A New Buffer for Gallium-68 Labeling Suitable for use in Nuclear Medicine; Triethanolamine (TEA).

BACKGROUND: Radiopharmaceuticals labeled with [68Ga] from positron emission tomography (PET) radionuclides are utilized in nuclear medicine for non-invasive in vivo molecular imaging. Buffer solutions for radiolabeling play an important role as choosing the right buffer for the reaction helps to obtain high yield radiopharmaceuticals. Zwitterionic organic buffer 4-(2- hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), sodium acetate (CH3COONa), sodium bicarbonate (NaHCO3) buffers are widely used for labeling of peptides with [68Ga]Cl3. They can be used for peptide labelings with the acidic [68Ga]Cl3 precursor of triethanolammonium (TEA) buffer. The cost and toxicity of TAE buffer are relatively low. METHOD: For [68Ga]GaPSMA-HBED-CC and [68Ga]GaDOTA-TATE labeling, the effectiveness of TEA buffer without chemical impurities in radiolabeling reactions and QC parameters in successful labeling was investigated. RESULTS: The method used to label [68Ga]Cl3 with PSMA-HBED-CC peptide in the presence of TEA buffer was successful when applied at room temperature. High purity radiosynthesis suitable for clinical use was performed to obtain DOTA-TATE peptide with the addition of 363K temperature and radical scavenger. Quality control tests with R-HPLC have shown that this method is suitable for clinical use. CONCLUSION: We present an alternative procedure for labeling PSMA-HBED-CC and DOTATATE peptides with [68GaCl3] to obtain high radioactive doses of final radiopharmaceutical products used in nuclear medicine clinical applications. We have provided a quality-controlled final product that can be used in clinical diagnostic procedures. With the use of an alternative buffer, these methods could be adapted to semi-automatic or automated modules routinely used in nuclear medicine laboratories to label [68Ga]-based radiopharmaceuticals.

Comparison of three different methods in [68 Ga]Ga-PSMA11 radiolabeling.

In this study, quality control parameters such as radiochemical yield, radiochemical purity, and in vitro stability of gallium (68 Ga)-prostate-specific membrane antigen-11 ([68 Ga]Ga-PSMA11) radiopharmaceutical obtained in a research laboratory with three different synthesis algorithms were evaluated and compared. Gallium (68 Ga) chloride precursor to be used in labeling in all three methods was obtained by using ITG brand 68 Ge/68 Ga generator. The first method for the [68 Ga]Ga-PSMA11 radiopharmaceutical was performed with the automated synthesis module, which is widely used in clinical practice. Its radiochemical yield, quality assurance, and stability met expectations. Radiolabeling success, suitability of quality control parameters, and in vitro stability of [68 Ga]Ga-PSMA11 radiopharmaceutical performed with ANMI kit were examined. The final product showed success in 68 Ga-complexation kinetics. All quality control criteria performed met the expectation for clinical applications. Direct cold labeling of PSMA11 ligand with sodium bicarbonate buffer was examined. Results were similar to the ANMI kit. Considering that all three methods are successful in radiochemical labeling, labeling with NaHCO3 buffer shows the labeling preference when we choose the cheap, practical, and easy labeling option.

Validation of HPLC method for the determination of chemical andradiochemical purity of a 68Ga-labelled EuK-Sub-kf-(3-iodo-y-) DOTAGA.

The prostate-specific membrane antigen (PSMA) represents an ideal biomarker for molecular imaging. Various PSMA-targeted radioligands are available for prostate cancer imaging. In this study, labeling of PSMA I&T with 68Ga, as well as validation of the radiochemical purity of the synthesis product by reverse phase radio high-performance liquid chromatography (HPLC) method are intended. Since the standard procedure for the quality control (QC) was not available, definition of chemical and radiochemical purity of 68Ga-PSMA I&T was carried out according to the Q2 (R1) ICH guideline. The standard QC tests were analyzed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. The method was evaluated in terms of linearity, precision and accuracy, LOQ, robustness parameters, and specificity. To assess the radiochemical and chemical purity of 68Ga-PSMA I&T, the developed method was validated to apply safely to patients. An excellent linearity was found between 1µg/mL and 30 µg/mL, with a limit of detection and limit of quantitation of 0.286 µg/mL and 0.866 µg/mL, respectively for 68Ga-PSMA I&T. The recovery was 96.8 ± 3.8%. The quality control of the final product was performed many times with validated radio-HPLC method and was found to comply with ICH requirements, thus demonstrating the accuracy and robustness of the method for routine clinical practice.

