The interaction of gadolinium complexes with isolated rat hepatocytes

The lanthanide metal, gadolinium, is currently used in contrast agents for magnetic resonance imaging. We have performed a study of the interaction between isolated rat hepatocytes and ¹⁵³Gd complexed to diethylene-triamine pentaacetic acid (DTPA) or to DTPA-albumin conjugates. The study shows that isolated hepatocytes are able to take up both types of ¹⁵³Gd complexes. The ¹⁵³Gd-DTPA-albumin complexes are apparently taken up by pinocytosis, and possibly receptor-mediated endocytosis and/or adsorptive endocytosis, whereas the uptake mechanism of ¹⁵³Gd-DTPA is unknown. The ¹⁵³Gd-DTPA-albumin complexes, but not the ¹⁵³Gd-DTPA complex, are degraded by the cell. The degradation is inhibited by ammonium chloride. Gadolinium is slowly released back to the medium after loading of the cells with both complex types. In the experiments reported here no evidence of any adverse effects on the hepatocyte resulting from exposure to the ¹⁵³Gd-complexes were observed.     

Experience on the neutron activation of natural/enriched Re,Sm, and Ho nuclides in a reactor for the production of radiotherapeutic radionuclides

In recent years, much effort has been concentrated on the use of Β-emitting radionuclides for the treatment of various cancers. The reports suggested the application of¹⁸⁶Re and¹⁵³Sm as radiotherapeutic radionuclides for the treatment of palliative widespread skeletal métastases, whereas¹⁶⁶Ho was suggested as an agent for radiation synovectomy. Hence, a study on the production of¹⁸⁶Re,¹⁵³Sm, and¹⁶⁶Ho radionuclides was carried out by neutron activation of the appropriate target materials using a Pakistan Atomic Research Reactor (PARR-1) at a neutrons flux of 1 x 10⁴ n/cm² s. These radionuclides were then converted to appropriate radiopharmaceuticals for their use on animals and patients. The targets of natural Re (metal), natural Sm₂O₃, enriched Sm₂O₃ (99.06%), Sm(NO₃)₃ (solid), Sm(NO₃)₃ (liquid), and Ho₂O₃ were irradiated in the PARR-1. After irradiation, the purity of these radionuclides were checked by a multichannel analyzer, Canberra series 85 (MCA) coupled with HPGe detector and then measured in radioisotope calibrator Capintec ionization chamber model CRC-5RH. The effect of the irradiation time and amount of target material was investigated on the production yields of the radionuclides. The results showed an increase in the specific activity of Re with an increase in the irradiation time from 1 to 72 h, whereas a decrease in the specific activity was observed with increase in the amount of Re from 10 to 100 mg. Similar results were obtained for¹⁵³Sm and¹⁶⁶Ho radionuclides. The results further indicated that the specific activity of powder target was much less than the liquid targets for¹⁵³Sm. Their conversion to the appropriate radiotherapeutic radiopharmaceuticals were also carried out by investigating the experimental conditions and acceptable quality of¹⁸⁶Re-HEDP and¹⁵³Sm-EDTMP complexes were prepared. These complexes were then used on animals and patients which showed good performance.     

Studies on Bacillus stearothermophilus. Part 1. Transformation of progesterone to a new metabolite 9,10-seco-4-pregnene-3,9,20-trione

When Bacillus stearothermophilus, a thermophilic bacterium isolated from the Kuwaiti desert, was incubated with exogenous progesterone for 24 h, three monohydroxylated metabolites were produced. 20α-Hydroxyprogesterone was the major metabolite produced in 60.8 relative percentage yield. The other two monohydroxylated metabolites were identified as 6β-hydroxyprogesterone and the rare 6α-hydroxyprogesterone in 21.0 and 13.6 relative percentage yields, respectively. A new metabolite 9,10-seco-4-pregnene-3,9,20-trione was isolated in 3.7 relative percentage yield. All metabolites were purified by preparative TLC and HPLC followed by their identification using ¹H, ¹³C NMR and other spectroscopic data.     

