High Specific Activity Research Articles

Flow-cytometric cell sorting coupled with UV mutagenesis for improving pectin lyase expression.

Introduction: Alkaline pectin lyase is an important enzyme with a wide range of applications in industrial production, It has been widely used in many important fields such as fruit juice processing and extraction, the dyeing and processing of cotton and linen textiles, degumming plant fibers, environmental industrial wastewater treatment, and pulp and paper production. PGLA-rep4 was previously generated as a modified alkaline pectin lyase with high specific activity at pH 11.0°C and 70°C. However, the pre-constructed high-activity pectin lyase expression strains are still difficult to apply in industrial production due to their limited enzymatic activity. We hope to solve these problems by combining modern breeding techniques with high-throughput equipment to rapidly screen alkaline pectin lyase with higher enzymatic activity and lower cost. Methods: We fused the genes encoding PGLA-rep4 and fluorescent protein egfp using a flexible linker peptide and ligated them into a temperature-sensitive plasmid, pKD46. The constructed screening plasmid pKD46-PGLA-rep4-egfp was then transformed into an expression host and screened via flow-cytometric cell sorting coupled with UV mutagenesis. Results: Following mutagenesis, primary screening, and secondary screening, the high-expression strain, named Escherichia coli BL21/1G3, was obtained. The screening plasmid pKD46-PGLA-rep4-egfp was eliminated, and the original expression plasmid pET28a-PGLA-rep4 was then retransformed into the mutant strains. After induction and fermentation, pectin lyase activity in E. coli BL21/1G3 was significantly increased (1.37-fold relative to that in the parental E. coli BL21/PGLA-rep4 strain, p < 0.001), and the highest activity was 230, 240U/mL at 144h. Genome sequencing revealed that genes encoding ribonuclease E (RNase E) and diadenosine tetraphosphatase (ApaH) of E. coli BL21/1G3 were mutated compared to the sequence in the original E. coli BL21 (DE3) strain, which could be associated with increased enzyme expression. Discussion: Our work provides an effective method for the construction of strains expressing pectin lyase at high levels.

Progress and prospect of clinical application of anti-rabies virus monoclonal antibody preparation

Rabies is a severe infectious disease caused by the rabies virus, which seriously damages the central nervous system. Once it occurs, the fatality rate is close to 100%. The World Health Organization's position paper on rabies vaccines recognizes that rabies immunoglobulin (RIG) should be used for post-exposure prophylaxis (PEP) in all category Ⅲ exposure for the first time, as well as in category Ⅱ exposure that suffer from severe immune deficiency, long-term massive use of immunosuppressants, and head and face exposure. The anti-rabies virus monoclonal antibody has high purity and specific activity, can be produced on a sustainable scale, and has no risk of blood source virus contamination. Preclinical pharmacodynamic studies and clinical trial results of the anti-rabies virus monoclonal antibody preparation have confirmed that the preparation has a broad-spectrum neutralization effect on the rabies virus. Additionally, its combined application with the vaccine has little impact on the active immunity of the vaccine. Therefore, the anti-rabies virus monoclonal antibody preparation shows great potential for clinical application in PEP.

Противогистаминные препараты в лечении аллергических заболеваний: не все так просто, как кажется!

According to WHO, up to 35% of the world's population suffers from allergic diseases, and this number is growing exponentially. Histamine has been proven to play a key physiological role in the pathogenesis of allergic disorders by affecting tissues through the activation of H1-receptors. H1-antagonists (antihistamines) are widely used to treat allergic disorders, being one of the most prescribed classes of drugs. The development of medications with high specific activity and low incidence of unwanted side effects is the main goal of pharmaceutical research, so antihistamines have evolved significantly since their first generation was introduced more than 50 years ago. This review analyzes aspects of classification and concepts of clinical use of antihistamines considering their individual specificity.

