A review on cardiac positron emission tomography/magnetic resonance imaging in diagnosis of cardivascular diseases / 生物医学工程学杂志

There are various examination methods for cardiovascular diseases. Non-invasive diagnosis and prognostic information acquisition are the current research hotspots of related imaging examinations. Positron emission tomography (PET)/magnetic resonance imaging (MRI) is a new advanced fusion imaging technology that combines the molecular imaging of PET with the soft tissue contrast function of MRI to achieve their complementary advantages. This article briefly introduces several major aspects of cardiac PET/MRI in the diagnosis of cardiovascular disease, including atherosclerosis, ischemic cardiomyopathy, nodular heart disease, and myocardial amyloidosis, in order to promote cardiac PET/MRI to be more widely used in precision medicine in this field.

18F-Berberine Derivatives: a Potential Molecular Imaging Agent for Tumor Targeting by PET/CT Tumor / 生物医学工程学杂志

Cancer is one of the main causes of death for human beings. Clinical oncologists increasingly rely upon imaging for diagnosis, stage, response assessment, and follow-up in cancer patient. However, 18F-FDG is not a tumor specific agent, inflammation and infection also have intensive uptake of 18F-FDG, resulting in false positive diagnosis, and some tumors have low uptake of 18F-FDG or even do not uptake 18F-FDG, leading to false negative diagnosis. So it is urgent to develop non-18F-FDG novel tumor targeting agent. Recently, a large number of researches in vitro have demonstrated that berberine has anti-tumor activity against a variety of tumor cells by inducing tumor cell apoptosis through inhibition of mitochondrial respiratory chain etc. So far, there is no credible evidence of berberine targeting in tumor in vivo. We proposed a hypothesis that berberine has the characteristics of tumor targeting biodistribution in vivo, and verified the proposal by 18F-berberine PET/CT imaging in VX2 muscle tumor-bearing rabbit model. In this review, we intend to give an overview of the progress of berberine anticancer, the structural bases of berberine anticancer and the uderlying molecular mechanisms of berberine anticancer indentified so far. We also introduce the first visualization of 18F labeled berberine derivatives targeting tumor in VX2 muscle tumor-bearing rabbit model by PET/CT. These breakthrough findings suggest that 18F-berberine derivatives as a potential PET/CT tumor targeted molecular imaging agent may have important implications for cancer targeting therapy, molecular imaging and modernization of Traditional Chinese Medicine.

Nuclear cardiology: the present functions and future perspectives / 生物医学工程学杂志

For the past decade, the diagnosis and treatment of coronary artery disease (CAD) has shifted from the traditional model by evaluating coronary artery stenosis with morphological imaging methods to a novel model by focusing on the detection of ischemia for risk stratification. The myocardial perfusion imaging (MPI) using stress single photon emission computed tomography (SPECT) has become the most commonly used stress imaging technique for the diagnosis and treatment of patients with suspected or known CAD. It has got strong supports, including those of the American College of Cardiology, American Heart Association, American Society of Nuclear Cardiology (ACC/AHA/ASNC) and other numerous clinical guidelines. They all stressed that the SPECT MPI is recommended to be used as the "gate keeper" to coronary angiography in order to prevent unnecessary intervention test and save the cost. However, in China the introduction and application of nuclear cardiology was late and highly unbalanced. This leads to the lack of understanding of nuclear cardiology in some clinicians, and there often is misunderstanding on correct selection of coronary angiography, cardiac CT, CT coronary angiography and others for diagnosis and treatment of CAD which results in a trend of over-application of these traditional techniques. In this article, we will focus on the status of nuclear cardiology, including SPECT, positron emission tomography (PET) MPI in the patients with CAD for the diagnosis of ischemia, risk stratification and management decision-making, and also compare it with the traditional morphological imaging techniques. In addition, we will briefly introduce the recent advances in cardiac hybrid imaging and molecular imaging. The aim of this paper is to popularize the knowledge of nuclear cardiology, and promote the rational application of nuclear cardiology in China.

