FeCp 2 ), proved less efficient (1-10%). When stepwise poisoning was applied, the protection efficiency of iron-based and oxidizing compounds was higher in the long term than that of alkaline solids. Long-term experiments in mixed-flow reactors were performed with selected scavengers, revealing the following trend of protection efficiency: CaO 2 >Ca(OH) 2 >FeCp 2 . Under field-simulating conditions using a fixed-bed reactor, the combination of sulphide pre-oxidation in the water phase by H 2 O 2 and local scavenger-enhanced Pd protection was successful. The oxidizing agent H 2 O 2 does not disturb the Pd-catalysed reduction, while the

Postmortem scavenging by the Virginia opossum (Didelphis virginiana): Impact on taphonomic assemblages and progression.

Science.gov (United States)

King, Kama A; Lord, Wayne D; Ketchum, Heather R; O'Brien, R Christopher

2016-09-01

The Virginia opossum (Didelphis virginiana) is a highly active scavenger whose behavior has significant impacts on rates of decomposition and skeletonization, which have previously not been addressed. In this study, scavenging by the opossum led to the skeletonization of carcasses in half of the accumulated degree days (ADD) of a comparable non-scavenged control carcass. Opossums used body orifices, as well as natural tears caused by the decomposition process, to access internal tissues and consume them. This activity resulted in little movement of the carcass and the retained appearance of natural undisturbed decomposition. This concealed activity has the potential to cause drastically incorrect estimates of time since deposition and post-mortem interval. Scavenging by opossums was also found to leave distinct tooth mark and other defects on bone, which have not been previously distinguished in the literature. This research suggests, beyond effects on PMI, that scavenging by opossums has been historically overlooked and misattributed to canid scavengers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Process for scavenging hydrogen sulfide from hydrocarbon gases

International Nuclear Information System (INIS)

Fox, I.

1981-01-01

A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe 2 O 3 containing a crystalline phase of Fe 2 O 3 , Fe 3 O 4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected

Scavenging rate ecoassay: a potential indicator of estuary condition.

Science.gov (United States)

Porter, Augustine G; Scanes, Peter R

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

Contrasting Boundary Scavenging in two Eastern Boundary Current Regimes

Science.gov (United States)

Anderson, R. F.; Fleisher, M. Q.; Pavia, F. J.; Vivancos, S. M.; Lu, Y.; Zhang, P.; Cheng, H.; Edwards, R. L.

2016-02-01

We use data from two US GEOTRACES expeditions to compare boundary scavenging intensity in two eastern boundary current systems: the Canary Current off Mauritania and the Humboldt Current off Peru. Boundary scavenging refers to the enhanced removal of trace elements from the ocean by sorption to sinking particles in regions of greater than average particle abundance. Both regimes experience high rates of biological productivity and generation of biogenic particles, with rates of productivity potentially a little greater off Peru, whereas dust fluxes are an order of magnitude greater off NW Africa (see presentation by Vivancos et al., this meeting). Despite greater productivity off Peru, we find greater intensity of scavenging off NW Africa as measured by the residence time of dissolved 230Th integrated from the surface to a depth of 2500 m (10-11 years off NW Africa vs. 15-17 years off Peru). Dissolved 231Pa/230Th ratios off NW Africa (Hayes et al., Deep Sea Res.-II 116 (2015) 29-41) are nearly twice the values observed off Peru. We attribute this difference to the well-known tendency for lithogenic phases (dust) to strongly fractionate in favor of Th uptake during scavenging and removal, leaving the dissolved phase enriched in Pa. This behavior needs to be considered when interpreting sedimentary 231Pa/230Th ratios as a paleo proxy.

Scavenger and antioxidant properties of prenylflavones isolated from Artocarpus heterophyllus.

Science.gov (United States)

Ko, F N; Cheng, Z J; Lin, C N; Teng, C M

1998-07-15

The antioxidant properties of prenylflavones, isolated from Artocarpus heterophyllus Lam., was evaluated in this study. Among them, artocarpine, artocarpetin, artocarpetin A, and cycloheterophyllin diacetate and peracetate had no effect on iron-induced lipid peroxidation in rat brain homogenate. They also did not scavenge the stable free radical 1,1-diphenyl-2-picrylhydrazyl. In contrast, cycloheterophyllin and artonins A and B inhibited iron-induced lipid peroxidation in rat brain homogenate and scavenged 1,1-diphenyl-2-picrylhydrazyl. They also scavenged peroxyl radicals and hydroxyl radicals that were generated by 2,2'-azobis(2-amidinopropane) dihydrochloride and the Fe3+-ascorbate-EDTA-H2O2 system, respectively. However, they did not inhibit xanthine oxidase activity or scavenge superoxide anion, hydrogen peroxide, carbon radical, or peroxyl radicals derived from 2,2'-azobis(2,4-dimethylvaleronitrile) in hexane. Moreover, cycloheterophyllin and artonins A and B inhibited copper-catalyzed oxidation of human low-density lipoprotein, as measured by fluorescence intensity, thiobarbituric acid-reactive substance and conjugated-diene formations and electrophoretic mobility. It is concluded that cycloheterophyllin and artonins A and B serve as powerful antioxidants against lipid peroxidation when biomembranes are exposed to oxygen radicals.

Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris Leaves

NARCIS (Netherlands)

Dapkevicius, A.; Beek, van T.A.; Lelyveld, G.P.; Veldhuizen, van A.; Groot, de Æ.; Linssen, J.P.H.; Venskutonis, R.

2002-01-01

2,2-Diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity-guided fractionation of a leaf extract of Thymus vulgaris led to the isolation of the radical scavengers rosmarinic acid 1, eriodictyol, taxifolin, luteolin 7-glucuronide, p-cymene 2,3-diol, p-cymene 2,3-diol 6-6'-dimer, carvacrol,

Fatal embryo chondral damage associated with fluoroquinolones in eggs of threatened avian scavengers

International Nuclear Information System (INIS)

Lemus, J.A.; Blanco, G.; Arroyo, B.; Martinez, F.; Grande, J.

2009-01-01

Stabled livestock reared in housed conditions are often subjected to intensive treatments with veterinary drug, which residues may be present in livestock meat ingested by scavengers, but nothing is known about their presence in eggs of wild birds and their potential detrimental effects on breeding success. We searched for residues of veterinary drugs and other toxicants in infertile and embryonated unhatched eggs of griffon vultures (Gyps fulvus) and red kites (Milvus milvus), two threatened avian scavengers. Quinolones (ciprofloxacin and enrofloxacin) were found in most unhatched eggs of both scavenger species clearly associated with severe alterations in the development of embryo cartilage and bones that could preclude embryo movements and subsequently normal development, pre-hatch position and successful hatching. The detrimental effects on developing eggs of veterinary drugs from livestock operations may help to explain reduced breeding success of avian scavengers. - Fluoroquinolones used in livestock farming and found in eggs of avian scavenger caused severe alterations in embryo cartilage and bone development.

Fatal embryo chondral damage associated with fluoroquinolones in eggs of threatened avian scavengers

Energy Technology Data Exchange (ETDEWEB)

Lemus, J.A. [Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), J. Gutierrez Abascal 2, 28006 Madrid (Spain); Blanco, G., E-mail: gublanco2@yahoo.e [Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), J. Gutierrez Abascal 2, 28006 Madrid (Spain); Arroyo, B.; Martinez, F.; Grande, J. [Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), J. Gutierrez Abascal 2, 28006 Madrid (Spain)

2009-08-15

Stabled livestock reared in housed conditions are often subjected to intensive treatments with veterinary drug, which residues may be present in livestock meat ingested by scavengers, but nothing is known about their presence in eggs of wild birds and their potential detrimental effects on breeding success. We searched for residues of veterinary drugs and other toxicants in infertile and embryonated unhatched eggs of griffon vultures (Gyps fulvus) and red kites (Milvus milvus), two threatened avian scavengers. Quinolones (ciprofloxacin and enrofloxacin) were found in most unhatched eggs of both scavenger species clearly associated with severe alterations in the development of embryo cartilage and bones that could preclude embryo movements and subsequently normal development, pre-hatch position and successful hatching. The detrimental effects on developing eggs of veterinary drugs from livestock operations may help to explain reduced breeding success of avian scavengers. - Fluoroquinolones used in livestock farming and found in eggs of avian scavenger caused severe alterations in embryo cartilage and bone development.

Modelling the effect of boundary scavenging on Thorium and Protactinium profiles in the ocean

International Nuclear Information System (INIS)

Roy-Barman, M.

2009-01-01

The 'boundary scavenging' box model is a cornerstone of our understanding of the particle-reactive radionuclide fluxes between the open ocean and the ocean margins. However, it does not describe the radionuclide profiles in the water column. Here, I present the transport-reaction equations for radionuclides transported vertically by reversible scavenging on settling particles and laterally by horizontal currents between the margin and the open ocean. Analytical solutions of these equations are compared with existing data. In the Pacific Ocean, the model produces 'almost' linear 230 Th profiles (as observed in the data) despite lateral transport. However, omitting lateral transport biases the 230 Th based particle flux estimates by as much as 50%. 231 Pa profiles are well reproduced in the whole water column of the Pacific Margin and from the surface down to 3000 m in the Pacific subtropical gyre. Enhanced bottom scavenging or inflow of 231 Pa-poor equatorial water may account for the model-data discrepancy below 3000 m. The lithogenic 232 Th is modelled using the same transport parameters as 230 Th but a different source function. The main source of the 232 Th scavenged in the open Pacific is advection from the ocean margin, whereas a net flux of 230 Th produced in the open Pacific is advected and scavenged at the margin, illustrating boundary exchange. In the Arctic Ocean, the model reproduces 230 Th measured profiles that the uni-dimensional scavenging model or the scavenging-ventilation model failed to explain. Moreover, if lateral transport is ignored, the 230 Th based particle settling speed may by underestimated by a factor 4 at the Arctic Ocean margin. The very low scavenging rate in the open Arctic Ocean combined with the enhanced scavenging at the margin accounts for the lack of high 231 Pa/ 230 Th ratio in arctic sediments. (authors)

Radical Scavenging Capacity of Wine Anthocyanins Is Strongly pH-Dependent

NARCIS (Netherlands)

Borowski, T.; Tyrakowska, B.; Oszmianski, J.; Rietjens, I.M.C.M.

2005-01-01

The radical scavenging capacity of red wine anthocyanins was quantified by the so-called TEAC assay with special emphasis on the influence of pH and conjugation on this activity. The pH appears to be a dominant factor in the radical scavenging capacity of wine anthocyanins, with higher pH values

Numerical Investigation of the Scavenging Process in Marine Two-Stroke Diesel Engines

DEFF Research Database (Denmark)

Andersen, Fredrik Herland; Hult, Johan; Nogenmyr, Karl-Johan

2013-01-01

The scavenging process is an integral part of any two-stroke internal combustion engine cycle whether it is spark ignited or compression ignited. The scavenging process is responsible for transporting the burned gases from the previous working stroke out of the combustion chamber to allow...... for the fresh charge or fresh air to enter for the next combustion/working stroke. This implies that the scavenging process is responsible for setting the initial condition for the combustion process, consequently affecting fuel economy, power output and emission of hazardous gases. Two-stroke diesel engines...

Polyphenolic Compounds and Free Radical Scavenging Activity in Eight Lamiaceae Herbs of Manipur

Directory of Open Access Journals (Sweden)

Sandhyarani Devi KHOMDRAM

2011-05-01

Full Text Available Eight plants of Lamiaceae under subfamily Nepetoideae found in Manipur, India were selected for estimation of their polyphenolic compounds and free radical scavenging activity which is expressed on dry weight basis. In this present study, the total phenol and flavonoid contents as well as the free radical scavenging activity were studied using spectrophotometric method. The total phenol content was determined based on Folin-Ciocalteau reagent, flavonoid was determined by aluminium chloride spectrophotometric method and tannin by Folin Dennis Method. The free radical scavenging activity was determined by using DPPH radical which is expressed as IC50 (μg/ml. The total phenolic content varied from 21.39±0.927 to 46.28±0.543 mg/g, flavonoids content in the selected samples varied from 13.30±0.684 to 26.03±0.217 mg/g and tannin content varied from 8.72±0.160 to 17.04±0.206 mg/g. The free radical scavenging activity among the selected samples varied from 11.67±0.221 to 38.29±0.532 μg/ml. The correlation between the free radical scavenging activity with total phenol content (R2=0.511, with flavonoids (R2=0.241 and with tannin (R2=0.690 was calculated and maximum correlation value was found between tannin content and the free radical scavenging activity of the plant samples. The result supports that tannins were more responsible for free radical scavenging activity in the presently selected plants.

Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

OpenAIRE

Suvankar Das; Cristiane J. da Silva; Marina de M. Silva; Maria Dayanne de A. Dantas; Ângelo de Fátima; Ana Lúcia T. Góis Ruiz; Cleiton M. da Silva; João Ernesto de Carvalho; Josué C.C. Santos; Isis M. Figueiredo; Edeildo F. da Silva-Júnior; Thiago M. de Aquino; João X. de Araújo-Júnior; Goutam Brahmachari; Luzia Valentina Modolo

2018-01-01

Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the anion radical superoxide (·O2−). The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine...

Flavonoids as scavengers of nitric oxide radical.

NARCIS (Netherlands)

van Acker, S.A.B.E.; Tromp, M.N.J.L.; Haenen, G.R.M.M.; van der Vijgh, W.J.F.; Bast, A.

1995-01-01

Flavonoids are a group of naturally occurring compounds used, e.g., in the treatment of vascular endothelial damage. They are known to be excellent scavengers of oxygen free radicals. Since the nitric oxide radical (

Role of antioxidant scavenging enzymes and extracellular ...

African Journals Online (AJOL)

ChithrashreeGS

2012-08-23

Aug 23, 2012 ... peroxidase are two important antioxidant scavenging enzymes involved in ... Catalase was assayed using the method of Beers and Sizer. (1951) with .... yeast dextrose calcium carbonate agar (YDC) medium. Catalase and ...

Precipitation scavenging of tritiated water vapour (HTO)

International Nuclear Information System (INIS)

Ogram, G.L.

1985-10-01

Precipitation scavenging (or washout) is an important mechanism for the removal of HTO from the atmosphere. Methods of parameterizing the depletion of a plume of HTO released to the atmosphere are examined. Simple approaches, commonly used for atmospheric transport modelling purposes, such as the use of a constant washout coefficient or washout ratio, or the use of parameters based on equilibrium assumptions, are often not justified. It is shown that these parameters depend strongly on ambient temperature and plume dimensions, as well as rainfall rate. An approximate expression for washout ratio, as a function of these variables, is developed, and it is shown that near equilibrium washout conditions are only expected to hold at long plume travel distances. A possible method of treating scavenging by snow is also suggested

Scavenging in the genus Natrix

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Cesar Ayres

2012-07-01

Full Text Available Scavenging is reported as an unusual behaviour of snakes. However, it is likely more common than is supposed. Here I report the use of dead newts as prey source by water snakes of the genus Natrix at a dam in north-western Spain. Juveniles and adults viperine snakes (Natrix maura, and also an adult grass snake (Natrix natrix were found feeding on newt carcasses.

Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

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Avery E. Scherer

2017-02-01

Full Text Available By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging.

In vitro free radical scavenging activity of Ixora coccinea L

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Moni Rani Saha

2008-06-01

Full Text Available Antioxidant activity of the methanol extract of Ixora coccinea L. was determined by DPPH free radical scavenging assay, reducing power and total antioxidant capacity using phosphomolybdenum method. Preliminary phytochemical screening revealed that the extract of the flower of I. coccinea possesses flavonoids, steroids and tannin materials. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner and remarkable activities to scavenge reactive oxygen species (ROS may be attributed to the high amount of hydrophilic phenolics. In DPPH radical scavenging assay the IC50 value of the extract was found to be 100.53 μg/mL while ascorbic acid had the IC50 value 58.92 μg/mL. Moreover, I. coccinea extract showed strong reducing power and total antioxidant capacity.

Performance of zeolite scavenge column in Xe monitoring system

International Nuclear Information System (INIS)

Wang Qian; Wang Hongxia; Li Wei; Bian Zhishang

2010-01-01

In order to improve the performance of zeolite scavenge column, its ability of removal of humidity and carbon dioxide was studied by both static and dynamic approaches. The experimental results show that various factors, including the column length and diameter, the mass of zeolite, the content of water in air, the temperature rise during adsorption, and the activation effectiveness all effect the performance of zeolite column in scavenging humanity and carbon dioxide. Based on these results and previous experience, an optimized design of the zeolite column is made for use in xenon monitoring system. (authors)

Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

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B. Croft

2010-02-01

Full Text Available A diagnostic cloud nucleation scavenging scheme, which determines stratiform cloud scavenging ratios for both aerosol mass and number distributions, based on cloud droplet, and ice crystal number concentrations, is introduced into the ECHAM5-HAM global climate model. This scheme is coupled with a size-dependent in-cloud impaction scavenging parameterization for both cloud droplet-aerosol, and ice crystal-aerosol collisions. The aerosol mass scavenged in stratiform clouds is found to be primarily (>90% scavenged by cloud nucleation processes for all aerosol species, except for dust (50%. The aerosol number scavenged is primarily (>90% attributed to impaction. 99% of this impaction scavenging occurs in clouds with temperatures less than 273 K. Sensitivity studies are presented, which compare aerosol concentrations, burdens, and deposition for a variety of in-cloud scavenging approaches: prescribed fractions, a more computationally expensive prognostic aerosol cloud processing treatment, and the new diagnostic scheme, also with modified assumptions about in-cloud impaction and nucleation scavenging. Our results show that while uncertainties in the representation of in-cloud scavenging processes can lead to differences in the range of 20–30% for the predicted annual, global mean aerosol mass burdens, and near to 50% for accumulation mode aerosol number burden, the differences in predicted aerosol mass concentrations can be up to one order of magnitude, particularly for regions of the middle troposphere with temperatures below 273 K where mixed and ice phase clouds exist. Different parameterizations for impaction scavenging changed the predicted global, annual mean number removal attributed to ice clouds by seven-fold, and the global, annual dust mass removal attributed to impaction by two orders of magnitude. Closer agreement with observations of black carbon profiles from aircraft (increases near to one order of magnitude for mixed phase clouds

Investigation of the chemistry of liquid H{sub 2}S scavengers

Energy Technology Data Exchange (ETDEWEB)

Buhaug, Janne Bjoerntvedt

2002-07-01

The production of natural gas in the North Sea is facing a growing problem: contamination of the natural gas with dihydrogen sulfide, H{sub 2}S. As a gas reservoir is emptied, seawater containing sulfates is pumped into it, and the sulfates are reduced to dihydrogen sulfide by sulfate-reducing bacteria. Dihydrogen sulfide is then pumped up along with the oil, gas and water from the reservoir, causing severe corrosion of pipelines and contamination of the final natural gas product. Dihydrogen sulfide is extremely toxic, and in fields with especially large concentrations of H{sub 2}S this is a severe health risk for the platform workers. Hence, it is desirable to remove the dihydrogen sulfide at the earliest stage possible. There are four main methods for removing H{sub 2}S from natural gas: (1) Liquid scavengers, (2) Solid scavengers, (3) Liquid redox processes, (4) Amine / Claus catalyst. Liquid scavengers are widely used in the natural gas industry, especially at sites with relatively low concentrations of H{sub 2}S. As a rule of thumb, liquid scavengers are economically favourable at sites with a removal of less than 50 kg/day of H{sub 2}S. This thesis is concerned with the cyclic amine 1,3,5 -tris(2-hydroxyethyl)-1,3,5-triazinane, often referred to as Triazine. This is used in fields with relatively low concentration of H{sub 2}S and dominates the liquid scavenger market.

Free radical scavenging potential and HPTLC analysis of Indigofera tinctoria linn (Fabaceae

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Sakthivel Srinivasan

2016-04-01

Full Text Available The objective of this study was to evaluate the free radical scavenging potential and high performance thin layer chromatography (HPTLC fingerprinting of Indigofera tinctoria (I. tinctoria. Phytochemical analysis was carried out using standard methods, and free radical scavenging activity of the plant was determined using 2,2-diphenyl-1-picrylhydrazy (DPPH, nitric oxide (NO and superoxide anion (O2− radical scavenging capacities. HPTLC plate was kept in CAMAG TLC Scanner 3 and the Rf values at fingerprint data were recorded by WINCATS software. Aqueous extract of I. tinctoria reliably showed the total phenolics (267.2±2.42 mg/g, flavonoids (75.43±3.36 mg/g and antioxidants (349.11±8.04 mg/g. The extract was found to have DPPH (52.08%, NO (23.12% and O2− (26.79% scavenging activities at the concentration of 250 μg/mL and the results were statistically significant compared with ascorbic acid standard (p<0.05. HPTLC results confirmed that the extract contained several potential active components such as phenols, flavonoids, saponins and terpenoids as the slides revealed multi-colored bands of varying intensities. This study confirmed that the plant had multipotential antioxidant and free radicals scavenging activities.

A method for nitric oxide radical scavenging properties of sulfur containing compounds.

NARCIS (Netherlands)

Vriesman, M.F.; Haenen, G.R.M.M.; Westerveld, G.J.; Paquay, J.B.G.; Voss, H.P.; Bast, A.

1997-01-01

A new method for the quantification of the nitric oxide (NO) scavenging activity of compounds in aqueous solutions is described using an amperometric NO sensor. After correction for the spontaneous degradation of NO, second-order rate kinetics of the scavenging reaction are observed.

Modelling the effect of boundary scavenging on Thorium and Protactinium profiles in the ocean

Directory of Open Access Journals (Sweden)

M. Roy-Barman

2009-12-01

Full Text Available The "boundary scavenging" box model is a cornerstone of our understanding of the particle-reactive radionuclide fluxes between the open ocean and the ocean margins. However, it does not describe the radionuclide profiles in the water column. Here, I present the transport-reaction equations for radionuclides transported vertically by reversible scavenging on settling particles and laterally by horizontal currents between the margin and the open ocean. Analytical solutions of these equations are compared with existing data. In the Pacific Ocean, the model produces "almost" linear ²³⁰Th profiles (as observed in the data despite lateral transport. However, omitting lateral transport biaises the ²³⁰Th based particle flux estimates by as much as 50%. ²³¹Pa profiles are well reproduced in the whole water column of the Pacific Margin and from the surface down to 3000 m in the Pacific subtropical gyre. Enhanced bottom scavenging or inflow of ²³¹Pa-poor equatorial water may account for the model-data discrepancy below 3000 m. The lithogenic ²³²Th is modelled using the same transport parameters as ²³⁰Th but a different source function. The main source of the ²³²Th scavenged in the open Pacific is advection from the ocean margin, whereas a net flux of ²³⁰Th produced in the open Pacific is advected and scavenged at the margin, illustrating boundary exchange. In the Arctic Ocean, the model reproduces ²³⁰Th measured profiles that the uni-dimensional scavenging model or the scavenging-ventilation model failed to explain. Moreover, if lateral transport is ignored, the ²³⁰Th based particle settling speed may by underestimated by a factor 4 at the Arctic Ocean margin. The very low scavenging rate in the open Arctic Ocean combined with the enhanced scavenging at the margin accounts for the lack of high ²³¹Pa/²³⁰Th ratio in arctic

Scavenging by spiders (Araneae) and its relationship to pest management of the brown recluse spider.

