Synthesis,Acoustic Stability,and Pharmacologic Activities of Papaverine-Loaded Echogenic Liposomes for Ultrasound Controlled Drug Delivery

Background: development of encapsulated therapeutics that could be released upon ultrasound exposure has strong implications for enhancing drug effects at the target site. We have developed echogenic liposomes (ELIP) suitable for ultrasound imaging of blood flow and ultrasound-mediated intravascular drug release. Papaverine was chosen as the test drug because its clinical application requires high concentration in the target vascular bed but low concentration in the systemic circulation. Methods: the procedure for preparation of standard ELIP was modified by including Papaverine hydrochloride in the lipid hydration solution, followed by three freeze-thaw cycles to increase encapsulation of the drug. Sizing and encapsulation pharmacokinetics were performed using a Coulter counter and a phosphodiesterase activity assay. Stability of Papaverine-loaded ELIP (PELIP) was monitored with a clinical diagnostic ultrasound scanner equipped with a linear array transducer at a center frequency of 4.5 MHz by assessing the mean digital intensity within a region of interest over time. The stability of PELIP was compared to those of standard ELIP and Optison?. Results: relative to standard ELIP, PELIP were larger (median diameter?=?1.88?±?0.10 μm for PELIP vs 1.08?±?0.15 μm for ELIP) and had lower Mean Gray Scale Values (MGSV) (92?±?24.8 for PELIP compared to 142.3?±?10.7 for ELIP at lipid concentrations of 50 μg/ml). The maximum loading efficiency and mean encapsulated concentration were 24%?±?7% and 2.1?±?0.7 mg/ml, respectively. Papaverine retained its phosphodiesterase inhibitory activity when associated with PELIP. Furthermore, a fraction of this activity remained latent until released by dissolution of liposomal membranes with detergent. The stability of both PELIP and standard ELIP were similar, but both are greater than that of Optison?. Conclusions: our results suggest that PELIP have desirable physical, biochemical, biological, and acoustic characteristics for potential in vivo administration and ultrasound-controlled drug delivery.     

Inhibition of MMP-2 gene expression with small interfering RNA in rabbit vascular smooth muscle cells

Matrix metalloproteinase-2 (MMP-2) is constitutively expressed in vascular smooth muscle cells (VSMCs). Using small interfering RNA (siRNA), we evaluated the effect of MMP-2 inhibition in VSMCs in vitro and ex vivo. Rabbit VSMCs were transfected in vitro with 50 nmol/l MMP-2 siRNA or scramble siRNA. Flow cytometry and confocal microscopy showed cellular uptake of siRNA in approximately 80% of VSMCs. MMP-2 mRNA levels evaluated by real-time RT-PCR, pro-MMP-2 activity from conditioned culture media evaluated by gelatin zymography, and VSMC migration were reduced by 44 +/- 19%, 43 +/- 14%, and 36 +/- 14%, respectively, in MMP-2 siRNA-transfected compared with scramble siRNA-transfected VSMCs (P < 0.005 for all). Ex vivo MMP-2 siRNA transfection was performed 2 wk after balloon injury of hypercholesterolemic rabbit carotid arteries. Fluorescence microscopy showed circumferential siRNA uptake in neointimal cells. Gelatin zymography of carotid artery culture medium demonstrated a significant decrease of pro-MMP-2 activity in MMP-2 siRNA-transfected compared with scramble siRNA-transfected arteries (P < 0.01). Overall, our results demonstrate that in vitro MMP-2 siRNA transfection in VSMCs markedly inhibits MMP-2 gene expression and VSMC migration and that ex vivo delivery of MMP-2 siRNA in balloon-injured arteries reduces pro-MMP-2 activity in neointimal cells, suggesting that siRNA could be used to modify arterial biology in vivo.     