Preparation and quality control of 99mTc labeled MDR1 oligonucleotide DNAs / 生物医学工程学杂志

The aim of this study is to explore the optimal labeling condition of technetium-99m labeled antisense oligonucleotides (ASON) DNA and sense oligonueleotides (SON) DNA against multi-drug resistance gene-1 (MIDR1) mRNA, to prepare its two-step icefrozen kits, and to perform the quality control of technetium-99m labeled ASON and SON DNAs and its two-step icefrozen kits. A 20 mer single-stranded ASON sequence and its SON sequence against MDR1 mRNA were synthesized respectively, both of the ASON and SON DNAs were uniform phosphorothioated for this investigation with a primary amine on the 5'-end via a six-carbon alkyl linker, and then were labeled with technetium-99m by conjugating with the bifunctional chelator S-Acetyl NHS-MAG3 to form ASON- and SON-MAC3 DNAs. The optimal labeling condition was explored by varying the amount of ASON- and SON-MAG3 DNAs, SnCl2.2H2O and buffer, the pH value in the reaction medium was also adjusted. The technetium-99m labeled ASON and SON DNAs' two-step icefrozen kits were developed. The radiochemical purities, labeling stability of ASON- and SON-MAG3 DNAs in vivo and vitro were measured, and stability of the two-step icefrozen kits were also studied. The recycled rates of ASON- and SON-MAG3 DNAs were over 70% (n >6), the two-step icefrozen kits of ASON- and SON-MAG3 DNAs were colourless ice crystal. The radiochemical purities of technetium-99m labeled ASON- and SON-MAG3 DNAs were over 92 %. The radiochemical purities were over 90% after stored at room temperature for 24 hours. The kits were stable within 6 months when stored at 0 degrees C, the radiochemical purities of technetium-99m labeled ASON- and SON-MAG3 DNAs were still over 90%. The two-step icefrozen kits of ASON- and SON-MAG3 DNAs were successfully developed. The radiochemical purities were all over 90%. The labeling method was simple, feasible and efficient with good stability.

Experimental study of 99mTc-antisense DNA for tumor imaging / 生物医学工程学杂志

This study was performed to explore the feasibility of antisense imaging with radiolabeled antisense oligonucleotides DNA in tumored nude mice in vivo. Two different tumor cell lines, KB-G2 and KB-31,were used; both antisense and control sense DNAs were administrated intratumorally. The hybridization activities analysis of MAG3 conjugated DNAs oligonucleotides was demonstrated by Polyacrylamide Gel Electrophoresis. The whole body imaging was performed 22 h after administration of radiolabeled antisense and control sense DNAs at 1.0 microg DNAs (100 microCi) in 100 microl per animal. Then the animals were sacrificed at 24 h after administration and the organs and tissues were dissected and weighed; the radioactivity of each sample was detected by r-counter; injection dose percentage per gram tissue (%ID/g) was calculated and the biodistribution obtained. Both MAGS conjugated oligonucleotides DNAs and natural oligonucleotides DNAs have the same hybridization activities. The whole body images demonstrate improved targeting of antisense DNAs vs sense DNAs in the KB-G2 but not the KB-31 animals. Tumor levels in the KB-G2 animals were significantly higher for the antisense DNAs vs sense DNAs (14.7 vs 8.5% ID/g) while this difference (8.6 vs 4.3% ID/g) was insignificant in the KB-31 animals. Evidence for tumor targeting in vivo by an antisense in that mechanism has been obtained; statistically higher tumor accumulations of the 99mTc-antisense DNA were observed when compared to the control 99mTc-sense DNA. The successful localization of antisense DNA in tumor demonstrates that antisense tumor targeting in vivo is feasible even though improvement in tumor delivery and normal tissue clearance are needed for practical antisense imaging.