Bio-distribution study of Tc-99m HMPAO labeled platelet in healthy volunteer.

Objectives: The bio-distribution of Tc-99m HMPAO labeled platelets (LP), which could be used to image subtle thrombosis, is not reported in a human yet, which is the subject of the current study. Method: The platelets were extracted from 49 ml whole blood and labeled with Tc-99m HMPAO, then re-injected to the healthy volunteer. Anterior and posterior whole body imaging was done by a dual-head gamma camera 3, 18, 33, 46, 81, 124, 190 min and 15 hours after injection. Also a whole-body SPECT was done at 137 min post-injection. The area under the curves of the spleen, liver, left kidney, bladder, right lung, brain, and abdominal aorta ROIs was calculated to estimate the accumulation of labeled platelets within the organs. Results: The spleen was the target organ. The kidneys, liver, and heart were also remarkably visualized. The thyroid, stomach, bladder, or gastrointestinal (GI) uptake/activity was not significant. The stomach visualization was enhanced after ingestion at 60 min. The sagittal and lateral sinuses were delineated, and the background of the brain was very low. During the study, the area under the curve of activity was 738, 308, 302, 196, 230, 121, 79, 216, 529, 369, 162, and 54 counts. min/pixel for spleen, liver, heart, right lung, left kidney, right iliac artery, sagittal sinus, thyroid, bladder, stomach, GI, and background, respectively. Conclusion: The quality of the scan with low dose Tc-99m HMPAO LPs is optimal. We documented the bio-distribution of LPs. The optimal imaging time was 80-120 min post-injection when the free Tc-99m and GI transit were negligible. The sagittal and lateral sinuses were visualized enabling detection of possible clots in the vessels.

Potential use of cold plasma treatment for disinfection and quality preservation of grape inoculated with Botrytis cinerea.

Gray mold caused by Botrytis cinerea is a serious disease of grape (Vitis vinifera) during storage. The aim of this study is to evaluate the effect of atmosphere cold plasma (a novel and nonthermal technology) on inactivation of B. cinerea and preservation of chemical, physical, and mechanical characteristics of grape inoculated with B. cinerea. Herein, different time of cold plasma (0, 10, 20, and 40 s) was firstly considered to be the main factors, besides different storage time (1, 2, 3, 4, and 5 weeks) at 4°C. According to the results, plasma treatment exhibited inhibitory effect on gray mold percentage and microbial load of B. cinerea (log CFU g-1) during postharvest storage. So, in the last week, the gray mold percentage and microbial load in the control were 100% and 3.6 log CFU g-1, and in 40-s plasma were 4.5% and 2.53 log CFU g-1, respectively. Although the minimum infection and microbial load were observed in 40-s plasma, better postharvest quality preservation was observed in short-time cold plasma treatment (≤20 s). Forty-second plasma caused fruit tissue destruction and negatively decreased mechanical indices (Emod: 0.0028, Fmax = 1.78, and W = 3.18) and weight loss (91.9) in comparison with ≤20-s plasma, in which mechanical indices (Emod =0.0077, Fmax = 3.6, and W = 10.06) and weight loss (1/1) were higher. The long-time cold plasma treatment (40 s) had also maximum effects on color changes (10) and surface temperature (2.8°C). Although the highest TSS and TA were observed in 40-s Plasma, but different time of plasma treatments had no effect on pH. Altogether, these results indicate that the short-time cold plasma treatment can inactivate B. cinerea on grape berries and preserve crop quality properties.

Imidazo[1,2-a]quinazolines as novel, potent EGFR-TK inhibitors: Design, synthesis, bioactivity evaluation, and in silico studies.

