Reduction of myocardial infarct size by SM-198110, a novel Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> exchange inhibitor,in rabbits

The effects of 3-[2-({[amino(imino)methyl]amino}carbonyl)-4-chloro-1H-indol-1-yl]-1-propanesulphonic acid monohydrate (SM-198110), a novel potent Na⁺/H⁺ exchange inhibitor, and cariporide (Hoe642), another Na⁺/H⁺ exchange inhibitor, were studied in a myocardial ischaemia and reperfusion injury model. Anaesthetized rabbits were subjected to occlusion of the coronary artery for 30 min followed by reperfusion for 5 h. SM-198110 or cariporide was administered before ischaemia and before reperfusion. We also assessed the anti-necrotic effect of SM-198110 when given before reperfusion, both alone and together with glibenclamide, a K_ATP channel blocker, 5-hydroxydecanoate (5-HD), a mitochondrial K_ATP channel-selective blocker and 8-(p-sulphophenyl)-theophylline (8-SPT), an adenosine receptor blocker. The infarct size was reduced dose-dependently by i.v. administration of SM-198110 before ischaemia, with a significant reduction in serum creatine phosphokinase activity. Infarct sizes, normalized to the size of the area-at-risk (means±SE) were: vehicle 56.6±3.7%; low-dose SM-198110 39.2±6.3%; mid-dose 32.8±7.4% (P<0.05); high-dose 22.1±6.7% (P<0.01). This anti-necrotic effect of SM-198110 was achieved without significant haemodynamic changes. Cariporide given before ischaemia also reduced infarct size significantly and dose-dependently. SM-198110 administered before reperfusion also resulted in a dose-dependent reduction in the infarct size. Infarct sizes were: vehicle 56.6±3.7%; low-dose SM-198110 44.5±5.7%; mid-dose 36.3±6.6% (P<0.01); high-dose 34.7±3.8% (P<0.01). In contrast, cariporide given before reperfusion did not reduce infarct sizes significantly. The anti-necrotic effect of SM-198110 was observed even when given 10 min after the beginning of reperfusion. Glibenclamide and 5-HD abolished the anti-necrotic effect of treatment before reperfusion with SM-198110. However, the co-administration of 8-SPT with SM-198110 did not affect infarct size. These results suggest that, in addition to Na⁺/H⁺ exchange inhibition, mitochondrial and/or sarcolemmal K_ATP channels contribute to the anti-necrotic effect of SM-198110 when the latter is given before reperfusion.     

Comparative analysis of pharmacokinetic characteristics of radiopharmaceuticals based on the monopotassium salt of 1-hydroxyethylidenediphosphonic acid labeled by <Superscript>99m</Superscript>T9c and <Superscript>188</Superscript>Re

Investigation of pharmacokinetic characteristics of the ^99mTc- and ¹⁸⁸Re-labeled monopotassium salt of 1-hydroxyethylidenediphosphonic acid (KHEDP) in rats showed that the level of accumulated activity at 5 min and 1 and 3 h after i.v. injection of ¹⁸⁸Re-KHEDP is higher in most organs and tissues than that after injection of ^99mTc-KHEDP. In the subsequent period (6 and 24 h), the specific activities in the majority of soft organs and tissues equalized due to greater elimination of ¹⁸⁸Re-KHEDP. The dynamics of labeled drug accumulation in bone tissues is characterized by a gradual increase in the activity concentration followed by its slow decrease. The maximum accumulation of ^99mTc-KHEDP in bone was achieved within 3 – 6 h whereas the activity of ¹⁸⁸Re-KHEDP was at a maximum 1 h after injection. The activity gradually decreases after reaching the maximum value. The rate of ^99mTc-KHEDP elimination from bone is slower than that for ¹⁸⁸Re-KHEDP. The ratios of the specific activity in organs and tissues upon i.v. injection of ^99mTc-KHEDP and ¹⁸⁸Re-KHEDP are illustrated more clearly by the coefficients of differential accumulation (CDA) of activity in bone (bone of femur, rib, skull, and spine) relative to soft organs and tissues. The dynamics of the change in these values is characterized by a gradual increase over 24 h after injection. The growth is more pronounced for ¹⁸⁸Re-KHEDP than for ^99mTc-KHEDP. These data show that the elimination of activity from bone upon injection of ¹⁸⁸Re-KHEDP is faster than that for ^99mTc-KHEDP. A comparative analysis of the CDA values allows the dynamics of drug accumulation and elimination rates from soft organs and tissues to be evaluated in comparison to bone. Using the CDA values, it is also possible to determine the optimum conditions for carrying out scintigraphy studies of the skeleton using a gamma camera. The results from the study of the pharmacokinetic characteristics of ^99mTc-KHEDP and ¹⁸⁸Re-KHEDP in rats showed that these complexes have similar structures and substantially different biological properties, as indicated by the substantial differences in their in vivo behavior upon i.v. injection.     

