99mTc—Sulphur colloid: A freeze-dried,single-step kit for liver imaging

The formulation of a freeze-dried sulphide colloid kit, to be directly labelled with technetium is based on the preparation of tin/II/ sulphide precolloid, stabilized with carboxy methyl cellulose. The formation kinetics of the labelled colloid assessed by GCS-method showing a fast reduction of^99mTc-pertechnetate, forming reduced^99mTc-colloid with subsequent build-up of the labelled sulphur colloid. This is assumed to be due to the formation of^99mTc/V/ to be bound to sulphide precolloid of the kit. The blood clearance data of the labelled colloid in rabbits showed two exponential disappearance phases of radioactivity from blood with biological half times of 3 and 67 min. The results of organ distribution in mice show that more than 85% of the administered activity is accumulated in the liver indicating a high colloidal yield of optimal particle size. The dynamic studies of the labelled colloid achieved in normal subjects using gamma camera indicate a rapid blood clearance and high liver uptake with low surrounding tissue background.This work was performed under the auspices of the Iraqi Atomic Energy Organization and presented in part at the Fifth International Symposium on Radiopharmaceutical Chemistry, Tokyo, August 1984.     

Immobilized enzyme electrode for the determination of salicylate in blood serum

This determination of salicylate in blood serum is based on application of an immobilized enzyme electrode. Salicylate hydroxylase (E.C.1.14.13.1) is chemically immobilized onto a pig intestine mounted on an oxygen electrode. The signals are monitored amperometrically and the resulting output voltage is read using a simple adapter. The experimental parameters and possible interferences are discussed. Samples containing 1.0 × 10^?5?1.87 × 10^?3 M (1.6–300 μg ml^?1) salicylate were assayed with relative standard deviations between 1.3% and 6% and recoveries between 98.7 and 103%. Results obtained by the proposed method and by the established clinical method for randomly spiked pooled serum samples correlated well (r = 0.99).     

Ammonium tetraphenylborate-naphthalene adsorbent for the preconcentration and trace determination of iron in alloys and biological samples using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol by third derivative spectrophotometry

A solid ion-pair material produced from ammonium tetraphenylborate on naphthalene (ATPB-naphthalene) provides a simple, rapid, economical and selective technique for preconcentrating iron from approximately 500 ml of aqueous solution of standard alloys and biological samples. Iron reacts with 2-(5-bromo-2-pryidlazo)-5-diethylaminophenol (5-Br-PADAP) to form a water-soluble cationic complex. When the aqueous solution of this cationic species in the pH range 3.2-8.5 is passed over the adsorbent ATPB-naphthalene at a flow rate of 1 ml min(-1), it is quantitatively retained on naphthalene as an uncharged ion-associated complex. The solid mass from the column was dissolved out with 5 ml of dimethylformamide (DMF) and iron is determined by third derivative spectrophotometry by measuring the signal d(3)A/ dlambda(3) between lambda(2)(773 nm) and lambda(3)(737 nm). The calibration curve is linear over the concentration range 0.10-25.0 mug of iron in 5 ml of DMF solution. Eight replicate determinations of 5 mug of iron gave a mean intensity (peak-to-peak signal between lambda(2) and lambda(3)) of 1.534 with a relative standard deviation of 0.90%. The sensitivity of the method is 0.307 (d(3)A/dnm(3) )/mug found from the slope of the calibration curve. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of iron in various standard alloys and biological samples.     

Pyrazine Complexes of Octacyanometallates of Mo(IV) and W(IV) With 8-hydroxyquinoline: Synthesis,characterisation and thermal studies

The complexes formed by photosubstitution of pyrazine (Pz) in octacyanomolybdate(IV) and -tungstate(IV) with 8-hydroxyquinoline have been assigned the formulae [Mo(CN)₂(OH)₂(Pz)₂(OX)] and [W(CN)₂(OH)₂(Pz)₂(OX)·1.5H₂O]. Coordination of Pz as an unidentate ligand by donating a lone pair of electron from nitrogen is shown by an absorption peak between 8–11 µ. Mechanism for the thermal decomposition of the complexes has been given. The formation of tungsten metal as residue in case of II has been confirmed by XRD analysis. The kinetic and thermodynamic parameters like activation energy (E _a), pre-exponential factor (A) and entropy of activation (S ^#) were calculated employing different integral methods of Doyle, Coats and Redfern and Arrhenius.H for each stage of decomposition was obtained from DSC.This revised version was published online in November 2005 with corrections to the Cover Date.     

Adsorptive stripping voltammetric analysis of 2,4,6-tri(2′pyridyl)-1,3,5-triazine at a mercury electrode

The redox behaviour of adsorbed species of 2,4,6-tri(2-pyridyl)-1,3-5-triazine (TPTZ) at the surface of a mercury electrode was examined using cycling voltammetry. Based on the adsorption and accumulation of TPTZ at the charged mercury surface cathodic adsorptive stripping voltammetry (CSV) is applied for the trace determination of TPTZ using a differential pulse (DP) technique. Experimental and operational parameters for the quantitative analysis of TPTZ are optimized and the detection limit was found to be 3×10^–9 mol/l. The effect of some interferences, e.g. organic compounds, cations and anions, are investigated.     

