Effect of a novel polyethylene glycol compound on lung lavage in dogs after the inhalation of depleted uranium dust

Purpose: The purpose of this study was to assess the effect of a lavage solution containing methoxypolyethylene glycol 4-(3,4-dihydroxyphenethylamino)-4-oxobutanoate (MDO) for whole lung lavage (WLL) in dogs after the inhalation of depleted uranium (DU) dust at a dose of 30 mgUkg^?1.

Materials and methods: WLL was performed using lavage solutions made of normal saline (saline group) or normal saline plus MDO (MDO group) at 2 days post-DU exposure. Meanwhile, a control group was set up without any treatment.

Results: At 10 days post-DU exposure, the saline and MDO groups had a lower DU content in urine and lung compared with the DU group (without lavage), while the MDO group content was significantly lower than that in the saline group. In terms of blood urea nitrogen and creatinine levels, the DU group maintained relatively high levels from day 3 to day 10; the saline group levels were reduced compared with the DU group at day 8 and day 10, while the MDO group levels remained markedly lower than both the DU and saline group levels. Pathological changes in the lungs and kidneys showed that the saline group was improved compared with the DU group, but not as significantly as the MDO group.

Conclusions: In brief, WLL has a remarkable effect in promoting the decorporation of inhaled DU dust in the lungs of dogs. By comparison, a MDO-containing lavage solution has a better lavage effect than normal saline.     

Comparison of bifunctional chelates for 64Cu antibody imaging

Purpose  

Improved bifunctional chelates (BFCs) are needed to facilitate efficient ⁶⁴Cu radiolabeling of monoclonal antibodies (mAbs) under mild conditions and to yield stable, target-specific agents. The utility of two novel BFCs, 1-Oxa-4,7,10-triazacyclododecane-5-S-(4-isothiocyanatobenzyl)-4,7,10-triacetic acid (p-SCN-Bn-Oxo-DO3A) and 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-4-S-(4-isothiocyanatobenzyl)-3,6,9-triacetic acid (p-SCN-Bn-PCTA), for mAb imaging with ⁶⁴Cu were compared to the commonly used S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (p-SCN-Bn-DOTA).     

A potential of methoxpropamine to be a widespread recreational drug: it blocks NMDA receptors and inhibits NMDA receptor-mediated synaptic transmission in a brain preparation of mice

Purpose

The activity of N-methyl-d-aspartate (NMDA) receptors in the central nervous system is affected by many psychoactive drugs, such as 2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one (ketamine) and its analog 2-(3-methoxyphenyl)-2-(amino)cyclohexan-1-one (methoxetamine, MXE). Recreational use of MXE can cause acute toxicity, such as dissociative state and tachycardia. After MXE use, confusion, agitation, ataxia, and nystagmus are induced. Moreover, MXE-related deaths have been reported, and this compound is banned in many countries. Recently, MXE’s derivative, 2-(3-methoxyphenyl)-2-(propylamino)cyclohexan-1-one (methoxpropamine, MXPr), was reported as a new psychoactive substance and sold online as a designer drug. The aims were to determine how MXPr affects NMDA receptors in neurons and to compare the potency with MXE.

Methods

Cartwheel cells in the dorsal cochlear nucleus of mice were used as a model of NMDA receptor-expressing neurons, and patch-clamp method was performed for the recordings. NMDA-induced inward current was initially evoked by microiontophoresis application of NMDA onto the cartwheel cells, and the effects of MXPr, MXE, and (5R,10S)-(?+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801, as a positive control substance) on NMDA-induced response were examined. Moreover, the effects of MXPr on NMDA receptor-mediated excitatory postsynaptic currents were also investigated.

Results

The IC₅₀ of MXPr, MXE, and MK-801 on NMDA-induced response decreased in the following order: MXPr (1.647 μM)?>?MXE (0.841 μM)?>?MK-801 (0.060 μM), indicating that MXPr and MXE act as potent antagonists of NMDA receptors. MXPr suppressed NMDA receptor-mediated excitatory synaptic transmission in a dose-dependent manner.

Conclusions

MXPr, which may cause health and social damages to humans by blocking NMDA receptors, is a serious concern like MXE.