Science.gov (United States)

Vetter, Richard S

2011-06-01

Experiments reported in Sandidge (2003; Nature 426: 30) indicated that the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, preferred to scavenge dead prey over live prey and that the spiders were not detrimentally affected when fed insecticide-killed crickets. Extrapolations made in subsequent media coverage disseminating the results of this research made counter-intuitive statements that pesticide treatment in houses would increase brown recluse populations in homes. This information was presented as if the scavenging behavior was specialized in the brown recluse; however, it was more likely that this behavior has not been well studied in other species. To provide a comparison, the current laboratory study examined the likelihood of non-Loxosceles spiders to scavenge dead prey. Of 100 non-Loxosceles spiders that were tested (from 11 families, 24 genera, and at least 29 species from a variety of spider hunting guilds), 99 scavenged dead crickets when offered in petri dishes. Some of the spiders were webspinners in which real-world scavenging of dead prey is virtually impossible, yet they scavenge when given the opportunity. Therefore, scavenging is a flexible opportunistic predatory behavior that is spread across a variety of taxa and is not a unique behavior in brown recluses. These findings are discussed in relation to pest management practices.

Aerosol size-dependent below-cloud scavenging by rain and snow in the ECHAM5-HAM

Directory of Open Access Journals (Sweden)

R. Posselt

2009-07-01

Full Text Available Wet deposition processes are highly efficient in the removal of aerosols from the atmosphere, and thus strongly influence global aerosol concentrations, and clouds, and their respective radiative forcings. In this study, physically detailed size-dependent below-cloud scavenging parameterizations for rain and snow are implemented in the ECHAM5-HAM global aerosol-climate model. Previously, below-cloud scavenging by rain in the ECHAM5-HAM was simply a function of the aerosol mode, and then scaled by the rainfall rate. The below-cloud scavenging by snow was a function of the snowfall rate alone. The global mean aerosol optical depth, and sea salt burden are sensitive to the below-cloud scavenging coefficients, with reductions near to 15% when the more vigorous size-dependent below-cloud scavenging by rain and snow is implemented. The inclusion of a prognostic rain scheme significantly reduces the fractional importance of below-cloud scavenging since there is higher evaporation in the lower troposphere, increasing the global mean sea salt burden by almost 15%. Thermophoretic effects are shown to produce increases in the global and annual mean number removal of Aitken size particles of near to 10%, but very small increases (near 1% in the global mean below-cloud mass scavenging of carbonaceous and sulfate aerosols. Changes in the assumptions about the below-cloud scavenging by rain of particles with radius smaller than 10 nm do not cause any significant changes to the global and annual mean aerosol mass or number burdens, despite a change in the below-cloud number removal rate for nucleation mode particles by near to five-fold. Annual and zonal mean nucleation mode number concentrations are enhanced by up to 30% in the lower troposphere with the more vigourous size-dependent below-cloud scavenging. Closer agreement with different observations is found when the more physically detailed below-cloud scavenging parameterization is employed in the ECHAM5

Uses and flock management practices of scavenging chickens in Wolaita Zone of southern Ethiopia.

Science.gov (United States)

Desta, Takele Taye; Wakeyo, Oli

2012-03-01

Rearing of scavenging chickens is among the most commonly practiced farm activities in Ethiopia. This system is dominated by indigenous chickens. Output from indigenous chickens is low due to poor management and absence of intense selection that is intended to improve economically important traits. This showed that village chickens are rather evolved for adaptation traits. However, the level of risk is low, and this has made rearing of scavenging chickens a choice of farm activity for smallholder farmers. The objective of this study was to characterize the scavenging chickens' production system in Wolaita Zone. Single-visit survey involving individual interview of 119 farmers and 6 focus group discussions was used to collect the data. Our results showed that rearing of scavenging chickens was constrained especially by disease and predation problems. However, farmers proposed a set of solutions to minimize the effect of these problems. Rearing of scavenging chickens fulfils the multi-functional need of the society. This system has special features because it can sustain in its own without the need for modern commercial chicken farming facilities. However, farmers also reported the drawbacks of rearing of scavenging chickens and these mainly include uproot of garden crops and tiresomeness of the night watching. Selection of chickens was mainly depending on physically observed traits like body size and plumage colour. The initial foundation flock was mainly obtained from the local market. The ideal place for scavenging chickens production is the one that has intermediate weather condition and has some trees that can be used as shade; however, it was substantiated that it has to be free from bush and shrubs, weeds and wet lands. Therefore, these pieces of knowledge embedded among smallholder farmers need to be well documented and synthesized to design an appropriate type of technology packages that can be communicated back to farmers to improve productivity of the

Classification of ISO SWS 01 spectra of proto-planetary nebulae: a search for precursors of planetary nebulae with [WR] central stars

OpenAIRE

Szczerba, R.; Stasi{ń}ska, G.; Siódmiak, N.; Górny, S. K.

2002-01-01

We have analyzed ISO SWS 01 observations for 61 proto-planetary nebulae candidates and classified their spectra according to their dominant chemistry. On the basis of our classification and the more general classification of SWS 01 spectra by Kraemer et al. (2002) we discuss the connection between proto-planetary nebulae candidates and planetary nebulae, with emphasis on possible precursors of planetary nebulae with [WR] central stars.

CD8 Knockout Mice Are Protected from Challenge by Vaccination with WR201, a Live Attenuated Mutant of Brucella melitensis

Directory of Open Access Journals (Sweden)

Samuel L. Yingst

2013-01-01

Full Text Available CD8+ T cells have been reported to play an important role in defense against B. abortus infection in mouse models. In the present report, we use CD8 knockout mice to further elucidate the role of these cells in protection from B. melitensis infection. Mice were immunized orally by administration of B. melitensis WR201, a purine auxotrophic attenuated vaccine strain, then challenged intranasally with B. melitensis 16M. In some experiments, persistence of WR201 in the spleens of CD8 knockout mice was slightly longer than that in the spleens of normal mice. However, development of anti-LPS serum antibody, antigen-induced production of γ-interferon (IFN-γ by immune splenic lymphocytes, protection against intranasal challenge, and recovery of nonimmunized animals from intranasal challenge were similar between normal and knockout animals. Further, primary Brucella infection was not exacerbated in perforin knockout and Fas-deficient mice and these animals’ anti-Brucella immune responses were indistinguishable from those of normal mice. These results indicate that CD8+ T cells do not play an essential role as either cytotoxic cells or IFN-γ producers, yet they do participate in a specific immune response to immunization and challenge in this murine model of B. melitensis infection.

Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

Science.gov (United States)

Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.

2014-03-01

Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

Analysis of the Scavenging Process of a Two-Stroke Free-Piston Engine Based on the Selection of Scavenging Ports or Valves

Directory of Open Access Journals (Sweden)

Boru Jia

2018-02-01

Full Text Available The free-piston engine generator (FPEG is a linear energy conversion device with the objective of utilisation within a hybrid-electric automotive vehicle power system. In this research, the piston dynamic characteristics of an FPEG is compared with that of a conventional engine (CE of the same size, and the difference in the valve timing is compared for both port scavenging type and valve scavenging type, with the exhaust valve closing timing is selected as the parameter. A zero-dimensional simulation model is developed in Ricardo WAVE software (2016.1, with the piston dynamics obtained from the simulation model in Matlab/SIMULINK (R2017a. For the CE and FEPG using scavenging ports, in order to improve its power output to the same level as that of a CE, the inlet gas pressure is suggested to be improved to above 1.2 bar, approximately 0.2 bar higher than that used for a CE. If a CE cylinder with exhaust valves is adopted or referred to during the development of an FPEG prototype, the exhaust valve is suggested to be closed earlier to improve its power output, and a higher intake pressure is also suggested if its output power is expected to be the same or higher than that of a CE.

Free radical scavenging activity and lipid peroxidation inhibition of Hypericum helianthemoides (spach Boiss

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Soheila Moein

2015-06-01

Full Text Available Antioxidants are compounds that obstruct the oxidation of macromolecules in the body. In general, there are two categories of antioxidants, natural and synthetic. Recently, interest has been increased considerably for obtaining new natural antioxidants. In this study, the scavenging of free radicals such as DPPH, NO and OH by Hypericum helianthemoides extract was evaluated. Also, the antioxidant properties of this extract were evaluated by FRAP, FTC methods and determination phenolic compounds. The plant was collected from north of Fars Province and plant extraction was obtained using ethanol. In DPPH radical scavenging, different concentrations of the Hypericum extract were added to DPPH radical. In hydroxyl radical scavenging, Fenton reaction mixture, TCA and TBA were mixed with Hypericum extract. In nitric radical scavenging, nitropruside was mixed with Hypericum extract and then sulphanilic acid, naphthylene diamine were added. In determination of phenolic compounds, Folin-ciocalteu and sodium carbonate were added to Hypericum extract. In DPPH radical scavenging, the IC50 of Hypericum extract (309.35±6.5μg/ml was higher than the antioxidant standards, BHT (IC50=81.9±2.6 μg/ml and quercetin (IC50=60.04±6.48 μg/ml. The highest scavenging of hydroxyl radicals was observed in Hypericum extract (70.3±0.8%, 125 μg/ml. In gallic acid it was (73.8±3.3%. In 200 μg/ml of Hypericum extract scavenged NO radical (85.2±2.7%. In FRAP method, the IC50 of this extract was 109.7±10.5 μg/ml. In FTC method, the inhibition of lipid peroxidation by Hypericum extract, BHT and ascorbic acid were 59.2±2.2, 66.9±0.15, 64.06±0.02 respectively. Total phenol of the plant extract was 3±0.4 mg/g.

In vivo heme scavenging by Staphylococcus aureus IsdC and IsdE proteins

International Nuclear Information System (INIS)

Mack, John; Vermeiren, Christie; Heinrichs, David E.; Stillman, Martin J.

2004-01-01

We report the first characterization of the in vivo porphyrin scavenging abilities of two components of a newly discovered heme scavenging system involving iron-regulated surface determinant (Isd) proteins. These proteins are present within the cell envelope of the Gram-positive human pathogen Staphylococcus aureus. IsdC and IsdE, when expressed heterologously in Escherichia coli, efficiently scavenged intracellular heme and resulted in de novo heme synthesis in excess of 100-fold above background. Magnetic circular dichroism analyses showed that the heme-binding properties of the two proteins differ significantly from one another. IsdC bound almost exclusively free-base protoporphyrin IX, whereas the IsdE protein was associated with low spin Fe(III) and Fe(II) heme. These properties provide important insight into the possible mechanisms of iron scavenging from bound heme by Isd proteins

Free radical scavenging activity of Eagle tea and their flavonoids

Directory of Open Access Journals (Sweden)

Qiong Meng

2012-06-01

Full Text Available In this study, an online HPLC-DAD-MS coupled with 2,2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid diammonium salt (ABTS assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components. Twenty-three chromatographic peaks were detected, and nineteen components had free radical scavenging activity. Among them, eight compounds were identified as flavonoids (hyperin, isoquercitrin, quercitrin, quercetin, kaempferol, catechins, chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.

Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial

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Riaz U. Ahmed

2014-11-01

Full Text Available This letter presents the possibility of energy scavenging (ES utilizing the physics of acousto-elastic metamaterial (AEMM at low frequencies (<∼3KHz. It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester, simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz, maximum power in the micro Watts (∼35µW range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW between 0.2 KHz and 1.5 KHz acoustic frequencies.

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals.

Science.gov (United States)

Oliveira, Ivo; Coelho, Valentim; Baltasar, Raquel; Pereira, José Alberto; Baptista, Paula

2009-07-01

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin-Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS-NADH-nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC(50) 232.7 microg/mL) and DPPH scavenging effect (IC(50) 63.2 microg/mL) followed by water extracts (with IC(50) of 287.7 and 73.7 microg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC(50) 6.9 microg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.

Increasing land-use intensity reverses the relative occupancy of two quadrupedal scavengers.

Directory of Open Access Journals (Sweden)

Joshua P Twining

Full Text Available Human land use is continuously altering the natural environment, yet the greater ecological implications of this change for many groups that are key to healthy ecosystem functioning remains uncharacterised in the tropics. Terrestrial scavenging vertebrates are one such group, providing integral ecosystem services through the removal of carrion which is a crucial component of both nutrient cycling and disease dynamics. To explore how anthropogenic processes may affect forest scavengers, we investigated the changes in the relative occupancy of two important terrestrial scavengers along a gradient of land use intensity, ranging from protected forest to oil palm plantation in Borneo. We found the Malay civet (Viverra tangalunga had highest, albeit variable, occupancy in areas of low land use intensity and the Southeast Asian water monitor (Varanus salvator macromaculatus had highest occupancy in areas of high land use intensity. Land use had no effect on the combined occupancy of the two species. In high land use intensity sites, individual water monitors were larger and had better body condition, but at population level had a highly biased sex ratio with more males than females and increased signs of intraspecific conflict. We did not assess scavenging rate or efficiency as a process, but the high occupancy rates and apparent health of the scavengers in high land use intensity landscapes suggests this ecological process is robust to land use change.

Superoxide scavenging activity of pirfenidone-iron complex

International Nuclear Information System (INIS)

Mitani, Yoshihiro; Sato, Keizo; Muramoto, Yosuke; Karakawa, Tomohiro; Kitamado, Masataka; Iwanaga, Tatsuya; Nabeshima, Tetsuji; Maruyama, Kumiko; Nakagawa, Kazuko; Ishida, Kazuhiko; Sasamoto, Kazumi

2008-01-01

Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O 2 ·- ) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of O 2 ·- produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O 2 ·- released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O 2 ·- scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis

Radiation 2006. In association with the Polymer Division, Royal Australian Chemical Institute. Incorporating the 21st AINSE Radiation Chemistry Conference and the 18th Radiation Biology Conference, conference handbook

International Nuclear Information System (INIS)

Martin, R. F.; Smith, A.; Lobachevsky, P.; Karagiannis, T; Leung, B.; Andrau, L.; White, J.

2006-01-01

Full text: Methylproamine is the current lead compound of a new class of DNA-binding radioprotectors being developed in the Research Laboratories at the Peter MacCallum Cancer Centre in Melbourne. The salient features of methylproamine are its radioprotective potency and the generic nature of the apparent radioprotective mechanism. Like the 'classic' aminothiol radioprotectors exemplified by amifostine, methylproamine suppresses the initial radiochemical damage induced in DNA by ionising radiation. However, survival curve studies with cultured cells have demonstrated that methylproamine is 100-fold more potent than WR1065, the active metabolite of amifostine. The radioprotective mechanism seems to involve reduction by the DNA-bound drug of transient radiation-induced oxidising species on DNA. This mechanism implies some electron transfer along DNA, from the DNA-bound drug to the oxidising species. In vivo radioprotection of mouse lung, GI tract and bone marrow has been demonstrated following systemic administration of methylproamine to mice. The commercial potential of radioprotectors resides in two distinct arenas. Until recently, most of our efforts have focused on the use of methylproamine to protect normal tissues in cancer radiotherapy patients, but a quite different opportunity arises from the imperative to develop countermeasures to the threat of radiation terrorism. Our prospects in both arenas have been lifted by the results of synthesis and screening of a pilot library of ∼50 methylproamine analogues, promising the emergence of new lead drugs. In particular, although methylproamine is a potent radioprotector, at higher concentrations it becomes cytotoxic, but one member of the pilot library shows a wider efficacy 'window'. We plan to continue this lead optimisation process by synthesis and screening of a much larger library of analogues, and we are seeking the support of a commercial partner

XMM-Newton Detection of Hard X-Ray Emission in the Nitrogen-Type Wolf-Rayet Star WR 110

Science.gov (United States)

Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel; Schmutz, Werner

2002-06-01

We have used the excellent sensitivity of XMM-Newton to obtain the first high-quality X-ray spectrum of a Wolf-Rayet (W-R) star that is not known to be a member of a binary system. Our target, the nitrogen-type star WR 110 (HD 165688), was also observed and detected with the Very Large Array at four different frequencies. The radio flux density increases with frequency according to a power law Sν~ν+0.64+/-0.10, in very good agreement with the behavior expected for free-free wind emission. The radio data give an ionized mass-loss rate M=4.9×10-5 Msolar yr-1 for an assumed spherical constant-velocity wind. The undispersed CCD X-ray spectra reveal strong emission lines from He-like ions of Mg, Si, and S. The emission measure distribution shows a dominant contribution from cool plasma with a characteristic temperature kTcool~0.5 keV (~6 MK). Little or no excess absorption of this cool component above the value expected from the visual extinction is present. We conclude that the bulk of the cool plasma detected by XMM-Newton lies at hundreds of stellar radii or more if the wind is approximately spherical and homogeneous, but it could lie closer to the star if the wind is clumped. If the cool plasma is due to instability-driven wind shocks, then typical shock velocities are vs~340-550 km s-1 and the average filling factor of X-ray-emitting gas in the wind is no larger than f~10-6. A surprising result is the unambiguous detection of a hard X-ray component that is clearly seen in the hard-band images and the spectra. This hard component accounts for about half of the observed flux and can be acceptably fitted by a hot, optically thin thermal plasma or a power-law model. If the emission is thermal, then a temperature kThot>=3 keV is derived. Such high temperatures are not predicted by current instability-driven wind shock models, and a different mechanism is thus required to explain the hard X-rays. We examine several possible mechanisms and show that the hard emission

Applying Knowledge of Species-Typical Scavenging Behavior to the Search and Recovery of Mammalian Skeletal Remains.

Science.gov (United States)

Young, Alexandria; Stillman, Richard; Smith, Martin J; Korstjens, Amanda H

2016-03-01

Forensic investigations involving animal scavenging of human remains require a physical search of the scene and surrounding areas. However, there is currently no standard procedure in the U.K. for physical searches of scavenged human remains. The Winthrop and grid search methods used by police specialist searchers for scavenged remains were examined through the use of mock red fox (Vulpes vulpes) scatter scenes. Forty-two police specialist searchers from two different regions within the U.K. were divided between those briefed and not briefed with fox-typical scavenging information. Briefing searchers with scavenging information significantly affected the recovery of scattered bones (χ(2) = 11.45, df = 1, p = 0.001). Searchers briefed with scavenging information were 2.05 times more likely to recover bones. Adaptions to search methods used by searchers were evident on a regional level, such that searchers more accustom to a peri-urban to rural region recovered a higher percentage of scattered bones (58.33%, n = 84). © 2015 American Academy of Forensic Sciences.

Role of antioxidant scavenging enzymes and extracellular ...

African Journals Online (AJOL)

In the present work, we studied the role of antioxidant scavenging enzymes of plant pathogenic bacteria: catalase, ascorbate peroxidase and a virulence factor; extracelluar polysaccharide production in determining the virulence of Xanthomonas oryzae pv. oryzae (Xoo) isolates and its differential reaction to rice cultivars.

Multi-dimensional scavenging analysis of a free-piston linear alternator based on numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Mao, Jinlong; Zuo, Zhengxing; Li, Wen; Feng, Huihua [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2011-04-15

A free-piston linear alternator (FPLA) is being developed by the Beijing Institute of Technology to improve the thermal efficiency relative to conventional crank-driven engines. A two-stroke scavenging process recharges the engine and is crucial to realizing the continuous operation of a free-piston engine. In order to study the FPLA scavenging process, the scavenging system was configured using computational fluid dynamics. As the piston dynamics of the FPLA are different to conventional crank-driven two-stroke engines, a time-based numerical simulation program was built using Matlab to define the piston's motion profiles. A wide range of design and operating options were investigated including effective stroke length, valve overlapping distance, operating frequency and charging pressure to find out their effects on the scavenging performance. The results indicate that a combination of high effective stroke length to bore ratio and long valve overlapping distance with a low supercharging pressure has the potential to achieve high scavenging and trapping efficiencies with low short-circuiting losses. (author)

The evolution of the class A scavenger receptors

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Whelan Fiona J

2012-11-01

Full Text Available Abstract Background The class A scavenger receptors are a subclass of a diverse family of proteins defined based on their ability to bind modified lipoproteins. The 5 members of this family are strikingly variable in their protein structure and function, raising the question as to whether it is appropriate to group them as a family based on their ligand binding abilities. Results To investigate these relationships, we defined the domain architecture of each of the 5 members followed by collecting and annotating class A scavenger receptor mRNA and amino acid sequences from publicly available databases. Phylogenetic analyses, sequence alignments, and permutation tests revealed a common evolutionary ancestry of these proteins, indicating that they form a protein family. We postulate that 4 distinct gene duplication events and subsequent domain fusions, internal repeats, and deletions are responsible for the diverse protein structures and functions of this family. Despite variation in domain structure, there are highly conserved regions across all 5 members, indicating the possibility that these regions may represent key conserved functional motifs. Conclusions We have shown with significant evidence that the 5 members of the class A scavenger receptors form a protein family. We have indicated that these receptors have a common origin which may provide insight into future functional work with these proteins.

Using Scavenger Hunts to Familiarize Students with Scientific Journal Articles.

Science.gov (United States)

Lijek, Rebeccah S; Fankhauser, Sarah C

2016-03-01

Primary scientific literature can be difficult to navigate for anyone unfamiliar with its foreign, formal structure. We sought to create a fun, easy learning tool to help familiarize students of all ages with the structure of a scientific article. Our main learning objective was for the student to realize that science writing is formulaic-that specific information is found in predictable locations within an article-and that, with an understanding of the formula, anyone can comfortably navigate any journal article and accurately predict what to expect to find in each section. To this end, we designed a Journal Article Scavenger Hunt that requires the user to find and identify a series of commonplace features of a primary research article. The scavenger hunt activity is quick and easy to implement, and is adaptable to various ages and settings, including the classroom, lab, and at outreach events. The questions in the scavenger hunt can be scaled in difficulty and specificity to suit the instructor's needs. Over many years of using this activity, we have received positive feedback from students of all ages, from elementary school students to lay adult-learners as well as science teachers themselves. By making the unknown seem predictable and approachable, the scavenger hunt helps a variety of audiences feel more comfortable with science and more confident in their ability to engage directly with the scientific literature. Journal of Microbiology & Biology Education.