Modelling intravascular delivery from drug-eluting stents with biodurable coating: investigation of anisotropic vascular drug diffusivity and arterial drug distribution

In-stent restenosis occurs in coronary arteries after implantation of drug-eluting stents with non-uniform restenosis thickness distribution in the artery cross section. Knowledge of the spatio-temporal drug uptake in the arterial wall is useful for investigating restenosis growth but may often be very expensive/difficult to acquire experimentally. In this study, local delivery of a hydrophobic drug from a drug-eluting stent implanted in a coronary artery is mathematically modelled to investigate the drug release and spatio-temporal drug distribution in the arterial wall. The model integrates drug diffusion in the coating and drug diffusion with reversible binding in the arterial wall. The model is solved by the finite volume method for both high and low drug loadings relative to its solubility in the stent coating with varied isotropic–anisotropic vascular drug diffusivities. Drug release profiles in the coating are observed to depend not only on the coating drug diffusivity but also on the properties of the surrounding arterial wall. Time dependencies of the spatially averaged free- and bound-drug levels in the arterial wall on the coating and vascular drug diffusivities are discussed. Anisotropic vascular drug diffusivities result in slightly different average drug levels in the arterial wall but with very different spatial distributions. Higher circumferential vascular diffusivity results in more uniform drug loading in the upper layers and is potentially beneficial in reducing in-stent restenosis. An analytical expression is derived which can be used to determine regions in the arterial with higher free-drug concentration than bound-drug concentration.     

重组人白介素-10抑制晚期糖基化终产物诱导的大鼠血管平滑肌细胞和血管新生内膜的增殖

研究观察了重组人白介素10(rhIL-l0)对晚期糖基化终产物(AGE)刺激下离体大鼠胸主动脉血管平滑肌细胞增殖及对SD大鼠血管损伤后新生内膜增殖的影响。体外培养大鼠主动脉血管平滑肌细胞,采用MTS／PES法确定血管平滑肌细胞的增殖状态;应用流式细胞术测定细胞周期;利用p44／42磷酸化抗MAPK抗体的蛋白免疫印迹法测定p44／42 MAPK磷酸化蛋白表达。利用大鼠颈动脉血管损伤模型,观察rhIL—10对新生内膜增殖的影响。结果显示：(1)AGE处理组与对照组相比,AGE对血管平滑肌细胞增殖具有明显的刺激作用(P＜0．05)。rhIL-l0单独应用对血管平滑肌细胞生长没有影响(P＞0．05)。在AGE刺激下,低至100ng／ml的rhIL-l0可抑制血管平滑肌细胞的生长(P＜0．05)。(2)流式细胞术测定的结果显示,rhIL—10可以使AGE作用下的VSMC大部分处于Go／G1期,与对照组相比有明显差异(P＜0．01)。(3)AGE对p44／p42 MAPK磷酸化蛋白表达有显著的增强作用,此作用可被rhIL—10抑制(P＜0．001)。(4)大鼠颈动脉损伤后,rhIL—10治疗组的动脉血管新生内膜/中层面积比低于对照组约45％(P＜0．01)。表明抗炎细胞因子rhIL—10可抑制AGE诱导的大鼠血管平滑肌细胞增殖和血管新生内膜的增殖。     

Real-time technique for improving molecular imaging and guiding drug delivery in large blood vessels: in vitro and ex vivo results

Ultrasound-based molecular imaging employs targeted microbubbles to image vascular pathology. This approach also has the potential to monitor molecularly targeted microbubble-based drug delivery. We present an image-guided drug delivery technique that uses multiple pulses to translate, image, and cavitate microbubbles in real time. This technique can be applied to both imaging of pathology in large arteries (sizes and flow comparable to those in humans) and guiding localized drug delivery in blood vessels. The microbubble translation (or pushing) efficacy of this technique was compared in a variety of flow media: saline, viscous saline (4 cp), and bovine blood. It was observed that the performance of this approach was marginally better (by 6, 4, and 2 dB) in viscous saline than in bovine blood with varying levels of hematocrit (40%, 30%, and 10%). The drug delivery efficacy of this technique was evaluated by in vitro and ex vivo experiments. High-intensity pulses mediated fluorophore (DiI) deposition on endothelial cells (in vitro) without causing cell destruction. Ex vivo fluorophore delivery experiments conducted on swine carotids of 2 and 5 mm cross-section diameter demonstrated a high degree of correspondence in spatial localization of the fluorophore delivery between the ultrasound and composite fluorescence microscopy images of the arterial cross sections.     