Tyrosine protein kinases (TKs) have been proved to play substantial roles on many cellular processes and their overexpression tend to be found in various types of cancers. Therefore, over recent decades, numerous tyrosine protein kinase inhibitors particularly epidermal growth factor receptor (EGFR) inhibitors have been introduced to treat cancer. Present study describes a novel series of imidazo[1,2-a]quinazolines 18 as potential -inhibitors. These imidazoquinazolines (18a and 18o, in particular) had great anti-proliferative activities with IC50 values in the micromolar (µM) range against PC3, HepG2, HeLa, and MDA-MB-231 comparing with Erlotinib as reference marketed drug. Further evaluations on some derivatives revealed their potential to induce apoptotic cell death and cell growth arrest at G0 phase of the cell cycle. Afterwards, the kinase assay on the most potent compounds 18a and 18o demonstrated their inhibitory potencies and selectivity toward EGFR (with EGFR-IC50 values of 82.0 µM and 12.3 µM, respectively). Additionally, western blot analysis on these compounds 18a and 18o exhibited that they inhibited the phosphorylation of EGFR and its downstream molecule extracellular signal-regulated kinase (ERK1/2). However, the level of B-Actin phosphorylation was not changed. Finally, density functional theory calculations, docking study, and independent gradient model (IGM) were performed to illustrate the structure-activity relationship (SAR) and to assess the interactions between proteins and ligands. The results of molecular docking studies had great agreement with the obtained EGFR inhibitory results through in vitro evaluations.

Design, synthesis and evaluation of novel tetrahydropyridothienopyrimidin-ureas as cytotoxic and anti-angiogenic agents.

The novel derivatives of tetrahydropyridothienopyrimidine-based compounds have been designed and efficiently synthesized with good yields through seven steps reaction. The anticancer activity of compounds 11a-y has been evaluated against MCF-7, PC-3, HEPG-2, SW-480, and HUVEC cell lines by MTT assay. The target compounds showed IC50 values between 2.81-29.6 µg/mL and were compared with sorafenib as a reference drug. Among them, compound 11n showed high cytotoxic activity against four out of five examined cell lines and was 14 times more selective against MRC5. The flow cytometric analysis confirmed the induction of apoptotic cell death by this compound against HUVEC and MCF-7 cells. In addition, 11n caused sub-G1 phase arrest in the cell cycle arrest. Besides, this compound induced anti-angiogenesis in CAM assay and increased the level of caspase-3 by 5.2 fold. The western-blot analysis of the most active compound, 11n, revealed the inhibition of VEGFR-2 phosphorylation. Molecular docking study also showed the important interactions for compound 11n.

99m Technetium-HMPAO-labeled platelet scan in practice: Preparation, quality control, and biodistribution studies

Abstract There is no biodistribution or imaging data on 99mtechnetium (Tc)-hexamethyl propylamine oxime (HMPAO)-labeled platelets in the literature. The current study aimed to present updated information about the clinical procedures for preparation and use of labeled platelets. Following two-step centrifugation at 1500 and 2500 rpm, the platelets were extracted from whole blood into platelet-rich plasma (PRP) above the buffy coat and then from PRP into a platelet pellet at the bottom of the tube. The 99mTc-HMPAO-labeled platelets were inspected for purity, viability, release of 99mTc from platelets, and sterility. Also, microscopic examination and thin layer chromatography (TLC) were performed. Biodistribution was assessed following necropsy in BALB/c mice and through imaging of New Zealand rabbits. The separation ratio was estimated at 98%, and radiochemical purity was measured to be 80%. The labeling efficiency was above 30% in more than half of the assays (range: 17-43%). The release of 99mTc from platelets was 9% per hour at 37ºC. After 24 hours, stability was estimated at 54% in the human serum. The target organs of mice included the spleen and liver. In rabbits, the imaging results indicated liver as the target organ. Thyroid uptake was negligible up to 90 minutes. Based on the findings, extraction of platelets and labeling them with 99mTc-HMPAO is a feasible and safe approach in routine practice.

Design, synthesis and evaluation of novel thienopyrimidine-based agents bearing diaryl urea functionality as potential inhibitors of angiogenesis.