Intramuscular injection of 125I-botulinum neurotoxin-complex versus 125I-botulinum-free neurotoxin: time course of tissue distribution.

The diffusion from the site of intramuscular injection of 900 kDa botulinum neurotoxin-hemagglutinin complex (BoNT/A-complex) and 150 kDa free-botulinum neurotoxin (free-BoNT/A) was compared. Radioiodinated compounds were injected into the gastrocnemius muscle of rats (70Units (U) 125I-BoNT/A-complex, 67 or 344 U free-125I-BoNT/A, or free-125I-iodide) and the eyelids of rabbits (24 U 125I-BoNT/A-complex or 108 U free-125I-BoNT/A), and measured in various tissues at different time points. There were no detectable systemic effects or generalized botulinum neurotoxin toxicity in either rats or rabbits, indicating that most of the toxin, whether as 125I-BoNT/A-complex or free-125I-BoNT/A, remained at the injection site. In rats, 125I-BoNT/A-complex and free-125I-BoNT/A diffused in a pattern that was grossly similar. Almost no radioactivity was recovered from the brain. Radioactivity recovered from distant tissues (thyroid, skin, and contralateral muscle) was primarily attributable to either low molecular weight 125I-containing peptides or 125I-iodide. After injection into rabbit eyelids, neither 125I-BoNT/A-complex nor free-125I-BoNT/A spread to distant structures, including the eye. The results indicate that most of the neurotoxin does not diffuse from the injection site, whether in free or complexed form, and this may reduce the potential for systemic effects.     

Percutaneous absorption of [14C]methacrylamide in animals

Percutaneous absorption of [^l4C]methacrylamide was determined in rabbits, rats and mice. Radioactivity in blood of rabbits increased rapidly after IV injection, after topical application with a cloth and after direct topical application of a 15 or 5% test solution, suggesting high permeability of the skin for methacrylamide. Radioactivity then began to decrease exponentially within 1 h. Tissue radioactivity 24 h after IV dosing was high in blood, liver and serum, and low in brain, nerve and muscle. The radioactivity was more uniformly distributed with the exception of liver, after application with a cloth and after direct contact than after IV dosing. When the application site was washed with water after direct application, decline of radioactivity in blood was accelerated slightly and a decrease in radioactivity in some tissues was found, although the difference between non-wash and wash groups was not significant in either the declining curve or the tissue radioactivity, with the exception of serum for the latter. Between 25 and 60% of the radioactivity found in tissues was protein-bound after 24 h. Recovery of radioactivity in urine was highest after IV administration, intermediate after direct contact, and lowest after cloth application. Radioactivity in expired air and bile was small. Both radioactivity in tissues and its recovery in urine in rats, and tissue radioactivity in mice, were lower than in rabbits, when adjusted for dose per unit body weight, suggesting lower skin permeability for methacrylamide in the former species. In rats, radioactivity in some tissues was significantly decreased after washing. An autoradiographic study on rabbit skin indicated that the test material penetrated the skin largely through hair follicles.     

Preparation and evaluation of 188Re sulfide colloidal nanoparticles loaded biodegradable poly (L‐lactic acid) microspheres for radioembolization therapy