(Invited) Effect of Gaseous Tritium Environments on Betavoltaic Device Longevity

Direct betavoltaic energy conversion is a specialized energy harvesting technology, converting beta radiation from a radiation source directly into electricity using a semiconductor. Of the most common beta emitting isotopes, tritium betavoltaics hold promise owing to the high specific activity of solid tritium compounds, low shielding requirements and relatively high availability. Betavoltaic devices offer great promise to produce continuous quantities of nanowatt to microwatt power over the course of several years, particularly for low-power sensor, medical, and space applications where sunlight is too sparse for solar cell use or where battery replacement is challenging.Canadian Nuclear Laboratories (CNL) is currently developing betavoltaic devices based on tritium. CNL has unique facilities to produce, fabricate and test betavoltaic devices. Computational techniques have been used to address challenges of longevity and electron-hole pair generation in semiconductor materials, in particular (In,Ga)P. Long-term studies on test wafers in different tritium-containing environments and the effects on power output and longevity will also be discussed.

Optimization of Deuteron Irradiation of 176Yb for Producing 177Lu of High Specific Activity Exceeding 3000 GBq/mg.

The irradiation of 176Yb with deuterons offers a promising pathway for the production of the theranostic radionuclide 177Lu. To optimize this process, calculations integrating deuteron transport, isotope production, and decay have been performed. In pure 176Yb, the undesired production of 174g+mLu occurs at higher deuteron energies, corresponding to a distribution slightly shallower than that of 177Lu. Hence, 174g+mLu can be effectively filtered out by employing either a low-energy deuteron beam or stacked foils. The utilization of stacked foils enables the production of 177Lu using a high-energy linear accelerator. Another unwanted isotope, 176mLu, is produced roughly at the same depth as 177Lu, but its concentration can be significantly reduced by selecting an appropriate post-irradiation processing time, owing to its relatively short half-life. The modeling approach extended to the mapping of yields as a function of irradiation time and post-irradiation processing time. An optimized processing time window was identified. The study demonstrates that a high-energy deuteron beam can be employed to produce 177Lu with high specific activity exceeding 3000 GBq/mg. The effect of different purity levels (ranging from 98% to 100%) was also discussed. The impurity levels have a slight impact. The modeling demonstrates the feasibility of obtaining 177Lu with a specific activity > 3000 GBq/mg and radionuclidic purity > 99.5% when using a commercially available 176Yb target of 99.6% purity.

Extraction and purification of polyphenol oxidase from edible mushroom (Agaricus bisporus) and its use in the manufacture of pastries

This study aimed to extract and purify polyphenol oxidase enzyme (PPO) from mushrooms and use it in pastry industry. The enzyme was extracted from edible mushroom using different buffers and purified by several steps. Some Characterizations of the isolated PPO were studied. The activity of PPO was evaluated using spectrophotometric method and catechol as a substrate. Characterization studies indicated that the enzyme showed the highest specific activity 2087 U/mg protein at pH 6.0 using 0.2M phosphate buffer. The ratio of 1:2 (w:v) from mushroom: buffer was the best for obtaining the highest specific activity (2490 U/mg protein). The optimum time of extraction of PPO was 10 mins to obtain high specific activity (2625 U/mg protein). The precipitation of ammonium sulfate and ion-exchange chromatography techniques were performed to purify PPO. The precipitation with saturated solution of ammonium sulfate (70%) was used, the Specific activity was 4332.7 U/mg protein with purification fold of 1.7 and enzymatic yield of 65.5%. Ion exchange chromatography using DEAE cellulose column estimated that the purification times of the enzymatic extract were 6.01, with an enzymatic yield 22.3%. Storage study of the PPO in edible mushroom at 4oC for 3 months indicated that the PPO loss the stability gradually over time, 33% from its original activity retained after 32 days. It can be concluded that edible mushroom is a good source of PPO and the enzyme still active when the mushroom was stored for one month.

Linker-assisted engineering of chimeric xylanase-phytase for improved thermal tolerance of feed enzymes

