A radioimmunoassay for serum estradiol

A radioimmunoassay procedure to measure estradiol levels in human serum was developed using¹²⁵I labeled estradiol and antiestradiol antibody raised in-house using the estradiol-6-CMO-BSA as the immunogen. Controlled process serum was used to maintain the serum matrix and sample-standard identity. The assay was validated by analysing several (n=40) samples and comparing with established commercial assays. The assay had a sensitivity of 35 pg/mL and a range of 50 pg/mL to 5 ng/mL. The interassay C.V. were between 2 to 10% while the intraassay C.V. were between 2 and 8%. This assay is sensitive enough for monitoring ovulation and hypersecretions in ovarian tumours and was primarily developed to be used as an in-house assay in the local hospitals.     

Syntheses of haptens and hapten-protein conjugates for insecticide propoxur and cyhalothrin

A facile procedure was described for the hapten design of the N-methylcarbamate insecticide propoxur.Two new haptens of propoxur(hapten 1a and hapten 1b) were synthesized by introducing appropriate spacers in the pesticide aromatic moiety of the analyte molecular structure.First,the propoxur reacted with nitric acid to yield the intermediate product.Then hapten 1a was prepared via the reduction of the intermediate product,and hapten 1b was formed by the acylation of hapten 1a with succinic anhydride.In addi...     

Comparison study between direct and indirect labeling of estradiol for radioimmunoassay purpose

In the present study, estradiol (E₂) which contains an aromatic phenol ring in its chemical structure was chosen for direct and indirect labeling techniques using ¹²⁵I and chloramine-T oxidation method. In direct technique the hydrogen atom in phenol ring was replaced by a radioiodine atom directly, which in indirect one, histidine methyl ester (HME) was labeled firstly with ¹²⁵I using chloramine-T method then conjugated with E₂. The ¹²⁵I-labeled materials were purified using HPLC technique. The comparison study between the two obtained tracers was carried out in terms of radiochemical purity, binding percent, specific activity, non specific binding, binding displacement, shelf life using a radioimmunoassay (RIA) with specific antibody. The results indicated that indirect iodination of estradiol will cause significant increasing in studied parameters when combined with specific antibody than direct one.     

A new strategy for improved nicotine vaccines using conformationally constrained haptens

Constrained nicotine analogues were synthesized and coupled to the carrier protein KLH. The immunogenic effects were compared to those using our previously designed flexible nicotine hapten. Immunization of mice with the constrained hapten conjugates resulted in highly increased antibody titers and affinity for nicotine.     

Serum estradiol measurement by solid-phase chemiluminescence immunoassay and direct radioimmunoassay

Estradiol017β is determined in serum extracts by solid-phase chemiluminescence immunoassay. The results are compared with those obtained from unextracted serum in routine conditions with a commercial radioimmunoassay (r.i.a.) kit. For the chemiluminescence procedure, a purified monoclonal antibody to estradiol-6-carboxymethyloxime/bovine serum albumin and the homologous chemiluminescent marker conjugate estradiol-6-carboxymethyloxime aminobutylethylisoluminol are used. Bound and free ligand are separated by washing and simple centrifugation. Results obtained by the chemiluminescence assay (y) and by r.i.a. (x) on 170 serum specimens from women during ovulation induction showed good correlation (y = 1.01x ? 16 with r = 0.95). The methods are similar in selectivity, detection limit (ca. 10 ng l^?1) and precision (interassay relative standard deviation, 8–13%).     

Syntheses of new benzoxazole derivatives

2‐(Arylidene)cyanomethylbenzoxazoles have been prepared in water from benzoxazole‐2‐ylacetonitriles. Using multi‐component reactions, a variety of heterocycles containing benzoxazole and nitrile functionality has been prepared. J. Heterocyclic Chem., (2011).     

Syntheses of new binucleating heterocyclic ligands

The syntheses of five new mixed azine-azole binucleating ligands are described.     

