The development and validation of a high performance liquid chromatography method to determine the radiochemical purity of [177Lu]Lu-HA-DOTA-TATE in pharmaceutical preparations.

Lutetium-177 [177Lu] tetra-azacyclododecanetetra-acetic acid [DOTA]-(Tyr3)-octreotate [TATE] ([177Lu]Lu-DOTA-TATE) is a radiopeptide used for peptide receptor radionuclide therapy in patients with neuroendocrine tumours (NETs). This radiopeptide is made by labelling the ligand octreotate with Lutetium-177 using the linker DOTA. After labelling, and before clinical application quality control of the radiopeptide is needed and the radiochemical purity is assessed. Acceptance limits for radiochemical purity should be within 90-110% of the label claim for radiopharmaceuticals for diagnostic use and within 95-105% of the label claim for radiopharmaceuticals for therapeutic use. Moreover, the amount of unlabelled [177Lu]LuCl3 cannot exceed 2% of the radioactive dose. Since no monograph is available for [177Lu]Lu-DOTA-TATE in the European Pharmacopeia (Ph Eur), this article describes the development and validation of a high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection and radiodetection. A Waters Acquity Arc UHPLC system equipped with a Waters 2998 photodiode array (PDA) detector was used coupled to a Berthold Lb 514 Flowstar detector equipped with a BGO-X gamma measuring cell. A reversed phase Symmetry Shield C18 column (4.6 mm × 250 mm, 5 µm) was used for chromatographic separation. A flow of 1.5 mL/min was maintained during analysis, using 0.1% TFA in water as mobile phase A and 0.1% TFA in ACN as mobile phase B. The retention time was around 1.7 min and 13.5 min for [177Lu]LuCl3 and [177Lu]Lu-HA-DOTA-TATE, respectively. Stock solutions of [177Lu]LuCl3 were made by serial dilution and were injected to test for linearity, accuracy and precision, carry over and signal-to-noise ratio. A [177Lu]Lu-HA-DOTA-TATE sample was prepared and injected to determine the carry over. The results showed that the method is linear over a range of 0.300-130 MBq/mL, which covers the range for clinical samples, provided that the clinical sample is diluted ten times before analysis. The LLOQ can be measured accurately even after dilution, with a signal-to-noise ratio of at least 5. In short, the method is accurate, precise and sensitive and can be implemented as part of the quality control of [177Lu]Lu-HA-DOTA-TATE.

Moringa oleifera Leaf Extract Attenuates Pb Acetate-induced Testicular Damage in Rats.

BACKGROUND: Lead (Pb) remains a common contaminant in the environment in many parts of the world. Pb exposure adversely affects many human organs, including the gonads, via oxidant and inflammatory marker propagation in affected tissues. Moringa oleifera leaf extract (MOE) is a rich source of antioxidants, reported to have robust anti-inflammatory properties. AIMS: This investigation assessed whether MOE could mitigate testicular damage caused by Pb acetate treatment in rats. METHODS: Four experimental groups were used: control animals (saline only), MOE (MOE only), PbAc (Pb acetate injection only), and MOE+PbAc. All treatments were administered for two weeks, after which animals were sacrificed, and tissues and serum were examined. To confirm the potential antioxidant effect of MOE, the total polyphenolic (TP) and flavonoid (TF) concentrations were determined. RESULTS: The obtained results revealed that the TP concentration was 17.4 mg gallic acid equivalents per gram MOE dried weight and the TF concentration was 5.6 mg of quercetin equivalents per gram MOE dried weight. Moreover, MOE partially restored levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and testosterone and significantly attenuated oxidative stress biomarkers, malondialdehyde (MDA) and nitric oxide (NO), compared to levels observed in the PbAc-only group. MOE significantly increased the enzymatic and non-enzymatic antioxidant molecules superoxide dismutase (SOD) and catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR), and glutathione (GSH). Testicular levels of inflammatory cytokines tumor necrosis factor-alpha (TNFα) and interleukin-1beta (IL-1ß) were significantly decreased in MOE+PbAc compared to PbAc. MOE also significantly decreased pro-apoptotic Bax and caspase- 3 mRNA and protein levels and increased anti-apoptotic Bcl-2 mRNA and protein levels. CONCLUSION: MOE extract was associated with significant antioxidant, anti-inflammatory, and anti- apoptotic activity that ameliorated testicular damage induced by Pb acetate. MOE is proposed as a favorable adjuvant to existing treatments for Pb-induced toxicity.

Neodymium as an alternative contrast for uranium in electron microscopy.