Inhibition of angiogenesis is a promising strategy for the treatment of cancer. Herein, we describe the design and synthesis of thieno[2,3-d]pyrimidine-1,3,4-thiadiazole-aryl urea derivatives 11a-m to evaluate their efficacy in the chick chorioallantoic membrane (CAM) assay. Among target agents, 11i had a considerable activity against prostate cancer cell line, PC3 (IC50 = 3.6 µM). Moreover, induction of apoptosis, good inhibitory activity against the growth of capillary blood vessels, and inhibition of VEGFR-2 phosphorylation were noticeable parameters which convinced us that 11i could be considered as a promising candidate for the discovery of novel drugs to treat tumors, particularly prostate cancer.

Synthesis, radiolabelling, and biological assessment of folic acid-conjugated G-3 99mTc-dendrimer as the breast cancer molecular imaging agent.

Hence, in this study, the authors aimed to develop a dendrimer-based imaging agent comprised of poly(ethylene glycol) (PEG)-citrate, technetium-99 m (99mTc), and folic acid. The dendrimer-G3 was synthesised and conjugated with folic acid, which confirmed by Fourier transform infrared, proton nuclear magnetic resonance, dynamic light scattering, and transition electron microscopy. 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-Tetrazolium-5-Carboxanilide cytotoxicity assay kit was used to measure the cellular toxicity of dendrimer. Imaging and biodistribution studies were conducted on the mice bearing tumour. The results showed that the fabricated dendrimer-G3 has a size of 90 ± 3 nm, which was increased to 100 ± 4 nm following the conjugation with folic acid. The radiostablity investigation showed that the fabricated dendrimers were stable in the human serum at various times. Toxicity assessment confirmed no cellular toxicity against HEK-293 cells at 0.25, 0.5, 1, 2, 4, and 8 mg/µl concentrations. The in vivo studies demonstrated that the synthesised dendrimers were able to provide a bright SPECT image applicable for tumour detection. In conclusion, the authors' study documented the positive aspects of PEG-citrate dendrimer conjugated with folic acid as the SPECT contrast agent for breast cancer detection.

Application of radiolabeled peptides in tumor imaging and therapy.

Scientists are looking for new therapies to cope with the rise in cancer worldwide. Since cancer cells overexpress peptide receptors and owing to small size, easy uptake by tumor cells, easy preparation, and with no toxicity, the use of radiolabeled peptides with high specificity and affinity for accurate imaging and therapy has attracted much attention. To develop an ideal imaging or treatment radiolabeled peptide, there are some aspects in the components of radiolabeled peptide including radionuclide, peptide, chelator, and spacer that should be considered. Some peptides, including somatostatin, RGD, neurotensin, bombesin, exendin, vasoactive intestinal peptide, and gastrin are currently under (pre)clinical investigations. Today, nanoparticles are suitable tools for targeting peptide for molecular imaging and therapy of tumors with low toxicity. This paper presents some essential aspects in developing a valuable radiolabeled peptide and some radiolabeled peptides with regard to their applications in tumor imaging and therapy in pre-clinical and clinical phases.

Technetium-99 m-PEGylated dendrimer-G2-(Dabcyle-Lys6,Phe7)-pHBSP: A novel Nano-Radiotracer for molecular and early detecting of cardiac ischemic region.