Effects of harvest frequency and biosolids application on switchgrass yield,feedstock quality,and theoretical ethanol yield

Sustainable development of a bioenergy industry will require low‐cost, high‐yielding biomass feedstock of desirable quality. Switchgrass (Panicum virgatum L.) is one of the primary feedstock candidates in North America, but the potential to grow this biomass crop using fertility from biosolids has not been fully explored. The objective of this study was to examine the effects of harvest frequency and biosolids application on switchgrass in Virginia, USA. ‘Cave‐in‐Rock’ switchgrass from well‐established plots was cut once (November) or twice (July and November) per year between 2010 and 2012. Class A biosolids were applied once at rates of 0, 153, 306, and 459 kg N ha^?1 in May 2010. Biomass yield, neutral and acid detergent fiber, cellulose, hemicellulose, lignin, and ash were determined. Theoretical ethanol potential (TEP, l ethanol Mg^?1 biomass) and yield (TEY, l ethanol ha^?1) were calculated based on cellulose and hemicellulose concentrations. Cutting twice per season produced greater biomass yields than one cutting (11.7 vs. 9.8 Mg ha^?1) in 2011, but no differences were observed in other years. Cutting once produced feedstock with greater TEP (478 vs. 438 l Mg^?1), but no differences in TEY between cutting frequencies. Biosolids applied at 153, 306, and 459 kg N ha^?1 increased biomass yields by 25%, 37%, and 46%, and TEY by 25%, 34%, and 42%, respectively. Biosolids had inconsistent effects on feedstock quality and TEP. A single, end‐of‐season harvest likely will be preferred based on apparent advantages in feedstock quality. Biosolids can serve as an effective alternative to N fertilizer in switchgrass‐to‐energy systems.     

Synthesis and DNA‐Cleavage Activities of Dinuclear Copper(II) Complexes of Urea‐Bridged Macrocyclic Polyamines

Two dinuclear macrocyclic polyamine copper(II) (Cu^II) complexes, which have two cyclen units linked by urea, were synthesized as DNA‐cleavage agents. The structures of these new dinuclear complexes were identified by HR‐ESI‐MS and IR analyses. The catalytic activities of DNA cleavage of these dinuclear Cu^II complexes were subsequently studied. The results show that 6a was the better catalyst in the DNA‐cleavage process than 6b . The effects of reaction time and concentration of complexes were also investigated. The results indicate, that the Cu^II complexes could catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA; Form I) under physiological conditions to produce selectively nicked DNA (Form II; no Form III was produced) with high yields (nearly 100%) in short time in the absence of reductant or oxidant.     

Physical and structural characterization of yersiniophore, a siderophore produced by clinical isolates of Yersinia enterocolitica

Clinical isolates of Yersinia enterocolitca, which belong to mouse-lethal serotypes, produce the siderophore yersiniophore. Siderophore production was shown to be iron regulated and to reach maximum production in late log phase. Yersiniophore is a fluorescent siderophore with maximum excitation at 270 nm and a major emission peak at 428 nm. Absorption maxima were seen at 210 and 250 nm with a low broad peak from 280 to 320 nm. Purification of unchelated yersiniophore for structural analysis was made difficult by low yields (1–2 mg mg^-1), and susceptibility to acid hydrolysis, oxidation and possibly polymerization. Yersinophore was therefore purified as an Al³⁺ chelate, which was found to be stable in solution for several weeks. To purify Al³⁺-yersiniophore, unchelated yersiniophore was first extracted from culture supernatants with dichloromethane, concentrated by rotary evaporation and adsorbed to a DEAE-sephacel column. Al³⁺-yersiniophore was eluted with 0.01 m AlCl₃ and further purified by HPLC. The structure was established by a combination of elemental analysis, high resolution mass spectrometry and two-dimensional NMR experiments. Yersiniophore is a phenolate-thiazole siderophore with the formula C₂₁H₂₄N₃O₄S₃Al and a molecular weight of 505.07404 when chelated to Al³⁺. The structure of yersiniophore was determined to be closely related to the structures of pyochelin, produced by Pseudomonas aeruginosa, and anguibactin, produced by Vibrio anguillarum.     

Synthesis and luminescence properties of pyrazolone derivatives and their terbium complexes

Seven novel pyrazolone derivatives were synthesized and characterized by ¹H NMR and ¹³C NMR spectra, mass spectra, infrared spectra and elemental analysis. Their terbium complexes were prepared and characterized by elemental analysis, EDTA titrimetric analysis, UV/vis spectra, infrared spectra and molar conductivity, as well as thermal analysis. The fluorescence properties and fluorescence quantum yields of the complexes were investigated at room temperature. The results indicated that pyrazolone derivatives had good energy‐transfer efficiency for the terbium ion. All the terbium complexes emitted green fluorescence characteristic of terbium ions, possessed strong fluorescence intensity, and showed relatively high fluorescence quantum yields. Cyclic voltammograms of the terbium complexes were studied and the highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LUMO) energy levels of these complexes were estimated. Copyright © 2014 John Wiley & Sons, Ltd.     