Biological enzymes are multifunctional macromolecules that can perform hundreds of reactions simultaneously. An enzyme must possess specific characteristics to meet industrial needs, such as stability over a wide pH and temperature range and high specific activity. A phytase and xylanase mixture is generally added to poultry feed to improve the bird’s health and productivity. Despite this, animal farmers have noticed no difference in productivity, and a leading cause is the high temperature at which feed is pulverized, which inactivates enzymes. A thermo-stable enzyme system can overcome these hitches. Commonly, coatings and immobilization reduce losses caused by physical-chemical factors in feed processing and digestion. To this end, we engineered the multifunctional xylanase-phytase domains on a single polypeptide fused by a helical linker. First, the ideal linker sequence was chosen by computing each selected linker’s root mean square deviation (RMSD). The selected helical linker provides sufficient structural flexibility for substrate binding and product release evaluated by molecular docking and molecular dynamic simulation studies. Furthermore, a domain-domain interaction has stabilized the bridging partners, attaining the thermal optima for xylanase and phytase at 90 °C. Even at the above-optimal temperature (100 °C), the recombinant PLX was relatively stable and retained 64.2% and 59.2% activity for xylanase and phytase, respectively, when surveyed for ten hours. So far, to this date, this is the highest degree of thermostability achieved by any recombinant phytase or xylanase. Communicated by Ramaswamy H. Sarma

Improved Sugarcane-Based Fermentation Processes by an Industrial Fuel-Ethanol Yeast Strain.

In Brazil, sucrose-rich broths (cane juice and/or molasses) are used to produce billions of liters of both fuel ethanol and cachaça per year using selected Saccharomyces cerevisiae industrial strains. Considering the important role of feedstock (sugar) prices in the overall process economics, to improve sucrose fermentation the genetic characteristics of a group of eight fuel-ethanol and five cachaça industrial yeasts that tend to dominate the fermentors during the production season were determined by array comparative genomic hybridization. The widespread presence of genes encoding invertase at multiple telomeres has been shown to be a common feature of both baker's and distillers' yeast strains, and is postulated to be an adaptation to sucrose-rich broths. Our results show that only two strains (one fuel-ethanol and one cachaça yeast) have amplification of genes encoding invertase, with high specific activity. The other industrial yeast strains had a single locus (SUC2) in their genome, with different patterns of invertase activity. These results indicate that invertase activity probably does not limit sucrose fermentation during fuel-ethanol and cachaça production by these industrial strains. Using this knowledge, we changed the mode of sucrose metabolism of an industrial strain by avoiding extracellular invertase activity, overexpressing the intracellular invertase, and increasing its transport through the AGT1 permease. This approach allowed the direct consumption of the disaccharide by the cells, without releasing glucose or fructose into the medium, and a 11% higher ethanol production from sucrose by the modified industrial yeast, when compared to its parental strain.

CO2 methanation with high-loading mesoporous Ni/SiO2 catalysts: Toward high specific activity and new mechanistic insights

In the power-to-gas scenario, surplus renewable electricity is stored in the form of methane, by reacting green hydrogen with waste CO2 through the Sabatier reaction. Low-cost catalysts that feature a high activity at low temperature are needed. We disclose the sol–gel preparation of high-loading mesoporous Ni/SiO2 catalysts. (HR)-TEM, XRD, N2 physisorption, and H2 chemisorption show that small Ni particles (<5 nm) are obtained, even at loading up to 38 wt%. The best catalyst reached a specific activity of 10.2 µmolCH4.g−1.s−1 at 250 °C (TOF = 0.0155 s−1; almost 3 times higher than a reference catalyst prepared by impregnation). Being based on inert silica, these catalysts are ideal model materials to elucidate the reaction mechanism on nickel. Combining CO2-TPD, in-situ CO2-DRIFTS, and TPSR with DFT calculations, we show that CO2 methanation follows mostly the RWGS + CO-hydrogenation and the formate pathways, the former being dominant at low temperature.

Heterologous Expression and Characterization of a Thermostable α-L-Rhamnosidase from Thermoclostridium stercorarium subsp. thermolacticum DSM 2910 and Its Application in the Biotransformation of Rutin.