Comparison of Radiochemical and Chemical Impurities in Liquid Wastes of Two Different 68Ge/68Ga Generators used in Nuclear Medicine PET Chemistry

Objectives: Germanium-68/gallium-68 (68Ge/68Ga) generator eluate contains a number of metal cations that can compete with 68GaCl3, reducing specific radioactivity. The first step in peptide labeling with 68GaCl3 is to remove 68Ge and several other metals with a long half-life. In this purification step, the elution residue that is passed through the cartridge is collected in glass waste bottles. Waste management is included in good production practices, and in particular, the activity of long half-life 68Ge (270.95 days) and other toxic metal levels need to be examined. Our objective in this study is to determine the 68Ge activity in liquid waste produced by the generation of 68Ga and heavy metal concentrations from the generator column materials and to assess whether it can be disposed of as normal waste. Methods: Liquid wastes produced by passing the 68Ge/68Ga generator eluate of 2 different identities via PSH+ cartridge have been analyzed with the inductively coupled plasma mass spectrometry device in the advanced technology application and research center of our university. Results: The average of the 68Ge radioactive pollution was estimated to be 0.142 ppm (µg.mL-1) in the liquid waste analysis after passing through the PSH+ cartridge in the pre-elution in the GalluGEN brand generator. While there was no tin (Sn) impurity, it was determined that the average zinc (Zn) was 1.95 ppm (µg.mL-1) and the average aluminum (Al) impurity was 10.95 ppm (µg.mL-1). While no 68Ge radioactive pollution was determined in the iThemba LABS brand generator, the average Sn was 0.098 ppm (µg.mL-1), average Zn 48.6 ppm (µg.mL-1), and average Al impurity 4.135 ppm (µg.mL-1). Conclusion: All 68Ge/68Ga generators produced have their own certificates. Metallic contamination in the postmarking waste of 68Ge/68Ga generators can be different. It would be a safe method to keep these wastes in place until they are dumped into the sewage systems, given their half-lives in terms of long half-life radioactive metallic contamination.

Physiological Animal Imaging with 68Ga-Citrate.

BACKGROUND: Gallium-68 is an ideal research and hospital-based PET radioisotope. The uptake mechanism of Gallium citrate is a combination of specific and non-specific processes, for example, vasodilatation, increased vascular permeability, plasma transferrin binding and lactoferrin and siderophores. OBJECTIVE: In this study, by applying the 68Ge/68Ga generator product, a simple technique for the synthesis and quality control of 68Ga-citrate was introduced and was followed by preliminary animal studies. METHODS: The synthesis of 68Ga-citrate was performed with a cationic method using the Scintomics automated synthesis system (Scintomics GmbH GRP module 4V). Since the standard procedure for quality control (QC) was not available, the definition of chemical and radiochemical purity of 68Ga-citrate was carried out according to the ICH Q2(R1) guideline. The standard QC tests were analysed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. In this study, a New Zealand rabbit weighing 2520 g was used for PET/CT images. RESULTS: 68Ga-citrate synthesis was performed by a cationic method without using organic solvents. The labelling efficiency was found to be >98%. The HPLC method used to assess the radiochemical purity of 68Ga -citrate was validated as rapid, accurate and reproducible enough to apply it to patients safely. The physiological distribution of 68Ga-citrate was investigated in a healthy rabbit. The blood pool, liver, spleen, kidneys and growth plates were the most common sites of 68Ga-citrate involvement.