In cardiac ischemic disorder, pyroglutamate helix B surface peptide (pHBSP) which derived from erythropoietin causes to increase cell stability. To improve the serum stability of pHBSP, two lipophilic amino acids Arg6, Ala7 were replaced with Fmoc-(Dabcyle)-Lys-OH and Fmoc-Phe-OH during the peptide synthesis. This peptide was subsequently conjugated to PEGylated dendrimer-G2 and labeled with 99mTcO4- to detect cardiac ischemic region. Radiochemical purity (RCP) of 99mTc-PEGylated dendrimer-G2-(Dabcyle-Lys6,Phe7)-pHBSP was evaluated by ITLC method. In addition, the radiopeptide was investigated for stability in human serum and binding affinity to hypoxic cells in myocardium H9c2 cell lines. Biodistribution and SPECT/CT scintigraphy were assessed in cardiac ischemic rats. Radiochemical yield indicated that the anionic dendrimer has a very high potential to complex formation with 99mTcO-4 (RCP > 94%) which was stable in human serum with RCP 89% up to 6 h. The binding of 99mTc- nanoconjugate to hypoxic cells was significantly more than normoxic cells (3-fold higher compared to normoxic cells at 1 h). In biodistribution studies, erythropoietin receptor-Beta common receptor (EPO-BcR)-positive uptake in the cardiac ischemic region was 3.62 ± 0.44% ID/g 30 min post injection. SPECT imaging showed a prominent uptake of 99mTc-nanoconjugate in EPO-BcR expressing ischemic heart.

Imaging of Clot by 99mTc-HMPAO Labeled Platelet in Animal Model Induced Thrombosis.

99mTc-HMPAO labeled platelet (LP) imaging may integrate thrombosis imaging into routine clinical procedures. In the current study, we assessed the feasibility of the use of 99mTc-HMPAO LP for imaging of small clots in an animal model. Thrombosis was induced by application of FeCl3 solution in the distal part of the inferior vena cava (IVC) of a 6100 g anesthetized rabbit and in a male Wistar rat weighing 420 g. Twenty minutes later, 178 MBq 99mTc-HMPAO LP was injected. 99mTc-HMPAO LP preparation was done as defined and standardized in a previous report. Whole body and SPECT imaging were done 60, 90, and 120 min after tracer injection. Then, the clotted part of the vein was extracted and then its activity and pathologic evaluations were compared with the proximal part of the IVC at a similar volume. A 17 × 6 mm clot was clearly detected with both planar and SPECT imaging. The count to pixel ratio (CPR) of the clotted part of the vein was 35, 40, and 40 compared to the non-clotted vein (i.e. 19, 18, and 21) at 60, 90, and 120 min, respectively. After clot extraction, the CPR decreased to 14. The clot activity was 0.44 MBq compared to 0.01 MBq of the normal control vein. Also, clot induction was pathologically proven. 99mTc-HMPAO LP preparation is logistically possible in clinical nuclear medicine and the ability of imaging small size clots encourages future trials for real clinical thrombotic scenarios.

6-Cinnamoyl-4-arylaminothienopyrimidines as highly potent cytotoxic agents: Design, synthesis and structure-activity relationship studies.

In this paper, we described the synthesis and cytotoxic activities of two new series of thieno[2,3-d]pyrimidine and thieno[3,2-d] pyrimidine derivatives. Most of the synthesized compounds had significant antiproliferative activities against PC3, MDA-MB-231, A549, and HeLa cell lines in comparison to the reference drug, erlotinib. Compounds N-(4-((3,5-dichlorophenyl)amino)thieno[2,3-d]pyrimidin-6-yl)cinnamamide 8e and (E)-N-(4-((3,4-dichlorophenyl)amino)thieno[2,3-d]pyrimidin-6-yl)-3-(4-methoxyphenyl)acrylamide 8g with IC50 values of 4 nM and 33 nM, respectively, against HeLa cell line were chosen for further studies. The apoptosis induced activity and cell cycle arrest were determined and the results provided evidence that these compounds induced cell death via apoptosis and arrested cell growth in sub-G1 phase. In addition, western blot analysis manifested the promising result of suppressing the EGFR signaling pathway (p-EGFR/p-ERK1/2). The docking studies appreciated the considerable potency of compound 8e based on hydrogen and covalent binding interactions. Eventually, in silico pharmacokinetic prediction indicated the acceptable bioavailability of all final compounds.

Clinical use of 99mTc-HMPAO-labeled platelets in cerebral sinus thrombosis imaging.

