1-H-1-(3-[18F]fluoro-2-hydroxypropyl)-2-nitroimidazole ([18F]FMISO), is the most used hypoxia-imaging agent in oncology and we have recently reported a fully automated procedure for
its synthesis using the Nuclear Interface FDG module and a single neutral alumina column for purification. Using 1-(2′-nitro-1′-imidazolyl)-2-O-tetra-hydropyranyl-3-O-toluenesulfonylpropanediol (NITTP) as the precursor, we have investigated the yield of [18F]FMISO using different reaction times, temperatures, and the amount of precursor. The overall yield was 48.4 ± 1.2% (n = 3), (without decay correction) obtained using 10 mg NITTP with the radio-fluorination carried out at 145 °C for 3 min followed
by acid hydrolysis for 3 min at 125 °C in a total synthesis time of 32 ± 1 min. Increasing the precursor amount to 25 mg did
not improve the overall yield under identical reaction conditions, with the decay uncorrected yield being 46.8 ± 1.6% (n = 3), but rather made the production less economical. It was also observed that the yield increased linearly with the amount
of NITTP used, from 2.5 to 10 mg and plateaued from 10 to 25 mg. Radio-fluorination efficiency at four different conditions
was also compared. It was also observed by radio thin layer chromatography (radio-TLC) that the duration of radio-fluorination
of NITTP, not the radio-fluorination temperature favoured the formation of labeled thermally degraded product, but the single
neutral alumina column purification was sufficient enough to obtain [18F]FMISO devoid of any radiochemical as well as cold impurities.
[18F]-3′-deoxy-3′-fluorothymidine ([18F]FLT) is an established positron emission tomograph (PET)—radiopharmaceutical to study cell-proliferation rate in tumors.
Very low practical yield, uncertain and time-consuming high performance liquid chromatography (HPLC) purification, are the
main obstacles for the routine use of [18F]FLT in clinical PET. To obviate these difficulties, we have developed a fully automated radiosynthesis procedure for [18F]FLT using 5′-O-(4,4′-dimethoxytriphenylmethyl)-2,3′-anhydro-thymidine (DMTThy) and simplified single neutral alumina column purification.
The [18F]FLT yield was 8.48 ± 0.93% (n = 5) (without radioactive decay correction) in a synthesis time of 68 ± 3 min. The radiochemical purity was greater than
95% as confirmed by analytical HPLC using reference standard FLT and also free of non-radioactive impurity. Soluble aluminum
in the final product was much below the permissible limits. Di-methyl sulfoxide (DMSO), the reaction medium, could be detected
in the final product in trace amounts, well below the permissible levels. The synthesized [18F]FLT was sterile and bacterial endotoxin free by appropriate tests. PET imaging study in normal rabbits showed distinct localization
of [18F]FLT in organs having rapid cell division rate like bone marrow, guts and snout and the excretion was through the renal route.
There were no significant uptakes in bone and brain. The former finding confirms the in vivo stability of the [18F]FLT. This simplified radiosynthesis procedure can easily be adapted in any commercial or indigenous [18F]FDG synthesis module for routine [18F]FLT synthesis without the need of additional automation for HPLC purification.
A method is described for the extractive separation and spectrophotometric determination of uranium(VI) from an aqueous solution of pH 5.0–7.0 using benzoylacetone (bzac) and pyridine (py) dissolved in toluene as extractants. The extracted species are UO2(bzac(2·2py. The method provides separation of uranium(VI) from lanthanum(III), samarium(III), neodymium(III), cerium(III) and thorium(IV). The method is precise, accurate, fast and selective.
A solvent extraction method has been proposed for the extractive separation of uranium using triphenylphosphine oxide (TPPO) dissolved in toluene as an extractant. Various parameters affecting extraction conditions such as TPPO concentration, nitric acid concentration, period of equilibration, diluents and effect of diverse ions have been studied. The method permits separation of uranium from binary mixtures containing thorium(IV), cerium(IV), titanium(IV), zirconium(IV), hafnium(IV), copper(II), vanadium(V), and chromium(VI) and is applicable to the analysis of uranium in real and synthetic samples. The method is precise, accurate, fast and selective.