Radioembolization with radioactive microspheres has been an effective method for the treatment of liver lesions. The aim of this study was to prepare carrier‐free ¹⁸⁸Re loaded poly (L‐lactic acid) (PLLA) microspheres through ¹⁸⁸Re sulfide colloidal nanoparticles (¹⁸⁸Re‐SC nanoparticles). The formation of ¹⁸⁸Re‐SC nanoparticles was confirmed by ultraviolet‐visible spectrophotometry. The labeling yield of ¹⁸⁸Re‐SC nanoparticles was verified using the RTLC method. Effects of synthesis parameters on morphology and size of prepared ¹⁸⁸Re‐sulfide colloidal‐PLLA microspheres (¹⁸⁸Re‐SC‐PLLA microspheres) were studied by scanning electron microscopy. In vitro stability of ¹⁸⁸Re‐SC‐PLLA microspheres was investigated in normal saline at room temperature and in human serum at 37°C. In vivo distribution studies and gamma camera imaging were performed in healthy BALB / c mice. The microspheres could be prepared with sizes between 13 and 48 μm (modal value 29 μm) and radiolabeling efficiency >99%. After incubation, the microspheres were found stable in vitro up to 72 hours. The biodistribution after intravenous injection in healthy BALB / c mice showed high accumulation in lung as a first capture pathway organ for microsphere followed by great retention over 48 hours for these microspheres. These data show that ¹⁸⁸Re‐SC‐PLLA microspheres are suitable candidate for clinical studies.     

Synthesis of 99mTc‐labeled organo‐germanium nanoparticles and their in vivo study as a spleen imaging agent

^99mTc‐Labeled organo‐germanium nanoparticles ranging in size from 60 to 80 nm were newly developed for a spleen imaging agent. The radiolabeled nanoparticles were prepared with a high labeling efficiency (over 99%) and they also showed an excellent stability at room temperature for 6 h. The biodistribution data of the nanoparticles injected into rats via intravenous routes showed a notably higher accumulation in the spleen when compared to other reticuloendothelial system organs. Gamma image of the rabbits obtained after an intravenous injection of the nanoparticles revealed a localization of the radioactivity mainly in the spleen and the liver. Copyright © 2006 John Wiley & Sons, Ltd.     

Abnormal activation of Na<Superscript>+</Superscript>-K<Superscript>+</Superscript> pump in aortas from rats with endotoxaemia

A diminished reactivity to several vasoconstrictor agents is usually observed in blood vessels obtained from animals with endotoxic shock. The contractile state of vascular smooth muscle is influenced by the activity of the electrogenical sodium (Na⁺-K⁺) pump. Thus, we examined inhibitors and agonists of nitric oxide (NO)-guanosine 3':5'-cyclic monophosphate (cGMP) on contractions to phenylephrine (PE) and relaxations to potassium in isolated aortic segments from rats treated with bacterial endotoxin (lipopolysaccharide, LPS) for 6 h (i.e. to mimic a shock syndrome). Endotoxaemia for 6 h was associated with a severe hypotension and vascular hyporeactivity to noradrenaline and an increased plasma nitrate level in vivo. The PE-induced contraction was attenuated in aortic smooth muscle obtained from rats with endotoxic shock while the potassium-induced relaxation was greater in these preparations. Ouabain dose-dependently inhibited the potassium-induced relaxation in aortas from normal and endotoxaemic rats. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one enhanced the PE-induced contraction in endotoxaemic rats only, whereas it attenuated the difference of potassium-induced relaxation between normal and endotoxaemic rats. In contrast, in aortas obtained from normal rats, 8-bromo-cGMP reduced the PE-induced contraction and enhanced the potassium-induced relaxation to the level as seen in endotoxaemic animals. In aortas obtained from endotoxaemic rats, methylene blue further restored the PE-induced contraction to the normal and abolished the difference of potassium-induced relaxation between normal and endotoxaemic rats. These results suggest that the Na⁺-K⁺ pump in the vascular bed of animals with endotoxic shock is abnormally activated and this augmented activation is modulated by cGMP.     

Synthesis and biological characterization of <Superscript>99m</Superscript>Tc-labeled ciprofloxacin

Investigations aimed at the creation of a standard kit for the synthesis of ^99mTc-labeled ciprofloxacin (fluoroquinolone antibiotic) have been carried out. For isotope labeling, eluate from a technetium-99m generator was added to dry sterile mixtures of ciprofloxacin hydrochloride (CFH) with a reducing agent (tin chloride, SnCl₂) in various ratios. The mixtures were incubated for 20 min at room temperature. The influence of components of the reaction mixture on the amount of radiochemical impurity in the resulting radiopharmaceuticals was estimated using TLC. Three ^99mTc-containing complexes and a colloid related to the hydrolysis of tin compounds were formed. The tin content in each complex has been determined by introducing a ^117mSn isotope label. Ways to decrease colloid formation by changing the pH of the medium and by reducing the SnCl₂ concentration in the kit have been investigated. The kit composition has been optimized. It is established that radiopharmaceuticals containing less than 0.175 mg SnCl₂ per 5 mg CFH can be used without additional filtration. Tests on experimental animals (rabbits) with model inflammation in soft tissues showed the functional suitability of ^99mTc-labeled ciprofloxacin for diagnosis of infectious-inflammatory processes.     