Magnetic resonance imaging (MRI) and computed tomography (CT) are not always conclusive for the detection of cerebral venous sinus thrombosis (CVST). 99mTc-HMPAO-labeled platelets may be useful in cases with high clinical suspicion. Three patients with headaches with or without intraparenchymal hemorrhage that were highly suspected to have CVST, despite inconclusive anatomical imaging, were selected for inclusion in the study. Platelets were extracted by two rounds of centrifugation from 49 ml of the patient's whole blood. The platelets were labeled with 99mTc-HMPAO and any unbound 99mTc was removed by centrifugation. The re-suspension of 99mTc-HMPAO-labeled platelets in cell-free plasma was reinjected into the patients. After 2 h, planar and single photon emission computed tomography (SPECT) images of the head were obtained. Extensive clots were detected in all three patients, illustrated in the planar image and even clearer in the SPECT images. We propose that 99mTc-HMPAO-labeled platelet scan is a favorable imaging method for patients suspected to have CVST with inconclusive CT and MRI results.

Technetium-99m chelator-free radiolabeling of specific glutamine tumor imaging nanoprobe: in vitro and in vivo evaluations.

INTRODUCTION: Nowadays, molecular imaging radiopharmaceuticals', nanoparticles', and/or small-molecule biomarkers' applications are increasing rapidly worldwide. Thus, researchers focus on providing the novel, safe, and cost-effective ones. MATERIALS AND METHODS: In the present experiment, technetium-99m (99mTc)-labeled PEG-citrate dendrimer-G2 conjugated with glutamine (nanoconjugate) was designed and assessed as a novel tumor imaging probe both in vitro and in vivo. Nanoconjugate was synthesized and the synthesis was confirmed by Fourier transform infrared, proton nuclear magnetic resonance, liquid chromatography-mass spectrometry, dynamic light scattering, and static light scattering techniques. The toxicity was assessed by XTT and apoptosis and necrosis methods. RESULTS: Radiochemical purity indicates that the anionic dendrimer has a very high potential to complex formation with 99mTc and is also very stable in the human serum in different times. Results from the imaging procedures showed potential ability of nanoconjugates to detect tumor site. CONCLUSION: Suitable features of the anionic dendrimer show that it is a promising agent to improve nanoradiopharmaceuticals.

99mTc-radiolabeled GE11-modified peptide for ovarian tumor targeting.

BACKGROUND: Ovarian cancer is a serious threat for women health and the early diagnosis of this cancer might improves the survival rate of patients. The use of the targeted radiopharmaceuticals could be a non-invasive and logical method for tumor imaging. The aim of this study was to radiolabel GE11 peptide as a new specific probe for imaging of ovarian tumor. METHODS: HYNIC-SSS-GE11 peptide was labeled with 99mTc using tricine as a coligand. The 99mTc-tricine-HYNIC-SSS-GE11 peptide was evaluated for specific cellular binding in three cell lines with different levels of EGFR expression. Tumor targeting was assessed in SKOV3 tumor bearing mice. RESULTS: By using tricine as a coligand, labeling yield was more than 98% and the stability of the radiolabelled peptide in human serum up to 4 h was 96%. The in vitro cell uptake test showed that this radiolabeled peptide had a good affinity to SKOV3 cells with dissociation constant of 73 nM. The in vivo results showed a tumor/muscle ratio of 3.2 at 4 h following injection of 99mTc-tricine-HYNIC-SSS-GE11 peptide. CONCLUSIONS: Results of this study showed that 99mTc-tricine-HYNIC-SSS-GE11 peptide could be a promising tool for diagnosis and staging of ovarian cancer. 99mTc-tricine-HYNIC-SSS-GE11, a novl targeted agent for ovarian tumor imaging.

Development of a Radiolabeled Amlodipine Analog for L-type Calcium Channel Imaging.