Uranyl acetate is the standard contrasting agent in electron microscopy (EM), but it is toxic and radioactive. We reasoned neodymium acetate might substitute uranyl acetate as a contrasting agent, and we find that neodymium acetate indeed can replace uranyl acetate in several routine applications. Since neodymium acetate is not toxic, not radioactive and easy to use, we foresee neodymium will replace uranyl in many EM sample preparation applications worldwide.

Nanofocused synchrotron X-ray absorption studies of the intracellular redox state of an organometallic complex in cancer cells.

Synchrotron nanoprobe X-ray absorption (XAS) studies of a potent organo-osmium arene anticancer complex in ovarian cancer cells at subcellular resolution allow detection and quantification of both OsII and OsIII species, which are distributed heterogeneously in different areas of the cells.

A Fluorescent ESIPT Probe for Imaging CO-Releasing Molecule-3 in Living Systems.

CO-releasing molecule-3 (CORM-3) has been widely used recently as a convenient and safe CO donor to release exogenous CO in living cells and to study the effects of CO on cellular systems. Accordingly, development of effective methods for detecting and tracking CORM-3 in living systems is of great significance. In this work, a readily available fluorescent probe for detection of CORM-3 was reported for the first time. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye phthalimide and uses the reducing ability of CORM-3 to convert a nitro group to an amino group, and more importantly, it can be used for rapid, highly selective, and sensitive detection of CORM-3 with a distinct turn-on green fluorescence change in aqueous solution, living cells, and animals, thus providing a useful tool for studying CORM-3 in living systems.

A fluorogenic BODIPY molecular rotor as an apoptosis marker.

Based on a BODIPY molecular rotor and a zinc-dipicolylamine receptor, we designed a fluorogenic probe for the detection of apoptosis. Being poorly emissive in solution and with healthy cells, it selectively binds phosphatidylserine of early apoptotic cells and internalizes into late apoptotic cells, lighting up its green fluorescence.

Probing the effects of different lead compounds on the bioavailability of lead to plants.

Lead (Pb) is an important pollutant and is released into the environment in many forms. Different lead compounds have a variety of solubilities and so may impact on lead bioavailability and toxicity when added to soil. In this experimental study, we investigated the bioavailability of Pb in soil spiked with 300, 900 and 1500 mg/kg of Pb-acetate, PbCl2 and PbO using lettuce and wallaby grass. The concentration of Pb in the shoots of both species from control soils (2-3 mg/kg) was similar to previously reported concentrations in plants grown on uncontaminated soils. The Pb concentrations in the plant shoots increased with Pb concentrations in soil for lettuce (R2 = 0.526, P < 0.001) and wallaby grass (R2 = 0.776, P < 0.001). This study demonstrated that Pb bioavailability in soil was not affected by the type of Pb compound added to the soil for both plant species up to 1500 mg/kg Pb concentrations. Instead, the Pb concentration in the plant was best predicted by the total concentration of lead in the soil, irrespective of the original lead compound added to the soil. This research suggests that the original Pb compounds that contaminated the soil are unlikely to be an important factor in assessing Pb bioavailability, and hence risk, in soils.

Chimeric mouse model for MRI contrast agent evaluation.

PURPOSE: While rodents are the primary animal models for contrast agent evaluation, rodents can potentially misrepresent human organ clearance of newly developed contrast agents. For example, gadolinium (Gd)-BOPTA has ~50% hepatic clearance in rodents, but ~5% in humans. This study demonstrates the benefit of chimeric mice expressing human hepatic OATPs (organic anion-transporting polypeptides) to improve evaluation of novel contrast agents for clinical use. METHODS: FVB (wild-type) and OATP1B1/1B3 knock-in mice were injected with hepatospecific MRI contrast agents (Gd-EOB-DTPA, Gd-BOPTA) and nonspecific Gd-DTPA. T1 -weighted dynamic contrast-enhanced MRI was performed on mice injected intravenously. Hepatic MRI signal enhancement was calculated per time point. Mass of gadolinium cleared per time point and percentage elimination by means of feces and urine were also measured. RESULTS: Following intravenous injection of Gd-BOPTA in chimeric OATP1B1/1B3 knock-in mice, hepatic MRI signal enhancement and elimination by liver was more reflective of human hepatic clearance than that measured in wild-type mice. Gd-BOPTA hepatic MRI signal enhancement was reduced to 22% relative to wild-type mice. Gd-BOPTA elimination in wild-type mice was 83% fecal compared with 32% fecal in chimeric mice. Hepatic MRI signal enhancement and elimination for Gd-EOB-DTPA and Gd-DTPA were similar between wild-type and chimeric cohorts. CONCLUSION: Hepatic MRI signal enhancement and elimination of Gd-EOB-DTPA, Gd-BOPTA, and Gd-DTPA in chimeric OATP1B1/1B3 knock-in mice closely mimics that seen in humans. This study provides evidence that the chimeric knock-in mouse is a more useful screening tool for novel MRI contrast agents destined for clinical use as compared to the traditionally used wild-type models.