<Emphasis Type="Italic">In vivo</Emphasis> kinetics and biodistribution of HB-110, a novel HBV DNA vaccine,after administration in Mice

This study investigated the pharmacokinetic profile and biodistribution of HB-110, a novel HBV therapeutic vaccine candidate, in mice. HB-110 was rapidly degraded in the blood after i.v. injection with a half-life of 1.9+/-0.083 min, and was no longer detected at 60 min except in one individual near the detection limit. In the i.m. injection, plasmid DNA was detectable at the injection site until 11 days after administration, but the amounts were just above the detection limit. The blood concentration of HB-110 showed a maximum of 604 pg/mL at 15 min after i.m. injection, which was followed by degradation to undetectable levels at 90 min. The plasmid DNA in tissues peaked at 90 min after administration. The highest concentration of plasmid DNA was detected in the liver (24.172 pg/mg tissue), and considerable amounts were also observed in the lung (9.467 pg/mg tissue) and spleen (7.688 pg/mg tissue). The amount of plasmid DNA in tissues was 2 to 3 orders of magnitude lower than in the injection site at the same time points. The HB-110 concentration in tissues, including gonads, decreased rapidly and was undetectable 24 h after administration.     

Biodistribution and safety studies of hDel-1 plasmid-based gene therapy in mouse and rabbit models

A plasmid encoding the human developmentally regulated endothelial locus-1 (hDel-1) protein formulated with poloxamer 188 is a potential gene therapy for peripheral arterial disease in man. As a prelude to clinical trials, the biodistribution and safety of this therapy were evaluated after intramuscular and intravenous administration in mice and rabbits. In mice, plasmid DNA persisted at the intramuscular injection site for at least 28 days, but was barely detectable in distal tissues by 24 h and essentially cleared by 28 days. By 24 h after intravenous administration, plasmid DNA was readily detected in blood, muscle, and lungs but sporadically and at low levels in other tissues. At 28 days, plasmid DNA was readily detectable only at the intravenous injection site (tail) after low- and high-dose administration, and sporadically in blood and muscle after high-dose administration. In rabbits, the highest intramuscular (4.2 mg kg(-1)) or intravenous (3.7 mg kg(-1)) dose caused no deaths; no treatment-related clinical signs; no changes in body weight, clinical pathology parameters, ophthalmology, ECG, or histopathology; and no detectable increase in antinuclear antibodies by 28 days. The results supported testing of hDel-1 plasmid-based gene therapy in phase I clinical trials.     

Site-specific<Superscript>99m</Superscript>Tc-labeling of antibody using dihydrazinophthalazine (DHZ) conjugation to Fc region of heavy chain

The development of an antibody labeling method with 99mTc is important for cancer imaging. Most bifunctional chelate methods for 99mTc labeling of antibody incorporate a 99mTc chelator through a linkage to lysine residue. In the present study, a novel site-specific 99mTc labeling method at carbohydrate side chain in the Fc region of 2 antibodies (T101 and rabbit anti-human serum albumin antibody (RPAb)) using dihydrazinophthalazine (DHZ) which has 2 hydrazino groups was developed. The antibodies were oxidized with sodium periodate to produce aldehyde on the Fc region. Then, one hydrazine group of DHZ was conjugated with an aldehyde group of antibody through the formation of a hydrazone. The other hydrazine group was used for labeling with 99mTc. The number of conjugated DHZ was 1.7 per antibody. 99mTc labeling efficiency was 46-85% for T101 and 67-87% for RPAb. Indirect labeling with DHZ conjugated antibodies showed higher stability than direct labeling with reduced antibodies. High immunoreactivities were conserved for both indirectly and directly labeled antibodies. A biodistribution study found high blood activity related to directly labeled T101 at early time point as well as low liver activity due to indirectly labeled T101 at later time point. However, these findings do not affect practical use. No significantly different biodistribution was observed in the other organs. The research concluded that DHZ can be used as a site-specific bifunctional chelating agent for labeling antibody with 99mTc. Moreover, 99mTc labeled antibody via DHZ was found to have excellent chemical and biological properties for nuclear medicine imaging.     