Toxicity, biodistribution and radioprotective capacity of l-homocysteine thiolactone in CNS tissues and tumors in rodents: comparison with prior results with phosphorothioates

International Nuclear Information System (INIS)

Spence, Alexander M.; Rasey, Janet S.; Dwyer-Hansen, Lori; Grunbaum, Zdenka; Livesey, John; Chin, Lay; Nelson, Norma; Stein, Donna; Krohn, Kenneth A.; Ali-Osman, Francis

1995-01-01

l-Homocysteine thiolactone (L-HCTL) was evaluated for its potential as an intravenously-administered central nervous system (CNS) radioprotector in C3H mice and F344 rats. Toxicity assessments in the mouse yielded a LD 50 of 297 mg/kg and in the rat 389 mg/kg. Biodistribution studies in tumor-bearing mice showed that brain specimens contained more label at 10 min than the tumors but less at 30 or 60 min. Brain uptake relative to the tumors, the brain/tumor ratio, ranged between 0.5 and 3.3. The cervical spinal cord of non-tumor-bearing rats was irradiated with 32 Gy 137 Cs with or without prior treatment with l-HCTL following which the time to forelimb or hindlimb paralysis was measured to determine the relative protective factors (RPFs) for this radiation dose. For forelimb paralysis the RPF was 1.9 (± 1.0, SD) and for hindlimb it was 2.0 (± 1.1, SD). 36B-10 glioma cells irradiated in vitro with or without l-HCTL and assayed for colony forming capacity demonstrated a dose modifying factor (DMF) of only 1.15 (± 0.16, SE). Rats bearing intracerebral 36B-10 glioma received 137 Cs irradiation with or without l-HCTL after which the tumors were similarly assayed in vitro. From this the glioma DMF was 1.2 (± 0.30, SE). Compared to prior results with phosphorothioates our data show that the toxicity of l-HCTL is roughly the same as WR2721, WR77913 and WR3689 and that it distributes at higher levels in the CNS after systemic administration. l-HCTL may well equal these phosphorothioates at protecting normal CNS tissue without requiring administration directly into the cerebrospinal fluid-containing spaces and it does not protect the 36B-10 glioma

Phytochemical screening, free radical scavenging and antibacterial ...

African Journals Online (AJOL)

Cassia sieberiana is a tropical plant, widely distributed throughout Sudan and Guinea savannah. It is used in traditional medicine for the treatment of malarial, cancer and stomach ache. The study was conducted to screen for phytochemicals, free radical scavenging and antibacterial potentials of the root bark.

Recovery of Li from alloys of Al- Li and Li- Al using engineered scavenger compounds

Science.gov (United States)

Riley, W. D.; Jong, B. W.; Collins, W. K.; Gerdemann, S. J.

1994-01-01

A method of producing lithium of high purity from lithium aluminum alloys using an engineered scavenger compound, comprising: I) preparing an engineered scavenger compound by: a) mixing and heating compounds of TiO2 and Li2CO3 at a temperature sufficient to dry the compounds and convert Li.sub.2 CO.sub.3 to Li.sub.2 O; and b) mixing and heating the compounds at a temperature sufficient to produce a scavenger Li.sub.2 O.3TiO.sub.2 compound; II) loading the scavenger into one of two electrode baskets in a three electrode cell reactor and placing an Al-Li alloy in a second electrode basket of the three electrode cell reactor; III) heating the cell to a temperature sufficient to enable a mixture of KCl-LiCl contained in a crucible in the cell to reach its melting point and become a molten bath; IV) immersing the baskets in the bath until an electrical connection is made between the baskets to charge the scavenger compound with Li until there is an initial current and voltage followed by a fall off ending current and voltage; and V) making a connection between the basket electrode containing engineered scavenger compound and a steel rod electrode disposed between the basket electrodes and applying a current to cause Li to leave the scavenger compound and become electrodeposited on the steel rod electrode.

Coupling hydrodynamics with comoving frame radiative transfer. I. A unified approach for OB and WR stars

Science.gov (United States)

Sander, A. A. C.; Hamann, W.-R.; Todt, H.; Hainich, R.; Shenar, T.

2017-07-01

Context. For more than two decades, stellar atmosphere codes have been used to derive the stellar and wind parameters of massive stars. Although they have become a powerful tool and sufficiently reproduce the observed spectral appearance, they can hardly be used for more than measuring parameters. One major obstacle is their inconsistency between the calculated radiation field and the wind stratification due to the usage of prescribed mass-loss rates and wind-velocity fields. Aims: We present the concepts for a new generation of hydrodynamically consistent non-local thermodynamical equilibrium (non-LTE) stellar atmosphere models that allow for detailed studies of radiation-driven stellar winds. As a first demonstration, this new kind of model is applied to a massive O star. Methods: Based on earlier works, the PoWR code has been extended with the option to consistently solve the hydrodynamic equation together with the statistical equations and the radiative transfer in order to obtain a hydrodynamically consistent atmosphere stratification. In these models, the whole velocity field is iteratively updated together with an adjustment of the mass-loss rate. Results: The concepts for obtaining hydrodynamically consistent models using a comoving-frame radiative transfer are outlined. To provide a useful benchmark, we present a demonstration model, which was motivated to describe the well-studied O4 supergiant ζPup. The obtained stellar and wind parameters are within the current range of literature values. Conclusions: For the first time, the PoWR code has been used to obtain a hydrodynamically consistent model for a massive O star. This has been achieved by a profound revision of earlier concepts used for Wolf-Rayet stars. The velocity field is shaped by various elements contributing to the radiative acceleration, especially in the outer wind. The results further indicate that for more dense winds deviations from a standard β-law occur.

Consumption of Big Game Remains by Scavengers: A Potential Risk as Regards Disease Transmission in Central Spain

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Ricardo Carrasco-Garcia

2018-03-01

Full Text Available Understanding the role that facultative scavenger species may play in spreading infectious pathogens, and even becoming reservoirs for humans, domestic and wild ungulates or, on the contrary, preventing the spread of disease, requires a prior understanding of the pattern of carrion scavenging in specific scenarios. The objectives of this paper are (i to describe the guild of vertebrate scavengers and (ii to study the species-specific, habitat, and management-related factors involved in the usage of gut piles in South Central Spain (SCS, a tuberculosis (TB endemic area. We used camera trapping at 18 hunting piles on seven hunting estates. A total of eight bird and five mammal taxa were detected at the remains of hunting piles. The most frequently detected species in terms of number of gut piles visited (78% and scavenged (61% was the red fox Vulpes vulpes, followed by the griffon vulture Gyps fulvus (56% as regards both presence and scavenging and the raven Corvus corax (61 and 39% as regards presence and scavenging, respectively. We evidenced that griffon vultures accounted for most of the scavenging activity in open habitats, while facultative mammal scavengers, red fox, and wild boar Sus scrofa made the highest contribution to scavenging in vegetation-covered habitats. In the case of wild boar, the gut piles deposited during the evening and night favored higher rates of scavenging, while the opposite pattern was observed for griffons. Overall, our findings suggest that when disposing of hunting remains in areas of risk as regards disease transmission it is particularly important to consider the access that facultative mammals, and especially wild boar, have to material, while the presence of the resource needs to be safeguarded to protect specialist scavengers of conservation value. These results are of particular relevance in the case of wild boar in the current context of re-emerging TB and emerging African swine fever (ASF in Europe.

21 CFR 868.5430 - Gas-scavenging apparatus.

Science.gov (United States)

2010-04-01

...) Identification. A gas-scavenging apparatus is a device intended to collect excess anesthetic, analgesic, or trace gases or vapors from a patient's breathing system, ventilator, or extracorporeal pump-oxygenator, and to conduct these gases out of the area by means of an exhaust system. (b) Classification. Class II...

Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic ...

African Journals Online (AJOL)

Antioxidant Capacity, Radical Scavenging Kinetics and Phenolic Profile of Methanol Extracts of Wild Plants of Southern Sonora, Mexico. EF Moran-Palacio, LA Zamora-Álvarez, NA Stephens-Camacho, GA Yáñez- Farías, A Virgen-Ortiz, O Martínez-Cruz, JA Rosas-Rodríguez ...

In vitro free radical scavenging activity of ethanolic extract of the whole plant of Evolvulus alsinoides (L.) L.

Science.gov (United States)

Gomathi, Duraisamy; Ravikumar, Ganesan; Kalaiselvi, Manokaran; Vidya, Balasubramaniam; Uma, Chandrasekar

2015-06-01

To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction, superoxide radical scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard. The extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner. Evolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.

Body Size as a Driver of Scavenging in Theropod Dinosaurs.

Science.gov (United States)

Kane, Adam; Healy, Kevin; Ruxton, Graeme D; Jackson, Andrew L

2016-06-01

Theropod dinosaurs dominated Earth's terrestrial ecosystem as a diverse group of predators for more than 160 million years, yet little is known about their foraging ecology. Maintaining a balanced energy budget presented a major challenge for therapods, which ranged from the chicken-sized Microraptor up to the whale-sized Giganotosaurus, in the face of intense competition and the demands of ontogenetic growth. Facultative scavenging, a behavior present in almost all modern predators, may have been important in supplementing energetically expensive lifestyles. By using agent-based models based on the allometric relationship between size and foraging behaviors, we show that theropods between 27 and 1,044 kg would have gained a significant energetic advantage over individuals at both the small and large extremes of theropod body mass through their scavenging efficiency. These results were robust to rate of competition, primary productivity, and detection distance. Our models demonstrate the potential importance of facultative scavenging in theropods and the role of body size in defining its prevalence in Mesozoic terrestrial systems.

Turbulent swirling flow in a dynamic model of a uniflow-scavenged two-stroke engine

Science.gov (United States)

Ingvorsen, K. M.; Meyer, K. E.; Walther, J. H.; Mayer, S.

2014-06-01

It is desirable to use computational fluid dynamics for optimization of the in-cylinder processes in low-speed two-stroke uniflow-scavenged marine diesel engines. However, the complex nature of the turbulent swirling in-cylinder flow necessitates experimental data for validation of the used turbulence models. In the present work, the flow in a dynamic scale model of a uniflow-scavenged cylinder is investigated experimentally. The model has a transparent cylinder and a moving piston driven by a linear motor. The flow is investigated using phase-locked stereoscopic particle image velocimetry (PIV) and time-resolved laser Doppler anemometry (LDA). Radial profiles of the phase-locked mean and rms velocities are computed from the velocity fields recorded with PIV, and the accuracy of the obtained profiles is demonstrated by comparison with reference LDA measurements. Measurements are carried out at five axial positions for 15 different times during the engine cycle and show the temporal and spatial development of the swirling in-cylinder flow. The tangential velocity profiles in the bottom of the cylinder near the end of the scavenge process are characterized by a concentrated swirl resulting in wake-like axial velocity profiles and the occurrence of a vortex breakdown. After scavenge port closing, the axial velocity profiles indicate that large transient swirl-induced structures exist in the cylinder. Comparison with profiles obtained under steady-flow conditions shows that the scavenge flow cannot be assumed to be quasi-steady. The temporal development of the swirl strength is investigated by computing the angular momentum. The swirl strength shows an exponential decay from scavenge port closing to scavenge port opening corresponding to a reduction of 34 %, which is in good agreement with theoretical predictions.

Intracellular ROS protection efficiency and free radical-scavenging activity of curcumin.

Directory of Open Access Journals (Sweden)

Abolfazl Barzegar

Full Text Available Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H₂O₂, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a β-diketone and several π electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm.

In vitro free radical scavenging activity of platinum nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Aki; Kajita, Masashi; Kim, Juewon; Kanayama, Atsuhiro; Miyamoto, Yusei [Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bioscience Building 402, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 (Japan); Takahashi, Kyoko; Mashino, Tadahiko, E-mail: yusei74@k.u-tokyo.ac.j [Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato, Tokyo 105-8512 (Japan)

2009-11-11

A polyacrylic acid (PAA)-protected platinum nanoparticle species (PAA-Pt) was prepared by alcohol reduction of hexachloroplatinate. The PAA-Pt nanoparticles were well dispersed and homogeneous in size with an average diameter of 2.0 {+-} 0.4 nm (n = 200). We used electron spin resonance to quantify the residual peroxyl radical AOO. generated from 2,2-azobis (2-aminopropane) dihydrochloride (AAPH) by thermal decomposition in the presence of O{sub 2} and a spectrophotometric method to quantify the residual 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. PAA-Pt scavenged these two radicals in a dose-dependent manner. Platinum was the functional component. PAA-Pt reduced the rate of oxygen consumption required for linoleic acid peroxidation initiated by AOO. generated from AAPH, indicating inhibition of the propagation of linolate peroxidation. A thiobarbituric acid test also revealed dose-dependent inhibition of the linolate peroxidation by PAA-Pt. Fifty micromolar platinum, as PAA-Pt, completely quenched 250 {mu}M DPPH radical for 5 min. Even when twice diluted in half, the PAA-Pt still quenched 100% of the 250 {mu}M DPPH radical. The scavenging activity of PAA-Pt is durable. These observations suggest that PAA-Pt is an efficient scavenger of free radicals.

Performance of Chickens under Semi-scavenging Conditions: A ...

African Journals Online (AJOL)

Performance of Chickens under Semi-scavenging Conditions: A Case Study of ... per household was lost per year due to diseases, predators, accidents, and theft. ... as well as chicken house construction so as to avoid the risks of predators.

Possibilities of the combined use of non-steroidal anti-inflammatory drugs and sulfhydryl compounds in radioprotection

International Nuclear Information System (INIS)

Kozubik, A.; Pospisil, M.; Netikova, J.

1991-01-01

The combined preirradiation administration of indomethacin and cystamine was found to enhance synergistically the recovery of hemopoiesis in sublethally gamma-irradiated mice. This effect can be explained by a common operation of two mechanisms of radioprotection, i.e. of an increased survival of hemopoietic stem cells due to cystamine action and of stimulatory effects of indomethacin on the proliferation of surviving cells, mediated by the inhibition of prostaglandin synthesis. Attempts to prove such enhancement of protective effects on irradiated mice in terms of postirradiation lethality were unsuccessful. The reason seems to be the influence of toxic effects of the indomethacin-cystamine combination on the gastrointestinal tract. When using the less toxic combination, i.e. diclofenac and WR-2721, the additivity of protective effects is manifested even in the survival of lethally irradiated mice. The results suggest that under suitable conditions avoiding the unfavourable toxic effects, non-steroidal anti-inflammatory drugs can be successfully used with the aim to enhance the efficiency of sulfhydryl radioprotectors. (orig.) [de

Development of cancer immunotherapy

International Nuclear Information System (INIS)

Yun, Yeon Sook; Chung, H. Y.; Yi, S. Y.; Kim, K. W.; Kim, B. K.; Chung, I. S.; Park, J. Y.

1999-04-01

To increase the curative rate of cancer patients, we developed ideal biological response modifier from medicinal plants: Ginsan, KC68IId-8, KC-8Ala, KG-30. Ginsan activated natural killer cell activity of spleen cells more than 5.4 times than lentinan, 1.4 times than picibanil. Radioprotective activity of Ginsan is stronger than WR2721, glucan, and selenium. The immunogenicity of MOPC tumor cells was augmented by treatment with IL-10 antisense oligonucleotide and by transfection with VEGF sense-, antisense gene. The immunogenicity of MOPC tumor cells was augmented by treatment with IL-10 antisense oligonucleotide and by transfection with VEGF sense-, antisense gene. The immunogenicity of A20 tumor cells was also augmented by transfection with B7.1 gene. The immunosuppression of gamma-irradiation was due to the reduction of Th1 sytokine gene expression through STAT pathway. These research will devote to develop new cancer immunotherapy and to reduce side effect of cancer radiotherapy and chemotherapy

Development of cancer immunotherapy

Energy Technology Data Exchange (ETDEWEB)

Yun, Yeon Sook; Chung, H. Y.; Yi, S. Y.; Kim, K. W.; Kim, B. K.; Chung, I. S.; Park, J. Y

1999-04-01

To increase the curative rate of cancer patients, we developed ideal biological response modifier from medicinal plants: Ginsan, KC68IId-8, KC-8Ala, KG-30. Ginsan activated natural killer cell activity of spleen cells more than 5.4 times than lentinan, 1.4 times than picibanil. Radioprotective activity of Ginsan is stronger than WR2721, glucan, and selenium. The immunogenicity of MOPC tumor cells was augmented by treatment with IL-10 antisense oligonucleotide and by transfection with VEGF sense-, antisense gene. The immunogenicity of MOPC tumor cells was augmented by treatment with IL-10 antisense oligonucleotide and by transfection with VEGF sense-, antisense gene. The immunogenicity of A20 tumor cells was also augmented by transfection with B7.1 gene. The immunosuppression of gamma-irradiation was due to the reduction of Th1 sytokine gene expression through STAT pathway. These research will devote to develop new cancer immunotherapy and to reduce side effect of cancer radiotherapy and chemotherapy.

Antimicrobial and free radical scavenging activities of five ...

African Journals Online (AJOL)

Extracts from five indigenous Palestinian medicinal plants including Rosmarinus officinalis, Pisidium guajava, Punica granatum peel, grape seeds and Teucrium polium were investigated for antimicrobial and free radical scavenging activities against eight microorganisms, using well diffusion method. The microorganisms ...

Effect of concentration and molecular weight of chitosan and its derivative on the free radical scavenging ability.

Science.gov (United States)

Li, Huili; Xu, Qing; Chen, Yun; Wan, Ajun

2014-03-01

Chitosan is a biodegradable and biocompatible natural scaffold material, which has numerous applications in biomedical sciences. In this study, the in vitro antioxidant activity of chitosan scaffold material was investigated by the chemiluminescence signal generated from the hydroxyl radical (•OH) scavenging assay. The scavenging mechanism was also discussed. The results indicated that the free radical scavenging ability of chitosan scaffold material significantly depends on the chitosan concentration and shows interesting kinetic change. Within the experimental concentration range, the optimal concentration of chitosan was 0.2 mg/mL. The molecular weight of chitosan also attributed to the free radical scavenging ability. Comparison between chitosan and its derivative found that carboxymethyl chitosan possessed higher scavenging ability. Copyright © 2013 Society of Plastics Engineers.

Ultimate Scaling of High-κ Gate Dielectrics: Higher-κ or Interfacial Layer Scavenging?

Directory of Open Access Journals (Sweden)

Takashi Ando

2012-03-01

Full Text Available Current status and challenges of aggressive equivalent-oxide-thickness (EOT scaling of high-κ gate dielectrics via higher-κ ( > 20 materials and interfacial layer (IL scavenging techniques are reviewed. La-based higher-κ materials show aggressive EOT scaling (0.5–0.8 nm, but with effective workfunction (EWF values suitable only for n-type field-effect-transistor (FET. Further exploration for p-type FET-compatible higher-κ materials is needed. Meanwhile, IL scavenging is a promising approach to extend Hf-based high-κ dielectrics to future nodes. Remote IL scavenging techniques enable EOT scaling below 0.5 nm. Mobility-EOT trends in the literature suggest that short-channel performance improvement is attainable with aggressive EOT scaling via IL scavenging or La-silicate formation. However, extreme IL scaling (e.g., zero-IL is accompanied by loss of EWF control and with severe penalty in reliability. Therefore, highly precise IL thickness control in an ultra-thin IL regime ( < 0.5 nm will be the key technology to satisfy both performance and reliability requirements for future CMOS devices.

Study of anti-oxidation and scavenging effects on free radicals of quercetin

International Nuclear Information System (INIS)

Wang Chongdao; Qiang Yizhong; Lao Qinhua; Shao Yuan

1999-01-01

The effects of Quercetin on the contents of lipid peroxides (LPO) in the mice caused by γ-whole-body irradiation by method of the modified spectrophotometry of TBA, and the scavenging effects of Quercetin on the free radicals of DNA induced by radiation exposure by means of ESR technique were investigated. The results demonstrates that Quercetin has a good anti-oxidation effect and is very effective in scavenging of free radicals

Increasing land-use intensity reverses the relative occupancy of two quadrupedal scavengers

OpenAIRE

Twining, Joshua P.; Bernard, Henry; Ewers, Robert M.

2017-01-01

Human land use is continuously altering the natural environment, yet the greater ecological implications of this change for many groups that are key to healthy ecosystem functioning remains uncharacterised in the tropics. Terrestrial scavenging vertebrates are one such group, providing integral ecosystem services through the removal of carrion which is a crucial component of both nutrient cycling and disease dynamics. To explore how anthropogenic processes may affect forest scavengers, we inv...

Energy scavenging from environmental vibration.

Energy Technology Data Exchange (ETDEWEB)

Galchev, Tzeno (University of Michigan); Apblett, Christopher Alan; Najafi, Khalil (University of Michigan)

2009-10-01

The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The

Precipitation Scavenging of Aerosol Particles at a Rural Site in the Czech Republic.

Czech Academy of Sciences Publication Activity Database

Zíková, Naděžda; Ždímal, Vladimír

2016-01-01

Roč. 67, č. 2016 (2016), s. 27343 ISSN 0280-6509 R&D Projects: GA ČR GAP209/11/1342 EU Projects: European Commission(XE) 654109 - ACTRIS-2; European Commission(XE) 262254 - ACTRIS Institutional support: RVO:67985858 Keywords : below- cloud scavenging * in- cloud scavenging * hydrometeors Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.402, year: 2015

Apoptotic and free radical scavenging properties of the methanolic extract of Gentianella alborosea.

Science.gov (United States)

Acero, Nuria; Llinares, Francisco; Galán de Mera, Antonio; Oltra, Beatriz; Muñoz-Mingarro, Dolores

2006-09-01

Gentianella alborosea ("Hercampure") is a Peruvian species used in folk medicine for the treatment of a variety of health disorders. We tested the free radical scavenging (DPPH) and induction of apoptosis on a human uterus tumor cell line (HeLa) by its methanolic extract. The results showed a noticeable radical scavenging activity and a dose-dependent apoptotic effect.

[In vitro anti-inflammatory and free radical scavenging activities of flavans from Ilex centrochinensis].

Science.gov (United States)

Li, Lu-jun; Yu, Li-juan; Li, Yan-ci; Liu, Meng-yuan; Wu, Zheng-zhi

2015-04-01

This study was carried out to evaluate the anti-inflammatory and free radical scavenging activities of flavans from flex centrochinensis S. Y. Hu in vitro and their structure-activity relationship. LPS-stimulated RAW 264.7 macrophage was used as inflammatory model. MTT assay for cell availability, Griess reaction for nitric oxide (NO) production, the content of TNF-alpha, IL-1beta, IL-6 and PGE, were detected with ELISA kits; DPPH, superoxide anion and hydroxyl free radicals scavenging activities were also investigated. According to the result, all flavans tested exhibited anti-inflammatory effect in different levels. Among them, compounds 1, 3, 4 and 6 showed potent anti-inflammatory effect through the inhibition of NO, TNF-alpha, IL-lp and IL-6, of which 1 was the most effective inhibitor, however, 2 and 5 were relatively weak or inactive. The order of free radical scavenging activities was similar to that of anti-inflammatory activities. Therefore, these results suggest that 3, 4 and 6, especially of 1, were,in part responsible for the anti-inflammatory and free radical scavenging activity of Ilex centrochinensis. Hydroxyl group at 4'-position of B-ring plays an important role in the anti-inflammatory and free radical scavenging capacities.