[Determination of organo-tin residues in edible vegetable oil by positive chemical ionization-gas chromatography-mass spectrometry].

For the determination of organo-tin residues in edible vegetable oil, a method was developed based on gas chromatography-mass spectrometric (GC-MS) with positive chemical ionization (PCI). The edible oil samples were first dissolved by cyclohexane-ethyl acetate (1:1, v/v), and then purified by gel permeation chromatography (GPC). After derivatization by sodium tetraethylborate, the samples were analyzed by GC-MS with PCI source in the single ion monitor (SIM) mode. The seven organo-tin compounds showed good linear relationships in the range of 20-2000 µg/L and the correlation coefficients exceeded 0.99. The limits of quantitation (LOQs) and the average recoveries of the seven organo-tin compounds were 0.3-1.2 µg/kg and 66.2%-103.2%, respectively, and the relative standard deviations were less than 11.5% at three spike levels (0.05, 0.10, and 0.20 mg/kg). The method showed good linearity and high sensitivity and can be used for the determination of organo-tin residues in edible vegetable oil.

Noninvasive Imaging of Endothelial Damage in Patients With Different HbA1c Levels: A Proof-of-Concept Study.

The aim of this study was to compare endothelial permeability, which is considered a hallmark of coronary artery disease, between patients with different HbA1c levels using an albumin-binding magnetic resonance (MR) probe. This cross-sectional study included 26 patients with clinical indication for X-ray angiography who were classified into three groups according to HbA1c level (<5.7% [<39 mmol/mol], 5.7-6.4% [39-47 mmol/mol], and ≥6.5% [48 mmol/mol]). Subjects underwent gadofosveset-enhanced coronary magnetic resonance and X-ray angiography including optical coherence within 24 h. Contrast-to-noise ratios (CNRs) were assessed to measure the probe uptake in the coronary wall by coronary segment, excluding those with culprit lesions in X-ray angiography. In the group of patients with HbA1c levels between 5.7 and 6.4%, 0.30 increased normalized CNR values were measured, compared with patients with HbA1c levels <5.7% (0.30 [95% CI 0.04, 0.57]). In patients with HbA1c levels ≥6.5%, we found 0.57 higher normalized CNR values compared with patients with normal HbA1c levels (0.57 [95% CI 0.28, 0.85]) and 0.26 higher CNR values for patients with HbA1c level ≥6.5% compared with patients with HbA1c levels between 5.7 and 6.4% (0.26 [95% CI -0.04, 0.57]). Additionally, late atherosclerotic lesions were more common in patients with high HbA1c levels (HbA1c ≥6.5%, n = 14 [74%]; HbA1c 5.7-6.4%, n = 6 [60%]; and HbA1c <5.7%, n = 10 [53%]). In conclusion, coronary MRI in combination with an albumin-binding MR probe suggests that both patients with intermediate and patients with high HbA1c levels are associated with a higher extent of endothelial damage of the coronary arteries compared with patients with HbA1c levels <5.7%.

Examining mineral-associated soil organic matter pools through depth in harvested forest soil profiles.