An α-L-rhamnosidase gene from Thermoclostridium. stercorarium subsp. thermolacticum DSM 2910 (TstRhaA) was cloned and expressed. The maximum TstRhaA activity of the protein reached 25.2 U/ml, and the molecular mass was approximately 106.6 kDa. The protein was purified 8.0-fold by Ni-TED affinity with an overall recovery of 16.6% and a specific activity of 187.9 U/mg. TstRhaA activity was the highest at 65°C and pH 6.5. In addition, it exhibited excellent thermal stability, better pH stability, good tolerance to low concentrations of organic reagents, and high catalytic activity for p-nitrophenyl-α-L-rhamnopyranoside (pNPR). Substrate specificity studies showed that TstRhaA exhibited a high specific activity for rutin. At 60°C, pH 6.5, and 0.3 U/ml enzyme dosage, 60 g/l rutin was converted to 45.55 g/l isoquercitrin within 150 min. The molar conversion rate of rutin and the yield of isoquercitrin were 99.8% and 12.22 g/l/h, respectively. The results suggested that TstRhaA could be used for mass production of isoquercitrin.

Synthesis of novel DOTA-/AAZTA-based bifunctional chelators: Solution thermodynamics, peptidomimetic conjugation, and radiopharmaceutical evaluation

Bifunctional chelators (BFCs), which link metallic radionuclide and a targeting vector, are some of the most crucial components of metallic radionuclide-based radiopharmaceuticals for positron-emission computed tomography (PET) imaging. In this study, we designed and synthesized two versatile BFCs, p-NCS-Ph-DE4TA and p-NCS-Ph-AAZ4TA, and we conjugated them with a prostate-specific membrane antigen (PSMA) inhibitor. These two chelators showed high affinity for Ga (III) according to a study of the thermodynamics and kinetics and DFT calculations. The labeled PSMA targeted probes, [68Ga]Ga-p-NCS-Ph-DE4TA-PSMA and [68Ga]Ga-p-NCS-Ph-AAZ4TA-PSMA, maintained excellent stability in vitro, and they exhibited high specific activity when binding to PSMA. A PET/CT imaging study in mice bearing SMMC-7721 hepatocellular carcinoma xenografts demonstrated clear visualization of tumors with a high tumor uptake and low background level, indicating the excellent performance in vivo and specific activity when targeting hepatocellular carcinomas. In summary, p-NCS-Ph-DE4TA and p-NCS-Ph-AAZ4TA are leading developmental candidates for PET imaging for tumor diagnosis.

Improving the cellobiose hydrolysis activity of glucose-stimulating β-glucosidase Bgl2A

β-Glucosidases with high catalytic activity and glucose tolerant properties possess promising applications in lignocellulose-based industries. To obtain enzymes possessing these properties, a semi-rational strategy was employed to engineer the glucose-stimulating β-glucosidase Bgl2A for high cellobiose hydrolysis activity. A total of 18 mutants were constructed. A22S, V224D, and A22S/V224D exhibited high specific activities of 272.06, 237.60, and 239.29 U/mg toward cellobiose, which were 2.5- to 2.8-fold of Bgl2A. A22S, V224D, and A22S/V224D exhibited increased kcat values, which were 2.7- to 3.1-fold of Bgl2A. A22S and V224D maintained glucose-stimulating property, whereas A22S/V224D lost it. Using 150 g/L cellobiose as the substrate, the amount of glucose produced by A22S was the highest, yielding 129.70 g/L glucose after 3 h reaction at 35 °C. The synergistic effects of the engineered enzymes with commercial cellulase on hydrolyzing cellulose were investigated. Supplemented with the commercial cellulase and A22S, the highest glucose amount of 23.30 g/L was yielded from cellulose with hydrolysis rate of 21.02 %. Given its high cellobiose hydrolysis activity and glucose-stimulating properties, A22S can be used as a component of enzyme cocktail to match mesophilic cellulases for efficient cellulose hydrolysis.

Highly Selective Synthesis of Monoclinic-Phased Platinum-Tellurium Nanotrepang for Direct Formic Acid Oxidation Catalysis.