The study is aimed at the analysis and identification of radiochemical and chemical impurities present in [18F]FLT synthesized by a simplified combination-column purification procedure, instead of the currently used HPLC purification.
HPLC analysis of the final product showed an anionic radioactive byproduct, which was established as [18F]4-FBSA. The identity of the product was also confirmed by the radiofluorination of nosyl chloride. Mass spectrum analysis
of both a decayed sample of [18F]FLT and fluorinated nosyl chloride showed a major peak at 242. We have also investigated the possible interference of this
byproduct during PET-imaging in rabbits.
In the recent years, it has been noted that microorganisms with acquired resistance to almost all available potent antibiotics are increasing worldwide. Hence, the use of antibiotics in every clinical setup has to be organized to avoid irrational use of antibiotics. This study was aimed to establish the pattern of antibiotic sensitivity and relevance of antimicrobial resistance in aerobic Gram-negative bacilli. A total of 103 aerobic Gram-negative bacteria namely Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Citrobacter koserii, Proteus spp., and Pseudomonas aeruginosa were collected from tertiary care centers around Chennai. Kirby–Bauer Disk Diffusion test and study for genes of cephalosporin, carbapenem, and aminoglycoside resistance were done. A descriptive analysis of the data on altogether 103 clinical urine isolates was performed. All strains showed susceptibility to colistin. The frequency of genes encoding 16S rRNA methylases armA and rmtB were 7.8% and 6.8%, respectively. Among metallo-β-lactamases, blaVIM, blaIMP, and blaNDM-1 were detected in 6.8%, 3.8%, and 3.8%, respectively. One E. coli strain harbored blaSIM-1 gene. Cumulative analysis of data suggested that 30% of the strains carried more than one resistance gene. The current research evidenced the increasing frequency of resistance mechanisms in India. Combined approach of antibiotic restriction, effective surveillance, and good infection control practices are essential to overcome antibiotic resistance.
The terrestrial gamma-radiation in soil and sand samples collected around Kudankulam nuclear power plant site, i.e., in Radhapuram
Taluk of Tirunelveli District has been measured using NaI(T1) gamma-ray spectrometer. In the soil samples total dose due to
three primordial radionuclides lies in the range of 13.1–168.2 nGy/h with a geometric mean of 137.2 nGy/h, which yields an
annual effective dose of 0.17 mSv/y. In the sand samples the total dose due to three primordial radionuclides has been found
to be in the range of 38.1–1964.4 nGy/h with a geometric mean of 300.8 nGy/h, which gives an annual effective dose of 0.37
mSv/y which is well below the permissible limit (1 mSv).
Recombinant antibody fragments like single chain variable fragments (scFvs) represent an attractive yet powerful alternative to immunoglobulins and hold great potential in the development of clinical diagnostic/therapeutic reagents. Structurally, scFvs are the smallest antibody fragments capable of retaining the antigen-binding capacity of whole antibodies and are composed of an immunoglobulin (Ig) variable light (VL) and variable heavy (VH) chain joined by a flexible polypeptide linker. In the present study, we constructed a scFv against bovine IgA from a hybridoma cell line IL-A71 that secretes a monoclonal antibody against bovine IgA using recombinant DNA technology. The scFv was expressed in Escherichia coli and purified using immobilized metal affinity chromatography (IMAC). The binding activity and specificity of the scFv was established by its non-reactivity toward other classes of immunoglobulins as determined by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis. Kinetic measurement of the scFv indicated that the recombinant antibody fragment had an affinity in picomolar range toward purified IgA. Furthermore, the scFv was used to develop a sensitive ELISA for the detection of foot and mouth disease virus (FMDV) carrier animals.