Mineral-associated organic matter is associated with a suite of soil minerals that can confer stability, resulting in the potential for long-term storage of carbon (C). Not all interactions impart the same level of protection, however; evidence is suggesting that C in certain mineral pools is dynamic and vulnerable to disturbance in the decades following harvesting. The objective of this research was to describe and characterize organic matter-mineral interactions through depth in horizons of soils of contrasting stand age. Sequential selective dissolutions representing increasingly stable mineral-associated organic matter pools from water soluble minerals (deionized water), organo-metal complexes (Na-pyrophosphate), poorly-crystalline minerals (HCl hydroxylamine), and crystalline secondary minerals (Na-dithionite HCl)) were carried out for Ae, Bf and BC horizons sampled from a Young and Mature forest site (35 and 110 years post-harvest) in Mooseland, Nova Scotia, Canada. Sequential selective dissolution extracts were analyzed for C, δ13C, iron (Fe) and aluminum (Al). Organo-metal complexes (OMC) were the largest mineral-associated OM pool in all horizons. This pool dominated the C distribution in B horizons (~60-70% of Bf bulk C), with a minor contribution from poorly-crystalline (PCrys), crystalline (Crys) minerals and water soluble (WS) associations. C in OMC and PCrys pools explained the variation in bulk C in horizons through depth at both sites. Twice as much C in OMC pools was measured at the Mature site compared to the Young site in the Bf horizons, supported by higher C:(Fe+Al) ratios. Isotopic analysis indicated that this extraction procedure isolated distinct mineral-associated OM pools. δ13C signatures of pyrophosphate-extracted OMC pools ranged from -27‰ to -28‰, similar to δ13C of bulk C and to plant-derived humic acids and associated biomass. The water soluble phase (mean δ13C = -29 ‰) was up to 2 ‰ more depleted, whereas the δ13C of Crys pools were more enriched in 13C (-13‰ to -16 ‰) compared to bulk soil. The results from this study suggest that association with minerals does not necessarily confer stability: organo-metal pools dominate in podzol horizons through depth, and contribute most to C storage, but are potentially susceptible to destabilization following the physical changes resulting from forest harvesting disturbance.

Evaluation of anti-tyrosinase activity of Allium ursinum extracts and their metal complexes.

BACKGROUND: A. ursinum is found to contain high levels of some beneficial phenolic and poly phenolic compounds were found to be effective in scavenging DPPH radicals and tyroinase inhibition. The aim of this study was to evaluate the anti-tyrosinase and antioxidant activity of three different extracts from the ultrasound-assisted method and their metal complexes from A. ursinum to discover new candidates for food additives, cosmetic and pharmaceutical products. METHODS: Water, 70% ethanol and absolute ethanol extract of Allium ursinum and their man- ganese and zinc-complexes were characterized by FT-IR and UV-Vis spectra and their antioxidant and anti- tyrosinase activity determined using DPPH radical scavenging and mushroom tyrosinase assay. RESULTS: The antioxidant activity of the water extract was superior to other samples, while the 70% ethanol extract exhibited the highest anti-tyrosinase activity. Metal complex formation of the extracts led to a signifi- cantly lower antioxidant effect. The tyrosinase inhibition strongly related to the metal ion and extraction sol- vent. All the zinc complexes had lower anti-tyrosinase activity than their extracts, while the manganese com- plex of the water and absolute ethanol extracts exhibited higher anti-tyrosinase activity than related extracts. CONCLUSIONS: This study shows that Mn complex of A. ursinum extracts, based on the solvent extraction, could increase tyrosinase inhibition activity and could be a good candidate for intended cosmetic applications and food additives.

Half-Sandwich Iridium and Ruthenium Complexes: Effective Tracking in Cells and Anticancer Studies.

Half-sandwich metal-based anticancer complexes suffer from uncertain targets and mechanisms of action. Herein we report the observation of the images of half-sandwich iridium and ruthenium complexes in cells detected by confocal microscopy. The confocal microscopy images showed that the cyclopentadienyl iridium complex 1 mainly accumulated in nuclei in A549 lung cancer cells, whereas the arene ruthenium complex 3 is located in mitochondria and lysosomes, mostly in mitochondria, although both complexes entered A549 cells mainly through energy-dependent active transport. The nuclear morphological changes caused by Ir complex 1 were also detected by confocal microscopy. Ir complex 1 is more potent than cisplatin toward A549 and HeLa cells. DNA binding studies involved interaction with the nucleobases 9-ethylguanine, 9-methyladenine, ctDNA, and plasmid DNA. The determination of bovine serum albumin binding was also performed. Hydrolysis, stability, nucleobase binding, and catalytic NAD+/NADH hydride transfer tests for complexes 1 and 3 were also carried out. Both complexes activated depolarization of mitochondrial membrane potential and intracellular ROS overproduction and induced cell apoptosis. Complex 3 arrested the cell cycle at the G0/G1 phase by inactivation of CDK 4/cyclin D1. This work paves the way to track and monitor half-sandwich metal complexes in cells, shines a light on understanding their mechanism of action, and indicates their potential application as theranostic agents.

Stoichiometry, polarity, and organometallics in solid-phase extracted dissolved organic matter of the Elbe-Weser estuary.