Growth kinetics and stoichiometry of Mentha citrata shooty teratomas transformed by Agrobacterium tumefaciens

Summary Culture characteristics of genetically transformed Mentha citrata shooty teratomas were studied in liquid Murashige and Skoog and Gamborg's B5 media. Based on calculated kinetic and yield parameters, a stoichiometric equation was developed to describe growth in media containing both nitrate and ammonia. Measurements of oxygen uptake rate showed that delivery of adequate oxygen to completely submerged shoots depends on the elimination of hydrodynamic boundary layers at high external liquid velocity.     

The influence of bile salts on the response of liposomes to ultrasound

Context: Triggering drug release from delivery vehicles with ultrasound has potential applications in targeted drug delivery. It was hypothesized that the addition of bile salts would increase the sensitivity of liposomes to ultrasound through creation of defects.

Objective: The aim of this study was to investigate whether incorporating bile salts into liposomes would lead to differential effects on their response to low and high frequency ultrasound.

Materials and methods: Cholate, chenodeoxycholate, ursodeoxycholate, glycocholate and taurocholate were the selected bile salts. Response to ultrasound was characterized by measuring the release of carboxyfluorescein (CF).

Results: At 30?kHz ultrasound, taurocholate containing liposomes were most responsive and released 70% (±2) CF after 30 seconds of sonication. Compared to this, liposomes that did not contain bile salts released just 7% (±2). At 1.1?MHz ultrasound, all liposome formulations were unresponsive. To increase the response of liposomes at 1.1?MHz ultrasound, a combination of membrane destabilizers were added to DSPC liposomes. DOPE, a hexagonal phase lipid was used in combination with taurocholate. Surprisingly, liposomes containing DOPE and taurocholate were more resistant to 1.1?MHz ultrasound than ones containing only DOPE.

Discussion: This suggests that the sensitivity of liposomes towards ultrasound may not simply be defined by a single membrane component but instead depends on the interaction between constituting lipid components. Furthermore, strategies other than membrane destabilization may be required to sensitize liposomes towards high frequency ultrasound.

Conclusion: Bile salts may be used to increase or decrease the sensitivity of liposomes to low frequency ultrasound.     

Layer-specific arterial micromechanics and microstructure: Influences of age,anatomical location,and processing technique

The importance of matrix micromechanics is increasingly recognized in cardiovascular research due to the intimate role they play in local vascular cell physiology. However, variations in micromechanics among arterial layers (i.e. intima, media, adventitia), as well as dependency on local matrix composition and/or structure, anatomical location or developmental stage remain largely unknown. This study determined layer-specific stiffness in elastic arteries, including the main pulmonary artery, ascending aorta, and carotid artery using atomic force indentation. To compare stiffness with age and frozen processing techniques, neonatal and adult pulmonary arteries were tested, while fresh (vibratomed) and frozen (cryotomed) tissues were tested from the adult aorta. Results revealed that the mean compressive modulus varied among the intima, sub-luminal media, inner-middle media, and adventitia layers in the range of 1–10 kPa for adult arteries. Adult samples, when compared to neonatal pulmonary arteries, exhibited increased stiffness in all layers except adventitia. Compared to freshly isolated samples, frozen preparation yielded small stiffness increases in each layer to varied degrees, thus inaccurately representing physiological stiffness. To interpret micromechanics measurements, composition and structure analyses of structural matrix proteins were conducted with histology and multiphoton imaging modalities including second harmonic generation and two-photon fluorescence. Composition analysis of matrix protein area density demonstrated that decrease in the elastin-to-collagen and/or glycosaminoglycan-to-collagen ratios corresponded to stiffness increases in identical layers among different types of arteries. However, composition analysis was insufficient to interpret stiffness variations between layers which had dissimilar microstructure. Detailed microstructure analyses may contribute to more complete understanding of arterial micromechanics.     

