Ionizing radiation-induced cancer: perplexities of the bystander effect.

Ionizing radiation (IR) is a carcinogen. This has been established beyond doubt from many years of studies such as those conducted among the survivors of the atomic bomb attacks on Hiroshima and Nagasaki and later from the Chernobyl accident. Despite immense progress in the field of carcinogenesis, complete understanding of the underlying mechanisms behind IR-induced cancer remains elusive. In particular, the long gestation period between exposure to IR and the onset of cancer, frequently unpredictable, and sometimes lasting for many years, remains poorly understood. The centrality of DNA damage and misrepair in carcinogenesis research has not entirely benefited IR-induced cancer research and the past decade has seen a shift in understanding radiation-driven cellular mechanisms beyond simplistic models of targeted DNA damage. This paper presents a viewpoint on the gaps in our knowledge of IR-induced cancer with a focus on the non-targeted bystander effect, the mechanisms underlying which may be key to radiotherapeutic advances.

Ni-Doped ZnO Thin Films: Deposition, Characterization and Photocatalytic Applications.

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10-3 and 1.14×10-3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.

Effects of copper on development and survival rate of Paphia malabarica Chemnitz larvae under low saline condition.

Venerid clam, Paphia malabarica Chemnitz, is the commercially exploited species distributed exclusively in Vembanad Lake and Ashtamudi estuary, along the south west coast of India. In this study, the survival rate and development of P. malabarica larvae were studied for 3 days in ambient salinity (33), copper (2.5 microg Cu2+ l(-1)), reduced salinities (25 and 20) and a combination of copper in low salinities. No significant differences were found in larval development between treatments. The survival rates decreased considerably with low salinities although the combination of copper and low salinity gave synergistic effects. The reduced survival in low salinities would limit population growth of this species in estuarine areas experiencing low salinities and also explains the absence of larval settlement on habitats close to harbors or river mouths.

(3R*,4R*,5S*)-4-(4-Methyl-phen-yl)-2,3-diphenyl-7-[(R*)-1-phenyl-ethyl]-1-oxa-2,7-diaza-spiro-[4.5]decan-10-one oxime.

In the title compound, C(34)H(35)N(3)O(2), the polysubstituted piperidine ring adopts a chair conformation and the isoxazolidine ring is in an envelope form. The mol-ecules are linked into a chain along the b axis by O-H⋯N, C-H⋯O and C-H⋯N inter-actions. The chains are cross-linked via weak C-H⋯π inter-actions.

A comparative study of patient-controlled epidural diamorphine, subcutaneous diamorphine and an epidural diamorphine/bupivacaine combination for postoperative pain.

This randomized double blind study investigates the relative efficacies of controlled analgesia (PCA) regimens in three different patient groups: epidural diamorphine 2.5 mg followed by PCA bolus 1 mg with a 20-min lockout (Gp1), subcutaneous diamorphine 2.5 mg followed by PCA bolus with a 10-min lockout period (Gp2) and epidural diamorphine 2.5 mg in 4 mL of 0.125% (w/v) bupivacaine followed by a PCA bolus of 1 mg diamorphine in 4 mL 0.125% (w/v) bupivacaine with a 20-min lockout (Gp3). Patients were evaluated at 0, 1, 2, 3, 4, 8, 12, 16, 20, 24 and 48 h. Patients in Gp2 consumed significantly more diamorphine than those in Gp1 or Gp3 (P < 0.05), but their pain scores were higher only at 1, 2 and 3 h (P < 0.05) with respect to Gp3 and at 1 h with respect to Gp1. Fewer side effects (sedation, pruritus and nausea as assessed by anti-emetic requirements) occurred in Gp2 compared to Gp1 (P < 0.05). Fewer patients in Gp2 required catheterization than in Gp3 (P < 0.05). This study indicates that the use of PCA epidural diamorphine, either alone or in combination with bupivacaine, reduces the dose requirement for analgesia but offers little clinical advantage over subcutaneous PCA diamorphine.

Bilirubin as an anti precipitant against copper mediated denaturation of bovine serum albumin: formation of copper-bilirubin complex.

BR forms a beautiful 1:1 greenish complex with Cu2+, having a characteristic absorption maximum at 343 nm. To our knowledge, this is the first metal complex of bilirubin in aqueous solution so far to be reported. It has also been shown that bilirubin (BR) at a concentration more than protein binding capacity has a definite role as an anti precipitant of bovine serum albumin by excess copper. At a concentration of 1 x 10(-3) moll-1 of the Cu-BR complex, the colour becomes greenish black. The rate of formation of this Cu-BR complex when BR extracts copper from copper-albumin complex as obtained in our experiment is 34.981 mol-1 s-1. The Cu-BR complex is stable at a pH ranging from 3.5 to 13.2, and also can scavenge radicals like CCl3OO., eaq- and OH.. Addition of excess copper sulfate to the solution of this complex causes a greenish black precipitate which can be re dissolved in HCl but insoluble in 99% ethanol. The complex does not give positive test in Gmelin reaction for bile pigments. The fluorescence spectrum of the complex in solution exhibits a peak at 450 nm when excited at 343 nm. The precipitated complex is insoluble in a number of solvents like ether, xylene, benzene, acetone, chloroform-methanol mixture and DMSO. These results show that BR may protect mammals from copper poisoning.

Hydrated Electrons in a Quaternary Microemulsion System: A Pulse Radiolysis Study

Using the technique of pulse radiolysis, hydrated electrons have been produced and studied in quaternary microemulsion (sodium lauryl sulfate (NaLS)/water/cyclohexane/1-pentanol) system. Remarkably high lifetimes ( approximately 20 &mgr;s) for hydrated electrons have been obtained. In general, these are two orders of magnitude higher than those reported earlier in reverse micelles. The water droplet sizes and location of the probes have been determined from the decay kinetics of hydrated electrons. The yields and half-lives (t 1/2 ) of the hydrated electrons vary smoothly as the water droplet sizes are changed. We believe that these studies will be useful not only in interpreting electron transfer reactions occurring in small water pockets in biological systems but also in the production of metal nanoclusters by radiation chemical method.

Oxidation reactions of a bovine serum albumin-bilirubin complex. A pulse radiolysis study.

Using the technique of pulse radiolysis, oxidation studies of the bovine serum albumin-bilirubin (BSA-BR) system with radicals like CCl3OO., N3., (SCN)2.-, Br2.- and OH. generated in neutral and alkaline medium are reported. In a neutral solution, BSA protects the bound BR very efficiently from the attack of these radicals. The experimental k/k' values for the reaction of CCl3OO., N3. and Br2.- radicals are 2.46, 1.78 and 2.55 respectively, where k and k' are the bimolecular rate constants for the formation of the semi-oxidized BSA and BR radicals respectively. The calculated ratios from our measurements of rate constants k and k' are 0.16, 0.28 and 1.38 for CCl3OO., N3. and Br2.- respectively. These values indicate protection of BR by BSA from free radical attack. For Br2.- radical-induced oxidation of the BSA-BR system, a radical transfer from protein to BR was observed. OH. shows very fast adduct formation with both BSA and BR. The bimolecular rate constant for the formation of BR-OH adducts at PH 8+/- 0.2 is 9.5 x 10(9) dm3 mol-1 s-1 (540 nm). OH. adds to BSA at neutral pH with a rate constant of 3.0 +/- 1.0 x 10(10) dm3 mol-1 s-1 (305 nm). In the BSA-BR complex, BSA fully protects BR from OH. attack and the (BSA-BR)-OH adduct further reacts with free BR molecule if present in solution.