     

PARP inhibitor attenuated colony formation can be restored by MAP kinase inhibitors in different irradiated cancer cell lines

Abstract

Purpose: Sensitizing cancer cells to irradiation is a major challenge in clinical oncology. We aimed to define the signal transduction pathways involved in poly(ADP-ribose) polymerase (PARP) inhibitor-induced radiosensitization in various mammalian cancer lines.

Materials and methods: Clonogenic survival assays and Western blot examinations were performed following telecobalt irradiation of cancer cells in the presence or absence of various combinations of PARP- and selective mitogen-activated protein kinase (MAPK) inhibitors.

Results: HO3089 resulted in significant cytotoxicity when combined with irradiation. In human U251 glioblastoma and A549 lung cancer cell lines, Erk1/2 and JNK/SAPK were found to mediate this effect of HO3089 since inhibitors of these kinases ameliorated it. In murine 4T1 breast cancer cell line, p38 MAPK rather than Erk1/2 or JNK/SAPK was identified as the main mediator of HO3089's radiosensitizing effect. Besides the aforementioned changes in kinase signaling, we detected increased p53, unchanged Bax and decreased Bcl-2 expression in the A549 cell line.

Conclusions: HO3089 sensitizes cancer cells to photon irradiation via proapoptotic processes where p53 plays a crucial role. Activation of MAPK pathways is regarded the consequence of irradiation-induced DNA damage, thus their inhibition can counteract the radiosenzitizing effect of the PARP inhibitor.     

Orally administered DTPA di-ethyl ester for decorporation of 241Am in dogs: Assessment of safety and efficacy in an inhalation-contamination model

Abstract

Purpose: Currently two injectable products of diethylenetriaminepentaacetic acid (DTPA) are U.S. Food and Drug Administration (FDA)-approved for decorporation of ²⁴¹Am; however, an oral product is considered more amenable in a mass casualty situation. The di-ethyl ester of DTPA, named C2E2, is being developed as an oral drug for treatment of internal radionuclide contamination.

Materials and methods: Single-dose decorporation efficacy of C2E2 administered 24-h post contamination was determined in beagle dogs using a ²⁴¹Am nitrate inhalation contamination model. Single and multiple dose toxicity studies in beagle dogs were performed as part of an initial safety assessment program. In addition, the genotoxic potential of C2E2 was evaluated by the in vitro bacterial reverse mutation Ames test, mammalian cell chromosome aberration cytogenetic assay and an in vivo micronucleus test.

Results: Oral administration of C2E2 significantly increased ²⁴¹Am elimination over untreated controls and significantly reduced the retention of ²⁴¹Am in tissues, especially liver, kidney, lung and bone. Daily dosing of 200 mg/kg/day for 10 days was well tolerated in dogs. C2E2 was found to be neither mutagenic or clastogenic.

Conclusions: The di-ethyl ester of DTPA (C2E2) was shown to effectively enhance the elimination of ²⁴¹Am after oral administration in a dog inhalation-contamination model and was well tolerated in toxicity studies.     

Low dose of uranium induces multigenerational epigenetic effects in rat kidney

Purpose: A protocol of chronic exposure to low dose of uranium was established in order to distinguish the sexual differences and the developmental process that are critical windows for epigenetic effects over generations.

Methods: Both male and female rats were contaminated through their drinking water with a non-toxic solution of uranyl nitrate for 9 months. The exposed generation (F0) and the following two generations (F1 and F2) were examined. Clinical monitoring, global DNA methylation profile and DNA methyltransferases (DNMTs) gene expression were analyzed in kidneys.

Results: While the body weight of F1 males increased, a small decrease in kidney and body weight was observed in F2 males. In addition, global DNA hypermethylation profile in kidney cells was observed in F1 and F2 males. qPCR results reveal a significant increase of methyltransferase genes expression (DNMT1 and DNMT3a) for F2 females.

Conclusions: In the field of public health policy and to raise attention to generational effects for the risk assessment of the environmental exposures, low doses of uranium do not imply clinical effects on adult exposed rats. However, our results confirm the importance of the developmental windows’ sensitivity in addition to the sexual dimorphisms of the offspring.     