Variations of Antioxidant Properties and NO Scavenging Abilities during Fermentation of Tea

Science.gov (United States)

Xu, Yang; Zhao, Hang; Zhang, Min; Li, Chun-Jie; Lin, Xue-Zhen; Sheng, Jun; Shi, Wei

2011-01-01

Tea is known as one of the most popular beverages in the world, which is believed to be beneficial for health. The main components in tea will change a lot depending on the different processes of fermentation, and thus the effects of different teas on human health may differ. The aim of this study is to explore the varied abilities of reactive oxygen species (ROS) and nitric oxide (NO) scavenging during the fermentation of tea. In this study, we conducted the in vitro experiments which involved some reaction systems indicating the abilities of scavenging ROS and NO. We also investigated the effects of tea and their components (catechins, theabrownins, caffeine) on the intracellular levels of ROS and NO, using Raw 264.7 cells as the model. We found that regardless of whether it was out of cell system or in Raw 264.7 cells, the abilities of scavenging ROS would decrease during the fermentation of tea. Further, the post-fermented pu-erh tea showed the best effect on inhibiting the lipopolysaccharide (LPS)-induced production of NO. These findings indicated that the fermentation process caused a change of the components which might be due to the changes of their antioxidant properties and NO scavenging abilities. PMID:21845097

Reward Your Students with an Online Scavenger Hunt!

Science.gov (United States)

Board, Keith

2013-01-01

Do you have a class of students who do excellent work and whom you would like to give an enjoyable reward? Try an "Internet scavenger hunt" for a fun and educational change of pace! This article shares how to run the activity.

Effect of an inefficient electron scavenger on infrared- and visible-absorbing electrons in an ethanol matrix

International Nuclear Information System (INIS)

Noda, S.; Yoshida, K.; Ogasawara, M.; Yoshida, H.

1980-01-01

In order to obtain a deeper insight into the initial localization and the subsequent stabilization of electrons and to unravel the detailed mechanism of the electron scavenging reaction in a glassy ethanol matrix, spectrophotometric studies have been made on this matrix with toluene, an inefficient electron scavenger, γ irradiated at 4.2 0 K. Inhomogeneous depletion of the trapped electron spectrum by toluene indicates that IR-absorbing (lambda/sub max/ = 1500 nm) and visible-absorbing (lambda/sub max/ = 640 nm) electrons are initially generated, but that the former are unstable at higher temperature. Toluene scavenges the IR-absorbing electrons more efficiently by a factor of 10 than the visible-absorbing electrons. This selectivity is much higher than that of an efficient scavenger, such as benzyl chloride, as previously reported. The electron scavenging reaction results in the formation of the transient radical anion of toluene, which is readily protonated to yield the methylcyclohexadienyl radical at 77 0 K. 3 figures

Hemoglobin and heme scavenger receptors

DEFF Research Database (Denmark)

Nielsen, Marianne Jensby; Møller, Holger Jon; Moestrup, Søren Kragh

2010-01-01

Heme, the functional group of hemoglobin, myoglobin, and other hemoproteins, is a highly toxic substance when it appears in the extracellular milieu. To circumvent potential harmful effects of heme from hemoproteins released during physiological or pathological cell damage (such as hemolysis...... and rhabdomyolysis), specific high capacity scavenging systems have evolved in the mammalian organism. Two major systems, which essentially function in a similar way by means of a circulating latent plasma carrier protein that upon ligand binding is recognized by a receptor, are represented by a) the hemoglobin...

Computational studies of free radical-scavenging properties of phenolic compounds.

Science.gov (United States)

Alov, Petko; Tsakovska, Ivanka; Pajeva, Ilza

2015-01-01

For more than half a century free radical-induced alterations at cellular and organ levels have been investigated as a probable underlying mechanism of a number of adverse health conditions. Consequently, significant research efforts have been spent for discovering more effective and potent antioxidants / free radical scavengers for treatment of these adverse conditions. Being by far the most used antioxidants among natural and synthetic compounds, mono- and polyphenols have been the focus of both experimental and computational research on mechanisms of free radical scavenging. Quantum chemical studies have provided a significant amount of data on mechanisms of reactions between phenolic compounds and free radicals outlining a number of properties with a key role for the radical scavenging activity and capacity of phenolics. The obtained quantum chemical parameters together with other molecular descriptors have been used in quantitative structure-activity relationship (QSAR) analyses for the design of new more effective phenolic antioxidants and for identification of the most useful natural antioxidant phenolics. This review aims at presenting the state of the art in quantum chemical and QSAR studies of phenolic antioxidants and at analysing the trends observed in the field in the last decade.

Shape similarities and differences in the skulls of scavenging raptors.

Science.gov (United States)

Guangdi, S I; Dong, Yiyi; Ma, Yujun; Zhang, Zihui

2015-04-01

Feeding adaptations are a conspicuous feature of avian evolution. Bill and cranial shape as well as the jaw muscles are closely related to diet choice and feeding behaviors. Diurnal raptors of Falconiformes exhibit a wide range of foraging behaviors and prey preferences, and are assigned to seven dietary groups in this study. Skulls of 156 species are compared from the dorsal, lateral and ventral views, by using geometric morphometric techniques with those landmarks capturing as much information as possible on the overall shape of cranium, bill, orbits, nostrils and attachment area for different jaw muscles. The morphometric data showed that the skull shape of scavengers differ significantly from other raptors, primarily because of different feeding adaptations. As a result of convergent evolution, different scavengers share generalized common morphology, possessing relatively slender and lower skulls, longer bills, smaller and more sideward orbits, and more caudally positioned quadrates. Significant phylogenetic signals suggested that phylogeny also played important role in shape variation within scavengers. New World vultures can be distinguished by their large nostrils, narrow crania and small orbits; Caracaras typically show large palatines, crania and orbits, as well as short, deep and sharp bill.

Results of the indoor radiological survey at the W.R. Grace Co., Curtis Bay site, Baltimore, Maryland

International Nuclear Information System (INIS)

Cottrell, W.D.; Foley, R.D.; Johnson, C.A.

1989-07-01

The W.R. Grace Company, Davison Chemical Division, conducted developmental research and extraction of thorium from monazite ore at its Curtis Bay facility in Baltimore, Maryland, during the 1950s under contract to the Atomic Energy Commission (AEC). Only one of the numerous buildings on the site was used for these operations. A 1979 aerial survey of the site for the Department of Energy (DOE) indicated that a comprehensive ground survey was required to determine whether or not any contamination remained from the AEC activities in that building. A radiological scoping survey performed later that year for DOE by a team from the Measurement Applications and Development Group of the Health and Safety Research Division, Oak Ridge National Laboratory (ORNL), disclosed surface contamination (alpha) levels in excess of DOE criteria on all five levels of the building. As a result of this finding, two additional surveys were performed in 1986 by ORNL at the request of DOE to evaluate any present or potential health risk. They are detailed in this report. The results of the 1986 surveys revealed several areas having elevated levels of radiation as a result of significant quantities of thorium on some building surfaces such as floors and ceiling beams. Most areas were small spots and in locations of low occupancy; thus, the possibility for significant exposure to workers was judged to be low. To confirm this evaluation, annual radiation exposure estimates for workers frequenting the few, larger contaminated areas on the site were derived using ORNL survey data and occupancy factors provided by the W.R. Grace Company. Estimates ranged from 27 to 41 mrem/yr or a maximum of 41% of the basic dose limit of 100 mrem/yr for members of the general public. 2 refs., 14 figs., 8 tabs

Simulation Modeling Method and Experimental Investigation on the Uniflow Scavenging System of an Opposed-Piston Folded-Cranktrain Diesel Engine

Directory of Open Access Journals (Sweden)

Fukang Ma

2017-05-01

Full Text Available The scavenging process for opposed-piston folded-cranktrain (OPFC diesel engines can be described by the time evolution of the in-cylinder and exhaust chamber residual gas rates. The relation curve of in-cylinder and exhaust chamber residual gas rate is called scavenging profile, which is calculated through the changes of in-cylinder and exhaust chamber gas compositions determined by computational fluid dynamics (CFD simulation. The scavenging profile is used to calculate the scavenging process by mono-dimensional (1D simulation. The tracer gas method (TGM is employed to validate the accuracy of the scavenging profile. At the same time, the gas exchange performance under different intake and exhaust state parameters was examined based on the TGM. The results show that the scavenging process from 1D simulation and experiment match well, which means the scavenging model obtained by CFD simulation performs well and validation of its effectiveness by TGM is possible. The difference between intake and exhaust pressure has a significant positive effect on the gas exchange performance and trapped gas mass, but the pressure difference has little effect on the scavenging efficiency and the trapped air mass if the delivery ratio exceeds 1.4.

The scavenging effects of tea polyphenol and quercetin on active oxygen species

International Nuclear Information System (INIS)

Fang Ruoying; Cheng Jiwu; Hu Tianxi; Tu Tiechen; Dong Jirong; Wang Wenfeng; Lin Nianyun

1993-01-01

The abilities of scavenging active oxygen species, O 2 free radical and OH., by tea polyphenols and quercetin have been studied by chemiluminescence, ESR and pulse radiolysis. Tea polyphenols and quercetin are all phenolic antioxidants. The synergetic studies show that both tea polyphenols and quercetin are strong free radical scavengers. Tea polyphenols are better than quercetin. the results from CL studies are in good accord with those from ESR and PR studies

Nature or Nurture? Gender Roles Scavenger Hunt

Science.gov (United States)

Whalen, Shannon; Maurer-Starks, Suanne

2008-01-01

The examination of gender roles and stereotypes and their subsequent impact on sexual behavior is a concept for discussion in many sex education courses in college and sex education units in high school. This analysis often leads to a discussion of the impact of nature vs. nurture on gender roles. The gender roles scavenger hunt is an interactive…

Free radical scavenging potential, reducing power, phenolic and biochemical constituents of Porphyra species from India

Digital Repository Service at National Institute of Oceanography (India)

Pise, N.M.; Jena, K.B.; Maharana, D.; Gaikwad, D.; Jagtap, T.G.

. Antioxidant potentials of algae were assessed through phenolic content, 2, 2-diphenyl-1- picrylhydrazyl (DPPH) activity, hydrogen peroxide (H sub(2)O sub(2)), scavenging power and reducing potential. A dose-dependent free radical scavenging action against DPPH...

The French Paradox: Determining the Superoxide-Scavenging Capacity of Red Wine and Other Beverages

Science.gov (United States)

Logan, Barry A.; Hammond, Matthew P.; Stormo, Benjamin M.

2008-01-01

Plant-derived phenolic compounds such as those found in red wine, tea, and certain fruit juices may protect against cardiovascular disease by detoxifying (scavenging) superoxide and other unstable reactive oxygen species. We present a laboratory exercise that can be used to assess the superoxide-scavenging capacity of beverages. Among the…

A BINARY ORBIT FOR THE MASSIVE, EVOLVED STAR HDE 326823, A WR+O SYSTEM PROGENITOR

International Nuclear Information System (INIS)

Richardson, N. D.; Gies, D. R.; Williams, S. J.

2011-01-01

The hot star HDE 326823 is a candidate transition-phase object that is evolving into a nitrogen-enriched Wolf-Rayet star. It is also a known low-amplitude, photometric variable with a 6.123 day period. We present new, high- and moderate-resolution spectroscopy of HDE 326823, and we show that the absorption lines show coherent Doppler shifts with this period while the emission lines display little or no velocity variation. We interpret the absorption line shifts as the orbital motion of the apparently brighter star in a close, interacting binary. We argue that this star is losing mass to a mass gainer star hidden in a thick accretion torus and to a circumbinary disk that is the source of the emission lines. HDE 326823 probably belongs to a class of objects that produce short-period WR+O binaries.

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

Science.gov (United States)

Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

2009-01-01

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

[Correlation Between Functional Groups and Radical Scavenging Activities of Acidic Polysaccharides from Dendrobium].

Science.gov (United States)

Liao, Ying; Yuan, Wen-yu; Zheng, Wen-ke; Luo, Ao-xue; Fan, Yi-jun

2015-11-01

To compare the radical scavenging activity of five different acidic polysaccharides, and to find the correlation with the functional groups. Alkali extraction method and Stepwise ethanol precipitation method were used to extract and concentrate the five Dendrobium polysaccharides, and to determine the contents of sulfuric acid and uronic acid of each kind of acidic polysaccharides, and the scavenging activity to ABTS+ radical and hydroxyl radical. Functional group structures were examined by FTIR Spectrometer. Five kinds of Dendrobium polysaccharides had different ability of scavenging ABTS+ free radical and hydroxyl free radical. Moreover, the study had shown that five kinds of antioxidant activity of acidic polysaccharides had obvious correlation withuronic acid and sulfuric acid. The antioxidant activity of each sample was positively correlated with the content of uronic acid, and negatively correlated with the content of sulfuric acid. Sulfuric acid can inhibit the antioxidant activity of acidic polysaccharide but uronic acid can enhance the free radical scavenging activity. By analyzing the structure characteristics of five acidic polysaccharides, all samples have similar structures, however, Dendrobium denneanum, Dendrobium devonianum and Dendrobium officinale which had β configuration have higher antioxidant activity than Dendrobium nobile and Dendrobium fimbriatum which had a configuration.

Gallic acid as an oxygen scavenger in bio-based multilayer packaging films

OpenAIRE

Pant, Astrid; Sängerlaub, Sven; Müller, Kajetan

2017-01-01

Oxygen scavengers are used in food packaging to protect oxygen-sensitive food products. A mixture of gallic acid (GA) and sodium carbonate was used as an oxygen scavenger (OSc) in bio-based multilayer packaging films produced in a three-step process: compounding, flat film extrusion, and lamination. We investigated the film surface color as well as oxygen absorption at different relative humidities (RHs) and temperatures, and compared the oxygen absorption of OSc powder, monolayer films, and ...

Development of nitroxide radicals–containing polymer for scavenging reactive oxygen species from cigarette smoke

International Nuclear Information System (INIS)

Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

2014-01-01

We developed a nitroxide radicals–containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV–visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke. (papers)

Free radical scavenging activity and phenolic contents of ...

African Journals Online (AJOL)

Anthocleista djalonensis extract is widely used in Nigerian folk medicine to treat conditions whose pathogenesis implicate oxidative stress, such as diabetes and hepatitis. However, little is known of the mechanism underlying these activities. In this study, the free radical scavenging potential of a methanol extract of A.

The significance of cooking for early hominin scavenging.

Science.gov (United States)

Smith, Alex R; Carmody, Rachel N; Dutton, Rachel J; Wrangham, Richard W

2015-07-01

Meat scavenged by early Homo could have contributed importantly to a higher-quality diet. However, it has been suggested that because carrion would normally have been contaminated by bacteria it would have been dangerous and therefore eaten rarely prior to the advent of cooking. In this study, we quantified bacterial loads on two tissues apparently eaten by hominins, meat and bone marrow. We tested the following three hypotheses: (1) the bacterial loads on exposed surfaces of raw meat increase within 24 h to potentially dangerous levels, (2) simple roasting of meat on hot coals kills most bacteria, and (3) fewer bacteria grow on marrow than on meat, making marrow a relatively safe food. Our results supported all three hypotheses. Our experimental data imply that early hominins would have found it difficult to scavenge safely without focusing on marrow, employing strategies of carrion selection to minimize pathogen load, or cooking. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

Energy Technology Data Exchange (ETDEWEB)

Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

2006-03-15

Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)

Evaluation of Free Radical Scavenging Activity in Ethanolic Extract from Promising Accessions of Curcuma aeruginosa RoxB.

Directory of Open Access Journals (Sweden)

Waras Nurcholis

2017-11-01

Full Text Available This study evaluated the free radical scavenging activity in ethanolic extracts from 20 accessions of Curcuma aeruginosa. The radical scavenging activity of the extract accessions was investigated with 2,2-diphenyl-1-picrylhydrazyl (DPPH radical. IC50 values for DPPH radical scavenging activity ranged from 89.81 to 505.65 µg mL-1. Based on IC50 values, twenty accessions of C. aeruginosa can be divided into three groups: strong (two accessions; moderate (seventeen accessions; and low (one accession of DPPH scavenger. Sukoharjo (SH and Muara Bungo (MB showed promising accessions for antioxidant potential, thus these accessions important to selection for future breeding program in pharmaceutical products.

CXCR7 functions as a scavenger for CXCL12 and CXCL11.

Directory of Open Access Journals (Sweden)

Ulrike Naumann

2010-02-01

Full Text Available CXCR7 (RDC1, the recently discovered second receptor for CXCL12, is phylogenetically closely related to chemokine receptors, but fails to couple to G-proteins and to induce typical chemokine receptor mediated cellular responses. The function of CXCR7 is controversial. Some studies suggest a signaling activity in mammalian cells and zebrafish embryos, while others indicate a decoy activity in fish. Here we investigated the two propositions in human tissues.We provide evidence and mechanistic insight that CXCR7 acts as specific scavenger for CXCL12 and CXCL11 mediating effective ligand internalization and targeting of the chemokine cargo for degradation. Consistently, CXCR7 continuously cycles between the plasma membrane and intracellular compartments in the absence and presence of ligand, both in mammalian cells and in zebrafish. In accordance with the proposed activity as a scavenger receptor CXCR7-dependent chemokine degradation does not become saturated with increasing ligand concentrations. Active CXCL12 sequestration by CXCR7 is demonstrated in adult mouse heart valves and human umbilical vein endothelium.The finding that CXCR7 specifically scavenges CXCL12 suggests a critical function of the receptor in modulating the activity of the ubiquitously expressed CXCR4 in development and tumor formation. Scavenger activity of CXCR7 might also be important for the fine tuning of the mobility of hematopoietic cells in the bone marrow and lymphoid organs.

Radical scavenging potentials of single and combinatorial herbal formulations in vitro

Directory of Open Access Journals (Sweden)

Okey A. Ojiako

2016-04-01

Full Text Available Reactive oxygen and nitrogen species (RONS are involved in deleterious/beneficial biological processes. The present study sought to investigate the capacity of single and combinatorial herbal formulations of Acanthus montanus, Emilia coccinea, Hibiscus rosasinensis, and Asystasia gangetica to act as superoxide radicals (SOR, hydrogen peroxide (HP, nitric oxide radical (NOR, hydroxyl radical (HR, and 2,2-diphenyl-1-picrylhydrazyl (DPPH radical antagonists using in vitro models. The herbal extracts were single herbal formulations (SHfs, double herbal formulations (DHfs, triple herbal formulations (THfs, and a quadruple herbal formulation (QHf. The phytochemical composition and radical scavenging capacity index (SCI of the herbal formulations were measured using standard methods. The flavonoids were the most abundant phytochemicals present in the herbal extracts. The SCI50 defined the concentration (μg/mL of herbal formulation required to scavenge 50% of the investigated radicals. The SHfs, DHfs, THfs, and QHf SCI50 against the radicals followed the order HR > SOR > DPPH radical > HP > NOR. Although the various herbal formulations exhibited ambivalent antioxidant activities in terms of their radical scavenging capabilities, a broad survey of the results of the present study showed that combinatorial herbal formulations (DHfs, THfs, and QHf appeared to exhibit lower radical scavenging capacities than those of the SHfs in vitro.

Nitric oxide radical scavenging potential of some Elburz medicinal ...

African Journals Online (AJOL)

ONOS

2010-08-09

Aug 9, 2010 ... NO is also implicated in inflammation and other pathological ... adhesion and prevention of smooth muscle cell prolife- ... reduce NO levels is making use of NO scavengers. For ..... human nutrition and health are considerable.

Identification, characterisation and composition of scavengeable feed resources for rural poultry production in Central Tanzania

NARCIS (Netherlands)

Goromela, E.H.; Kwakkel, R.P.; Verstegen, M.W.A.; Katule, A.M.

2007-01-01

A participatory study was carried out in four villages of central Tanzania to appraise existing and potential scavengeable feed resources available for rural poultry. In addition, proximate analysis of selected scavengeable feed resources including chicken crop and gizzards contents was carried out

Tourism in protected areas: Disentangling road and traffic effects on intra-guild scavenging processes.

Science.gov (United States)

Donázar, José Antonio; Ceballos, Olga; Cortés-Avizanda, Ainara

2018-07-15

The expansion of road networks and the increase in traffic have emerged in recent years as key threats to the conservation of biodiversity. This is particularly concerning in many protected areas because the increase of recreational activities requiring the use of vehicles. Effects of roads and traffic within guild scenarios and ecological processes remain however poorly known. Here we examined how road proximity and traffic intensity influence patterns of resource use in an Old-World avian scavenger guild living in a protected natural park in northern Spain. We experimentally placed 130 carcasses at different distances from a scenic road in the centre of the park. Vehicles were recorded by means of traffic counters which revealed that maximum numbers were reached during weekends and holidays and during the middle hours of the day. Avian scavenger attendance at carcasses was recorded by means of camera-traps. Obligated scavengers, Eurasian griffon (Gyps fulvus) and Egyptian vultures (Neophron percnopterus) were frequently observed (59.4% and 37.7% of the consumed carcasses) together with five other facultative scavenger species. We found that the richness (number of species) and the probability of consumption of the resource were reduced the smaller the distance to the road and in days with higher traffic intensity. The same factors affected the probability of presence of all the scavenger species. Moreover, some of them, notably griffon vultures, showed hourly patterns of carcass attendance suggesting avoidance of maximum traffic levels. Our results highlight that roads and traffic would trigger consequences on the structure and functioning of scavenger food webs, which may be particularly concerning in protected areas with remarkable levels of biodiversity. Future regulations at protected areas should couple both traffic and tourist affluence with wildlife conservation. In this way important ecological processes would be preserved while maintaining a good

Simulation Modeling and Optimization of Uniflow Scavenging System Parameters on Opposed-Piston Two-Stroke Engines

Directory of Open Access Journals (Sweden)

Fukang Ma

2018-04-01

Full Text Available Based on the introduction of opposed-piston two-stroke (OP2S gasoline direct injection (GDI engines, the OP2S-GDI engine working principle and scavenging process were analyzed. GT-Power software was employed to model the working process based on the structural style and principle of OP2S-GDI engine. The tracer gas method and OP2S-GDI engine experiment were employed for model validation at full load of 6000 rpm. The OP2S-GDI engine scavenging system parameters were optimized, including intake port height stroke ratio, intake port circumference ratio, exhaust port height stroke ratio, exhaust port circumference ratio, and opposed-piston motion phase difference. At the same time, the effect of the port height stroke ratio and opposed-piston motion phase difference on effective compression ratio and expansion ratio were considered, and the indicated work was employed as the optimization objective. A three-level orthogonal experiment was applied in the calculation process to reduce the calculation work. The influence and correlation coefficient on the scavenging efficiency and delivery ratio were investigated by the orthogonal experiment analysis of intake and exhaust port height stroke ratio and circular utilization. The effect of the scavenging system parameters on delivery ratio, scavenging efficiency and indicated work were calculated to obtain the best parameters. The results show that intake port height stroke ratio is the main factor for the delivery ratio, while exhaust port height stroke ratio is the main factor to engine delivery ratio and scavenging efficiency.