PURPOSE: The non-invasive imaging and quantification of L-type calcium channels (also known as dihydropyridine channels) in living tissues is of great interest in diagnosis of congestive heart failure, myocardial hypertrophy, irritable bowel syndrome etc. METHODS: Technetium-99m labeled amlodipine conjugate ([99mTc]-DTPA-AMLO) was prepared starting freshly eluted (<1 h) 99mTechnetium pertechnetate (86.5 MBq) and conjugated DTPAAMLO at pH 5 in 30 min at room temperature in high radiochemical purity (>99%, RTLC; specific activity: 55-60 GBq/mmol). The calcium channel blockade activity (CCBA) and apoptosis/necrosis assay of DTPA-amlodipine conjugate evaluations were performed for the conjugate. Log P, stability, bio-distribution and imaging studies were performed for the tracer followed by biodistribution studies as well as imaging. RESULTS: The conjugate demonstrated low toxicity on MCF-7 cells and CCBA (at µm level) compared to the amlodipine. The tracer was stable up to 4 h in final production and presence of human serum and log P (-0.49) was consistent with a water soluble complex. The tracer was excreted through kidneys and liver as expected for dihydropyridines; excluding excretory organs, calcium channel rich smooth muscle cells; including colon, intestine and lungs which demonstrated significant uptake. SPECT images supported the bio-distribution data up to 4 h. CONCLUSION: significant uptake of [99mTc]-DTPA-AMLO was obtained in calcium channel rich organs. The complex can be a candidate for further SPECT imaging for L-type calcium channels.

Novel 99mTc-Radiolabeled Anionic Linear Globular PEG-Based Dendrimer-Chlorambucil: Non-Invasive Method for In-Vivo Biodistribution.

Chlorambucil (CBL) is an alkylating agent, which widely use in the treatment of various types of tumors. The main purpose of this study is to evaluate the in-vivo biodistribution of CBL conjugated to the anionic dendrimer, which has a great ability to labeled with 99mTc through binding to carboxylate terminate groups. Whole body scans were used to analyze the percentage of the injected dose in different times. Radiochemical purity (RCP) and in-vivo biodistribution were also calculated with the SPECT/CT instrument. Our study proposes a new method for RCP determination and shows that this carrier is a promising agent to complex with the 99mTc and biological assessment.

The paradox role of caspase cascade in ionizing radiation therapy.

Radiotherapy alone or in combination with chemotherapy/surgery is widely used for treatment of cancers. It reduces tumor growth and prevents metastasis. While ionizing radiation activates caspase cascade resulted in apoptosis in cancer cells, it also stimulates tumor cell re-population that leads to reduce the effectiveness of the radiation therapy. This review describes the mechanisms for paradox role of caspase cascade in cancer therapy and discusses the logical and practical strategies for improvement the therapeutic index of radiotherapy through enhancement of radiosensitivity and decreasing the rate of tumor recurrence.

Preparation and preclinical evaluation of 68Ga-DOTA-amlodipine for L-type calcium channel imaging.

AIM: In order to develop a possible tracer for L-type calcium channel imaging, we here report the development of a Ga-68 amlodipine derivative for possible PET imaging. MATERIALS AND METHODS: Amlodipine DOTA conjugate was synthesized, characterized and went through calcium channel blockade, toxicity, apoptosis/necrosis tests. [68Ga] DOTA AMLO was prepared at optimized conditions followed by stability tests, partition coefficient determination and biodistribution studies using tissue counting and co incidence imaging up to 2 h. RESULTS: [68Ga] DOTA AMLO was prepared at pH 4-5 in 7-10 min at 95°C in high radiochemical purity (>99%, radio thin layer chromatography; specific activity: 1.9-2.1 GBq/mmol) and was stable up to 4 h with a log P of -0.94. Calcium channel rich tissues including myocardium, and tissues with smooth muscle cells such as colon, intestine, and lungs demonstrated significant uptake. Co incidence images supported the biodistribution data up to 2 h. CONCLUSIONS: The complex can be a candidate for further positron emission tomography imaging for L type calcium channels.