Nrf2在姜黄素保护UVB所致细胞氧化损伤中的作用

目的 研究姜黄素对UVB导致的小鼠胚胎成纤维细胞（MEF）活性氧（ROS）水平升高和细胞死亡的影响,并探讨转录因子Nrf2在其中的作用。方法 小鼠胚胎成纤维细胞经25 μmol/L的姜黄素预处理或无预处理,接受不同剂量的UVB辐射后培养12 h后采用MTT法、荧光探针法和免疫印迹法检测Nrf2敲除MEF细胞存活率、ROS水平和Nrf2、HO1等蛋白表达水平,并进行比较。结果 50 mJ/cm²的UVB照射导致MEF细胞内ROS水平在6 h内升高（t=16.65,P<0.05）,存活率则在24 h后降低（t=15.89,P<0.05）;而姜黄素预处理可以显著减轻UVB导致的ROS水平升高（t=11.88,P<0.05）和存活率降低（t=3.77,P<0.05）。UVB照射提高了Nrf2、HO1和磷酸化JNK、ERK的蛋白水平;姜黄素预处理则进一步增加了辐射诱导的Nrf2和HO1蛋白水平,但抑制了UVB照射导致的磷酸化JNK、ERK水平增加,而对p38没有明显影响。在Nrf2敲除的MEF中,UVB照射诱导的Nrf2和HO1蛋白水平被显著抑制,同时50 mJ/cm²的UVB照射导致ROS水平升高15倍（t=16.73,P<0.05）,细胞存活率降低至对照组的42.7%（t=-8.23,P<0.05）,且姜黄素的保护作用也显著降低。结论 Nrf2对UVB导致的细胞氧化损伤有保护作用,姜黄素可通过激活Nrf2信号来减轻UVB导致的细胞ROS水平升高和存活率降低。     

Health effects of occupational exposure to uranium: Do physicochemical properties matter?

Abstract

Purpose: Physicochemical properties of uranium, including isotopic composition and solubility, are determinants of its toxicity. We reviewed epidemiological studies in civilian and military workers known to be exposed to uranium with different physicochemical properties to investigate its long-term effects, such as cancerous and circulatory diseases.

Materials and methods: We systematically searched the Pubmed and the Scopus databases to identify studies of uranium- processing workers (published between 1980 and 2013) and veterans of the wars in the Persian Gulf and the Balkans (published between 1991 and 2013) in which defined outcomes, such as lung, lymphohematopoietic, kidney cancers, and circulatory diseases were examined. Results from these studies in terms of risk of each health outcome (mortality or incidence) and analyses of dose-response relationship were examined to present the impact of uranium physicochemical properties on the observed results.

Results: Twenty-seven articles were reviewed. There is some evidence for increased lung cancer risk among uranium-processing workers. The evidence is less strong for lymphohematopoietic cancer. We found that most of the studies insufficiently assessed the physicochemical properties of uranium and some of them used proxies for the exposure assessment and risk estimation analyses. Studies of veterans of the wars in the Persian Gulf and the Balkans are uninformative in respect to internal uranium exposure.

Conclusions: Existing epidemiological data on the physicochemical properties of uranium and associated health outcomes are inconclusive. Further studies among certain groups of uranium-processing workers (uranium-enrichment and fuel-fabrication workers) could contribute to our knowledge of the health effects of uranium with respect to its physicochemical properties.     

Preclinical evaluation of an 18F-labelled β1-adrenoceptor selective radioligand based on ICI 89,406

PurposeRadioligand binding studies indicate a down-regulation of myocardial β₁-adrenoceptors (β₁-AR) in cardiac disease which may or may not be associated with a decrease in β₂-ARs. We have chosen ICI 89,406, a β₁-selective AR antagonist, as the lead structure to develop new β₁-AR radioligands for PET and have synthesised a fluoro-ethoxy derivative (F-ICI).Methods(S)-N-[2-[3-(2-Cyano-phenoxy)-2-hydroxy-propylamino]-ethyl]-N′-[4-(2-[¹⁸F]fluoro-ethoxy)-phenyl]-urea ((S)-[¹⁸F]F-ICI) was synthesised. Myocardial uptake of radioactivity after intravenous injection of (S)-[¹⁸F]F-ICI into adult CD₁ mice or Wistar rats was assessed with positron emission tomography (PET) and postmortem dissection. Metabolism was assessed by high-performance liquid chromatography analysis of plasma and urine.ResultsThe heart was visualised with PET after injection of (S)-[¹⁸F]F-ICI but neither unlabelled F-ICI nor propranolol (non-selective β-AR antagonist) injected 15 min after (S)-[¹⁸F]F-ICI affected myocardial radioactivity. Ex vivo dissection demonstrated that predosing with propranolol or CGP 20712 (β₁-selective AR-antagonist) did not affect myocardial radioactivity. Radiometabolites rapidly appeared in plasma and both (S)-[¹⁸F]F-ICI and radiometabolites accumulated in urine.ConclusionsMyocardial uptake of (S)-[¹⁸F]F-ICI after intravenous injection was mainly at sites unrelated to β₁-ARs. (S)-[¹⁸F]F-ICI is not a suitable β₁-selective-AR radioligand for PET.     