The synthetic potential of immobilised cells of Capsicum frutescens Mill cv. annuum

Cells of Capsicum frutescens Mill. cv. annuum, immobilised in reticulate polyurethane foam, produced higher yields of capsaicin, the pungent principle of Chilli pepper fruits, than did freely-suspended cells, when batch-cultured in a medium conducive to culture growth. In the absence of specific precursors to capsaicin, immobilised cells produced between two and three orders of magnitude higher yields than did suspended cells over 5-d or 10-d culture periods (typically up to 4 or 5 mg capsaicin g^-1 dry weight l^-1 medium compared with up to 30 g g^-1l^-1, respectively). These results were reflected by an increased rate and extent of incorporation of L-[U-¹⁴C]phenylalanine into capsaicin in immobilised as compared with freely-suspended cells, and evidence is presented for an inverse relationship between incorporation of [¹⁴C]phenylalanine into protein and capsaicin. The accumulation of capsaicin can be experimentally manipulated and increased by supplementing the medium with precursors of capsaicin such as phenylalanine and isocapric acid and by reducing the growth rate of immobilised cells by omitting growth regulators from the medium. The importance of these observations is discussed.Abbreviations HPLC high-performance liquid chromatography - Phe phenylalanine - TLC thin-layer chromatography     

Synthesis of [11C]sodium thiocyanate for in vivo studies of anion kinetics using positron emission tomography (PET)

Sodium thiocyanate (NaSCN) was labelled with carbon-11 for in vivo studies of anion kinetics using positron emission tomography (PET). The synthesis was complete in 35 min from end of bombardment using [¹¹Qammonium cyanide as the labelled precursor. [¹¹C]NaSCN was produced by the reaction of [¹¹C]sodium cyanide with elemental sulfur and subsequently separated by semi-preparative high performance liquid chromatography (HPLC). Radiochemical yields (isolated) were of the order of 25%. The specific activity was 18 GBq/mmol and the radiochemical purity better than 99%. A PET study performed in a healthy volunteer showed distribution of [¹¹C]SCN⁻ to areas corresponding to cortical fluid spaces known to be accessible to inorganic ions such as Cl⁻. An accumulation of the tracer was observed during the 70 min investigation, indicating at least three compartments of distribution.     

A chromatographic study of the composition of [99mTc]Tc(Sn)EHDP complexes

Tc(Sn)EHDP complexes were prepared under different reaction conditions, and the composition of the reaction mixture was investigated by anion exchange HPLC on Aminex A 28. The effects of the following variables were studied: pH, concentrations of EHDP and Tc, and identity of the inorganic ions in the reaction mixture (Cl⁻, SO²⁻₄ or ClO⁻₄). From the results, conclusions could be drawn on the composition of the various Tc-EHDP complexes in the reaction mixture.     

Estimated human absorbed dose of a new 153Sm bone seeking agent based on biodistribution data in mice: Comparison with 153Sm-EDTMP

PurposeThe main goal in radiotherapy is to deliver the absorbed dose within the target organs in highest possible amount, while the absorbed dose of the other organs, especially the critical organs, should be kept as low as possible. In this work, the absorbed dose to human organs for a new ¹⁵³Sm bone-seeking agent was investigated.Methods¹⁵³Sm-(4-{[(bis(phosphonomethyl))carbamoyl]methyl}-7,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl) acetic acid (¹⁵³Sm-BPAMD) complex was successfully prepared. The biodistribution of the complex was investigated in male Syrian mice up to 48 h post injection. The human absorbed dose of the complex was estimated based on the biodistribution data of the mice by radiation absorbed dose assessment resource (RADAR) method. The target to non-target absorbed dose ratios for ¹⁵³Sm-BPAMD were compared with these ratios for ¹⁵³Sm-EDTMP.ResultsThe highest absorbed dose for ¹⁵³Sm-BPAMD was observed in bone surface with 5.828 mGy/MBq. The dose ratios of the bone surface to the red marrow and to the total body for ¹⁵³Sm-BPAMD were 5.3 and 20.0, respectively, while these ratios for ¹⁵³Sm-EDTMP were 4.4 and 18.3, respectively. This means, for a given dose to the bone surface as the target organ, the red marrow (as the main critical organ) and the total body would receive lesser absorbed dose in the case of ¹⁵³Sm-BPAMD.ConclusionsGenerally, the human absorbed dose estimation of ¹⁵³Sm-BPAMD indicated that all other tissues approximately received insignificant absorbed dose in comparison with bone surface and therefore can be regarded as a new potential agent for bone pain palliation therapy.     