Imaging gene expression in the brain with peptide nucleic acid (PNA) antisense radiopharmaceuticals and drug targeting technology

Summary Antisense oligomers are potential pharmaceutical and radiopharmaceutical agents that can be used to modulate and image gene expression. Progress within vivo gene targeting using antisense-based therapeutics has been slower than expected during the last decade, owing to poor trans-cellular delivery of antisense agents. This chapter suggests that if antisense pharmacology is merged with drug targeting technology, then membrane barriers can be circumvented and antisense agents can be delivered to tissuesin vivo. Without the application of drug targeting, the likelihood of success for an antisense drug development program is low, particularly for the brain which is protected by the blood-brain barrier (BBB). Among the different classes of antisense agents, peptide nucleic acids (PNA) present advantages forin vivo applications over conventional and modified oligodeoxynucleotides (ODN), including phosphorothioates (PS)-ODN. Some advantages of PNAs include their electrically neutral backbone, low toxicity to neural cells, resistance to nucleases and peptidases, and lack of binding to plasma proteins. PNAs are poorly transported through cellular membranes, however, including the BBB and the brain cell membrane (BCM). Because the mRNA target for the antisense agent lies within the cytosol of the target cell, the BBB and the BCM must be circumventedin vivo, which is possible with the use of chimeric peptide drug targeting technology. Chimeric peptides are formed by conjugation of a non-transportable drug, such as a PNA, to a drug delivery vector. The vector undergoes receptor-mediated transcytosis (RMT) through the BBB and receptor-mediated endocytosis through the BCMin vivo. When labeled with a radioisotope (e.g.,¹²⁵I or¹¹¹In), the antisense chimeric peptide provides imaging of gene expression in the brainin vivo in a sequence-specific manner. Further development of antisense radiopharmaceutical agents may allow forin vivo imaging of genes in pathological states, and may provide tools for the analysis of novel genes with functional genomics.     

The effects of pulsed magnetic field exposure on the permeability of leukemia cancer cells

Purpose: The newer methods of cancer treatment require new idea of drug delivery in cancer cells. Due to numerous researches electromagnetic field affect on cell function and cell membrane for possible therapeutic and drug delivery. In this article, we determined in vitro uptake of fluorescent dyes into the attached K562 cells due to time-varying magnetic field exposure. Method and material: The K562 cells were exposed to magnetic pulses via Magstim stimulator and double 70?mm coil. The strength and duration of pulses in all experiments were the same and three different frequencies of 0.25, 1 and 10?Hz pulses for 56, 112 and 28 numbers of pulses were applied (nine experimental groups) and uptake of Ly and PI was measured in each group. Result: Our results show that magnetic field can efficiently increase permeability. Among the treatment groups, the system gives the optimal permeabilization when cells are exposed to a train of 28 pulses with 1?Hz frequency.     

Targeting alphavbeta3 and alpha5beta1 for gene delivery to proliferating VSMCs: synergistic effect of TGF-beta1

TGF-beta1 levels increase after vascular injury and promote vascular smooth muscle cell (VSMC) proliferation. We define a nonviral gene delivery system that targets alphavbeta3 and alpha5beta1 integrins that are expressed on proliferating VSMCs and strongly induced by TGF-beta1. A 15-amino acid RGDNP-containing peptide from American Pit Viper venom was linked to a Lys(16) peptide as vector (molossin vector) and complexed with Lipofectamine or fusogenic peptide for delivery of luciferase or beta-galactosidase reporter genes to primary cultures of human, rabbit, and rat VSMCs. Preincubation of VSMCs with TGF-beta1 for 24 h, but not with PDGF-BB, interferon-gamma, TNF-alpha, nor PMA, increased alphavbeta3 and alpha5beta1 expressions on VSMCs and enhanced gene delivery of molossin vector. Thus beta-galactosidase activity increased from 35 +/- 5% (controls) to 75 +/- 5% after TGF-beta1 treatment, and luciferase activity increased fourfold over control values. Potential use of this system in vessel bypass surgery was examined in an ex vivo rat aortic organ culture model after endothelial damage. Molossin vector system delivered beta-galactosidase to VSMCs in the vessel wall that remained for up to 12 days posttransfection. The molossin vector system, when combined with TGF-beta1, enhances gene delivery to proliferating VSMCs and might have clinical applications for certain vasculoproliferative diseases.     