Collective dosimetry to distinguish occupational exposure to natural uranium from alimentary uranium background in bioassay measurements

Abstract

Purpose: To assess occupational exposure from uranium bioassay results which are low and impacted by dietary intakes.

Material and methods: First, the bioassay results of a group of workers exposed to UO₂ were compiled along with results of a control group. A Bayesian approach was developed to account for dietary intakes in the calculation of the committed effective dose from occupational exposure of a group of workers.

Results: Significant differences in uranium bioassay between the exposed and control groups were found establishing an occupational contamination of the exposed group of workers. Because uranium alimentary excretion estimated from the control group is very variable leading to unreliable individual dose assessment, a collective dosimetric approach was chosen. Applying the Bayesian method, all annual committed effective doses for the exposed group were estimated to be below 0.5 mSv with 95% confidence.

Conclusions: The Bayesian method presented here is well designed to derive best estimate and dose distribution for a group of workers when a contamination is difficult to discriminate from a natural background or alimentary excretion.     

In vivo selective binding of (R)-[11C]rolipram to phosphodiesterase-4 provides the basis for studying intracellular cAMP signaling in the myocardium and other peripheral tissues

IntroductionPhosphodiesterase-4 (PDE4) enzymes specifically break down the second messenger cAMP, thereby terminating the intracellular signaling cascade that plays an essential role in neurohormonal modulation of many physiological systems. PDE4 activity and expression are regulated by cAMP levels, suggesting that measurement of PDE4 provides an index of intracellular cAMP signaling.MethodsMale Sprague–Dawley rats were administered (R)- or the less active enantiomer (S)-[¹¹C]rolipram and sacrificed 30 min later with tracer retention measured in various tissues. Co-injections with saturating doses of unlabeled (R)-rolipram, (S)-rolipram and Ro 20-1724, as well as subtype-selective PDE inhibitors vinpocetine, Bay 60-7550, cilostazol and zaprinast were used to establish binding selectivity for PDE4 over PDE1, PDE2, PDE3 and PDE5 subtypes, respectively. Autoradiography was performed to substantiate results of biodistribution studies in the myocardium.ResultsIn vivo (R)-[¹¹C]rolipram retention was dose-dependently reduced by co-injections of (R)-rolipram and (S)-rolipram (ED₅₀ values of 0.03 mg/kg and 0.2 mg/kg, respectively). Vinpocetine, Bay 60-7550, cilostazol and zaprinast had no effect on (R)-[¹¹C]rolipram binding, while (R)-rolipram and Ro 20-1724 reduced the tracer uptake to nonspecific levels in PDE4-rich tissues.ConclusionsIn addition to the brain, (R)-[¹¹C]rolipram binds selectively to PDE4 across all cardiac regions, skeletal muscle, lungs and pancreas, but not in the adipose tissues. In vivo findings were confirmed by in vitro autoradiography studies, suggesting that (R)-[¹¹C]rolipram can be applied to evaluate alterations in central and peripheral PDE4 levels and cAMP-mediated signaling.     

The Relationship between the Magnitude of the Effect and the Oxygen-concentration in Irradiation Experiments on Tradescantia Pollen-tube Chromosomes

Summary

The enhancement of killing by γ-irradiation, which is seen when E. coli K 1060 are cooled below the transition temperature of their membrane lipids, is blocked by procaine-HCl. These data are consistent with the hypothesis that increased killing associated with irradiation at 0°C is the result of membrane microviscosity increases, since procaine is known to fluidize membranes.

A cooling enhancement ratio (c.e.r.) is defined as the ratio of radiation D₀ at 22°C to its value at 0°C. The c.e.r. for oxygen-bubbled cells is 1·5 and for nitrogen-bubbled cells is 2·1. In the presence of 25 mM procaine the respective c.e.r. values are 1·08 and 1·29.