Antioxidant and Nitrite-Scavenging Capacities of Phenolic Compounds from Sugarcane (Saccharum officinarum L. Tops

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Jian Sun

2014-08-01

Full Text Available Sugarcane tops were extracted with 50% ethanol and fractionated by petroleum ether, ethyl acetate (EtOAc, and n-butyl alcohol successively. Eight phenolic compounds in EtOAc extracts were purified through silica gel and Sephadex LH-20 column chromatographies, and then identified by nuclear magnetic resonance and electrospray ionization mass spectra. The results showed that eight phenolic compounds from EtOAc extracts were identified as caffeic acid, cis-p-hydroxycinnamic acid, quercetin, apigenin, albanin A, australone A, moracin M, and 5'-geranyl-5,7,2',4'-tetrahydroxyflavone. The antioxidant and nitrite-scavenging capacities of different solvent extracts correlated positively with their total phenolic (TP contents. Amongst various extracts, EtOAc extracts possessed the highest TP content and presented the strongest oxygen radical absorbance capacity (ORAC, 1,1'-diphenyl-2-picrylhydrazyl (DPPH radical-scavenging capacity, 2,2'-azobis-3-ethylbenthiaazoline-6-sulfonic acid (ABTS radical-scavenging capacity, ferric reducing antioxidant power (FRAP and nitrite-scavenging capacity. Thus, sugarcane tops could be promoted as a source of natural antioxidant.

Influence of starvation, triton WR-1339 and [131I]-human serum albumin on rat liver lysosomes

International Nuclear Information System (INIS)

Harikumar, P.; Ninjoor, V.

1986-01-01

The response of rat liver lysosomes to starvation and administration of lysosomotropic agents viz. Triton WR-1339 and [ 131 I]-human serum albumin, was assessed in terms of their distribution pattern after isopycnic sucrose density gradient centrifugation. Starvation induced changes in lysosomes appeared to be similar to that produced by the detergent uptake. Both the treatments caused a distinct decline in the equilibration densities of the organelles. On the other hand, injected labelled protein failed to comigrate with the lysosomal markers in starved as well as Triton treated rats and conspicuously remained in a region of high specific gravity in the gradient. These findings indicate retarded fusion between secondary lysosomes and [ 131 I]-human serum albumin containing phagosomes in the livers of rats subjected to starvation or detergent treatment. (author)

Diet and scavenging habits of the smooth skate Dipturus innominatus.

Science.gov (United States)

Forman, J S; Dunn, M R

2012-04-01

The diet of smooth skate Dipturus innominatus was determined from examination of stomach contents of 321 specimens of 29·3-152·0 cm pelvic length, sampled from research and commercial trawlers at depths of 231-789 m on Chatham Rise, New Zealand. The diet was dominated by the benthic decapods Metanephrops challengeri and Munida gracilis, the natant decapod Campylonotus rathbunae and fishes from 17 families, of which hoki Macruronus novaezelandiae, sea perch Helicolenus barathri, various Macrouridae and a variety of discarded fishes were the most important. Multivariate analyses indicated the best predictors of diet variability were D. innominatus length and a spatial model. The diet of small D. innominatus was predominantly small crustaceans, with larger crustaceans, fishes and then scavenged discarded fishes increasing in importance as D. innominatus got larger. Scavenged discards were obvious as fish heads or tails only, or skeletal remains after filleting, often from pelagic species. Demersal fish prey were most frequent on the south and west Chatham Rise, in areas where commercial fishing was most active. Dipturus innominatus are highly vulnerable to overfishing, but discarding practices by commercial fishing vessels may provide a positive feedback to populations through improved scavenging opportunities. © 2012 NIWA. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Separation of nanoparticles: Filtration and scavenging from waste incineration plants.

Science.gov (United States)

Förster, Henning; Thajudeen, Thaseem; Funk, Christine; Peukert, Wolfgang

2016-06-01

Increased amounts of nanoparticles are applied in products of everyday life and despite material recycling efforts, at the end of their life cycle they are fed into waste incineration plants. This raises the question on the fate of nanoparticles during incineration. In terms of environmental impact the key question is how well airborne nanoparticles are removed by separation processes on their way to the bag house filters and by the existing filtration process based on pulse-jet cleanable fibrous filter media. Therefore, we investigate the scavenging and the filtration of metal nanoparticles under typical conditions in waste incineration plants. The scavenging process is investigated by a population balance model while the nanoparticle filtration experiments are realized in a filter test rig. The results show that depending on the particle sizes, in some cases nearly 80% of the nanoparticles are scavenged by fly ash particles before they reach the bag house filter. For the filtration step dust cakes with a pressure drop of 500Pa or higher are found to be very effective in preventing nanoparticles from penetrating through the filter. Thus, regeneration of the filter must be undertaken with care in order to guarantee highly efficient collection of particles even in the lower nanometre size regime. Copyright © 2016 Elsevier Ltd. All rights reserved.

An investigation of red fox (Vulpes vulpes) and Eurasian badger (Meles meles) scavenging, scattering, and removal of deer remains: forensic implications and applications.

Science.gov (United States)

Young, Alexandria; Márquez-Grant, Nicholas; Stillman, Richard; Smith, Martin J; Korstjens, Amanda H

2015-01-01

Within northwest Europe, especially the United Kingdom, the red fox (Vulpes vulpes) and the Eurasian Badger (Meles meles) are the largest wild scavengers capable of modifying a set of remains through scavenging. Knowledge of region-specific and species-typical scavenging behaviors of scavengers within the crime scene area and surroundings can aid in more efficient and accurate interpretations. The scavenging behaviors of captive and wild foxes and badgers were recorded and compared through actualistic methods and direct observation. The scavenging by wild foxes and badgers of surface-deposited baits and whole deer (Cervus nippon; Capreolus capreolus) in a woodland was observed and analyzed. Wild foxes were found to scavenge deer more frequently than badgers. The scavenging of deer remains by foxes was also compared with forensic cases. The scavenging pattern and recovery distances of deer and human remains scavenged by foxes were similar but were potentially affected by the condition and deposition of a body, and the presence of clothing. © 2014 American Academy of Forensic Sciences.

Identification of Radical Scavenging Compounds in Rhaponticum carthamoides by Means of LC-DAD-SPE-NMR

NARCIS (Netherlands)

Miliauskas, G.; Beek, van T.A.; Waard, de P.; Venskutonis, R.P.; Sudhölter, E.J.R.

2005-01-01

A hyphenated LC-DAD-SPE-NMR setup in combination with on-line radical scavenging detection has been applied for the identification of radical scavenging compounds in extracts of Rhaponticum carthamoides. After NMR measurements, the pure compounds were infused into a mass spectrometer. The technique

Smooth Interfacial Scavenging for Resistive Switching Oxide via the Formation of Highly Uniform Layers of Amorphous TaOx.

Science.gov (United States)

Tsurumaki-Fukuchi, Atsushi; Nakagawa, Ryosuke; Arita, Masashi; Takahashi, Yasuo

2018-02-14

We demonstrate that the inclusion of a Ta interfacial layer is a remarkably effective strategy for forming interfacial oxygen defects at metal/oxide junctions. The insertion of an interfacial layer of a reactive metal, that is, a "scavenging" layer, has been recently proposed as a way to create a high concentration of oxygen defects at an interface in redox-based resistive switching devices, and growing interest has been given to the underlying mechanism. Through structural and chemical analyses of Pt/metal/SrTiO 3 /Pt structures, we reveal that the rate and amount of oxygen scavenging are not directly determined by the formation free energies in the oxidation reactions of the scavenging metal and unveil the important roles of oxygen diffusibility. Active oxygen scavenging and highly uniform oxidation via scavenging are revealed for a Ta interfacial layer with high oxygen diffusibility. In addition, the Ta scavenging layer is shown to exhibit a highly uniform structure and to form a very flat interface with SrTiO 3 , which are advantageous for the fabrication of a steep metal/oxide contact.

Trypsin Binding with Copper Ions Scavenges Superoxide: Molecular Dynamics-Based Mechanism Investigation

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Xin Li

2018-01-01

Full Text Available Trypsin is a serine protease, which has been proved to be a novel superoxide scavenger. The burst of superoxide induced by polychlorinated biphenyls can be impeded by trypsin in both wild type and sod knockout mutants of Escherichia coli. The experimental results demonstrated that the activities of superoxide scavenging of trypsin were significantly accelerated by Cu ions. Also, with the addition of Cu ions, a new β-sheet (β7 transited from a random coil in the Cu(II-trypsin (TP system, which was favorable for the formation of more contacts with other sheets of trypsin. Residue–residue network analysis and the porcupine plots proved that the Cu ion in trypsin strengthened some native interactions among residues, which ultimately resulted in much greater stability of the Cu(II-TP system. Moreover, compact and stable trypsin structures with Cu ions might be responsible for significantly provoking the activity of superoxide scavenging.

Free radical scavenging window of infertile patients with polycystic ovary syndrome: correlation with embryo quality.

Science.gov (United States)

Huang, Bo; Li, Zhou; Ren, Xinling; Ai, Jihui; Zhu, Lixia; Jin, Lei

2017-06-01

The activity of free radicals in follicular fluid was related to ovarian responsiveness, in vitro fertilization (IVF), and embryo transfer success rate. However, studies analyzing the relationship between the free radical scavenging capacity and embryo quality of infertile women with polycystic ovarian syndrome (PCOS) were lacking. The aim of this study was to evaluate the relationship between the free radical scavenging window of women with PCOS and their embryo quality. The free radical scavenging capacity of follicular fluid from women with PCOS was determined by a,a-diphenyl-b-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzthiazoline-6-sulphonic acid) assay, superoxide radical, and reactive oxygen species (ROS) assay. In the DPPH and ROS assays, the follicular fluid from grades I and II embryos was significantly higher than the follicular fluid from grades III and IVembryos. The lower control limit of DPPH radical scavenging capacity and upper control limit of ROS level were 13.2% and 109.0 cps, respectively. The calculated lower control limit and upper control limit were further confirmed in the follicular fluid of embryos of all grades. These cut-off values of free radical scavenging activity of follicular fluid could assist embryologists in choosing the development of embryos in PCOS patients undergoing IVF.

Antioxidant properties of a radical-scavenging peptide purified from enzymatically prepared fish skin gelatin hydrolysate.

Science.gov (United States)

Mendis, Eresha; Rajapakse, Niranjan; Kim, Se-Kwon

2005-02-09

Hoki (Johnius belengerii) skin gelatin was hydrolyzed with three commercial enzymes to identify radical-scavenging potencies of derived peptides. Peptides derived from tryptic hydrolysate exhibited the highest scavenging activities on superoxide, carbon-centered 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assessed by ESR spectroscopy. Following consecutive chromatographic separations of tryptic hydroolysate, the peptide sequence His-Gly-Pro-Leu-Gly-Pro-Leu (797 Da) acted as a strong radical scavenger under studied conditions. Further, this peptide could act as an antioxidant against linoleic acid peroxidation and the activity was closer to the highly active synthetic antioxidant butylated hydroxytoluene (BHT). In addition, antioxidative enzyme levels in cultured human hepatoma cells were increased in the presence of this peptide and it was presumed to be the peptide involved in maintaining the redox balance in the cell environment. Present data indicate that free-radical-scavenging activities of hoki skin gelatin peptides substantially contribute to their antioxidant properties measured in different oxidative systems.

Chemical Constituents with Free-Radical-Scavenging Activities from the Stem of Microcos paniculata

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Yu Chen

2010-08-01

Full Text Available The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate (ABTS and Co (II EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc extract showed the highest free-radical-scavenging activity compared with the other three (n-BuOH, water and petroleum ether extracts. Free-radical-scavenging assay-guided chromatographic separation of the EtOAc extract, using a normal-phase and reverse-phase silica gel column chromatography yielded five compounds: a new triterpene named methyl 3b-O-p-hydroxy-E-cinnamoyloxy-2a,23-dihydroxyolean-12-en-28-oate (1, whose spectral data are presented for the first time, together with four known compounds, epicatechin (2, 3-trans-feruloyl maslinic acid (3, maslinic acid (4 and sucrose (5. All of the compounds were isolated from Microcos paniculata for the first time. The compounds were identified by spectroscopic methods. Among them, compound 2 displayed significant free-radical-scavenging activity which is similar to that of standard antioxidant ascorbic acid (VC and therefore may be a promising natural antioxidant.

Free radical scavenging and cytotoxic activity of five commercial ...

African Journals Online (AJOL)

Polygonum cuspidatum), and pomegranate (Punica granatum). It shows radical scavenging activity in the following order, according to their median effective concentration (EC

Invertebrates outcompete vertebrate facultative scavengers in simulated lynx kills in the Bavarian Forest National Park, Germany

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Ray, R.–R.

2014-06-01

Full Text Available Understanding the role of scavengers in ecosystems is important for species conservation and wildlife management. We used road–killed animals, 15 in summer 2003 (June–August and nine in winter 2003/2004 (from November to January, to test the following hypotheses: (1 vertebrate scavengers such as raven (Corvus corax, red fox (Vulpes vulpes and wild boar (Sus scrofa consume a higher proportion of the carcasses than invertebrates; (2 the consumption rate is higher in winter than in summer due to the scarcity of other food resources; and (3 vertebrate scavengers are effective competitors of Eurasian lynx. We monitored 65 animals belonging to eight different mammal and bird species with camera traps. Surprisingly, Eurasian lynx (Lynx lynx was the most important vertebrate scavenger. However, in both seasons, the consumption of vertebrate scavengers was of minor impact. In summer, the carcasses were completely consumed within 10 days, mostly by invertebrates. In winter, only 5% of the carcasses were consumed within 10 days and 16% within 15 days. We conclude that vertebrates in the Bavarian Forest National Park are not strong competitors for lynx.

Efficient scavenging of β-carotene radical cations by antiinflammatory salicylates

DEFF Research Database (Denmark)

Cheng, Hong; Liang, Ran; Han, Rui-Min

2014-01-01

by the anion of salicylic acid with 2.2 × 10 L mol s, but still of possible importance for light-exposed tissue. Surprisingly, acetylsalicylate, the aspirin anion, reacts with an intermediate rate in a reaction assigned to the anion of the mixed acetic-salicylic acid anhydride formed through base induced......The radical cation generated during photobleaching of β-carotene is scavenged efficiently by the anion of methyl salicylate from wintergreen oil in a second-order reaction approaching the diffusion limit with k = 3.2 × 10 L mol s in 9:1 v/v chloroform-methanol at 23 °C, less efficiently...... rearrangements. The relative scavenging rate of the β-carotene radical cation by the three salicylates is supported by DFT-calculations....

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.).

Science.gov (United States)

Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo

2005-04-06

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.

Effects of Scavenging System Configuration on In-Cylinder Air Flow Organization of an Opposed-Piston Two-Stroke Engine

Directory of Open Access Journals (Sweden)

Fukang Ma

2015-06-01

Full Text Available In-cylinder air flow is very important from the point of view of mixture formation and combustion. In this direction, intake chamber structure and piston crown shape play a very crucial role for in-cylinder air pattern of opposed-piston two-stroke (OP2S engines. This study is concerned with the three-dimensional (3D computational fluid dynamics (CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the zero-dimensional (0D parametric model. Three configurations viz., a flat piston uniform scavenging chamber, a flat piston non-uniform scavenging chamber and a pit piston non-uniform scavenging chamber have been studied. 0D model analysis of in-cylinder air flow is consistent with 3D CFD simulation. It is concluded that a pit piston non-uniform scavenging chamber is the best design from the point of view of tumble ratio, turbulent kinetic energy and turbulent intensity, which play very important roles in imparting proper air motion. Meanwhile a flat piston uniform scavenging chamber can organize a higher swirl ratio and lower tumble ratio which is important to improve the scavenging process.

Scavenging of particulate elemental carbon into stratus cloud

Energy Technology Data Exchange (ETDEWEB)

Kaneyasu, Naoki; Maeda, Takahisa [National Inst. for Resources and Environment, Tsukuba (Japan)

1995-12-31

The role of atmospheric aerosols on the alternation of cloud radiative properties has widely been recognized since 1977 when Tomey and his coworkers have numerically demonstrated the effect of increased cloud condensation nuclei (CCN). At the same time, cloud processes are one of the most important factor in controlling the residence time of atmospheric aerosols through the wet removal process. The redistribution of the size and the composition of pre-cloud aerosols is also the important role of cloud process on the nature of atmospheric aerosols. In order to study these cloud-aerosol interaction phenomena, the incorporation of aerosols into cloud droplets is the first mechanism to be investigated. Among the several mechanisms for the incorporation of aerosols into cloud droplets, nucleation scavenging, is the potentially important process in the view of cloud-aerosol interactions. This critical supersaturation for a given radius of a particle can be theoretically calculated only for pure species, e.g., NaCl. However, a significant portion of the atmospheric aerosols is in the form of internal mixture of multiple components, such as SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +} and particulate elemental carbon. The knowledge acquired by field measurements is therefore essential on this subject. The present study focuses on the scavenging of major components of urban atmospheric aerosols, in particular the incorporation of particulate elemental carbon into stratus cloud. Particulate elemental carbon is the strongest light absorbing species in visible region, and has potential to change the optical property of cloud. On the basis of the measurements conducted at a mountain located in the suburb of Tokyo Metropolitan area, Japan, some insights on the scavenging of particulate elemental carbon into cloud droplet will be presented

Scavenging of particulate elemental carbon into stratus cloud

Energy Technology Data Exchange (ETDEWEB)

Kaneyasu, Naoki; Maeda, Takahisa [National Inst. for Resources and Environment, Tsukuba (Japan)

1996-12-31

The role of atmospheric aerosols on the alternation of cloud radiative properties has widely been recognized since 1977 when Tomey and his coworkers have numerically demonstrated the effect of increased cloud condensation nuclei (CCN). At the same time, cloud processes are one of the most important factor in controlling the residence time of atmospheric aerosols through the wet removal process. The redistribution of the size and the composition of pre-cloud aerosols is also the important role of cloud process on the nature of atmospheric aerosols. In order to study these cloud-aerosol interaction phenomena, the incorporation of aerosols into cloud droplets is the first mechanism to be investigated. Among the several mechanisms for the incorporation of aerosols into cloud droplets, nucleation scavenging, is the potentially important process in the view of cloud-aerosol interactions. This critical supersaturation for a given radius of a particle can be theoretically calculated only for pure species, e.g., NaCl. However, a significant portion of the atmospheric aerosols is in the form of internal mixture of multiple components, such as SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +} and particulate elemental carbon. The knowledge acquired by field measurements is therefore essential on this subject. The present study focuses on the scavenging of major components of urban atmospheric aerosols, in particular the incorporation of particulate elemental carbon into stratus cloud. Particulate elemental carbon is the strongest light absorbing species in visible region, and has potential to change the optical property of cloud. On the basis of the measurements conducted at a mountain located in the suburb of Tokyo Metropolitan area, Japan, some insights on the scavenging of particulate elemental carbon into cloud droplet will be presented

Radiation therapy and concurrent fixed dose amifostine with escalating doses of twice-weekly gemcitabine in advanced pancreatic cancer

International Nuclear Information System (INIS)

Yavuz, A. Aydin; Aydin, Fazil; Yavuz, Melek N.; Ilis, Esra; Ozdemir, Feyyaz

2001-01-01

Purpose: To determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of twice-weekly gemcitabine (TW-G) when administered in conjunction with fixed dose amifostine (A) during external radiotherapy (RT) in patients with advanced pancreatic cancer. Methods and Materials: Ten patients with previously untreated, locally advanced, or asymptomatic-metastatic pancreatic adenocarcinoma were enrolled in this study. RT was delivered by using the standard four-field technique (1.8 Gy daily fractions, 45 Gy followed by a boost of 5.4 Gy, in 5-1/2 weeks). The starting dose of TW-G was 60 mg/m 2 (i.v., 30-min infusion), which is equal to the upper limit of previously reported MTD of TW-G when given without A during RT. A was given just before the TW-G, at a fixed dose of 340 mg/m 2 (i.v., rapid infusion). TW-G doses were escalated by 30-mg/m 2 increments in successive cohorts of 3 to 6 additional patients until DLT was observed. Toxicities were graded using the Radiation Therapy Oncology Group and National Cancer Institute Common Toxicity Criteria, version 2.0. Results: In general, therapy was well tolerated in patients treated at the first two dose levels of 60 mg/m 2 and 90 mg/m 2 . The DLT of TW-G given in conjunction with A during RT were neutropenia, thrombocytopenia, and nausea/vomiting at the dose level of 120 mg/m 2 . Of the 10 patients eligible for a median follow-up of 10 months, 5 remain alive; 1 complete responder, 3 partial responders, and 1 with stable disease. Conclusion: A dose of TW-G at a level of 90 mg/m 2 produced tolerable toxicity and it may possess significant activity when delivered in conjunction with 340 mg/m 2 dose of A during RT of the upper abdomen. Due to the higher MTD of TW-G seen in our study, we consider that the A supplementation may optimize the therapeutic index of TW-G-based chemoradiotherapy protocols in patients with pancreatic carcinoma

Demonstration of physical phenomenas and scavenging activity from d-psicose and methionine maillard reaction products

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Arum Tiyas Suminar

2017-01-01

Full Text Available Maillard reaction has been well understood as a non-enzymatic reaction between reducing sugars and amino acids to generate the Maillard reaction products (MRPs. This study is aimed to demonstrate the browning intensity, color development, spectra measurements, scavenging activity, and the correlation between browning intensity and scavenging activity of the MRPs generated from D-Psicose and Methionine (Psi-Met at 50℃. The browning intensity of MRPs was investigated based on the absorbance using spectrophotometer at 420 nm, the color development was observed using digital colorimeter to gained L*a*b* value then calculated as browning index, the spectra development was analyzed using spectrophotometer at 190 - 750 nm, and the scavenging activity was determined with ABTS method using spectrophotometer at 734 nm. The browning intensity, color development, and scavenging activity were improved along with the increase in heating process. Based on spectra analysis, MRPs from Psi-Met was initially detected at 21 h and Psi at 24 h of heating treatment, which indicating that Psi-Met have faster and better reaction than Psi during heating process. Positive non-linear and significant correlation between browning intensity and scavenging activity were assigned. This finding may provide beneficial information of D-psicose and MRPs to the next scientific research and to the food industries which applies MRPs in their products.