Designing efficient formic acid oxidation reaction (FAOR) catalysts with remarkable membrane electrode assembly (MEA) performance in a direct formic acid fuel cell (DFAFC) medium is significant yet challenging. Herein, we report that the monoclinic-phased platinum-tellurium nanotrepang (m-PtTe NT) can be adopted as a highly active, selective, and stable FAOR catalyst with a desirable direct reaction pathway. The m-PtTe NT exhibits the high specific and mass activities of 6.78 mA cm-2 and 3.2 A mgPt-1, respectively, which are 35.7/22.9, 2.8/2.6, and 3.9/2.9 times higher than those of commercial Pt/C, rhombohedral-phased Pt2Te3 NT (r-Pt2Te3 NT), and trigonal-phased PtTe2 NT (t-PtTe2 NT), respectively. Simultaneously, the highest reaction tendency for the direct FAOR pathway and the best tolerance to poisonous CO intermediate can also be realized by m-PtTe NT. More importantly, even in a single-cell medium, the m-PtTe NT can display a much higher MEA power density (171.4 mW cm-2) and stability (53.2% voltage loss after 5660 s) than those of commercial Pt/C, demonstrating the great potential in operating DFAFC device. The in-situ Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy jointly demonstrate that the unique nanostructure of m-PtTe NT can effectively optimize dehydrogenation steps and inhibit the CO intermediate adsorption, as well as promote the oxidation of noxious CO intermediate, thus achieving the great improvement of FAOR activity, poisoning tolerance, and stability. Density functional theory calculations further reveal that the direct pathway is the most favorable on m-PtTe NT than r-Pt2Te3 NT and t-PtTe2 NT. The higher activation energy to produce CO and the relatively weaker binding with CO of m-PtTe NT result in the better CO tolerance. This work achieves remarkable FAOR and MEA performances of advanced Pt-based anodic catalysts for DFAFCs via a phase engineering strategy.

Soil Enzyme Activity in Natural and Ploughed Catenas as Parameters of Physiological State of Microbial Communities

The study of soil microbial biomass and enzymatic activity of natural and anthropogenically transformed ecosystems was carried out. The catenas of virgin luvisols and chernozems of the Belogorye Natural Reserve and the catenas of arable soils were studied under similar geomorphological and lithological conditions. The activities of enzymes involved in the cycles of carbon (β-glucosidase and xylosidase), nitrogen (chitinase), and phosphorus (acid and alkaline phosphatase) was studied. It has been established that a decrease in soil microbial biomass as a result of ploughing is not accompanied by an equivalent decrease in the enzymatic activity of the soil. Differences in the enzymatic activity of different soils types were revealed, which indicates differences in the structure of the microbial community and the type of phytocenoses. Patterns of changes in the enzymatic activity of soils in watershed areas, in the transit and accumulative parts of catenas have been established. The values of specific enzymes activities (enzymatic activities per unit of microbial biomass) were calculated. The obtained patterns of changes in the specific enzymatic activity of arable soils indicate that, despite the loss of organic matter and a decrease in microbial biomass as a result of plowing, the physiological efficiency of the microbial community of agrochernozem is higher than in virgin soil. High specific enzymatic activity in arable soils is associated with higher rate of enzyme production by soil microorganisms due to land use changes.

Optimized production, purification, and radiolabeling of the 203Pb/212Pb theranostic pair for nuclear medicine

TRIUMF is one of the only laboratories in the world able to produce both lead-203 (203Pb, t1/2 = 51.9 h) and 212Pb (t1/2 = 10.6 h) onsite via its 13 and 500 MeV cyclotrons, respectively. Together, 203Pb and 212Pb form an element-equivalent theranostic pair that potentiate image-guided, personalized cancer treatment, using 203Pb as a single-photon emission computed tomography (SPECT) source, and 212Pb for targeted alpha therapy. In this study, improvements to 203Pb production were accomplished by manufacturing electroplated, silver-backed thallium (Tl) targets to improve target thermal stability, which allow for higher currents during irradiation. We implemented a novel, two-column purification method that employs selective Tl precipitation (203Pb only) alongside extraction and anion exchange chromatography to elute high specific activity and chemical purity 203/212Pb in a minimal volume of dilute acid, without the need for evaporation. Optimization of the purification method translated to improvements in radiolabeling yields and apparent molar activity of lead chelators TCMC (S-2-(4-Isothiocyanatobenzyl)-1,4,7,10-tetraaza-1,4,7,10-tetra(2-carbamoylmethyl)cyclododecane) and Crypt-OH, a derivative of a [2.2.2]-cryptand.