Imaging collagen in intact viable healthy and atherosclerotic arteries using fluorescently labeled CNA35 and two-photon laser scanning microscopy

We evaluated CNA35 as a collagen marker in healthy and atherosclerotic arteries of mice after both ex vivo and in vivo administration and as a molecular imaging agent for the detection of atherosclerosis. CNA35 conjugated with fluorescent Oregon Green 488 (CNA35/OG488) was administered ex vivo to mounted viable muscular (uterine), elastic (carotid), and atherosclerotic (carotid) arteries and fresh arterial rings. Two-photon microscopy was used for imaging. CNA35/OG488 labeling in healthy elastic arteries was compared with collagen type I, III, and IV antibody labeling in histologic sections. For in vivo labeling experiments, CNA35/OG488 was injected intravenously in C57BL6/J and apolipoprotein E(-/-) mice. Ex vivo CNA35/OG488 strongly labeled collagen in the tunica adventitia, media, and intima of muscular arteries. In healthy elastic arteries, tunica adventitia was strongly labeled, but labeling in tunica media and intima was prevented by endothelium and elastic laminae. Histology confirmed the affinity of CNA35 for type I, III, and IV collagen in arteries. Strong CNA35/OG488 labeling was found in atherosclerotic plaques. In vivo applied CNA35/OG488 minimally labeled the tunica intima of healthy carotid arteries. Atherosclerotic plaques in apolipoprotein E(-/-) mice exhibited large uptake. CNA35/OG488 imaging in organs revealed endothelium as a limiting barrier for in vivo uptake. CNA35/OG488 is a good molecular imaging agent for atherosclerosis.     

Differential regulation of L-type Ca2+ channels in cerebral and mesenteric arteries after simulated microgravity in rats and its intervention by standing

This study was designed to clarify whether simulated microgravity can induce differential changes in the current and protein expression of the L-type Ca(2+) channel (Ca(L)) in cerebral and mesenteric arteries and whether these changes can be prevented by daily short-duration -G(x) exposure. Tail suspension [hindlimb unloading (HU)] for 3 and 28 days was used to simulate short- and medium-term microgravity-induced deconditioning effects. Standing (STD) for 1 h/day was used to provide -G(x) as a countermeasure. Whole cell patch-clamp experiments revealed an increase in current density of Ca(L) of vascular smooth muscle cells (VSMCs) isolated from cerebral arteries of rats subjected to HU and a decrease in VSMCs from mesenteric arteries. Western blot analysis revealed a significant increase and decrease of Ca(L) channel protein expression in cerebral and small mesenteric arterial VSMCs, respectively, only after 28 days of HU. STD for 1 h/day did not prevent the increase of Ca(L) current density in cerebral arterial VSMCs, but it prevented completely (within 3 days) and partially (28 days) the decrease of Ca(L) current density in small mesenteric arterial VSMCs. Consistent with the changes in Ca(L) current, STD for 1 h/day did not prevent the increase of Ca(L) expression in cerebrovascular myocytes but did prevent the reduction of Ca(L) expression in mesenteric arterial VSMCs subjected to 28 days of HU. These data indicate that simulated microgravity up- and downregulates the current and expression of Ca(L) in cerebral and hindquarter VSMCs, respectively. STD for 1 h/day differentially counteracted the changes of Ca(L) function and expression in cerebral and hindquarter arterial VSMCs of HU rats, suggesting the complexity of the underlying mechanisms in the effectiveness of intermittent artificial gravity for prevention of postflight cardiovascular deconditioning, which needs further clarification.     

Ultrasound-enhanced bevacizumab release from echogenic liposomes for inhibition of atheroma progression

Context: Bevacizumab (BEV) is a monoclonal antibody to vascular endothelial growth factor (VEGF) that ameliorates atheroma progression by inhibiting neovascularization.