Effects of white rice, brown rice and germinated brown rice on antioxidant status of type 2 diabetic rats.

Science.gov (United States)

Imam, Mustapha Umar; Musa, Siti Nor Asma; Azmi, Nur Hanisah; Ismail, Maznah

2012-10-10

Oxidative stress is implicated in the pathogenesis of diabetic complications, and can be increased by diet like white rice (WR). Though brown rice (BR) and germinated brown rice (GBR) have high antioxidant potentials as a result of their bioactive compounds, reports of their effects on oxidative stress-related conditions such as type 2 diabetes are lacking. We hypothesized therefore that if BR and GBR were to improve antioxidant status, they would be better for rice consuming populations instead of the commonly consumed WR that is known to promote oxidative stress. This will then provide further reasons why less consumption of WR should be encouraged. We studied the effects of GBR on antioxidant status in type 2 diabetic rats, induced using a high-fat diet and streptozotocin injection, and also evaluated the effects of WR, BR and GBR on catalase and superoxide dismutase genes. As dietary components, BR and GBR improved glycemia and kidney hydroxyl radical scavenging activities, and prevented the deterioration of total antioxidant status in type 2 diabetic rats. Similarly, GBR preserved liver enzymes, as well as serum creatinine. There seem to be evidence that upregulation of superoxide dismutase gene may likely be an underlying mechanism for antioxidant effects of BR and GBR. Our results provide insight into the effects of different rice types on antioxidant status in type 2 diabetes. The results also suggest that WR consumption, contrary to BR and GBR, may worsen antioxidant status that may lead to more damage by free radicals. From the data so far, the antioxidant effects of BR and GBR are worth studying further especially on a long term to determine their effects on development of oxidative stress-related problems, which WR consumption predisposes to.

Effects of White Rice, Brown Rice and Germinated Brown Rice on Antioxidant Status of Type 2 Diabetic Rats

Directory of Open Access Journals (Sweden)

Maznah Ismail

2012-10-01

Full Text Available Oxidative stress is implicated in the pathogenesis of diabetic complications, and can be increased by diet like white rice (WR. Though brown rice (BR and germinated brown rice (GBR have high antioxidant potentials as a result of their bioactive compounds, reports of their effects on oxidative stress-related conditions such as type 2 diabetes are lacking. We hypothesized therefore that if BR and GBR were to improve antioxidant status, they would be better for rice consuming populations instead of the commonly consumed WR that is known to promote oxidative stress. This will then provide further reasons why less consumption of WR should be encouraged. We studied the effects of GBR on antioxidant status in type 2 diabetic rats, induced using a high-fat diet and streptozotocin injection, and also evaluated the effects of WR, BR and GBR on catalase and superoxide dismutase genes. As dietary components, BR and GBR improved glycemia and kidney hydroxyl radical scavenging activities, and prevented the deterioration of total antioxidant status in type 2 diabetic rats. Similarly, GBR preserved liver enzymes, as well as serum creatinine. There seem to be evidence that upregulation of superoxide dismutase gene may likely be an underlying mechanism for antioxidant effects of BR and GBR. Our results provide insight into the effects of different rice types on antioxidant status in type 2 diabetes. The results also suggest that WR consumption, contrary to BR and GBR, may worsen antioxidant status that may lead to more damage by free radicals. From the data so far, the antioxidant effects of BR and GBR are worth studying further especially on a long term to determine their effects on development of oxidative stress-related problems, which WR consumption predisposes to.

Studies on free radical scavenging activity in Chinese seaweeds part I. Screening results

Science.gov (United States)

Yan, Xiao-Jun; Fang, Guo-Ming; Lou, Qing-Xiang

1999-09-01

Antioxidants have attracted the attention of researchers due to their beneficial effects as free radical scavengers. Application of a stable free radical named 1, 1-diphenyl-2-picrylhydrazyl(DPPH) to screen the free radical scavenging activity in 27 species of Chinese seaweed showed that 15 of them had significant activity in at least one of the organic solvent extracts. The most interesting seaweed species were Gelidium amansii, Gloiosiphonia capillaris, Polysiphonia urceolata, Sargassum kjellmanianum, Desmarestia viridis, and Rhodomela teres.

How Predictability of Feeding Patches Affects Home Range and Foraging Habitat Selection in Avian Social Scavengers?

NARCIS (Netherlands)

Monsarrat, S.; Benhamou, S.; Sarrazin, F.; Bessa-Gomes, C.; Bouten, W.; Duriez, O.

2013-01-01

Feeding stations are commonly used to sustain conservation programs of scavengers but their impact on behaviour is still debated. They increase the temporal and spatial predictability of food resources while scavengers have supposedly evolved to search for unpredictable resources. In the Grands

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity.

Science.gov (United States)

Li, Qing; Sun, Xueqi; Gu, Guodong; Guo, Zhanyong

2018-03-28

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating "click reaction" with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC 50 radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains.

Radical scavenging compounds from the aerial parts of ...

African Journals Online (AJOL)

Results: The ethyl acetate and n-butanol fractions were the most active fractions and contained apigenin, apigenin glucuronide, luteolin, caffeic acid, methyl caffeate, rosmarinic acid and methyl rosmarinate as the radical scavenging compounds with EC50 values of 26.67 ± 0.31, 185.89 ± 1.02, 5.35 ± 0.31, 3.92 ± 0.06, ...

Genetic Variant of the Scavenger Receptor BI in Humans

NARCIS (Netherlands)

Vergeer, Menno; Korporaal, Suzanne J. A.; Franssen, Remco; Meurs, Illiana; Out, Ruud; Hovingh, G. Kees; Hoekstra, Menno; Sierts, Jeroen A.; Dallinga-Thie, Geesje M.; Motazacker, Mohammad Mahdi; Holleboom, Adriaan G.; van Berkel, Theo J. C.; Kastelein, John J. P.; van Eck, Miranda; Kuivenhoven, Jan Albert

2011-01-01

BACKGROUND In mice, the scavenger receptor class B type I (SR-BI) is essential for the delivery of high-density lipoprotein (HDL) cholesterol to the liver and steroidogenic organs. Paradoxically, elevated HDL cholesterol levels are associated with increased atherosclerosis in SR-BI-knockout mice. It

Genetic variant of the scavenger receptor BI in humans

NARCIS (Netherlands)

Vergeer, Menno; Korporaal, Suzanne J A; Franssen, Remco; Meurs, Illiana; Out, Ruud; Hovingh, G Kees; Hoekstra, Menno; Sierts, Jeroen A; Dallinga-Thie, Geesje M; Motazacker, Mohammad Mahdi; Holleboom, Adriaan G; Van Berkel, Theo J C; Kastelein, John J P; Van Eck, Miranda; Kuivenhoven, Jan Albert

2011-01-01

BACKGROUND: In mice, the scavenger receptor class B type I (SR-BI) is essential for the delivery of high-density lipoprotein (HDL) cholesterol to the liver and steroidogenic organs. Paradoxically, elevated HDL cholesterol levels are associated with increased atherosclerosis in SR-BI-knockout mice.

In vitro antioxidant and free radical scavenging activity of different parts of Tabebuia pallida growing in Bangladesh.

Science.gov (United States)

Rahman, Md Mahbubur; Islam, Md Badrul; Biswas, Mohitosh; Khurshid Alam, A H M

2015-10-30

In humans, many diseases are associated with the accumulation of free radicals. Antioxidants can scavenge free radicals and minimize their impact. Therefore, the search for naturally occurring antioxidants of plant origin is imperative. Here, we aimed to investigate the antioxidant and free radical scavenging properties of methanolic extracts from Tabebuia pallida (T. pallida) stem bark (TPSB), root bark (TPRB), leaves (TPL), and flowers (TPF). The antioxidant and free radical scavenging activity were determined by several standard methods using spectrophotomer. Total phenolic and flavonoid contents were estimated using Folin-Ciocalteu reagent and aluminum chloride colorimetric assay methods, respectively. Among the extracts, TPL showed the highest total antioxidant capacity followed by TPRB, TPF, and TPSB. Based on DPPH and hydroxyl radical scavenging activity, TPL showed strong scavenging activity (91.05 ± 1.10 and 62.00 ± 0.57) with IC50 of 9.20 ± 0.28 and 46.00 ± 2.84 μg/mL, respectively when compared with standard BHT (IC50 of 7.00 ± 0.25 μg/mL) and CA (75.00 ± 0.14 μg/mL). These results suggest that TPL had the highest radical scavenging activity among the extractives that closely resembled the standard's. In lipid peroxidation inhibition assay, TPL exhibited the most potent inhibitory activity (83.18 ± 2.12 %) with IC50 of 12.00 ± 2.12 μg/mL, which closely resembled standard CA (IC50 of 10.50 ± 0.28 μg/mL). Also, the reducing capacity on ferrous ion was in the following order: TPL > TPRB > TF > TPSB. The phenolic and flavonoid contents of TPL were higher than other extractives. A positive correlation (p value free radical (DPPH(·) and (·)OH) scavenging efficiencies and lipid peroxidation inhibition activity. Methanolic extract of T. pallida leaf is a potential source of natural antioxidants and serves as an effective free radical scavenger and/or inhibitor. Hence, T. pallida might be a good plant-based pharmaceutical product for several

Evaluation of antioxidant, free radical scavenging and antimicrobial, activity of Quercus incana Roxb.

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Rizwana eSarwar

2015-11-01

Full Text Available Considering the indigenous utilization of Quercus incana Roxb., the present study deals with the investigation of antioxidant, free radical scavenging activity, total phenolic content and antimicrobial activity of Quercus incana Roxb. In vitro antioxidant activity of the plant fractions were determined by DPPH and NO scavenging method. Total phenolic contents were determined by gallic acid equivalent (GAE and antimicrobial activities were determined by agar well diffusion method. It was observed that Quercus incana Roxb. showed significant antibacterial activity against Gram-positive and Gram-negative bacteria. n-Butanol fraction showed maximum activity against Micrococcus leuteus with 19 mm zone of inhibition. n-Butanol fraction of Quercus incana Roxb. showed immense antifungal activity against Aspergillus niger (32 mm ± 0.55 and Aspergillus flavus (28 mm ± 0.45. Similarly n-butanol fraction showed relatively good antioxidant activity with IC50 value of 55.4 ± 0.21μg/mL. The NO scavenging activity of ethyl acetate fraction (IC50 = 23.21 ± 0.31 μg/mL was fairly good compared to other fractions. The current study of Quercus incana Roxb. suggests the presences of synergetic action of some biological active compounds that may be present in the leaves of medicinal plant. Further studies are needed to better characterize the important active constituents responsible for the antimicrobial, antioxidant and free radical scavenging activity.

Lipid organics in background aerosols, cloudwater, and snow and implication for organic scavenging

International Nuclear Information System (INIS)

Groellert, C.

1998-01-01

During three years free tropospheric snow, aerosol, and cloudwater samples were collected at Mount Sonnblick, Austria, at an elevation of 3106 m a.s.l. The samples were analyzed for their lipid organic trace components using extraction with n-hexane as sample pretreatment and gas chromatography-mass spectrometry-flame ionization detection for identification and quantification of the substances. The main components identified in all the samples were the phthalic acid esters which are of anthropogenic origin. Of further interest were aliphatic alcohols (not detected in aerosols) and phenols. They are of biogenic origin. The concentrations were found to be higher in spring than in the fall season. To compare the concentrations of aerosol, cloudwater and snow samples scavenging ratios (aerosol to snow), scavenging efficiencies (aerosol to cloud) and cloud to snow ratios were calculated for the first time for organic compounds. Scavenging ratios were 10 to 100 times lower, scavenging efficiencies 2 to 10 times lower than sulfate. This can result from the poor watersolubility of the compounds or from gas phase sorptions on the filter surface (overestimation of aerosol concentrations). The cloud to snow ratios were generally higher than for sulfate. However, a few components exhibited very low cloud to snow ratios which might be due to additional sources in snow for these substances (alcohols). (author)

Highly functionalized piperidines: Free radical scavenging, anticancer activity, DNA interaction and correlation with biological activity

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Suvankar Das

2018-01-01

Full Text Available Twenty-five piperidines were studied as potential radical scavengers and antitumor agents. Quantitative interaction of compounds with ctDNA using spectroscopic techniques was also evaluated. Our results demonstrate that the evaluated piperidines possesses different abilities to scavenge the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH and the anion radical superoxide (·O2−. The piperidine 19 was the most potent radical DPPH scavenger, while the most effective to ·O2− scavenger was piperidine 10. In general, U251, MCF7, NCI/ADR-RES, NCI-H460 and HT29 cells were least sensitive to the tested compounds and all compounds were considerably more toxic to the studied cancer cell lines than to the normal cell line HaCaT. The binding mode of the compounds and ctDNA was preferably via intercalation. In addition, these results were confirmed based on theoretical studies. Finally, a linear and exponential correlation between interaction constant (Kb and GI50 for several human cancer cell was observed.

Scavenger Receptors and Resistance to Inhaled Allergens

Science.gov (United States)

2010-02-01

throughput manner which will enable future studies. We plan to continue two especially interesting aspects of these studies. First, the epigenetic control...directs mod- ified proteins to antigen presentation. Eur. J. Immunol. 29: 512–521. 30. Granucci, F., F. Petralia, M. Urbano , S. Citterio, F. Di Tota, L...11 Suppl:S32-6. 50. Granucci F, Petralia F, Urbano M, Citterio S, Di Tota F, Santambrogio L, Ricciardi-Castagnoli P: The scavenger receptor MARCO

Comparative investigation of the free radical scavenging potential and anticancer property of Diospyros blancoi (Ebenaceae

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Muhammad Ali Khan

2016-05-01

Conclusions: Our results indicate that Diospyros blancoi stem bark had the significant highest antioxidant and free radical scavenging properties as well as moderate anticancer activity. Hence, we assume that the anticancer activity of this plant can be, at least in part, attributed to its content in phenolic compounds as well as its significant free radical scavenging properties.

Clustered DNA damage on subcellular level: effect of scavengers

Czech Academy of Sciences Publication Activity Database

Pachnerová Brabcová, Kateřina; Sihver, L.; Yasuda, N.; Matuo, Y.; Štěpán, Václav; Davídková, Marie

2014-01-01

Roč. 53, č. 4 (2014), s. 705-712 ISSN 0301-634X R&D Projects: GA MŠk LD12008 Institutional support: RVO:61389005 Keywords : clustered damage * indirect effects * haevy ion * plasmid in liquid water * scavenger Subject RIV: BO - Biophysics Impact factor: 1.528, year: 2014

Antioxidant and Free Radical Scavenging Capacity of Seed and Shell Essential Oils Extracted from Abrus precatorius (L

Directory of Open Access Journals (Sweden)

Sunday O. Okoh

2014-04-01

Full Text Available Essential oils from plants have been proven safe as natural antioxidants, and few are already marketed as digestive enhancers as well as in prevention of several degenerative diseases. This study evaluated the antioxidant capacity of seed and shell essential oils of Abrus precatorius (L, a herb used for ethno-medicinal practices in Nigeria. The essential oils were obtained by hydro-distillation. The ability of the oils to act as hydrogen/electrons donor or scavenger of radicals were determined by in-vitro antioxidant assays using 2,2-diphenyl-2-picryl-hydrazyl free radical (DPPH. scavenging; 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS radical scavenging; lipid peroxide and nitric oxide radicals scavenging assays. The IC50 of the seed and shell oils (2.10 mg/mL and 1.20 mg/mL respectively showed that antioxidant activity is higher than that for the standard drugs (3.20 mg/mL and 3.40 mg/mL for the nitric oxide scavenging assay. The lipid peroxidation radical activity of the oils were similar to vitamin C, weak DPPH and ABTS radical scavenging activities were discovered in comparison to vitamin C and rutin. Generally, in the four antioxidant assays, a significant correlation existed between concentrations of the oils and percentage inhibition of free radicals and lipid peroxidation. The composition of A. precatorius essential oils reported earlier may account for their antioxidant capacity.

Free Radical Scavenging Activity of Scoparia dulcis Extract.

Science.gov (United States)

Babincová, M.; Sourivong, P.

2001-01-01

We studied the scavenging capabilities of an extract of Scoparia dulcis (a cosmopolitan weed widespread in Laos and Vietnam) for 1-diphenyl-2-picrylhydrazyl and measured hemoglobin-catalyzed linoleic acid peroxidation with an oxygen electrode. Our results demonstrated strong antioxidant activity corresponding to mitigation of the generation of hydroxyl radicals, a possible rationale for the observed therapeutic effects of this weed.

Evaluation of Antioxidant and Free Radical Scavenging Abilities of ...

African Journals Online (AJOL)

Objective: This study was aimed at determining the antioxidants and free radical scavenging abilities of some packaged fruit juices (PFJ) widely used as source of fluids in Nigeria. Materials and methods: Packaged fruit juice samples produced by The Coca cola Company and Chi company namely: Apple(AP), blackcurrant, ...

Antioxidant and free radical scavenging activities of plant extracts ...

African Journals Online (AJOL)

Twenty-two species of medicinal plants collected in the Mexican state of Morelos were selected to evaluate their free radical scavenging and antioxidant activities. The extracts from the aerial parts of the plants were obtained using hexane, acetone and methanol (66 extracts). The initial qualitative screening of antioxidants ...

Free radical scavenging and COX-2 inhibition by simple colon metabolites of polyphenols: A theoretical approach.

Science.gov (United States)

Amić, Ana; Marković, Zoran; Marković, Jasmina M Dimitrić; Jeremić, Svetlana; Lučić, Bono; Amić, Dragan

2016-12-01

Free radical scavenging and inhibitory potency against cyclooxygenase-2 (COX-2) by two abundant colon metabolites of polyphenols, i.e., 3-hydroxyphenylacetic acid (3-HPAA) and 4-hydroxyphenylpropionic acid (4-HPPA) were theoretically studied. Different free radical scavenging mechanisms are investigated in water and pentyl ethanoate as a solvent. By considering electronic properties of scavenged free radicals, hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms are found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of free radicals indicates 3-HPAA and 4-HPPA as potent scavengers. Their reactivity toward free radicals was predicted to decrease as follows: hydroxyl>alkoxyls>phenoxyl≈peroxyls>superoxide. Shown free radical scavenging potency of 3-HPAA and 4-HPPA along with their high μM concentration produced by microbial colon degradation of polyphenols could enable at least in situ inactivation of free radicals. Docking analysis with structural forms of 3-HPAA and 4-HPPA indicates dianionic ligands as potent inhibitors of COX-2, an inducible enzyme involved in colon carcinogenesis. Obtained results suggest that suppressing levels of free radicals and COX-2 could be achieved by 3-HPAA and 4-HPPA indicating that these compounds may contribute to reduced risk of colon cancer development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Is the scavenger receptor MARCO a new immune checkpoint?

Science.gov (United States)

Arredouani, Mohamed S

2014-11-01

Whereas macrophages use the scavenger receptor MARCO primarily in antimicrobial immunity by interacting with both exogenous and endogenous environments, in dendritic cells (DCs) MARCO is believed to pleiotropically link innate to adaptive immunity. MARCO exerts a significant modulatory effect on TLR-induced DC activation, thus offering novel avenues in cancer immunotherapy.

Scavenger receptor AI/II truncation, lung function and COPD

DEFF Research Database (Denmark)

Thomsen, M; Nordestgaard, B G; Tybjaerg-Hansen, A

2011-01-01

The scavenger receptor A-I/II (SRA-I/II) on alveolar macrophages is involved in recognition and clearance of modified lipids and inhaled particulates. A rare variant of the SRA-I/II gene, Arg293X, truncates the distal collagen-like domain, which is essential for ligand recognition. We tested whet...

Hydroxyl radical-scavenging property of secoisolariciresinol diglucoside (SDG) isolated from flax-seed.

Science.gov (United States)

Prasad, K

1997-03-01

Recently there has been a moderate resurgence in the use of flax-seed in a variety of ways including bread. The scientific basis of its use is very limited. There is some claim for beneficial effects in cancer and lupus nephritis. These claims could be due to its ability to scavenge oxygen radicals. However, its antioxidant activity is not known. Recently a method has been developed to isolate secoisolariciresinol diglucoside (SDG) from defatted flax-seed in large quantity (patent pending). We investigated the ability of SDG to scavenge .OH using high pressure liquid chromatography (HPLC) method. .OH was generated by photolysis of H2O2 (1.25-10.0 mumoles/ml) with ultraviolet light and was trapped with salicylic acid which is hydroxylated to produce .OH-adduct products 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA. H2O2 produced a concentration-dependent .OH as estimated by 2,3-DHBA and 2,5-DHBA. A standard curve was constructed for known concentrations of 2,3-DHBA and 2,5-DHBA against corresponding area under the peaks which then was used for measurement of 2,3-DHBA and 2,5-DHBA generated by UV irradiation of H2O2 in the presence of salicylic acid. SDG in the concentration range of 25, 50, 100, 250, 500, 750, 1000 and 2000 micrograms/ml (36.4, 72.8, 145.6, 364.0, 728.0, 1092.0, 1456.0 and 2912.0 microM respectively) produced a concentration-dependent decrease in the formation of 2,3-DHBA and 2,5-DHBA, the inhibition being 4 and 4.65% respectively with 25 micrograms/ml (36.4 microM) and 82 and 74% respectively with 2000 micrograms/ml (2912.0 microM). The decrease in .OH-adduct products was due to scavenging of .OH and not by scavenging of formed 2,3-DHBA and 2,5-DHBA. SDG prevented the lipid peroxidation of liver homogenate in a concentration-dependent manner in the concentration range from 319.3-2554.4 microM. These results suggest that SDG scavenges .OH and therefore has an antioxidant activity.

Scavenger removal: Bird and bat carcass persistence in a tropical wind farm

Science.gov (United States)

Villegas-Patraca, Rafael; Macías-Sánchez, Samuel; MacGregor-Fors, Ian; Muñoz-Robles, Carlos

2012-08-01

Energy produced by wind farms has diverse positive environmental effects, but can also be related to negative impacts, including wildlife mortality through collisions with wind turbines. Bird and bat mortality caused by collisions with wind turbines can be estimated indirectly by counting carcasses within wind farms. However, carcass removal by scavengers often biases such measurements. In this study, we identified the main scavengers removing bird and bat carcasses in a tropical wind farm. A known fate analysis was done to assess the effect of carcass type (i.e., small bird, large bird, bat), vegetation type (i.e., secondary vegetation, croplands) and season (dry and rainy seasons of 2009) on carcass persistence rates. We identified three main scavenger groups, with mammals being the most abundant group. Our results show high rates of carcass removal relative to previous studies, especially for bats; there were fewer remaining carcasses after 20 days in our tropical site than in non-tropical environments reported elsewhere. We found a higher carcass persistence rate during the rainy season than in the dry season, possibly due to a greater abundance of food resources for scavenger organisms in the rainy season. Although we found some evidence for higher persistence rates for large bird carcasses than for small bird and bat carcasses during the rainy season, overall carcass type was not a strong predictor of persistence rates. Similarly, we did not find a strong effect of vegetation type on carcass persistence rates. Results suggest that in order to estimate accurate bird and bat mortality in tropical wind farm areas, seasonality should be incorporated to correction factors of carcass removal rates.