Comparative biodistribution studies of technetium‐99 m radiolabeled amphiphilic nanoparticles using three different reducing agents during the labeling procedure

Considering the confusing biodistribution data through the literature and few reported alerts as well as our preliminary biodistribution results, we decided to evaluate the interaction and interference of the commonly present ^99mTc (technetium‐99m)‐stannic oxide colloid during the direct stannous chloride ^99mTc‐labeling procedure and to assess its influence on the biodistribution pattern of amphiphilic poly(lactic‐co‐glycolic acid) nanoparticles. In order to confirm our thesis, beside stannous chloride, we employed two different reducing agents that don't form colloidal particles. The use of sodium borohydride was previously reported in the literature, whereas sodium dithionite was adapted for the first time in the ^99mTc direct labeling procedure for nanoparticles. The results in our paper clearly differentiate among samples with and without colloidal impurities originating from the labeling procedure with a logical follow up of the radiochemical, physicochemical evaluation, and biodistribution studies clarifying previously reported data on stannic oxide colloidal interference. ^99mTc‐nanoparticle complex labeled with sodium dithionite as reducing agent illustrated appropriate labeling efficacy, stability, and potential for further use in biodistribution studies thus providing solution for the problem of low‐complex stability when sodium borohydride is used and colloidal stannic oxide interference for stannous chloride procedure. Copyright © 2013 John Wiley & Sons, Ltd.     

Role of sarcoplasmic reticulum Ca<Superscript>2+</Superscript> content in Ca<Superscript>2+</Superscript> entry of bovine airway smooth muscle cells

Depletion of intracellular Ca²⁺ stores induces the opening of an unknown Ca²⁺ entry pathway to the cell. We measured the intracellular free-Ca²⁺ concentration ([Ca²⁺]i) at different sarcoplasmic reticulum (SR) Ca²⁺ content in fura-2-loaded smooth muscle cells isolated from bovine tracheas. The absence of Ca²⁺ in the extracellular medium generated a time-dependent decrement in [Ca²⁺]i which was proportional to the reduction in the SR-Ca²⁺ content. This SR-Ca²⁺ level was indirectly determined by measuring the amount of Ca²⁺ released by caffeine. Ca²⁺ restoration at different times after Ca²⁺-free incubation (2, 4, 6 and 10 min) induced an increment of [Ca²⁺]i. This increase in [Ca²⁺]i was considered as Ca²⁺ entry to the cell. The rate of this entry was slow (~0.3 nM/s) when SR-Ca²⁺ content was higher than 50% (2 and 4 min in Ca²⁺-free medium), and significantly (p<0.01) accelerated (>1.0 nM/s) when SR-Ca²⁺ content was lower than 50% (6 and 10 min in Ca²⁺-free medium). Thapsigargin significantly induced a higher rate of this Ca²⁺ entry (p<0.01). Variations in Ca²⁺ influx after SR-Ca²⁺ depletion were estimated more directly by a Mn²⁺ quench approach. Ca²⁺ restoration to the medium 4 min after Ca²⁺ removal did not modify the Mn²⁺ influx. However, when Ca²⁺ was added after 10 min in Ca²⁺-free medium, an increment of Mn²⁺ influx was observed, corroborating an increase in Ca²⁺ entry. The fast Ca²⁺ influx was Ni²⁺ sensitive but was not affected by other known capacitative Ca²⁺ entry blockers such as La³⁺, Mg²⁺, SKF 96365 and 2-APB. It was also not affected by the blockage of L-type Ca2⁺ channels with methoxyverapamil or by the sustained K⁺-induced depolarisation. The slow Ca²⁺ influx was only sensitive to SKF 96365. In conclusion, our results indicate that in bovine airway smooth muscle cells Ca²⁺ influx after SR-Ca²⁺ depletion has two rates: A) The slow Ca²⁺ influx, which occurred in cells with more than 50% of their SR-Ca²⁺ content, is sensitive to SKF 96365 and appears to be a non-capacitative Ca²⁺ entry; and B) The fast Ca²⁺ influx, observed in cells with less than 50% of their SR-Ca²⁺ content, is probably a capacitative Ca²⁺ entry and was only Ni²⁺-sensitive.     