Dissolved organic matter (DOM) is ubiquitous in natural waters and plays a central role in the biogeochemistry in riverine, estuarine and marine environments. This study quantifies and characterizes solid-phase extractable DOM and trace element complexation at different salinities in the Weser and Elbe River, northern Germany, and the North Sea. Dissolved organic carbon (DOC), total dissolved nitrogen (TDN), Co and Cu concentrations were analyzed in original water samples. Solid-phase extracted (SPE) water samples were analyzed for DOC (DOCSPE), dissolved organic nitrogen (DONSPE), sulfur (DOSSPE) and trace metal (51V, 52Cr, 59Co, 60Ni, 63Cu, 75As) concentrations. Additionally, different pre-treatment conditions (acidification vs. non-acidification prior to SPE) were tested. In agreement with previous studies, acidification led to generally higher recoveries for DOM and trace metals. Overall, higher DOM and trace metal concentrations and subsequently higher complexation of trace metals with carbon and sulfur-containing organic complexes were found in riverine compared to marine samples. With increasing salinity, the concentrations of DOM decreased due to estuarine mixing. However, the slightly lower relative decrease of both, DOCSPE and DONSPE (~77%) compared to DOSSPE (~86%) suggests slightly faster removal processes for DOSSPE. A similar distribution of trace metal and carbon and sulfur containing DOM concentrations with salinity indicates complexation of trace metals with organic ligands. This is further supported by an increase in Co and Cu concentration after oxidation of organic complexes by UV treatment. Additionally, the complexation of metals with organic ligands (analyzed by comparing metal/DOCSPE and metal/DOSSPE ratios) decreased in the order Cu > As > Ni > Cr > Co and thus followed the Irving-Williams order. Differences in riverine and marine trace metal containing DOMSPE are summarized by their average molar ratios of (C107N4P0.013S1)1000V0.05Cr0.33Co0.19Ni0.39Cu3.41As0.47 in the riverine endmember and (C163N7P0.055S1)1000V0.05Cr0.47Co0.16Ni0.07Cu4.05As0.58 in the marine endmember.

Selective binding of an organoruthenium complex to G-rich human telomeric sequence by tandem mass spectrometry.

RATIONALE: Human telomeric DNA is reported to be a potential target for anticancer organometallic ruthenium(II) complexes, however, the interaction sites were not clearly discriminated and identified. METHODS: In the current study, tandem mass spectrometry (MS/MS) using collision-induced dissociation (CID) was firstly introduced to identify the interaction sites of an organometallic ruthenium(II) complex [(η6 -biphenyl)Ru(en)Cl][PF6 ] (1; en = ethylenediamine) with 5'-T1 T2 A3 G4 G5 G6 -3' (I), the repeating unit of human telomeric DNA, in both positive- and negative-ion mode at a low reaction molar ratio (1/I = 0.2) which was applied to preserve the site selectivity. RESULTS: Mass spectrometric results showed that mono-ruthenated I was the main product under the conditions. In positive-ion mode, MS/MS results indicated that ruthenium complex 1 binds to T2 or G6 in strand I. However, in negative-ion mode, no efficient information was obtained for exact identification of ruthenation sites which may be attributed to losses of fragment ions due to charge neutralization by the coordination of the positively charged ruthenium complex to the short MS/MS fragments. CONCLUSIONS: This is the first report of using top-down MS to characterize the interactions of organometallic ruthenium(II) complexes and human telomeric DNA. Thymine can be thermodynamically competitive with guanine for binding to ruthenium complexes even at low reaction molar ratio, which inspired us to explore in greater depth the significance of thymine binding.

Review: ecotoxicity of organic and organo-metallic antifouling co-biocides and implications for environmental hazard and risk assessments in aquatic ecosystems.

Hazard assessments of Irgarol 1051, diuron, 2-(thiocyanomethylthio)benzothiazole (TCMTB), dichloro-octylisothiazolin (DCOIT), chlorothalonil, dichlofluanid, thiram, zinc pyrithione, copper pyrithione, triphenylborane pyridine (TPBP), capsaicin, nonivamide, tralopyril and medetomidine were performed to establish robust environmental quality standards (EQS), based on predicted no effect concentrations (PNECs). Microalgae, zooplankton, fish and amphibians were the most sensitive ecological groups to all the antifoulants evaluated, especially in the early life stages. No differences were identified between freshwater and seawater species. The use of toxicity tests with non-standard species is encouraged because they increase the datasets, allowing EQS to be derived from probabilistic-based PNECs whilst reducing uncertainties. The global ban of tributyltin (TBT) has been heralded as a major environmental success; however, substitute antifoulants may also pose risks to aquatic ecosystems. Environmental risk assessments (ERAs) have driven decision-makings for regulating antifouling products, but in many countries there is still a lack of regulation of antifouling biocides which should be addressed.