The oxygen enhancement ratio (o.e.r.) at 22°C is 3·43 and at 0°C is 2·45. The addition of procaine does not change the o.e.r. Thus, the temperature effect on o.e.r. does not appear to be related to membrane fluidity.     

In vitro structure–activity relationship of Re-cyclized octreotide analogues

IntroductionDevelopment of radiolabeled octreotide analogues is of interest for targeting somatostatin receptor (SSTR)-positive tumors for diagnostic and therapeutic purposes. We are investigating a direct labeling approach for incorporation of a Re ion into octreotide analogues, where the peptide sequences are cyclized via coordination to Re rather than through a disulfide bridge.MethodsVarious octreotide analogue sequences and coordination systems (e.g., S₂N₂ and S₃N) were synthesized and cyclized with nonradioactive Re. In vitro competitive binding assays with ¹¹¹In-DOTA-Tyr³-octreotide in AR42J rat pancreatic tumor cells yielded IC₅₀ values as a measure of SSTR affinity of the Re-cyclized analogues. Three-dimensional structures of Re-cyclized Tyr³-octreotate and its disulfide-bridged analogue were calculated from two-dimensional NMR experiments to visualize the effect of metal cyclization on the analogue's pharmacophore.ResultsOnly two of the 11 Re-cyclized analogues investigated showed moderate in vitro binding affinity toward somatostatin subtype 2 receptors. Three-dimensional molecular structures of Re- and disulfide-cyclized Tyr³-octreotate were calculated, and both of their pharmacophore turns appear to be very similar with minor differences due to metal coordination to the amide nitrogen of one of the pharmacophore amino acids.ConclusionsVarious Re-cyclized analogues were developed and analogue 4 had moderate affinity toward somatostatin subtype 2 receptors. In vitro stable studies that are in progress showed stable radiometal cyclization of octreotide analogues via NS₃ and N₂S₂ coordination forming five- and six-membered chelate rings. In vivo biodistribution studies are underway of ^99mTc-cyclized analogue 4.     

保乳术后放疗影响标记夹几何体变化的相关因素分析

目的探讨保乳术后全乳调强放疗中标记夹所形成几何体体积、位置、形态的变化规律及相关影响因素。方法回顾性分析2021年10月至2022年9月苏州大学附属第一医院18例保乳术后调强放疗患者, 依据定位CT和放疗0、10、20、30、40、50 Gy时的锥形束CT(CBCT), 读取瘤床标记夹坐标信息, 获取每次摆位误差。利用凸包计算程序构建几何体, 分别计算出几何体基于定位CT的体积(Vct)、6次CBCT的体积(V0～5);比较6次CBCT与定位CT的几何体质心位移(D0～5)和包含度(DI0～5)。照射剂量分别对V0～5、D0～5、DI0～5的影响采用配对t检验或秩和检验;D0～5分别与同次三维方向摆位误差的相关性, V0～5变化率均值(AV)、D0～5均值(AD)、DI0～5均值(ADI)分别与体质量指数(BMI)、全乳体积(VB)、乳轴高(H)、手术至放疗时间间隔(T)的相关性, 均采用Pearson相关分析;几何体所处象限(Q)和几何体于胸壁贴离状态(S)分别对AV、AD、ADI的影响采用单因素方差分析。结果 D5与D0、D1、D2差异均有统计学意义(t=-3.27、-4.52、-...     

Design and synthesis of new agents for neuronal nicotinic acetylcholine receptor (nAChRs) imaging