Examination of metallic impurities of 68Ge/68Ga generators used for radioactive labeling of peptides in clinical PET applications.

BACKGROUND/AIM: Especially suitable for PET due to its nuclear physical and radiochemical properties, the positron emitter Gallium-68 (Ga) occurs by electron capture from Germanium-68 (Ge). In such a radionuclide generator, the germanium is bound to an insoluble, inert column matrix and forms a secular radioactive balance with 68Ga obtained in the hour. As a result of the limited radiochemical selectivity of the elution process, the eluate obtained is basically contaminated with the main nuclide traces, so that the eluate becomes a mixture of Ga and Ge radionuclides. Also, the generator eluate contains a number to metal cations that reduce specific radioactivity and can compete with 68Ga. The presence of toxic metal that can be found in the eluate carries the risks of contamination at every step from the production of generators to radiopharmaceutical production. MATERIALS AND METHOD: In our study, by collecting the eluate of the Ge/Ga generators used with different identities in different centers in Turkey, we report comparative analysis of metal contamination in the generator eluate. The eluates of 68Ge/68Ga generators to five different identities were collected. Eluates were analyzed by inductively coupled plasma-mass spectrometry. RESULTS AND CONCLUSION: As a result, each generator contains metallic impurities different from its certificate.

High-Efficiency Cationic Labeling Algorithm of Macroaggregated Albumin with 68 Gallium / 대한핵의학회잡지

Purpose@#The generator product radionuclide gallium-68( 68 Ga) is widely used for PET/CT imaging agents and the 68 Ga-labeled MAA is an attractive alternative to 99m Tc-labeled MAA. Using a commercially available MAA labeling kit for 99m Tc, we presented a reliable synthesis protocol with a highly efficient, organic solvent-free cationic method in GMP conditions in the Scintomics automated synthesis unit. @*Methods@#The labeling process was performed by incubating for 7 min at 90 ° C in the borax vial containing the generator product68 GaCl 3 MAA-HEPES eluted from the PSH + cartridge with 1.5 mL 5 molar NaCl. Quality control of the final product content was examined, and radiopharmaceutical production was carried out in accordance with GMP guidelines. @*Results@#68 Ga eluted from the generator was obtained in more than 99% radiochemical purity and efficiency. In this case, the labeling efficiency was found to be >99%. When the results of SEM-EDX analysis in the final product were examined, it was determined that most of toxic metals were no appreciable in the product content. @*Conclusions@#The radiochemical and chemical purity of the final product allows direct use without purification steps to remove “free 68 Ga” or other toxic compounds.

68Ga-citrate positron emission tomography/computed tomography findings in an experimental model of acute appendicitis in rabbits.

OBJECTIVE: Acute appendicitis (AA) is a common urgent surgical situation of the gastrointestinal tract. Gallium-68 (68Ga)-citrate has been recently investigated as a radiopharmaceutical for infection and inflammation imaging. Aim of the study was to determine the effectiveness of 68Ga-citrate positron emission tomography/computed tomography (PET/CT) imaging in rabbits with experimentally induced AA. MATERIALS AND METHODS: In the AA group (n=6), the appendices of the rabbits were surgically ligated. The sham group (n=6) was used as control. Gallium-68-citrate was synthesized. All rabbits were imaged using 68Ga-citrate PET/CT at 36th following the establishment of experimental models, and at 36th h, all rabbits were appendectomised. Appendices were examined histopathologically. Blood samples were drawn from all rabbits at the beginning and end of the experimental process. Interleukin-6 (IL-6) and procalcitonin (Pct) levels were measured. Acute appendicitis was confirmed histopathologically and biochemically. RESULTS: Gallium-68-citrate PET/CT showed acute appendicitis in all rabbits. The sensitivity, specificity and accuracy of 68Ga-citrate PET/CT in AA were 100%, 83.3% and 91.7%, respectively. CONCLUSION: Acute appendicitis is accurately imaged in an experimental rabbit model by using 68Ga-citrate with PET/CT.