Naturally Occurring Radioactive Materials in the Soil of Near Basra Oil Company Fields

The present study aimed to determine the levels of contamination with Natural Occurring Radioactive Materials NORM in one of the south oil company fields. The external gamma absorbed dose rate Dγ measured in units of µSv/h was caused by gamma rays of Radium 222, Radium 228 (Thorium 232), and Potassium 40, respectively. The largest value is 9.220 µSv/h. It was found that the highest specific activity (concentration) for Radium 226 is 1136 Bq/kg and the lowest is 0.06 and the highest specific activity for Radium 228 is 721 Bq/kg and the lowest is 0.02 Bq/kg. As for Radium 224, its highest specific activity is 631 Bq/kg and the lowest is 0.02 Bq/kg. Radium-228 is higher than that of Radium-224 or Radium-226, as the Radium-224 is from the Uranium-232 series, and the Radium-228 and Radium-224 are from the Thorium-232 series, meaning that the percentage of the daughters of the Thorium chain is lower than the percentage of the daughters of the Thorium chain Uranium, because the half-life of Radium-226 is 1600 years, which is greater than the half-life of Radium-228, which is 5.75 years. A comparison was made between the local results with the results of soil in Amman. Methods of treating pollution with natural radioactive materials in the oil industry were also discussed.

Surface Ligand Engineering Ruthenium Nanozyme Superior to Horseradish Peroxidase for Enhanced Immunoassay.

Nanozymes have great potential to be used as an alternative to natural enzymes in a variety of fields. However, low catalytic activity compared with natural enzymes limits their practical use. It is still challenging to design nanozymes comparable to their natural counterparts in terms of the specific activity. In this study, a surface engineering strategy is employed to improve the specific activity of Ru nanozymes using charge-transferrable ligands such as polystyrene sulfonate (PSS). PSS-modified Ru nanozyme exhibits a peroxidase-like specific activity of up to 2820Umg-1 , which is twice that of horseradish peroxidase (1305Umg-1 ). Mechanism studies suggest that PSS readily accepts negative charge from Ru, thus reducing the affinity between Ru and ·OH. Importantly, the modified Ru-peroxidasenanozyme is successfully used to develop an immunoassay for human alpha-fetoprotein and achieves a 140-fold increase in detection sensitivity compared with traditional horseradish-peroxidase-based enzyme-linked immunosorbent assay. Therefore, this work provides a feasible route to design nanozymes with high specific activity that meets the practical use as an alternative to natural enzymes.

Antibody and Nanobody Radiolabeling with Copper-64: Solid vs. Liquid Target Approach.

Antibody and nanobody-based copper-64 radiopharmaceuticals are increasingly being proposed as theranostic tools in multiple human diseases. While the production of copper-64 using solid targets has been established for many years, its use is limited due to the complexity of solid target systems, which are available in only a few cyclotrons worldwide. In contrast, liquid targets, available in virtually in all cyclotrons, constitute a practical and reliable alternative. In this study, we discuss the production, purification, and radiolabeling of antibodies and nanobodies using copper-64 obtained from both solid and liquid targets. Copper-64 production from solid targets was performed on a TR-19 cyclotron with an energy of 11.7 MeV, while liquid target production was obtained by bombarding a nickel-64 solution using an IBA Cyclone Kiube cyclotron with 16.9 MeV on target. Copper-64 was purified from both solid and liquid targets and used to radiolabel NODAGA-Nb, NOTA-Nb, and DOTA-Trastuzumab conjugates. Stability studies were conducted on all radioimmunoconjugates in mouse serum, PBS, and DTPA. Irradiation of the solid target yielded 13.5 ± 0.5 GBq with a beam current of 25 ± 1.2 μA and an irradiation time of 6 h. On the other hand, irradiation of the liquid target resulted in 2.8 ± 1.3 GBq at the end of bombardment (EOB) with a beam current of 54.5 ± 7.8 μA and an irradiation time of 4.1 ± 1.3 h. Successful radiolabeling of NODAGA-Nb, NOTA-Nb, and DOTA-Trastuzumab with copper-64 from both solid and liquid targets was achieved. Specific activities (SA) obtained with the solid target were 0.11, 0.19, and 0.33 MBq/μg for NODAGA-Nb, NOTA-Nb, and DOTA-trastuzumab, respectively. For the liquid target, the corresponding SA values were 0.15, 0.12, and 0.30 MBq/μg. Furthermore, all three radiopharmaceuticals demonstrated stability under the testing conditions. While solid targets have the potential to produce significantly higher activity in a single run, the liquid process offers advantages such as speed, ease of automation, and the feasibility of back-to-back production using a medical cyclotron. In this study, successful radiolabeling of antibodies and nanobodies was achieved using both solid and liquid targets approaches. The radiolabeled compounds exhibited high radiochemical purity and specific activity, rendering them suitable for subsequent in vivo pre-clinical imaging studies.

