Myocardial 99mTc-sestamibi extraction and washout in hypertensive heart failure using an isolated rat heart

Dynamic and Assembly Characteristics of Deep-Cavity Basket Acting as a Host for Inclusion Complexation of Mitoxantrone in Biotic and Abiotic Systems

We describe the preparation, dynamic, assembly characteristics of vase-shaped basket 13- along with its ability to form an inclusion complex with anticancer drug mitoxantrone in abiotic and biotic systems. This novel cavitand has a deep nonpolar pocket consisting of three naphthalimide sides fused to a bicyclic platform at the bottom while carrying polar glycines at the top. The results of 1 H Nuclear Magnetic Resonance (NMR), 1 H NMR Chemical Exchange Saturation Transfer (CEST), Calorimetry, Hybrid Replica Exchange Molecular Dynamics (REMD), and Microcrystal Electron Diffraction (MicroED) measurements are in line with 1 forming dimer [12 ]6- , to be in equilibrium with monomers 1(R) 3- (relaxed) and 1(S) 3- (squeezed). Through simultaneous line-shape analysis of 1 H NMR data, kinetic and thermodynamic parameters characterizing these equilibria were quantified. Basket 1(R) 3- includes anticancer drug mitoxantrone (MTO2+ ) in its pocket to give stable binary complex [MTO⊂1]- (Kd =2.1 μM) that can be precipitated in vitro with UV light or pH as stimuli. Both in vitro and in vivo studies showed that the basket is nontoxic, while at a higher proportion with respect to MTO it reduced its cytotoxicity in vitro. With well-characterized internal dynamics and dimerization, the ability to include mitoxantrone, and biocompatibility, the stage is set to develop sequestering agents from deep-cavity baskets.

Clinical application of ultrasound for preparation of (99m)Tc-sestamibi complex

OBJECTIVE

The main aim of this investigation is the clinical application of ultrasound irradiation technique as an alternative method to reconstitute sestamibi kits in comparison of water boiling bath method.

METHODS

The 740-3700 MBq (20-100 mCi) (99m)Tc-MIBI (sestamibi) complex samples were prepared due to ultrasound irradiation technique or boiled water bath method as a standard method. Twenty patients (8 men and 12 women; age range 30-72, median 52.45 years) have been referred to Golestan hospital for myocardial perfusion imaging (MPI). The subjects have been divided randomly into group A (3 men, 7 women, age range 36-67, median 51.7 years) and group B (5 men, 5 women, age range 30-72, median 50.3 years), respectively. The (99m)Tc-MIBI radiopharmaceuticals have been prepared by Ultrasound irradiation technique administrated to group A and (99m)Tc-MIBI complex samples due to the boiled water bath technique administrated to the other group. For all patients, the 2-day stress/rest MPI protocol was performed.

RESULTS

The radio-HPLC and TLC studies have indicated that the (99m)Tc-MIBI complex samples with good yields could be prepared successfully due to new developed technique. The scintigraphy imaging studies have demonstrated that the (99m)Tc-sestamibi prepared due to the above-mentioned modalities shows very identical biodistribution in the heart, thyroid, lung, liver, gallbladder, kidneys, stomach, large intestine and bladder of the subjects. Any unexpected accumulation of radiotracer samples have not been observed in our approach.

CONCLUSIONS

The ultrasound irradiation technique is convenient and sufficient method to prepare (99m)Tc-sestamibi. It can be recommended as an alternative method to reconstitute sestamibi kits particularly in emergency situations to reduce potentially medical risk by avoiding any delay in acute therapy for myocardial infarction.

Investigation of cyanine dyes for in vivo optical imaging of altered mitochondrial membrane potential in tumors

Mitochondrial membrane potential (Δψm ) alteration is an important target for cancer diagnosis. In this study, we designed a series of near-infrared fluorescent cationic cyanine dyes with varying alkyl chain lengths (IC7-1 derivatives) to provide diverse lipophilicities and serum albumin-binding rates, and we evaluated the usefulness of these derivatives for in vivo Δψm imaging. IC7-1 derivatives with side chains from methyl to hexyl (IC7-1-Me to IC7-1-He) were synthesized, and their optical properties were measured. Cellular uptake and intracellular distribution were investigated with depolarized HeLa cells from carbonyl cyanine m-chlorophenylhydrazone (CCCP) treatment using a spectrofluorometer and a fluorescence microscope. Serum albumin-binding rates were evaluated using albumin-binding inhibitors. In vivo optical imaging was performed with HeLa cell xenograft mice following intravenous administration of IC7-1 derivatives with or without warfarin and CCCP as in vivo blocking agents. IC7-1 derivatives showing maximum excitation and emission wavelengths at 823 nm and ~845 nm, respectively, were synthesized. IC7-1-Me to -Bu showed fluorescence in mitochondria that decreased with CCCP treatment in a concentration-dependent manner, which showed that IC7-1-Me to -Bu successfully indicated Δψm . Tumors were clearly visualized after IC7-1-Bu administration. Treatment with warfarin or CCCP significantly decreased IC7-1-Bu fluorescence in the tumor region. In summary, IC7-1-Bu exhibited fluorescence localized to mitochondria dependent on Δψm , which enabled clear in vivo tumor imaging via serum albumin as a drug carrier for effective tumor targeting. Our data suggest that IC7-1-Bu is a promising NIR probe for in vivo imaging of the altered Δψm of tumor cells.