IntroductionThe most abundant subtype of cerebral nicotinic acetylcholine receptors (nAChR), α4β2, plays a critical role in various brain functions and pathological states. Due to rapid technological progress in chemistry, bioinformatics, structural biology and computer technology, computer aided drug design (CADD) plays a more and more important role in today's drug discovery.MethodsTwo novel 3-pyridyl ether nicotinic ligands-3-((pyridine-2-yl)methoxy)-5-iodopyridine, and 3-(((S)-pyrrolidin-2-yl)methoxy)-5-((4-iodobenzyloxy)-methyl)pyridine were designed and synthesized and radiolabeled with I-125 based on our 3D-QSAR models reported previously. Their ability to label high-affinity brain nicotinic acetylcholine receptors (nAChRs) was evaluated.Results[¹²⁵I]3-((pyridin-2-yl)methoxy)-5-iodopyridine shows rapid accumulation and elimination with peak (1.86%ID/g) at 5 min post injection, but has high blood uptake. [¹²⁵I]3-(((S)-pyrrolidin-2-yl)methoxy)-5-((4-iodobenzyloxy)methyl)pyridine entered the brain with maximal uptake value 3.01%ID/g at 15 min after injection, and showed approximately 27% inhibition of radioactivity uptake in thalamus in mice pretreated with nicotine.ConclusionsThe results of this preliminary study show that [¹²⁵I]3-(((S)-pyrrolidin-2-yl)methoxy)-5-((4-iodobenzyloxy)methyl)pyridine shows relatively high uptake to the brain, however, since the in vivo selectivity for α4β2 nAChRs was not enough, [¹²⁵I]3-(((S)-pyrrolidin-2-yl)methoxy)-5-((4-iodobenzyloxy)methyl)pyridine does not have the required properties for imaging nAChRs using SPECT. Structure optimization is needed for specific visualization of brain α4β2 nAChRs in vivo.     

The Efficacy of DFO-HOPO,DTPA-DX and DTPA for Enhancing the Excretion of Plutonium and Americium from the Rat

Summary

A hydroxypridinone derivative of desferrioxamine (Na-DFO-HOPO), a dihydroxamic derivative of diethylenetriaminepenta-acetic acid (ZnNa-DTPA-DX), and DTPA (CaNa₃- and ZnNa₃-DTPA) were tested at dosages of 30 μmol kg^?1 for their ability to remove ²³⁸Pu or ²⁴¹Am from rats after their intravenous injection as citrate or inhalation as nitrate. The most effective treatment regimen for injected Pu was the repeated administration of DFO-HOPO; by 7 days the body content was reduced to 8% of that in untreated animals. Repeated dosages of 3 μmol kg^?1 DFO-HOPO were as effective as those of 30 μmol kg^?1 DTPA. After inhalation of Pu nitrate, repeated treatment with DTPA, DTPA-DX or DFO-HOPO reduced the body content by 7 days to, respectively, 10, 15 and 31% of those in untreated animals. After inhalation of Am, DTPA-DX and DTPA were equally effective, the body contents being reduced to 7% of control values with repeated treatment. Injection of DFO-HOPO was ineffective for enhancing the elimination of inhaled or injected Am. The results confirm the strategy of examining the use of siderophore analogues for the decorporation of Pu or Am. However, at present DTPA should remain the agent of choice, particularly after inhalation.     

Doses and lung cancer risks from exposure to radon and plutonium

Abstract

Purpose: Epidemiological studies of the French uranium miners and the plutonium workers at the Mayak nuclear facility have provided excess relative risk (ERR) estimates per unit absorbed lung dose from alpha radiation. The aim of this paper was to review these two studies and to derive values of the relative biological effectiveness (RBE) of alpha particles for the induction of lung cancer.

Materials and methods: We examined and compared the dosimetry assumptions and methodology used in the epidemiological studies of uranium miners and the plutonium workers. Values of RBE were obtained by comparing risk coefficients including comparison of lifetime risks for a given population. To do this, preliminary calculations of lifetime risks following inhalation of plutonium were carried out.

Results and conclusions: Published values of risk per unit dose following inhalation of radon progeny and plutonium were in agreement despite the very different dose distributions within the lungs and the different ways the doses were calculated. Values of RBE around 10–20 were obtained by comparing ERR values, but with wide uncertainty ranges. Comparing lifetime risks gave similar values (10, 19 and 21). This supports the use of a radiation weighting factor of 20 for alpha particles for radiation protection purposes.     

Apoptotic cell death in erythrocytes of p53-deficient medaka (Oryzias latipes) after γ-irradiation

Purpose: Previous studies have examined the effects of γ-irradiation (γ-IR) on wild-type and p53 mutant Medaka (Oryzias latipes) 24?hours after irradiation and in the present work, apoptosis and alterations in erythrocytes of 4, 8 and 24?h and 14 days after gamma-ray irradiation were reported as genotoxic biomarkers of γ-irradiation.