抗原诱导兔关节炎模型的建立及早期磁共振表现

目的建立抗原诱导兔关节炎模型并分析其早期磁共振表现。方法7只新西兰兔采用卵清白蛋白致敏后于右膝关节注射相同抗原进行关节炎动物模型的诱导,观察诱导后第5、15天膝关节磁共振表现并作病理对照。结果6只兔右膝关节炎诱导成功,平扫见关节滑模增生、关节积液增多,T1WI均显示为等或稍低信号,T2WI显示为不均匀高信号,两者不易区分,经Gd—DTPA增强扫描后关节滑膜显示为明显强化而关节积液未见明显强化。与第5天图像比较,关节内注射后15天滑膜增生更明显。组织学观察可见右膝关节滑膜增厚、衬里层细胞的增多,衬里及衬里下层炎性细胞浸润,炎性细胞大多为淋巴细胞、单核细胞和巨噬细胞细胞。结论从发病机理、病理表现及磁共振影像等各方面看,抗原诱导兔关节炎模型都是一种较理想的类风湿关节炎动物模型。     

Preparation of 68Ga‐Mg‐Ca‐phytate colloid and its evaluation as a liver imaging agent

The objective of this study was to investigate the radiosynthesis of ⁶⁸Ga‐Mg‐Ca‐phytate colloid and then characterise the formulation for radiochemical purity (RCP), radioactive particle size distribution, and biodistribution in normal rats. This radiocolloid was prepared by mixing an aqueous solution of phytic acid, ⁶⁸Ga³⁺ ions, a dispersant, Mg²⁺ and Ca²⁺ ions, and then heating the contents at 100°C for 5 minutes. After cooling the vial to 5°C, the solution was basified to pH 5 and stored in the cold. The resulting product contained 92±3% RCP ⁶⁸Ga‐colloidal particles and a low level (8±3%) of soluble ⁶⁸Ga‐Mg‐Ca‐phytate. Particle size experiments defined the radioactive particle population was 6±4% <20 nm, 90±6% 20 to 200 nm, and 4% were >200 nm in diameter. Intravenous injection of the ⁶⁸Ga‐colloid dispersion to rats resulted in 93% uptake by the liver plus spleen, 1% lungs, 1% total blood, and 6% in the carcass after 20 minutes. This optimal formulation remained stable at 5°C for 1½ hours in vitro, and it resulted in the same biodistribution as the formulation prepared at t  = 0 hours. The preclinical data so far indicate that ⁶⁸Ga‐Mg‐Ca‐colloid has excellent potential as a liver imaging agent.     

Sodium cholate,a solubilizing agent for the necrosis avid radioiodinated hypericin in rabbits with acute myocardial infarction

Abstract

Objectives: We determined whether sodium cholate (NaCh) could act as a solubilizing agent for the necrosis avid iodine-123-labeled hypericin (¹²³I-Hyp) and investigated biodistribution and targetability of this formulation in rabbits with acute myocardial infarction (AMI).

Materials and methods: Solubility of radioiodinated hypericin/hypericin (Hyp) in NaCh solutions was evaluated by microscopy. Hyp with ¹²³I-sodium iodide was performed using hydrogen peroxide as oxidant in 0.06?M NaCh. Radiochemical yield determination and purification were conducted using high performance liquid chromatography. ¹²³I-Hyp was solubilized in 0.06?M NaCh containing 1.9?×?10^?4?M Hyp. The formulation was macroscopically inspected and intravenously injected to five rabbits with AMI. At 24?h, biodistribution was evaluated by tissue gamma counting (TGC) and necrosis targetability was assessed by TGC, autoradiography, fluorescence examination and histology.

Results: Microscopically NaCh at 0.06?M shows the best properties for solubilizing the radioiodinated Hyp/Hyp. ¹²³I-Hyp in 0.06?M NaCh was achieved in 85% with radiochemical purity of 99% after purification. NaCh-dissolved ¹²³I-Hyp/Hyp shows no particles. By TGC, animals exhibited higher (p?=?0.003) radioactivity accumulation in AMI (0.8?±?0.2% ID/g) than in normal myocardium (0.05?±?0.02% ID/g), as confirmed by autoradiography, fluorescence measurement and histology. Among organs, the highest uptake of radioactivity was found in liver (15.7?±?0.6% ID), large (9.7?±?1.0% ID) and small (5.9?±?0.6% ID) intestines.