Syntheses of new diluents for medium birefringence liquid crystals materials

New liquid crystals of 3HEHV ((4-trans-propyl-cyclohexyl-1), (4?-vinyl-cyclohexyl-1?)-ethane-1,2) and 3HB2V ((4-trans-propyl-cyclohexyl-1), (4-butenyl-3,4)-benzene) were synthesised and evaluated as the diluents for medium birefringence liquid crystal mixtures. The procedures transferring cis-isomers into trans-isomers of the cyclohexane were described. The results showed that both 3HEHV and 3HB2V decrease the crystallisation temperature and the viscosities by doping them with the medium birefringence mixtures in a fraction of 15%. The characteristics of the structures are correlated with the properties of the mixtures.     

Syntheses of new functionalized azobenzenes for potential molecular electronic devices

New non-symmetrical azobenzene derivatives have been synthesized as potential molecular electronic switching device candidates. The Oxone^® mediated oxidation of anilines provided nitroso-functionalized arenes, which were then condensed with substituted anilines to provide a series of azobenzene derivatives that could be further converted into oligo(phenylene ethynylene)s or diazonium salts. The resulting thiolacetates, thiols, or diazonium salts are capable of forming molecular layers on the surface of gold or silicon, thereby paving the way for molecular electronics testing.     

Stabilization of antibodies by haptens

A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range 0.01 to 0.32 μg mL^–1 and for salicylic acid from 0.04 to 1.0 μg mL^–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide (0.20 μg mL^–1) and salicylic acid (0.50 μg mL^–1) were 1.1% and 35 h^–1, and 0.9% and 45 h^–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify to the usefulness of the proposed sensor. Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999     

Syntheses and structures of two new lithium-heptamolybdates

The synthesis, crystal structures, IR, UV–vis, ⁷Li NMR spectra, electrochemical investigations, and conductivity studies of two new lithium-heptamolybdates, (NH₄)₄[Li₂(H₂O)₇][Mo₇O₂₄]·H₂O (1) and (NH₄)₃[Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]·2H₂O (2), are reported. In 1 the (NH₄)⁺ and [Li₂(H₂O)₇]²⁺, cations are charge balanced by the heptamolybdate anion. In 2, the [Mo₇O₂₄]^6? anion is coordinated to three unique Li⁺ ions via a μ₆-hexadentate-binding mode resulting in the formation of a two-dimensional (2-D) [Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]^3? anionic complex, charge neutralized by three (NH₄)⁺ ions. The cations, anions, and the lattice water molecules in 1 and 2 are linked by weak H-bonding interactions.     

Syntheses and molecular structures of new cali

An unusual disproportionation reaction of the molybdenum(IV) and tungsten(IV) chlorides [MCl4L2] (M=Mo, L=Et2S, Et2O; M=W; L= Et2S) in the presence of p-tBu-calix[4]arene (Cax(OH)4) and triethylamine leads to d0 complexes [(CaxO4)[CaxO2(OH)2]M] (1) and d3 compounds (HNEt3)2[(CaxO4)2M2] (2). Complexes la (M = Mo), 1b (M = W), and the HCl adduct of 2a (M = Mo) have been structurally characterized. Compound 1a represents one of the few examples of a well-characterized molybdenum(VI) hexa-alkoxide complex of the type [Mo(OR)6]. Isolation and structural characterization of the side product [(CaxO4W)[kappa2(O)-kappa1(O)-CaxO3(OH)](CaxO4WCl)] (3) suggests the intermediacy of chloro-containing calix[4]arene complexes in these reaction mixtures. The reaction of 1a with HCI provides [CaxO4MoCl2] (4a), the first well-defined example of a mixed molybdenum(VI) alkoxide halide compound of the general formula [MoClx(OR)6-x].     