Reconditioning of the Leuven Isotope Separator as a test bench for radioactive ion beam development

Producing novel medical radionuclides in the quantities necessary for pre-clinical and clinical use requires an ion source able to handle high ion throughputs, operated efficiently, to deliver high specific activity samples. This is only possible with the understanding of how different parameters affect the ion source performance. Offline mass separators are needed to run systematic studies that would help us to derive the laws governing those ion sources. At KU Leuven, we are refurbishing the Leuven Isotope Separator, a mass separator previously used for implantations of radioisotopes in solid-state samples and Mössbauer spectroscopy. In the past couple of years, the machine has undergone significant updates and has been adapted to integrate the target ion source units used at CERN-ISOLDE. This paper discusses the modifications to the Leuven Isotope Separator, as well as its potential as a test bench for the study of radioactive ion beams in the future.

Preliminary biological evaluations of first brain‐penetrant GPR119‐based radiotracer in rodents and non‐human primates

AbstractBackgroundG‐protein‐coupled receptors (GPCRs) plays a key role in regulating glucose metabolism. While GPR119 (an important GPCR) agonists have shown potential for improving neurologic and cognitive function in patients with AD and type2 diabetes mellitus (T2DM), clinical interventions targeting GPR119 will require accurate in vivo measures such as PET imaging. We recently synthesized a series of novel piperdine analogs, identifying two analogs (T1 and T2) with high GPR119 binding potency (2‐5 nM) for PET radiochemistry. Here we report their radiochemistry and initial biological evaluations in neuronal cells, normal rodents, and monkeys (vervets).Method[18F]T1/T2 radiochemistry was performed in TRASIS‐AIO automated module following [18F]¯‐based nucleophilic substitution of corresponding precursors. [18F]T1 and T2 in vitro assays were performed in three patient‐derived cell lines with different GPR119 expression (MDM‐MD‐231&lt;NCI‐H1716&lt;HepG2), with and without GPR119 agonists and non‐radioactive T1/T2. Dynamic 0‐60 min brain microPET/CT imaging and biodistribution were performed in normal balb/c mice (n = 4). Healthy adult female vervets (n = 6, 4.5‐6.7 kg) underwent 0‐90 min brain PET imaging. Standard uptake value (SUVmax) and time‐activity curves (TACs) were calculated for whole brain PET/MR images.ResultBoth [18F]T1 and T2 were produced in high radiochemical purities (&gt;98%) and specific activities (∼3800‐4500 mCi/µmol), decay corrected to end of synthesis. Radioactive cell uptake was lower in MDM‐MD‐231 cells (lowest GPR119 expression) and higher in HepG2 cells (higher GPR119 expression); uptake also significantly increased with GPR119 agonists and T1/T2 treatments compared to baseline. [18F]T2 showed slightly better brain uptake in mice compared to [18F]T1 (SUVmax = 0.35±0.07 Vs. 0.55±0.09 g/mL). Biodistribution of [18F]T2 (%ID/mg = 1.01±0.09) also showed high brain uptake. SUVmax (avg = 2.6±0.1 g/mL) and TACs of both [18F]T1 and [18F]T2 in monkey brains demonstrated rapid distribution across BBB within 10 min and favorable clearance within 90 min of tracer injection (Fig 1).ConclusionRadiochemistry was successfully automated and optimized. Cell uptake showed direct relationships between radiotracer uptake and GPR119 expression. MicroPET imaging, biodistribution in rodents and monkey PET imaging demonstrated excellent brain uptake and favorable pharmacokinetics, indicating BBB penetration. These data suggest for the first time that [18F]T1 and T2 have potential for imaging GPR119 in brains of humans with AD or T2DM.