The efficacy of edaravone (radicut), a free radical scavenger, for cardiovascular disease.

Science.gov (United States)

Kikuchi, Kiyoshi; Tancharoen, Salunya; Takeshige, Nobuyuki; Yoshitomi, Munetake; Morioka, Motohiro; Murai, Yoshinaka; Tanaka, Eiichiro

2013-07-04

Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone.

Microglial Scavenger Receptors and Their Roles in the Pathogenesis of Alzheimer's Disease

Directory of Open Access Journals (Sweden)

Kim Wilkinson

2012-01-01

Full Text Available Alzheimer’s disease (AD is increasing in prevalence with the aging population. Deposition of amyloid-β (Aβ in the brain of AD patients is a hallmark of the disease and is associated with increased microglial numbers and activation state. The interaction of microglia with Aβ appears to play a dichotomous role in AD pathogenesis. On one hand, microglia can phagocytose and clear Aβ, but binding of microglia to Aβ also increases their ability to produce inflammatory cytokines, chemokines, and neurotoxic reactive oxygen species (ROS. Scavenger receptors, a group of evolutionally conserved proteins expressed on the surface of microglia act as receptors for Aβ. Of particular interest are SCARA-1 (scavenger receptor A-1, CD36, and RAGE (receptor for advanced glycation end products. SCARA-1 appears to be involved in the clearance of Aβ, while CD36 and RAGE are involved in activation of microglia by Aβ. In this review, we discuss the roles of various scavenger receptors in the interaction of microglia with Aβ and propose that these receptors play complementary, nonredundant functions in the development of AD pathology. We also discuss potential therapeutic applications for these receptors in AD.

Free radical scavenging activity of coenzyme Q measured by a chemiluminescent assay

International Nuclear Information System (INIS)

Battino, Maurizio; Ferri, Elida; Girotti, Stefano; Lenaz, Giorgio

1991-01-01

Involvement of coenzyme Q (CoQ) in anti-oxydant activities, in addition to its major redox role, has frequently been suggested in recent years. In order to elucidate if CoQ could really be engaged in scavenging free radicals produced endogenously in a biological system, an experimental system was developed in which beef heart mitochondria in the presence of a saturating NADH concentration and of rotenone produce free radicals. The presence of oxygen-reactive forms was easily detected by a luminol-dependent chemiluminescence process. The chemi-luminescence assay showed that short-chain CoQ homologues can act as pro-oxidants, enhancing free radical effects, while exogenous coenzyme Q 10 could scavenge free radicals, especially at very low concentration. In this system, exogenous CoQ 10 was more effective than α-tocopherol at the same concentration in scavenging free radicals. The molecular mechanism that leads to this activity is still unclear, but these results are of biochemical importance because they indicate that CoQ may act as an anti=oxidant in situations mimicking physiopathological conditions. This direct chemiluminescent method is promising for studies of biochemical processes which involve active oxygen species. (author). 24 refs.; 4 figs

Sensitization to heat by the polyamines and their analogs

Energy Technology Data Exchange (ETDEWEB)

Fuller, D.J.; Gerner, E.W.

1983-07-01

The polyamines putrescine, spermidine, and spermine have been shown to sensitize Chinese hamster ovary (CHO) cells to the cytotoxic effects of elevated temperatures. This sensitization occurs in the order spermine greater than spermidine greater than putrescine. A series of homologs of the diamine putrescine demonstrated little variance in the degree of potentiation until a chain length equivalent to that of spermidine was employed (1,8-diaminooctane). Two compounds bearing structural similarities to spermidine gave rather different results when combined with heat. Methylglyoxal bis(guanylhydrazone) (MGBG), an antiproliferative drug, sensitized cells to heat, while S-2-(3-aminopropylamino)-ethyl phosphoric acid (WR-2721), a radioprotector, had no measureable effect on 43 degrees C-induced cytotoxicity. Together, these results point out the primary importance of two terminal amino groups separated by either carbon, or carbon and nitrogen, atoms in an aliphatic chain in the observed sensitization of heat-induced cytotoxicity by polyamines. These data suggest specific dimensional characteristics of the presumed negatively charged structure(s) with which the polyamines are interacting to elicit this effect.

Scavenging capacity of medicinal plants against free radical-induced cellular damage by radiation and photoactivation

Energy Technology Data Exchange (ETDEWEB)

Gadkar, Shalaka [Ruia College, Mumbai (India); Mohan, H [Chemistry Group, Bhabha Atomic Research Centre, Mumbai (India); Kamat, J P [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

2004-01-01

The scavenging capacity of medicinal plants. Andrographis paniculata (Ap) and Swertia chirata (Sc) was examined against cellular damage, induced by radiation and photo-activation in sub-cellular membranes. The results demonstrated significant radical scavenging capacity of the extracts. The rate constants as evaluated by deoxyribose degradation studies and the pulse radiolysis studies carried in presence of ABTS radical well supported the antioxidant properties of the extracts. (author)

The oxygen-centered radicals scavenging activity of sulfasalazine and its metabolites. A direct protection of the bowel.

Science.gov (United States)

Prónai, L; Yukinobu, I; Láng, I; Fehér, J

1992-01-01

Oxygen-centered radicals, such as superoxide (O2-) and hydroxyl radicals (.OH) generated by phagocytes have been suggested to be involved in the pathogenesis of chronic inflammations of the bowel, such as Crohn's disease and colitis ulcerosa. Recently, sulfasalazine (SASP) and its metabolites have been reported to exert their effects as a direct scavenger of oxygen-centered radicals in the bowel. To scavenge oxygen-centered radicals in vivo, however, SASP and its metabolites have to react with O2- and/or .OH in vitro very rapidly, furthermore they have to reach an appropriate (possible millimolar) concentration range at the site of inflammation. To test this possibility, we investigated the direct O2- and .OH scavenging activity of SASP and its metabolites using the specific electron paramagnetic resonance/spin trapping method, and we compared the 50% inhibition rates of SASP and its metabolites with their known concentrations in the bowel and in the human plasma. It was found that SASP and its metabolites, such as 5-amino-salicylic acid (5-ASA), and acetyl-5-amino-salicylic acid (AC-5-ASA), but not sulfapyridine (SP) and acetyl-sulfapyridine (Ac-SP) have a direct O2- and .OH scavenging activity in vitro systems. Among the compounds, SASP and 5-ASA can reach a concentration which is appropriate to scavenge oxygen-centered radicals in the bowel but not in the human plasma. It was concluded that the in vivo antiinflammatory effects of SASP and its metabolites are, at least partly, due to the direct oxygen-centered scavenging activity of these drugs.

Scavenger receptors in human airway epithelial cells: role in response to double-stranded RNA.

Directory of Open Access Journals (Sweden)

Audrey Dieudonné

Full Text Available Scavenger receptors and Toll-like receptors (TLRs cooperate in response to danger signals to adjust the host immune response. The TLR3 agonist double stranded (dsRNA is an efficient activator of innate signalling in bronchial epithelial cells. In this study, we aimed at defining the role played by scavenger receptors expressed by bronchial epithelial cells in the control of the innate response to dsRNA both in vitro and in vivo. Expression of several scavenger receptor involved in pathogen recognition was first evaluated in human bronchial epithelial cells in steady-state and inflammatory conditions. Their implication in the uptake of dsRNA and the subsequent cell activation was evaluated in vitro by competition with ligand of scavenger receptors including maleylated ovalbumin and by RNA silencing. The capacity of maleylated ovalbumin to modulate lung inflammation induced by dsRNA was also investigated in mice. Exposure to tumor necrosis factor-α increased expression of the scavenger receptors LOX-1 and CXCL16 and the capacity to internalize maleylated ovalbumin, whereas activation by TLR ligands did not. In contrast, the expression of SR-B1 was not modulated in these conditions. Interestingly, supplementation with maleylated ovalbumin limited dsRNA uptake and inhibited subsequent activation of bronchial epithelial cells. RNA silencing of LOX-1 and SR-B1 strongly blocked the dsRNA-induced cytokine production. Finally, administration of maleylated ovalbumin in mice inhibited the dsRNA-induced infiltration and activation of inflammatory cells in bronchoalveolar spaces and lung draining lymph nodes. Together, our data characterize the function of SR-B1 and LOX-1 in bronchial epithelial cells and their implication in dsRNA-induced responses, a finding that might be relevant during respiratory viral infections.

Hydroxyl radical scavenging activity of peptide from sea cucumber ...

African Journals Online (AJOL)

enzyme complex, sea cucumber protein hydrolysis was carried out to obtain hydrolysates that have hydroxyl-radical-scavenging activity (HRSA). The hydrolytic process was monitored by HRSA and conditions for this process were optimized as follows: pH 6.5, temperature 35°C, 12 mg enzyme complex in a reaction solution ...

The scavenging of volatile anesthetic agents in the cardiovascular intensive care unit environment: a technical report.

Science.gov (United States)

Pickworth, Thomas; Jerath, Angela; DeVine, Rita; Kherani, Nazmin; Wąsowicz, Marcin

2013-01-01

The use of volatile-based sedation within critical care environments has been limited by difficulties of drug administration and safety concerns over environment pollution and staff exposure in an intensive care unit (ICU) with no scavenging. The aim of this study was to develop a simple scavenging system to be used with the Anesthesia Conserving Device (AnaConDa(®)) and to determine whether or not ambient concentrations of residual anesthetic are within current acceptable limits. The scavenging system consists of two Deltasorb(®) canisters attached to the ICU ventilator in series. AnaConDa is a miniature vaporizer designed to provide volatile-based sedation within an ICU. The first ten patients recruited into a larger randomized trial assessing outcomes after elective coronary graft bypass surgery were sedated within the cardiac ICU using either isoflurane or sevoflurane. Sedation was guided by the Sedation Agitation Scale, resulting in an end-tidal minimum anesthetic concentration of volatile agent ranging from 0.1-0.3. At one hour post ICU admission, infrared photometric analysis was used to assess environmental contamination at four points along the ventilator circuit and scavenging system and around the patient's head. All measurements taken within the patient's room were below 1 part per million, which satisfies criteria for occupational exposure. This study shows that volatile agents can be administered safely within critical care settings using a simple scavenging system. Our scavenging system used in conjunction with the AnaConDa device reduced the concentration of environmental contamination to a level that is acceptable to Canadian standards and standards in most Western countries and thus conforms to international safety standards. The related clinical trial was registered at www.clinicaltrials.gov (NCT01151254).

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity

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Qing Li

2018-03-01

Full Text Available Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating “click reaction” with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC50 < 0.01 mg mL−1 was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains.

An anaerobic bacterium, Bacteroides thetaiotaomicron, uses a consortium of enzymes to scavenge hydrogen peroxide

Science.gov (United States)

Mishra, Surabhi; Imlay, James A.

2013-01-01

Summary Obligate anaerobes are periodically exposed to oxygen, and it has been conjectured that on such occasions their low-potential biochemistry will predispose them to rapid ROS formation. We sought to identify scavenging enzymes that might protect the anaerobe Bacteroides thetaiotaomicron from the H2O2 that would be formed. Genetic analysis of eight candidate enzymes revealed that four of these scavenge H2O2 in vivo: rubrerythrins 1 and 2, AhpCF, and catalase E. The rubrerythrins served as key peroxidases under anoxic conditions. However, they quickly lost activity upon aeration, and AhpCF and catalase were induced to compensate. The AhpCF is an NADH peroxidase that effectively degraded low micromolar levels of H2O2, while the catalytic cycle of catalase enabled it to quickly degrade higher concentrations that might arise from exogenous sources. Using a non-scavenging mutant we verified that endogenous H2O2 formation was much higher in aerated B. thetaiotaomicron than in Escherichia coli. Indeed, the OxyR stress response to H2O2 was induced when B. thetaiotaomicron was aerated, and in that circumstance this response was necessary to forestall cell death. Thus aeration is a serious threat for this obligate anaerobe, and to cope it employs a set of defenses that includes a repertoire of complementary scavenging enzymes. PMID:24164536

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

Science.gov (United States)

Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

2015-01-01

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

Efficient Scavenging of Solar and Wind Energies in a Smart City.

Science.gov (United States)

Wang, Shuhua; Wang, Xue; Wang, Zhong Lin; Yang, Ya

2016-06-28

To realize the sustainable energy supply in a smart city, it is essential to maximize energy scavenging from the city environments for achieving the self-powered functions of some intelligent devices and sensors. Although the solar energy can be well harvested by using existing technologies, the large amounts of wasted wind energy in the city cannot be effectively utilized since conventional wind turbine generators can only be installed in remote areas due to their large volumes and safety issues. Here, we rationally design a hybridized nanogenerator, including a solar cell (SC) and a triboelectric nanogenerator (TENG), that can individually/simultaneously scavenge solar and wind energies, which can be extensively installed on the roofs of the city buildings. Under the same device area of about 120 mm × 22 mm, the SC can deliver a largest output power of about 8 mW, while the output power of the TENG can be up to 26 mW. Impedance matching between the SC and TENG has been achieved by using a transformer to decrease the impedance of the TENG. The hybridized nanogenerator has a larger output current and a better charging performance than that of the individual SC or TENG. This research presents a feasible approach to maximize solar and wind energies scavenging from the city environments with the aim to realize some self-powered functions in smart city.

Extracts, Anthocyanins and Procyanidins from Aronia melanocarpa as Radical Scavengers and Enzyme Inhibitors

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Hilde Barsett

2013-03-01

Full Text Available Extracts, subfractions, isolated anthocyanins and isolated procyanidins B2, B5 and C1 from the berries and bark of Aronia melanocarpa were investigated for their antioxidant and enzyme inhibitory activities. Four different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH radical, inhibition of 15-lipoxygenase (15-LO, inhibition of xanthine oxidase (XO and inhibition of α-glucosidase. Among the anthocyanins, cyanidin 3-arabinoside possessed the strongest and cyanidin 3-xyloside the weakest radical scavenging and enzyme inhibitory activity. These effects seem to be influenced by the sugar units linked to the anthocyanidin. Subfractions enriched in procyanidins were found to be potent α-glucosidase inhibitors; they possessed high radical scavenging properties, strong inhibitory activity towards 15-LO and moderate inhibitory activity towards XO. Trimeric procyanidin C1 showed higher activity in the biological assays compared to the dimeric procyanidins B2 and B5. This study suggests that different polyphenolic compounds of A. melanocarpa can have beneficial effects in reducing blood glucose levels due to inhibition of α-glucosidase and may have a potential to alleviate oxidative stress.

Numerical modeling of aerosol particles scavenging by drops as a process of air depollution

OpenAIRE

Cherrier , Gaël

2017-01-01

This PhD-Thesis is dedicated to the numerical modeling of aerosol particles scavenging by drops. Investigated situations are about aerosol particles of aerodynamic diameter ranging from 1 nm to 100 µm captured in the air by water drops of diameter varying between 80 µm and 600 µm, with corresponding droplet Reynolds number ranging between 1 and 100. This air depollution modeling is achieved in two steps. The first step consists in obtaining a scavenging kernel predicting the flow rate of aero...

Anti-oxidation and scavenging effects of some extracts from Chinese medicines on free radicals

International Nuclear Information System (INIS)

Wang Chongdao; Qiang Yizhong; Lao Qinhua; Cui Fengmei; Shao Yuan; Sun Cunpu

1999-11-01

The inhibiting effects of Chinonin, Quercetin and Tannic Acid on the lipid oxidation induced by radiation exposure were investigated by means of a modified TBA spectrophotometry. The scavenging effects on free radicals caused by γ-irradiation exposure of the three active principles were observed by technique of ESR. The results showed that anti-oxidation effects of Chinonin and Quercetin were better than that of Tannic Acid, while the scavenging effects of the three active principles on free radicals were similar

Extraction method for high free radical scavenging activity of Siamese neem tree flowers

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Worarat Chaisawangwong

2009-10-01

Full Text Available Siamese neem tree (Azadirachta indica A. Juss. var. siamensis Valeton is a medicinal plant found in Thailand. Youngleaves and young flowers of this plant are commonly consumed as a bitter tonic vegetable. The flowers are also used fortreatment of fever. The flower extract has been reported to exhibit in vitro free radical scavenging activity and can inhibitlipid peroxidation of bronchogenic cancer cell line. Active compounds in the flowers are flavonoids such as rutin andquercetin. The content of these compounds in the crude extract depends on the method of extraction. Therefore, the appropriateextraction method promoting high yield of total flavonoids and high free radical scavenging activity was investigated inthis study. Six different extraction methods, i.e. maceration, percolation, decoction, soxhlet extraction, ultrasonic extraction(UE, and microwave assisted extraction (MA were carried out for extracting dried powder of Siamese neem tree young flowers. The solvent used for maceration, percolation, and soxhlet extraction was 50% ethanol, while distilled water was used for decoction and MA, and both solvents were used for UE. The content of crude extract, free radical scavenging activity, and total flavonoids content of each extract were investigated and compared. Comparing the various extraction methods, decoction provided an extract containing a high amount of total flavonoids (17.54 mgRE/g extract and promoting the highest scavenging activity at EC50 11.36 g/ml. Decoction is also simple, cheap, and convenient and could be used in developing countries. Thus, it should be the recommended extraction method for the flowers of Siamese neem tree for furtherdevelopment of antioxidant pharmaceutical preparations.

Parameter Optimization on the Uniflow Scavenging System of an OP2S-GDI Engine Based on Indicated Mean Effective Pressure (IMEP

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Fu-Kang Ma

2017-03-01

Full Text Available In this paper, an opposed-piston two-stroke (OP2S gasoline direct injection (GDI engine is introduced and its working principles and scavenging process were analyzed. An optimization function was established to optimize the scavenging system parameters, include intake port height, exhaust port height, intake port circumference ratio, the exhaust port circumference ratio and opposed-piston motion phase difference. The effect of the port height on the effective compression ratio and effective expansion ratio were considered, and indicated mean effective pressure (IMEP was employed as the optimization objective instead of scavenging efficiency. Orthogonal experiments were employed to reduce the calculation work. The effect of the scavenging parameters on delivery ratio, trapping ratio, scavenging efficiency and indicated thermal efficiency were calculated, and the best parameters were also obtained by the optimization function. The results show that IMEP can be used as the optimization objective in the uniflow scavenging system; intake port height is the main factor to the delivery ratio, while exhaust port height is the main to engine trapping ratio, scavenging efficiency and indicated thermal efficiency; exhaust port height is the most important factor to effect the gas exchange process of OP2S-GDI engine.

Scavenger Receptor BI Plays a Role in Facilitating Chylomicron Metabolism

NARCIS (Netherlands)

Out, R.; Kruijt, J.K.; Rensen, P.C.N.; Hildebrand, R.B.; Vos, P. de; Eck, M. van; Berkel, T.J.C. van

2004-01-01

The function of scavenger receptor class B type I (SR-BI) in mediating the selective uptake of high density lipoprotein (HDL) cholesterol esters is well established. However, the potential role of SR-BI in chylomicron and chylomicron remnant metabolism is largely unknown. In the present

Hypolipidemic activity of Phellinus rimosus against triton WR-1339 and high cholesterol diet induced hyperlipidemic rats.

Science.gov (United States)

Rony, K A; Ajith, T A; Nima, N; Janardhanan, K K

2014-03-01

Patients with the risk for atherosclerotic disease will be targeted to reduce the existing hyperlipidemia. The hypolipidemic activity of Phellinus rimosus was studied using triton WR-1339 and high cholesterol diet (HCD) induced models. The triton induced elevated lipid profile was attenuated by P. rimosus or standard drug atorvastatin. Similarly, administration of P. rimosus along with HCD significantly decline serum triglyceride, total cholesterol, low-density lipoprotein, with elevating the high-density lipoprotein. Thiobarbituric acid reacting substances in heart and liver significantly decreased; where as activity of enzymatic antioxidants and level of reduced glutathione were significantly increased. In both models, P. rimosus extract showed a significant ameliorative effect on the elevated atherogenic index as well as LDL/HDL-C ratio. The hypolipidemic activity of P. rimosus can be ascribed to its inhibitory effect on the liver HMG CoA reductase activity. The results suggest the possible therapeutic potential of this fungus as hypolipidemic agent. Copyright © 2014 Elsevier B.V. All rights reserved.

High risk of lead contamination for scavengers in an area with high moose hunting success.

Science.gov (United States)

Legagneux, Pierre; Suffice, Pauline; Messier, Jean-Sébastien; Lelievre, Frédérick; Tremblay, Junior A; Maisonneuve, Charles; Saint-Louis, Richard; Bêty, Joël

2014-01-01

Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans) and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax), captured during the moose (Alces alces) hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg x L(-1), more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus), golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern) scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting.

High risk of lead contamination for scavengers in an area with high moose hunting success.

Directory of Open Access Journals (Sweden)

Pierre Legagneux

Full Text Available Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax, captured during the moose (Alces alces hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg x L(-1, more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus, golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting.

Radical-scavenging-linked antioxidant activities of extracts from black chokeberry and blueberry cultivated in Korea.