Synthesis of site-heterologous haptens for high-affinity anti-pyraclostrobin antibody generation

The design and synthesis of functional chemical derivatives of small organic molecules is usually a key step for the intricate production of a variety of bioconjugates. In this respect, the derivatization site at which the spacer arm is introduced in immunizing conjugates constitutes a highly critical parameter for the generation of high-affinity and selective antibodies. However, due to the usual complexity of the required synthetic procedures, the appropriate comparison of alternative tethering positions has often been neglected. In the present study, meticulous strategies were followed to prepare synthetic derivatives of pyraclostrobin with the same linkers located at diverse rationally-chosen sites. Activity appraisal of antibodies and bioconjugates was carried out by bidimensional competitive direct and indirect immunoassays, and a superior performance of two of the three synthesized haptens was found. Finally, a detailed analysis of the conformations of the target molecule and the synthesized haptens in aqueous solution was done using computer assisted molecular modeling techniques. This study suggested that the lower titers and affinities of one set of antibodies are most probably due to conformational effects of the spacer arm in the immunizing bioconjugate.     

Syntheses and crystal structures of two new pentaborates

Two new pentaborates, [Zn(DIEN)₂][B₅O₆(OH)₄]₂ (DIEN=diethylenetriamine) (I) and [B₅O₇(OH)₃Zn(TREN)] (TREN=tris(2-aminoethyl)amine) (II), have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, FTIR, elemental analysis and thermogravimetric analysis. Compound I crystallizes in the monoclinic system, space group P2₁/c (No. 14), , , , β=91.259(2)°, , Z=2. The structure consists of isolated borate polyanion [B₅O₆(OH)₄]⁻ and zinc complex cation [Zn(DIEN)₂]²⁺. The anionic units, [B₅O₆(OH)₄]⁻, are linked by hydrogen bonds to form a 3D supramolecular network containing large channels, in which the templating [Zn(DIEN)₂]²⁺ cation are located. II is monoclinic, P2₁/c (No. 14), , , , β=99.635(2)°, , Z=4. The structure of II is constructed from two distinct motifs, a usual [B₅O₇(OH)₃]²⁻ cluster and a supporting zinc complex [Zn(TREN)]²⁺, which are integrated through Zn-O-B linkage. This compound represents the first example of the combination of B-O cluster with transition-metal complex.     

Syntheses and biological properties of new 8-fluorocarbapenem derivatives

8-Fluorocarbapenem derivatives having various C-3 side chains were synthesized to study for the structure-activity relationship of carbapenems by in vitro biological evaluation. The introduction of fluorine at C-8 of racemic PS-5 led to slight improvements of the antimicrobial activity and the stability to renal dehydropeptidase-I. When D-cysteine was additionally introduced to the C-3 position of (+/-)-8-fluorocarbapenem, the diastereomeric separation of the 8-fluorocarbapenems became feasible. As expected from penicillins and cephalosporins, (+)-8-fluoro-3-D-cysteinylcarbapenem (+)-7a was antimicrobially active, whereas (-)-7b was inactive. It is worth noting, however, that (+)-7a was significantly more sensitive to renal dehydropeptidase-I than (-)-7b. Irrespective of the presence of fluorine at C-8, basic S-side chains at C-3, such as the pyridyl and pyrrolidyl groups, significantly improved in antimicrobial activity and dehydropeptidase-I stability. The combination of 8-fluorination with C-3 basic side chains in 7c--g resulted in a marked improvement of antimicrobial activity and dehydropeptidase-I stability.     

Syntheses and activities of new C10 beta-turn peptidomimetics

A program to identify small molecules that mimic or disrupt protein-protein interactions led us to design the peptidomimetics 1-3. Solid-phase syntheses of 1-3 were developed. The purities of the crude materials isolated from the resin tend to be highest for the S- and N-compounds 2 and 3 and better than in the corresponding syntheses of peptidomimetics A. The particular dipeptide units incorporated were chosen to correspond with the turn regions of the neurotrophins (e.g., nerve growth factor [NGF] and the neurotrophin factor-3 [NT-3]). Preliminary studies were performed to access the binding of these analogues to Trk receptors and their ability to induce cell survival (just as NGF and NT-3 do). Several active compounds were identified. However, poor water solubilities of some of the other compounds preclude reliable testing. Consequently, solid-phase modifications to the synthetic procedures were investigated to provide access to the derivatives 12-14 in which the aromatic nitro group is replaced by amine, guanidine, or sulfonamide functionalities. The latter are more acceptable pharmacophores than nitro groups and also tend to increase the water solubilities of the peptidomimetics.