Conclusion: Necrosis avidity of NaCh-dissolved ¹²³I-Hyp/Hyp and its hepatobiliary excretion were demonstrated. The suitability of NaCh as solubilizing agent of ¹²³I-Hyp for hotspot imaging of AMI was proved.     

<Emphasis Type="Italic">N</Emphasis><Superscript>4</Superscript>,<Emphasis Type="Italic">N</Emphasis><Superscript>9</Superscript>-Dioleoyl Spermine Is a Novel Nonviral Lipopolyamine Vector for Plasmid DNA Formulation

Purpose To study the effect of synthesized N⁴,N⁹-dioleoyl spermine on DNA condensation and then measure its transfection efficiency in cell culture.Methods The lipopolyamine was synthesized from the naturally occurring polyamine spermine. The ability of this novel compound to condense DNA was studied using ethidium bromide fluorescence quenching and light scattering assays. Transfection efficiency was studied in primary skin cells (FEK4) and in an immortalized cancer cell line (HtTA), and compared with the commercially available transfection formulations Lipofectin and Lipofectamine.Results The synthesized N⁴,N⁹-dioleoyl spermine formula is efficient at condensing calf thymus and circular plasmid DNA and effectively transfects both primary skin cells and cancer cell lines at low charge ratios of (+/– ammonium/phosphate) 2.5.Conclusions N⁴,N⁹-Dioleoyl spermine condenses DNA and achieves high transfection levels in cultured cells.     

Polymerization of ADP-Ribose Pyrophosphatase: conversion mechanism of Mg<Superscript>2+</Superscript>-dependent ADP-Ribose Pyrophosphatase into Mg<Superscript>2+</Superscript>-independent form

ADP-ribose pyrophosphatase (ADPRase) hydrolyzes ADP-ribose (ADPR) into AMP and ribose-5′-phosphate. It is classified into two groups, Mg2+-dependent and Mg2+-independent ADPRase, depending on its Mg2+ requirement. Here, we purified Mg2+-dependent ADPRase from rabbit liver and examined what factors affect Mg2+ requirement. The purified enzyme showed a single band with the molecular weight of 34 kDa on SDS-PAGE both in the presence and absence of 2-mercaptoethanol. The molecular weight of the native enzyme calculated by gel filtration was 68 kDa, indicating that ADPRase is a dimer made up of two identical subunits. Mg²⁺-dependent ADPRase with the highest ADPR affinity had aK _m of 160±10 μM and a pH optimum of around pH 9.5. Treatment of the purified ADPRase with heated cytosol fractions at 37°C for 3 h caused some changes in the chemical properties of the enzyme, including an increase in molecular weight, a decrease in solubility, and a loss of Mg²⁺-depen-dency. The molecular weight of the cytosol-treated ADPRase measured by gel filtration was over 420 kDa, suggesting, for the first time, that ADPRase could be polymerized by undefined cytoplasmic factors, and that polymerization is accompanied by changes in the solubility and metal ion dependency of the enzyme.     

Tris Lipidation--A Novel Drug Delivery System that Alters Biodistribution

Tris-lipidation uses Tris to produce drug-fatty acyl conjugates. Radiolabelled Tris-fatty acyl conjugates of methotrexate (MTX) were examined in biodistribution studies in BALB/c mice. Following delivery via a variety of routes, the Tris-lipidated compounds demonstrated features in common with other colloid drug delivery systems. Tissues of the reticuloendothelial system localised the drug following intravenous administration, and the compounds showed prolongation at the site of injection into muscle or fatty tissue, subcutaneously or when inhaled. These findings indicate that the Tris-lipidation platform could be classed as an alternative colloid drug delivery system.     

Tris lipidation--a novel drug delivery system that alters biodistribution

Tris-lipidation uses Tris to produce drug-fatty acyl conjugates. Radiolabelled Tris-fatty acyl conjugates of methotrexate (MTX) were examined in biodistribution studies in BALB/c mice. Following delivery via a variety of routes, the Tris-lipidated compounds demonstrated features in common with other colloid drug delivery systems. Tissues of the reticuloendothelial system localised the drug following intravenous administration, and the compounds showed prolongation at the site of injection into muscle or fatty tissue, subcutaneously or when inhaled. These findings indicate that the Tris-lipidation platform could be classed as an alternative colloid drug delivery system.