Detection of Pulmonary Embolism with Gallium-68 Macroaggregated Albumin Perfusion PET/CT: An Experimental Study in Rabbits.

This study was designed to evaluate the accuracy of detecting pulmonary embolism (PE) using the Technegas SPECT/CT combined with 68Ga PET/CT in a rabbit model. One hour after artificial PE (n = 6) and sham (n = 6) models were created, Technegas SPECT/CT ventilation and 68Ga-MAA PET/CT perfusion scan (V/Q scan) were performed. Ventilation imaging was performed first on all cases. Technegas SPECT/CT and 68Ga-MAA PET/CT images were evaluated by a nuclear medicine physician who recorded the presence, number, and location of PE on a per-lobe basis. The sensitivity, specificity, and accuracy of Technegas SPECT/CT and 68Ga-MAA PET/CT for detecting PE were calculated using a histopathological evaluation as a reference standard. A total of 60 lung lobes were evaluated in 12 rabbits, and PE was detected in 20 lobes in V/Q scans and histopathological analysis. The overall sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively, for both the Technegas SPECT/CT and 68Ga-MAA PET/CT V/Q scans. Technegas/68Ga-MAA V/Q scans have good sensitivity, specificity, and accuracy in the detection of PE in this animal model study.

Can YKL-40 be an Inflammatory Biomarker in Vitamin D Deficiency?

Vitamin D deficiency is associated with several non-homeostatic conditions and/or diseases like inflammation, atherosclerosis, cardiovascular disease and mortality. YKL-40 is a glycoprotein, secreted by macrophages, neutrophils and different cell types and it is also associated with inflammation and pathological tissue remodeling. In this study, we aimed to evaluate relationship between the proinflammatory biomarkers YKL-40 and hs-CRP levels and vitamin D deficiency. Our study group includes 45 subjects with vitamin D deficiency (Group 1) (20 M, 25 F; mean age 37.72 ± 7.70 years) and 40 age and sex-matched healthy subjects with normal serum levels of vitamin D (Group 2) (19 M, 21 F; mean age 39.26 ± 7.41 years). Plasma 25 (OH) vitamin D levels were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Plasma YKL-40 analysis was performed by ELISA. Serum hs-CRP levels were measured by nephelometric method. Plasma vitamin D levels below 20 ng/mL were accepted as vitamin D deficiency. Although we could not find any significant differences by means of serum hs-CRP levels between Group 1 and Group 2 (2.21 (0.27-11.70); 1.79 (0.16-9.85) mg/L, p = 0.247), plasma YKL-40 levels were significantly higher in group 1 than group2 (70.47 (17.84-198.50); 47.14 (4.80-135.48) ng/mL, p = 0.047). In literature, vitamin D deficiency is associated with inflammation. In our study, we found similar hs-CRP levels between groups and higher YKL-40 levels in group 1. Vitamin D deficiency may be related to high YKL-40 levels in terms of causing chronic inflammation.

Investigation of the inflammatory biomarkers of metabolic syndrome in adolescents.

BACKGROUND: Metabolic syndrome (MetS) is a chronic and multifactorial syndrome characterized by a low-grade chronic inflammation, and a major risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). In our study, we aimed to investigate the serum levels of high sensitive C-reactive protein (hs-CRP), haptoglobin (Hp), α2-macroglobulin (α2-MG), platelet factor-4 (PF-4), fetuin-A, serum amyloid P (SAP) and α1-acid glycoprotein (AGP) in an adolescent population with MetS. METHODS: This study was performed in 43 (18 males, 25 females) MetS adolescents between the ages of 13 and 17 years (14.70±1.15) and 43 lean controls were matched for age and sex. The serum levels of Hp, α2-MG, PF-4, fetuin-A, SAP and AGP were measured by using a multi-ELISA technique. RESULTS: Serum Hp, fetuin-A (p<0.01) and PF-4, hs-CRP, SAP, AGP (p<0.001) values of the MetS subjects were significantly higher than those of the controls. No difference was found in serum α2-MG levels between the MetS and control groups (p=0.184). CONCLUSIONS: This finding suggests the possibility of using these markers in diagnosis of MetS in adolescents to prevent future complications.