Adrenotensin: An ADM gene product with the opposite effects of ADM

The purpose of the present study was to investigate the effects of putative products of the ADM gene, other than ADM including, prodepin, proADM_45–92 and proADM_153–185 on cat pulmonary arterial (PA) rings with or without precontraction with U46619. Addition of proADM_153–185 (3×10⁻¹⁰−10⁻⁶M) increased tension in a concentration-dependent manner in cat PA rings without precontraction. When vessels were precontracted with U46619, ADM(3×10⁻¹⁰−10⁻⁶M) produced a concentration-dependent vasorelaxant response, whereas proADMus-iss produced a weak concentration-dependent contractile response. Prodepin and proADM_45–92 up to 10⁻⁶M had no activity on PA rings. Since proADM_{1531̄85}, similar to ADM, would be expected to be released in free form following endopeptidase-induced cleavage, the present data suggest proADM undergoes proteolytic processing to release peptides with divergent vascular effects.Thus, the present data also suggest that proADM_153–185 may represent a novel product of the ADM gene and term this putative new substance “adrenotensin”.     

Separation of complexes containing protein A and IgG or Fcγ fragments by high-performance liquid chromatography

Protein A of Staphylococcus aureus is a bivalent Fc receptor that can form complexes with immunoglobulin G (IgG) or Fcγ fragments that activate humoral (e.g., complement) and cellular (e.g., lymphocyte) components of the immune system both in vitro and in vivo. To obtain complexes formed between protein A of Staphylococcus aureus (SpA) and rabbit IgG or Fcγ fragments for purposes of characterizing their compositions and studying their biological activities, we have used high-performance liquid chromatography to separate complexes in 20 min. Complexes were prepared with trace amounts of ¹²⁵I-SpA and ¹³¹I-IgG or ¹³¹I-Fcγ to simplify the analyses. With excess molar amounts of IgG or Fcγ the complexes have the molecular formulas [(IgG)₂SpA]₂ or [(Fcγ)₂SpA]₂. With excess SpA, complexes corresponding to (IgG)(SpA) or (Fcγ)(SpA) are formed, perhaps with other complexes that have different ratios of components. Since SpA is a rod-shaped molecule it elutes at a molecular weight corresponding to 240,000 rather than the true value of 42,000. This behavior is reflected in the elution of certain complexes at shorter retention times than expected on the basis of actual molecular weights, and facilitates separation of complexes from free IgG or Fcγ. The true molecular weights and molecular formulas of complexes isolated by HPLC were verified by ultracentrifugation. This HPLC method was used to study the interconversion and stability of complexes.     

Ferricrocin - an ectomycorrhizal siderophore of Cenococcum geophilum

The ectomycorrhizal fungus Cenococcum geophilum was grown in low-iron medium and the excreted siderophores were extracted, purified and analyzed by HPLC. The principal hydroxamate siderophore produced, was identified as ferricrocin as confirmed by analytical HPLC, FAB-mass spectrometry and ¹H- and ¹³C-NMR spectra. Although the occurrence of ferricrocin has been shown earlier to occur in the ericoid mycorrhizal fungi, this is the first report of ferricrocin in a true ectomycorrhizal fungus which is taxonomically related to the ascomycetes.     

Synthesis,characterization and biodistribution of tris(β-diketonato)technetium(III) complexes

New tris(β-diketonato) complexes of trivalent ⁹⁹Tc/^99mTc with the ligands hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, and octane-3,5-dione were synthesized by reduction of pertechnetate with dithionite in the presence of excess β-diketone. The complexes were purified by HPLC, identified by elemental analysis and FAB mass spectrometry, and characterized by vis./u.v./i.r. spectrophotometry. The hexane-2,4-dionato complex crystallizes in the monoclinic space group P2₁/c, isostructurally with pentane-2,4-dionatotechnetium(III). Biodistribution measurements in mice showed the neutral and lipophilic ^99mTc-diketonato complexes to penetrate the blood-brain barrier. However, increasing lipophilicity decreased the brain uptake except for the heptane-2,4-dionato complex, which displayed the highest uptake of 0.82% injected dose/g.     