Objective: We aimed to determine whether BEV release from echogenic liposomes (BEV-ELIP) could be enhanced by color Doppler ultrasound (US) and whether the released BEV inhibits VEGF expression by endothelial cells in vitro.

Materials and methods: BEV-ELIP samples were subjected to 6?MHz color Doppler ultrasound (MI?=?0.4) for 5?min. We assessed release of BEV with a direct ELISA and with fluoresceinated BEV (FITC-BEV) loaded into ELIP by the same method. Human umbilical vein endothelial cell (HUVEC) cultures were stimulated to express VEGF by 10?nM phorbol-12-myristate 13-acetate (PMA). Cell-associated VEGF levels were determined using a cell-based ELISA.

Results: Overall, US caused an additional 100?µg of BEV to be released or exposed per BEV-ELIP aliquot within 60?min BEV-ELIP treated with US inhibited VEGF expression by 90% relative to non-treated controls and by 70% relative to BEV-ELIP without US. Also, US-treated BEV-ELIP inhibited HUVEC proliferation by 64% relative to untreated controls and by 45% relative to BEV-ELIP without US.

Discussion and conclusion: We have demonstrated that BEV-ELIP retains its VEGF-binding activity in a liposomal formulation and that clinical Doppler US can significantly increase that activity, both by releasing free BEV and by enhancing the surface exposure of the immunoreactive antibody.     

Sonoporation: Mechanistic insights and ongoing challenges for gene transfer

Microbubbles first developed as ultrasound contrast agents have been used to assist ultrasound for cellular drug and gene delivery. Their oscillation behavior during ultrasound exposure leads to transient membrane permeability of surrounding cells, facilitating targeted local delivery. The increased cell uptake of extracellular compounds by ultrasound in the presence of microbubbles is attributed to a phenomenon called sonoporation. In this review, we summarize current state of the art concerning microbubble–cell interactions and cellular effects leading to sonoporation and its application for gene delivery. Optimization of sonoporation protocol and composition of microbubbles for gene delivery are discussed.     

Imaging gene expression in the brain with peptide nucleic acid (PNA) antisense radiopharmaceuticals and drug targeting technology

Antisense oligomers are potential pharmaceutical and radiopharmaceutical agents that can be used to modulate and image gene expression. Progress with in vivogene targeting using antisense-based therapeutics has been slower than expected during the last decade, owing to poor trans-cellular delivery of antisense agents. This chapter suggests that if antisense pharmacology is merged with drug targeting technology, then membrane barriers can be circumvented and antisense agents can be delivered to tissues in vivo. Without the application of drug targeting, the likelihood of success for an antisense drug development program is low, particularly for the brain which is protected by the blood-brain barrier (BBB). Among the different classes of antisense agents, peptide nucleic acids (PNA) present advantages for in vivoapplications over conventional and modified oligodeoxynucleotides (ODN), including phosphorothioates (PS)-ODN. Some advantages of PNAs include their electrically neutral backbone, low toxicity to neural cells, resistance to nucleases and peptidases, and lack of binding to plasma proteins. PNAs are poorly transported through cellular membranes, however, including the BBB and the brain cell membrane (BCM). Because the mRNA target for the antisense agent lies within the cytosol of the target cell, the BBB and the BCM must be circumvented in vivo, which ispossible with the use of chimeric peptide drug targeting technology. Chimeric peptides are formed by conjugation of a non-transportable drug, such as a PNA, to a drug delivery vector. The vector undergoes receptor-mediated transcytosis (RMT) through the BBB and receptor-mediated endocytosis through the BCM in vivo. When labeled with a radioisotope (e.g., ¹²⁵I or ¹¹¹In), the antisense chimeric peptide provides imaging of gene expressionin the brain in vivoin a sequence-specific manner. Further development of antisense radiopharmaceutical agents may allow for in vivoimaging of genes in pathological states, and may provide tools for the analysis of novel genes with functional genomics.     