Separation of radioindium (N.C.A.) from neutron irradiated tin and cadmium on hydrated antimony pentoxide

Hydrated antimony pentoxide (HAP) as an absorbent for column operation has been prepared by hydrolysis of SbCl₅ with deionized water. Sorption behavior of Sn, Cd, Sb and In was studied on HAP in HCl medium. Radiochemical separation of no-carrier added^113mIn from¹¹³Sn/¹²⁵Sb and^115mIn from¹¹⁵Cd wa achieved over a HAPO column. The separated products were of high radionuclidic purity.     

Highly Efficient and Practical Syntheses of Lavendamycin Methyl Ester and Related Novel Quinolindiones

The novel 7-(N-formyl-, 7-(N-acetyl-, and 7-(N-isobutyrylamino)-2-methylquinoline-5,8-diones were synthesized in excellent overall yields in three steps via the nitration of the commercially available 8-hydroxy-2-methylquinoline followed by a reduction-acylation step and then oxidation. Acid hydrolysis of 7-(N-acetylamino)-2-methylquinoline-5,8-dione (14a) afforded the novel 7-aminoquinoline-5,8-dione 7 in excellent yields. Due to our efficient preparation of dione 14a, we now report a short and practical method for the total synthesis of the potent antitumor agent lavendamycin methyl ester (1b) with an excellent overall yield.     

Triosmium clusters derived from the reactions of thioureas with dodecacarbonyltriosmium: Crystal structures of [Os3(CO)11{η 1-SC(NMe2)2}], [Os3(CO)9(μ-OH)(μ-OMeOCO){η 1-SC(NMe2)2}] and [(μ-H)Os3(CO)9{μ 3-NHC(S)NH2}]

The reaction of [Os₃(CO)₁₂] with tetramethylthiourea in the presence of a methanolic solution of Me₃NO·2H₂O at 60° yields the compounds [Os₃(CO)₁₁{η ¹-SC(NMe₂)₂}] (1) in 56% yield and [Os₃(CO)₉(μ-OH)(μ-MeOCO){η ¹-SC(NMe₂)₂}] (2) in 10% yield in which the tetramethylthiourea ligand is coordinatedvia the sulfur atom at an equatorial position. Compound2 is a 50 e^? cluster with two metal-metal bonds and the hydroxy and methoxycarbonyl ligands bridging the open metal-metal edge. In contrast, the analogous reaction of [Os₃(CO)₁₂] with thiourea gives the compounts [(μ-H)Os₃(CO)₁₀{μ-NHC(S)NH₂}] (3) in 8% yield and [(μ-H)Os₃(CO)₉{₃-NHC(S)NH₂}] (4) in 30% yield. In3, the thioureato ligand bridges two osmium atomsvia the sulfur atom, whereas in4 in addition to the sulfur bridge, one of the nitrogen atoms of thioureato moiety bonds to the remaining osmium atom. The decacarbonyl compounds 3 can also be obtained in 50% yield from the reaction of [Os₃(CO)₁₀(MeCN)₂] with thiourea at ambient temperature. Compound3 converts to4 (65%) photochemically. Compound1 reacts with PPh₃ and acetonitrile at ambient temperature to give the simple substitution products [Os₃(CO)₁₁(PPh₃)] and [Os₃(CO)₁₁(MeCN)], respectively, while with pyridine, the oxidative addition product [(μ-H)Os₃(CO)₁₀(μ-NC₅H₄] is formed at 80°C. All the new compounds are characterized by IR,¹-H-NMR and elemental analysis together with the X-ray crystal structures of1,2 and4. Compound1 crystallizes in the triclinic space group P $P\bar 1$ with unit cell parametersa = 8.626(3) Å,b = 11.639(3) Å,c = 12.568(3_ Å,α = 84.67(2)°,β = 75.36(2)°,γ = 79.49(3)°,V = 1199(1) ų, andZ = 2. Least-squares refinement of 4585 reflections gave a final agreement factor ofR = 0.0766 (R _w = 0.0823). Compound2 crystallizes in the monoclinic space group P2_1/n with unit cell parametersa = 9.149(5) Å,b = 17.483(5) Å,c = 15.094(4) Å,β = 91.75(2)°,V = 2413(2) ų, andZ = 4. Least-squares refinement of 3632 reflections gave a final agreement factor ofR = 0.0603 (R _w = 0.0802). Compound4 crystallizes in the monoclinic space group C2/c with unit cell parametersa = 13.915(7) Å,b = 14.718(6) Å,c = 17.109(6) Å,β = 100.44(3)°,V = 3446(5) ų, andZ = 8. Least-squares refinement of 2910 reflections gave a final agreement factor ofR = 0.0763 (R _w = 0.0863).     

Cloning and expression of full-lengthTrichoderma reesi cellobiohydrolase I cDNAs inEscherichia coli

The process of converting lignocellulosic biomass to ethanol via fermentation depends on developing economic sources of cellulases.Trichoderma reesei cellobiohydrolase (CBH) I is a key enzyme in the fungal cellulase system; however, specific process application requirements make modification of the enzyme by site-directed mutagenesis (SDM) an attractive goal. To undertake SDM investigations, an efficient, cellulase-free host is required. To test the potential ofEscherichia coli as a host, T.reesei CBH I cDNA was expressed inE. coli strain GI 724 as a C-terminal fusion to thermostable thioredoxin protein. Full-length expression of CBH I was subsequently verified by molecular weight, Western blot analysis, and activity on soluble substrates.