Synthesis,radiochemistry and biological evaluation of technetium-99m complexes with 1,8-diamine-3,6-dithiaoctane (DDO) ligands

The synthesis, radiochemical analysis and biological characteristics of some 1,8-diamine-3,6-dithiaoctane derivatives labelled with Tc-99m are reported. Analysis by HPLC shows that most of the ^99mTc-chelates are multicomponent. Furthermore, almost all ^99mTc-complexes isolated by HPLC are lipophilic and stable in vitro. The biodistributions of the most lipophilic of these complexes were evaluated in mice. The N-morpholinylethyl and N,N'′-bisalicylyl derivatives of 1,8-diamine-3,6-dithiaoctane yielded ^99mTc-complexes which exhibit considerable uptake and retention in organs of interest, such as the heart and the brain.     

Synthesis and characterization of [Fe2OX6]2tau; (X = Cl,Br, I) complexes. Crystal and molecular structure of (BzPh3P)2 [Fe2OCl6]

Improved and simple methods for the preparation of [Fe₂OX₆]^2tau; (X = Cl Br I) complexes are described. The complexes were obtained in high and purified yields as the BzPh₃P⁺ or R₄N⁺ salts. An X-ray crystallographic study of (BzPh₃P)₂ [Fe₂OCl₆] revealed a structure for the complex anion in which the two iron atoms are linked by gdot; -oxo bridge and the terminal coordination sites are occupied by the chloride ligands. Mcolon; ssbauer and infrared spectra for the complexes are reported.     

Coproporphyrins,Uroporphyrins, and Their Metal Comlexes: Biosynthesis and Application to Immune Analysis and Diagnostic Methods

Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacterare proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, ¹H-NMR, mass spectrometry, and HPLC. Data showing the possibility of using coproporphyrin III–metal complexes as luminophores for fluorescence detection of tumors was gathered. The current and prospective uses of metal complexes of water-soluble natural porphyrins in advanced immunofluorescence assays are discussed.     

Preparation,HPLC studies and biological behaviour of 99mTc- and 99mTcN-radiopharmaceuticals based on quinoline type ligands

^99mTc-Complexes of oxine (ox), thiooxine (tox) and 8-hydroxy-5-quinolinesulphonic acid (HQS) were prepared by ligand exchange of ^99mTcNCl₄⁻ and by stannous and dithionite reduction of ^99mTcO₄⁻. HPLC studies showed that the ^99mTcN-tox preparation was almost pure TcN(tox)₂. ^99mTc(Sn)-ox yielded a number of peaks upon HPLC with the major peak being identified as TcO(ox)₂Cl. No other Tc-complexes responsible for other chromatographic peaks were identified. Biodistribution studies in mice showed that all complexes except ^99mTc-HQS were cleared essentially by the hepatobiliary pathway. The ^99mTc-HQS preparations showed increased renal clearance due to the increased aqueous solubility of the complexes resulting from the presence of the sulphonate group on the quinoline ring.     

The use of poly(L-proline)-Sepharose in the isolation of profilin and profilactin complexes

In the purification of proline hydroxylase by affinity chromatography on poly(L-proline)-Sepharose it was found earlier that two other components, profilin and the complex profilin-actin, also bind with high affinity to this matrix. We have exploited this observation to develop a rapid procedure for the isolation of profilin and profilin-actin complexes in high yields directly from high-speed supernatants of crude tissue-extracts. Through an extensive search for elution conditions, avoiding poly(L-proline) as the desorbant, we have found that active proteins can be recovered from the affinity column with a buffer containing 30% dimethyl sulphoxide. Subsequent chromatography on hydroxylapatite separates free profilin and the two isoforms of profilactin, profilin-actin_β and profilin-actin_γ. The profilin-actin complexes produced this way have high specific activities in the DNAase-inhibition assay, give rise to filaments on addition of Mg²⁺, and can be crystallized. From the isolated profilin-actin complexes the β- and γ-actin isoforms of non-muscle cells can easily be prepared in a polymerization competent form. Pure profilin is either obtained from an excess pool present in some extracts or by dissociation of profilin-actin complexes and removal of the actin.