Assessment of In vitro Antibacterial Activity and Cytotoxicity Effect of Nigella sativa Oil.

BACKGROUND: Methicillin resistance is a serious health concern since it has spread among Staphylococcus aureus and coagulase-negative Staphylococci (CoNS) that are frequent community and nosocomial pathogens worldwide. Methicillin-resistant strains are often resistant to other classes of antibiotics, making their treatment difficult. Nigella sativa oil is known to be active against Gram-positive cocci, yet its in vitro cytotoxicity is rarely investigated, is a proper and powerful candidate for treatment of methicillin-resistant isolates. OBJECTIVES: The aim of this study is to evaluate the in vitro antibacterial activity and cytotoxicity effect of N. sativa oil. MATERIALS AND METHODS: The minimal inhibitory concentrations (MICs) of N. sativa oil were determined by broth microdilution method against four different American Type Culture Collection strains, 45 clinical isolates of methicillin-resistant S. aureus (MRSA), and 77 methicillin-resistant CoNS (MRCoNS). The effects of different dilutions (0.25 µg/mL, 0.5 µg/mL, and 1 µg/mL) of N. sativa oil on the proliferation of gingival fibroblasts were evaluated. RESULTS: The MIC values of N. sativa oil against clinical isolates of Staphylococci were between <0.25 µg/mL and 1.0 µg/mL. Compared to the control group, there was no cytotoxic effect on the proliferation of the gingival fibroblasts. CONCLUSION: In the present study, the oil of N. sativa was very active against MRSA and MRCoNS and had no in vitro cytotoxicity at relevant concentrations. These findings emphasize that there is a requirement for further clinical trials on N. sativa oil for "safe" medical management of infections caused by methicillin-resistant Staphylococci. SUMMARY: The minimal inhibitory concentration (MIC) values of Nigella sativa oil against Staphylococcus aureus American Type Culture Collection (ATCC) 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 standard strains were 0.5 µg/mL, 2 µg/mL, 64 µg/mL, and 64 µg/mL, respectivelyThe N. sativa oil showed an excellent antibacterial activity against clinical isolates of methicillin-resistant S. aureus and methicillin-resistant coagulase-negative Staphylococci with very low MIC range of <0.25-1.0 µg/mLThe N. sativa oil exhibited no cytotoxic effect on the proliferation of the gingival fibroblasts. Abbreviation used: ATCC: American Type Culture Collection; CLSI: Clinical and Laboratory Standards Institute; CoNS: Coagulase-negative Staphylococci; DMEM: Dulbecco's modified Eagle's medium; DMSO: Dimethyl sulfoxide; FBS: Fetal bovine serum; HGF: Human gingival fibroblast; MIC: Minimal inhibitory concentration; MRCoNS: Methicillin-resistant CoNS; MRSA: Methicillin-resistant S. aureus.

Late-onset Streptococcus pasteurianus sepsis in a preterm baby in a neonatal intensive care unit.

Apnea, cyanosis, lethargy and prolongation in capillary filling time developed on the postnatal 37(th) day in a preterm baby who was born at the 30(th) gestational week with a birth weight of 1 300 g. Acute phase reactants and immature/total neutrophil count ratio were found to be high. The patient who was diagnosed with sepsis was successfully treated with meropenem which was started empirically. In his blood culture Streptococcus pasteurianus grew. S. pasteurianus is in the subgroup of streptococcus bovis which is one of the D group streptococci and its previous name is S. bovis type II/2. In the literature, there are very few cases of neonatal infection related with this bacterium. As far as we know, this is first case of neonatal sepsis caused by S. pasteurianus in Turkey. In addition, we tried to determine the clinical properties of neonatal infections arising from S. pasteurianus by reviewing the literature.