Science.gov (United States)

Hwang, Seok Joon; Yoon, Won Byong; Lee, Ok-Hwan; Cha, Seung Ju; Kim, Jong Dai

2014-03-01

The objective of this study was to investigate the radical-scavenging-linked antioxidant properties of the extracts from black chokeberry and blueberry cultivated in Korea. The 70% ethanol extracts were prepared from black chokeberry and blueberry, and evaluated for total phenolic content, total flavonoid content, total proanthocyanidin content, and antioxidative activities, using various in vitro assays, such as DPPH(2,2-diphenyl-1-picrylhydrazyl), ABTS(2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulphonic acid)) radical-scavenging activity, FRAP(ferric-reducing antioxidant power) and reducing power. The major phenolic compounds, including cyanidin-3-galactoside, cyanidin-3-arabinoside, neochlorogenic acid, procyanidin B1, were analysed by HPLC with a photodiode array detector. Results showed that total phenol, flavonoid and proanthocyanidin contents of black chokeberry extract were higher than those of blueberry extract. In addition, black chokeberry extract exhibited higher free radical-scavenging activity and reducing power than did blueberry extract. Cyanidin-3-galactoside was identified as a major phenolic compound, with considerable content in black chokeberry, that correlated with its higher antioxidant and radical-scavenging effects. These results suggest that black chokeberry extracts could be considered as a good source of natural antioxidants and functional food ingredients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simulation for estimation of hydrogen sulfide scavenger injection dose rate for treatment of crude oil

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T.M. Elshiekh

2015-12-01

Full Text Available The presence of hydrogen sulfide in the hydrocarbon fluids is a well known problem in many oil and gas fields. Hydrogen sulfide is an undesirable contaminant which presents many environmental and safety hazards. It is corrosive, malodorous, and toxic. Accordingly, a need has been long left in the industry to develop a process which can successfully remove hydrogen sulfide from the hydrocarbons or at least reduce its level during the production, storage or processing to a level that satisfies safety and product specification requirements. The common method used to remove or reduce the concentration of hydrogen sulfide in the hydrocarbon production fluids is to inject the hydrogen sulfide scavenger into the hydrocarbon stream. One of the chemicals produced by the Egyptian Petroleum Research Institute (EPRI is EPRI H2S scavenger. It is used in some of the Egyptian petroleum producing companies. The injection dose rate of H2S scavenger is usually determined by experimental lab tests and field trials. In this work, this injection dose rate is mathematically estimated by modeling and simulation of an oil producing field belonging to Petrobel Company in Egypt which uses EPRI H2S scavenger. Comparison between the calculated and practical values of injection dose rate emphasizes the real ability of the proposed equation.

The Efficacy of Edaravone (Radicut, a Free Radical Scavenger, for Cardiovascular Disease

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Eiichiro Tanaka

2013-07-01

Full Text Available Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone.

Free-Radical-Scavenging, Antityrosinase, and Cellular Melanogenesis Inhibitory Activities of Synthetic Isoflavones.

Science.gov (United States)

Lu, Tzy-Ming; Ko, Horng-Huey; Ng, Lean-Teik; Hsieh, Yen-Pin

2015-06-01

In this study, we examined the potential of synthetic isoflavones for application in cosmeceuticals. Twenty-five isoflavones were synthesized and their capacities of free-radical-scavenging and mushroom tyrosinase inhibition, as well as their impact on cell viability of B16F10 murine melanoma cells and HaCaT human keratinocytes were evaluated. Isoflavones that showed significant mushroom tyrosinase inhibitory activities were further studied on reduction of cellular melanin formation and antityrosinase activities in B16F10 melanocytes in vitro. Among the isoflavones tested, 6-hydroxydaidzein (2) was the strongest scavenger of both ABTS(.+) and DPPH(.) radicals with SC50 values of 11.3 ± 0.3 and 9.4 ± 0.1 μM, respectively. Texasin (20) exhibited the most potent inhibition of mushroom tyrosinase (IC50 14.9 ± 4.5 μM), whereas retusin (17) showed the most efficient inhibition both of cellular melanin formation and antityrosinase activity in B16F10 melanocytes, respectively. In summary, both retusin (17) and texasin (20) exhibited potent free-radical-scavenging capacities as well as efficient inhibition of cellular melanogenesis, suggesting that they are valuable hit compounds with potential for advanced cosmeceutical development. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Preparation of Egg White Liquid Hydrolysate (ELH) and Its Radical-Scavenging Activity

Science.gov (United States)

Noh, Dong Ouk; Suh, Hyung Joo

2015-01-01

In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of α-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of α-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and α-amino nitrogen content after 24 h-hydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (P<0.05) higher after enzymatic digestion. These results suggest that active peptides released from egg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products. PMID:26451355

Particle scavenging in a cylindrical ultrasonic standing wave field using levitated drops

Science.gov (United States)

Merrell, Tyler; Saylor, J. R.

2015-11-01

A cylindrical ultrasonic standing wave field was generated in a tube containing a flow of particles and fog. Both the particles and fog drops were concentrated in the nodes of the standing wave field where they combined and then grew large enough to fall out of the system. In this way particles were scavenged from the system, cleaning the air. While this approach has been attempted using a standing wave field established between disc-shaped transducers, a cylindrical resonator has not been used for this purpose heretofore. The resonator was constructed by bolting three Langevin transducers to an aluminum tube. The benefit of the cylindrical geometry is that the acoustic energy is focused. Furthermore, the residence time of the particle in the field can be increased by increasing the length of the resonator. An additional benefit of this approach is that tubes located downstream of the resonator were acoustically excited, acting as passive resonators that enhanced the scavenging process. The performance of this system on scavenging particles is presented as a function of particle diameter and volumetric flow rate. It is noted that, when operated without particles, the setup can be used to remove drops and shows promise for liquid aerosol retention from systems where these losses can be financially disadvantageous and/or hazardous.

Extraction and free radical scavenging activity of polysaccharide from 'Anji Baicha' (Camellia sinensis (L.) O. Kuntze).

Science.gov (United States)

Zhang, Zhongshan; Wang, Xiaomei; Li, Jingfen; Wang, Guozhi; Mao, Genxiang

2016-03-01

In this study, the optimization of the extraction conditions of polysaccharide from 'Anji Baicha' (Camellia sinensis (L.) O. Kuntze) (AP) was investigated by response surface methodology (RSM). Three main independent variables (extraction temperature, time, ratio of water to raw material) were taken into consideration. And then the free radical scavenging activities of the sample were investigated including scavenging effects of superoxide and hydroxyl radicals. The RSM analysis showed good correspondence between experimental and predicted values.. The optimal condition to obtain the highest yield of AP was determined as follows: temperature 76.79 °C, time 2.48 h, ratio of water to material 22.53 mL/g. For the free radical scavenging activity, the IC50 values of Vc and AP were 7.78 and 83.25 μg/mL. And for the scavenging effect on hydroxyl radical, that of AP and Vc were 1.80 and 1.69 mg/mL. AP showed excellent antioxidant activity. This exhibited AP had a good potential for antioxidant. The purification and structure needs to be study in further. Copyright © 2015 Elsevier B.V. All rights reserved.

Isolation and characterisation of in vitro and cellular free radical scavenging peptides from corn peptide fractions.

Science.gov (United States)

Wang, Liying; Ding, Long; Wang, Ying; Zhang, Yan; Liu, Jingbo

2015-02-16

Corn gluten meal, a corn processing industry by-product, is a good source for the preparation of bioactive peptides due to its special amino acid composition. In the present study, the in vitro and cellular free radical scavenging activities of corn peptide fractions (CPFs) were investigated. Results indicated that CPF1 (molecular weight less than 1 kDa) and CPF2 (molecular weight between 1 and 3 kDa) exhibited good hydroxyl radical, superoxide anion radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Meanwhile, the in vitro radical scavenging activity of CPF1 was slightly higher than that of CPF2. Both CPF1 and CPF2 also exhibited significant cytoprotective effects and intracellular reactive oxygen species scavenging activity in Caco-2 cells exposed to hydrogen peroxide (H2O2). The amino acid composition analysis revealed that the CPF were rich in hydrophobic amino acids, which comprised of more than 45% of total amino acids. An antioxidant peptide sequence of Tyr-Phe-Cys-Leu-Thr (YFCLT) was identified from CPF1 using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI TOF/TOF MS). The YFCLT exhibited excellent ABTS radical scavenging activity with a 50% effective concentration (EC50) value of 37.63 µM, which was much lower than that of Trolox. In conclusion, corn gluten meal might be a good source to prepare antioxidant peptides.

Radical-Scavenging Compounds from Olive Tree (Olea europaea L.) wood

NARCIS (Netherlands)

Pérez-Bonilla, M.; Salido, S.; Beek, van T.A.; Altarejos, J.

2014-01-01

The purpose of this study was to complete knowledge on the chemical composition and radical-scavenging activity of olive tree wood. Two new monoterpene glycosides, (-)-oleuropeic acid 6'-O-a-d-glucopyranosyl ester (6a) and (-)-perillic acid 1'-O-ß-d-primeverosyl ester (8), together with the known

In vitro anti-inflammatory and free radical scavenging activities of ...

African Journals Online (AJOL)

Methods: In vitro antioxidant activity was determined using free radical scavenging assays such as DPPH, ABTS and NO2. The antiinflammatory potential was carried out using inhibition of protein denaturation of egg albumin as a model of anti-inflammatory capacity. Results: Both the crude methanolic extract and saponins ...

Turbulent swirling flow in a dynamic model of a uniflow-scavenged two-stroke engine

DEFF Research Database (Denmark)

Ingvorsen, Kristian Mark; Meyer, Knud Erik; Walther, Jens Honore

2014-01-01

turbulence models. In the present work, the flow in a dynamic scale model of a uniflowscavenged cylinder is investigated experimentally. The model has a transparent cylinder and a moving piston driven by a linear motor. The flow is investigated using phase-locked stereoscopic particle image velocimetry (PIV...... cannot be assumed to be quasi-steady. The temporal development of the swirl strength is investigated by computing the angular momentum. The swirl strength shows an exponential decay from scavenge port closing to scavenge port opening corresponding to a reduction of 34 %, which is in good agreement...

The Evolution of the Scavenger Receptor Cysteine-Rich Domain of the Class A Scavenger Receptors

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Nicholas eYap

2015-07-01

Full Text Available The class A Scavenger Receptor (cA-SR family is a group of five evolutionarily related innate immune receptors. The cA-SRs are known for their promiscuous ligand binding; as they have been shown to bind bacteria such as Streptococcus pneumoniae, and Escherichia coli, as well as different modified forms of low-density lipoprotein. Three of the five family members possess a Scavenger Receptor Cysteine Rich (SRCR domain while the remaining two receptors lack the domain. Previous work has suggested that the Macrophage Associated Receptor with COllagenous structure (MARCO shares a recent common ancestor with the non-SRCR-containing receptors; however the origin of the SRCR domain within the cA-SRs remains unknown. We hypothesize that the SRCR domains of the cA-SRs have a common origin that predates teleost fish. Using the newly available sequence data from sea lamprey and ghost shark genome projects, we have shown that MARCO shares a common ancestor with the SRCR-containing proteins. In addition, we explored the evolutionary relationships within the SRCR domain by reconstructing the ancestral SRCR domains of the cA-SRs. We identified a motif that is highly conserved between the cA-SR SRCR domains and the ancestral SRCR domain that consist of WGTVCDD. We also show that the GRAEVYY motif, a functionally important motif within MARCO, is poorly conserved in the other cA-SRs and in the reconstructed ancestral domain. Further, we identified three sites within MARCO’s SRCR domain which are under positive selection. Two of these sites lie adjacent to the conserved WGTVCDD motif, and may indicate a potential biological function for these sites. Together these findings indicate a common origin of the SRCR domain within the cA-SRs; however different selective pressures between the proteins may have caused MARCOs SRCR domain to evolve to contain different functional motifs when compared to the other SRCR-containing cA-SRs.

Mercury transfer from fish carcasses to scavengers in boreal lakes: the use of stable isotopes of mercury

International Nuclear Information System (INIS)

Sarica, Jose; Amyot, Marc; Hare, Landis; Blanchfield, Paul; Bodaly, R.A.; Hintelmann, Holger; Lucotte, Marc

2005-01-01

Scavengers play an important role in the flow of energy, matter and pollutants through food webs. For methylmercury (MeHg), which biomagnifies along food chains, the movement of this metal from fish carcasses to aquatic scavengers has never been demonstrated. We measured the transfer of MeHg from fish carcasses to scavenging leeches in two lakes and in the laboratory. The results of a field experiment indicated that leeches were attracted to fish carcasses and that their Hg concentrations increased by as much as a factor of 5 during the time that Hg-rich fish were available for consumption. Under controlled conditions, we exposed leeches to 202 Hg-labelled fish that had been marked in situ following a whole lake 202 Hg addition. Leeches rapidly accumulated Hg from carcasses, and within two weeks assumed the isotopic signature of the carcasses. Necrophagous invertebrates could therefore return Hg from fish carcasses to other trophic levels in lakes. - Scavengers such as leeches accumulate mercury from fish carcasses which then may return into the food web

A new method for measuring scavenging activity of antioxidants to the hydroxyl radical formed by gamma-irradiation

International Nuclear Information System (INIS)

Yoshioka, Hiroe; Ohashi, Yasunori

2000-01-01

A new method using ESR spin trapping was proposed for measuring scavenging activity of antioxidants to the hydroxyl (OH) radical. (-)-epigallocatechin gallate (EGCg) and 5,5-dimethyl-l-pyrroline N-oxide (DMPO) were used as an antioxidant and a spin trapping agent, respectively. Conventional method using a Fenton reaction had some defects on the estimation of the activity, because antioxidant disturbed the generating system of OH radical besides it scavenged the spin adduct (DMPO-OH). This method used intense γ-irradiation as OH radical generating system, and the intensity decrease of DMPO-OH after the end of the irradiation was followed to obtain the rate constant of the scavenging of DMPO-OH with EGCg and to estimate the quantity of DMPO-OH formed during γ-irradiation. By using these values, the reaction rate constant between OH radical and EGCg was calculated as a ratio to that of DMPO. It was shown that this method is useful to compare precisely the OH radical scavenging activity of various antioxidants. (author)

Remarks relating to field experiments to measure the wet scavenging of tracer aerosols

International Nuclear Information System (INIS)

Stensland, G.J.

1977-12-01

An important question is whether or not the wet deposition of debris from a single (or multiple) airburst of a nuclear device poses a significant hazard to people on the ground. To answer this question for various scenarios, a basic understanding of the aerosol attachment rates to cloud water and raindrops is needed. The attachment rates can then be incorporated into the cloud physics scavenging models to make intelligent assessments. In order to gain an initial impression as to the importance (order of magnitude) of the wet scavenging effects and to provide the data to validate the cloud scavenging models, tracer release field experiments are useful and necessary. The major purpose of this report is to address questions related to the operation and interpretation of such field tracer efforts and in particular to consider the results from the August 3, 1972, Battelle Northwest Laboratory tracer experiment in St. Louis. The Battelle experiment involved the release of several aerosol tracers at 10,000 to 13,000 feet, near rain clouds, and the measurement of the resulting tracer in the rain collected at the ground level sampling sites

Phytochemical Analysis and Free Radical Scavenging Activity of Medicinal Plants Gnidia glauca and Dioscorea bulbifera

Science.gov (United States)

Ghosh, Sougata; Derle, Abhishek; Ahire, Mehul; More, Piyush; Jagtap, Soham; Phadatare, Suvarna D.; Patil, Ajay B.; Jabgunde, Amit M.; Sharma, Geeta K.; Shinde, Vaishali S.; Pardesi, Karishma; Dhavale, Dilip D.; Chopade, Balu A.

2013-01-01

Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS•+ and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS•+ radical with a second order rate constant of 2.33×106 and 1.72×106, respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48×106 and 4.46×106 were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C27H42O3) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important medicinal plants. PMID:24367520

Direct degradation of dyes by piezoelectric fibers through scavenging low frequency vibration

Science.gov (United States)

Zhu, Ruijian; Xu, Yunhua; Bai, Qing; Wang, Zengmei; Guo, Xinli; Kimura, Hideo

2018-06-01

A newly discovered nanometer material-mediated piezoelectrochemical (PZEC) for the direct conversion of mechanical energy to chemical energy has attracted increasing attention, for its great potential to be a green dye water decomposition technique. However, it is far from being a cost-effective and practical technique because only ultrasonic can be scavenged to decomposed organic pollutant in previous studies. Here, we prepared 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) piezoelectric fibers for the degradation of dye solution via slow stirring and studied the degradation mechanism. It provides a practical, green and low-cost method for decomposing organic dye by scavenging waste mechanical energy from the surrounding environment.

Mitochondrial respiration scavenges extramitochondrial superoxide anion via a nonenzymatic mechanism.

OpenAIRE

Guidot, D M; Repine, J E; Kitlowski, A D; Flores, S C; Nelson, S K; Wright, R M; McCord, J M

1995-01-01

We determined that mitochondrial respiration reduced cytosolic oxidant stress in vivo and scavenged extramitochondrial superoxide anion (O2-.) in vitro. First, Saccharomyces cerevisiae deficient in both the cytosolic antioxidant cupro-zinc superoxide dismutase (Cu,Zn-SOD) and electron transport (Rho0 state) grew poorly (P 0.05) in all yeast. Seco...

Ambient RF energy scavenging: GSM and WLAN power density measurements

NARCIS (Netherlands)

Visser, H.J.; Reniers, A.C.F.; Theeuwes, J.A.C.

2009-01-01

To assess the feasibility of ambient RF energy scavenging, a survey of expected power density levels distant from GSM-900 and GSM-1800 base stations has been conducted and power density measurements have been performed in a WLAN environment. It appears that for distances ranging from 25 m to 100 m

Preliminary assay on the radical scavenging activity of olive wood extracts

NARCIS (Netherlands)

Altarejos, J.; Salido, S.; Pérez-Bonilla, M.; Linares-Palomino, P.J.; Beek, van T.A.; Nogueras, M.; Sánchez, A.

2005-01-01

The dichloromethane and ethanol extracts of Olea europaea wood (picual olive cultivar) were screened for antioxidant activity, determined by the DPPH free radical scavenging assay. The ethanol extract displayed potent antioxidant activity. (c) 2005 Elsevier B.V. All rights reserved.

2,4,6-Trichlorophenylhydrazine Schiff bases as DPPH radical and super oxide anion scavengers.

Science.gov (United States)

Khan, Khalid Mohammed; Shah, Zarbad; Ahmad, Viqar Uddin; Khan, Momin; Taha, Muhammad; Rahim, Fazal; Ali, Sajjad; Ambreen, Nida; Perveen, Shahnaz; Choudhary, M Iqbal; Voelter, Wolfgang

2012-05-01

Syntheses of thirty 2,4,6-trichlorophenylhydrazine Schiff bases 1-30 were carried out and evaluated for their in vitro DPPH radical and super oxide anion scavenging activities. Compounds 1-30 have shown a varying degree of DPPH radical scavenging activity and their IC50 values range between 4.05-369.30 µM. The compounds 17, 28, 18, 14, 8, 15, 12, 2, 29, and 7 exhibited IC50 values ranging between 4.05±0.06-24.42±0.86 µM which are superior to standard n-propylgallate (IC50=30.12±0.27 µM). Selected compounds have shown a varying degree of superoxide anion radical scavenger activity and their IC50 values range between 91.23-406.90 µM. The compounds 28, 8, 17, 15, and 14, showed IC50 values between 91.23±1.2-105.31±2.29 µM which are superior to standard n-propylgallate (IC50=106.34±1.6 µM).

Synthesis and in Vitro Antioxidant Activity Evaluation of 3-Carboxycoumarin Derivatives and QSAR Study of Their DPPH• Radical Scavenging Activity

Directory of Open Access Journals (Sweden)

Maria Teresa Sumaya-Martínez

2012-12-01

Full Text Available The in vitro antioxidant activities of eight 3-carboxycoumarin derivatives were assayed by the quantitative 1,1-diphenyl-2-picrylhydrazil (DPPH• radical scavenging activity method. 3-Acetyl-6-hydroxy-2H-1-benzopyran-2-one (C1 and ethyl 6-hydroxy-2-oxo-2H-1-benzopyran-3-carboxylate (C2 presented the best radical-scavenging activity. A quantitative structure-activity relationship (QSAR study was performed and correlated with the experimental DPPH• scavenging data. We used structural, geometrical, topological and quantum-chemical descriptors selected with Genetic Algorithms in order to determine which of these parameters are responsible of the observed DPPH• radical scavenging activity. We constructed a back propagation neural network with the hydrophilic factor (Hy descriptor to generate an adequate architecture of neurons for the system description. The mathematical model showed a multiple determination coefficient of 0.9196 and a root mean squared error of 0.0851. Our results shows that the presence of hydroxyl groups on the ring structure of 3-carboxy-coumarins are correlated with the observed DPPH• radical scavenging activity effects.

Gallic Acid as an Oxygen Scavenger in Bio-Based Multilayer Packaging Films.

Science.gov (United States)

Pant, Astrid F; Sängerlaub, Sven; Müller, Kajetan

2017-05-03

Oxygen scavengers are used in food packaging to protect oxygen-sensitive food products. A mixture of gallic acid (GA) and sodium carbonate was used as an oxygen scavenger (OSc) in bio-based multilayer packaging films produced in a three-step process: compounding, flat film extrusion, and lamination. We investigated the film surface color as well as oxygen absorption at different relative humidities (RHs) and temperatures, and compared the oxygen absorption of OSc powder, monolayer films, and multilayer films. The films were initially brownish-red in color but changed to greenish-black during oxygen absorption under humid conditions. We observed a maximum absorption capacity of 447 mg O₂/g GA at 21 °C and 100% RH. The incorporation of GA into a polymer matrix reduced the rate of oxygen absorption compared to the GA powder because the polymer acted as a barrier to oxygen and water vapor diffusion. As expected, the temperature had a significant effect on the initial absorption rate of the multilayer films; the corresponding activation energy was 75.4 kJ/mol. Higher RH significantly increased the oxygen absorption rate. These results demonstrate for the first time the production and the properties of a bio-based multilayer packaging film with GA as the oxygen scavenger. Potential applications include the packaging of food products with high water activity (a w > 0.86).

An experimental evaluation of potential scavenger effects on snake road mortality detections

Science.gov (United States)

Hubbard, Kaylan A.; Chalfoun, Anna D.

2012-01-01

As road networks expand and collisions between vehicles and wildlife become more common, accurately quantifying mortality rates for the taxa that are most impacted will be critical. Snakes are especially vulnerable to collisions with vehicles because of their physiology and behavior. Reptile road mortality is typically quantified using driving or walking surveys; however, scavengers can rapidly remove carcasses from the road and cause underestimation of mortality. Our objective was to determine the effect that scavengers might have had on our ability to accurately detect reptile road mortality during over 150 h and 4,000 km of driving surveys through arid shrublands in southwest Wyoming, which resulted in only two observations of mortality. We developed unique simulated snake carcasses out of Burbot (Lota lota), a locally invasive fish species, and examined removal rates across three different road types at three study sites. Carcass size was not a significant predictor of time of removal, and carcass removal was comparable during the daytime and nighttime hours. However, removal of simulated carcasses was higher on paved roads than unpaved or two-track roads at all study sites, with an average of 75% of the carcasses missing within 60 h compared to 34% and 31%, respectively. Scavengers may therefore negatively impact the ability of researchers to accurately detect herpetofaunal road mortality, especially for paved roads where road mortality is likely the most prevalent.

Ground squirrel shooting and potential lead exposure in breeding avian scavengers

Science.gov (United States)

Herring, Garth; Eagles-Smith, Collin A.; Wagner, Mason T.

2016-01-01

Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding’s ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding’s ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson’s hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling’s mass, energy needs