Materials and methods: Sexually mature wild-type, WT (Hd-rR) and p53(?/?) adult female medaka (O. latipes) were exposed to 4?Gy dose of γ-IR and sampling were collected after 4, 8 and 24?h and 14 days.

Results: Apoptosis and morphological alterations were observed from 4?h after irradiation and remarkably increased 8?h after irradiation in the wild-type. Apoptotic cell death has been observed 8?h after irradiation most prominently but subtle in p53 mutant medaka. All these phenotypes were recovered 14 days after irradiation in both strains. Although no micronuclei were seen in any group, nuclear abnormalities were observed in red blood cells. Both apoptosis and morphological alterations in erythrocytes were decreased after 24 and 14 days after γ-irradiation.

Conclusions: We conclude that apoptosis and malformations caused by 4?Gy γ-irradiation in the erythrocytes of medaka fish occurs from 4–24?h and the initial response until 8?h was p53-dependent.     

Evaluation of novel bifunctional chelates for the development of Cu-64-based radiopharmaceuticals

BackgroundCurrently available bifunctional chelates (BFCs) for attaching Cu-64 to a targeting molecule are limited by either their radiolabeling conditions or in vivo stability. With the goal of identifying highly effective BFCs, we compared the properties of two novel BFCs, 1-oxa-4,7,10-triazacyclododecane-S-5-(4-nitrobenzyl)-4,7,10-triacetic acid (p-NO₂-Bn-Oxo) and 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-S-4-(4-nitrobenzyl)-3,6,9-triacetic acid (p-NO₂-Bn-PCTA), with the commonly used S-2-(4-nitrobenzyl)-1,4,7,10-tetraazacyclododecanetetraacetic acid (p-NO₂-Bn-DOTA).Methodsp-NO₂-Bn-DOTA, p-NO₂-Bn-Oxo and p-NO₂-Bn-PCTA were each radiolabeled with Cu-64 under various conditions to assess the reaction kinetics and robustness of the radiolabeling. Stability of each Cu-64 BFC complex was evaluated at low pH and in serum. Small animal positron emission tomography imaging and biodistribution studies in mice were undertaken.Resultsp-NO₂-Bn-Oxo and p-NO₂-Bn-PCTA possessed superior reaction kinetics compared to p-NO₂-Bn-DOTA under all radiolabeling conditions; >98% radiochemical yields were achieved in <5 min at room temperature even when using near stoichiometric amounts of BFC. Under nonideal conditions, such as low or high pH, high radiochemical yields were still achievable with the novel BFCs. The radiolabeled compounds were stable in serum and at pH 2 for 48 h. The imaging and biodistribution of the Cu-64-radiolabeled BFCs illustrated differences between the BFCs, including preferential clearance via the kidneys for the p-NO₂-Bn-PCTA Cu-64 complex.ConclusionsThe novel BFCs facilitated efficient Cu-64 radiolabeling under mild conditions to produce stable complexes at potentially high specific activities. These BFCs may find wide utility in the development of Cu-64-based radiopharmaceuticals.     

Transfer of useful variability of high grain iron and zinc from Aegilops kotschyi into wheat through seed irradiation approach

Purpose To transfer the 2S chromosomal fragment(s) of Aegilops kotschyi (2S^k) into the bread wheat genome which could lead to the biofortification of wheat with high grain iron and zinc content.

Materials and methods Wheat-Ae. kotschyi 2A/2S^k substitution lines with high grain iron and zinc content were used to transfer the gene/loci for high grain Fe and Zn content into wheat using seed irradiation approach.

Results Bread wheat plants derived from 40 krad-irradiated seeds showed the presence of univalents and multivalents during meiotic metaphase-I. Genomic in situ hybridization analysis of seed irradiation hybrid F₂ seedlings showed several terminal and interstitial signals indicated the introgression of Ae. kotschyi chromosome segments. This proves the efficacy of seed radiation hybrid approach in gene transfer experiments. All the radiation-treated hybrid plants with high grain Fe and Zn content were analyzed with wheat group 2 chromosome-specific polymorphic simple sequence repeat markers to identify the introgression of small alien chromosome fragment(s).

Conclusion Radiation-induced hybrids showed more than 65% increase in grain iron and 54% increase in Zn contents with better harvest index than the elite wheat cultivar WL711 indicating effective and compensating translocations of 2S^k fragments into wheat genome.