Imaging gene expression in the brain with peptide nucleic acid (PNA) antisense radiopharmaceuticals and drug targeting technology

Summary Antisense oligomers are potential pharmaceutical and radiopharmaceutical agents that can be used to modulate and image gene expression. Progress with in vivo gene targeting using antisense-based therapeutics has been slower than expected during the last decade, owing to poor trans-cellular delivery of antisense agents. This chapter suggests that if antisense pharmacology is merged with drug targeting technology, then membrane barriers can be circumvented and antisense agents can be delivered to tissues in vivo. Without the application of drug targeting, the likelihood of success for an antisense drug development program is low, particularly for the brain which is protected by the blood-brain barrier (BBB). Among the different classes of antisense agents, peptide nucleic acids (PNA) present advantages for in vivo applications over conventional and modified oligodeoxynucleotides (ODN), including phosphorothioates (PS)-ODN. Some advantages of PNAs include their electrically neutral backbone, low toxicity to neural cells, resistance to nucleases and peptidases, and lack of binding to plasma proteins. PNAs are poorly transported through cellular membranes, however, including the BBB and the brain cell membrane (BCM). Because the mRNA target for the antisense agent lies within the cytosol of the target cell, the BBB and the BCM must be circumvented in vivo, which is possible with the use of chimeric peptide drug targeting technology. Chimeric peptides are formed by conjugation of a non-transportable drug, such as a PNA, to a drug delivery vector. The vector undergoes receptor-mediated transcytosis (RMT) through the BBB and receptor-mediated endocytosis through the BCM in vivo. When labeled with a radioisotope (e.g., ¹²⁵I or ¹¹¹In), the antisense chimeric peptide provides imaging of gene expression in the brain in vivo in a sequence-specific manner. Further development of antisense radiopharmaceutical agents may allow for in vivo imaging of genes in pathological states, and may provide tools for the analysis of novel genes with functional genomics.     

Experimental measurements of elastic properties of media and adventitia of bovine carotid arteries

An experimental procedure is described which has been developed to measure the elastic properties of the outer (adventitial) and inner (medial) layers of excised bovine carotid arteries. The data analysis is based on a two-layered arterial wall model and the theory of large elastic deformations. The energy density functions for both layers are exponentials. The results show that the media and the adventitia are anisotropic; that the media is stiffer, more non-linear, and subjected to higher stresses than commonly assumed; and that both layers are stiffer in the axial direction than in the tangential direction.     

Direct Delivery of a Cytotoxic Anticancer Agent into the Metastatic Lymph Node Using Nano/Microbubbles and Ultrasound

Direct injection of an anticancer agent into a metastatic lymph node (LN) has not been used as a standard treatment because evidence concerning the efficacy of local administration of a drug into a metastatic LN has not been established. Here we show that the combination of intralymphatic drug delivery with nano/microbubbles (NMBs) and ultrasound has the potential to improve the chemotherapeutic effect. We delivered cis-diamminedichloroplatinum (II) (CDDP) into breast carcinoma cells in vitro and found that apoptotic processes were involved in the antitumor action. Next, we investigated the antitumor effect of intralymphatic chemotherapy with NMBs and ultrasound in an experimental model of LN metastasis using MXH10/Mo-lpr/lpr mice exhibiting lymphadenopathy. The combination of intralymphatic chemotherapy with NMBs and ultrasound has the potential to improve the delivery of CDDP into target LNs without damage to the surrounding normal tissues. The present study indicates that intralymphatic drug delivery with NMBs and ultrasound will potentially be of great benefit in the clinical setting.     

Study on the Multidrug Resistance 1 Gene Transfection Efficiency Using Adenovirus Vector Enhanced by Ultrasonic Microbubbles In Vitro

As gene delivery reagents, microbubbles have been successfully used in combination with ultrasound. Shock wave exposure has been shown to transfect cells with naked DNA in vitro, but it has not been tested whether the addition of microbubbles would enhance DNA uptake with adenovirus vector. Therefore, the aim of this study was to study the efficacy and safety of multidrug resistance 1 (MDR1) gene transfer into the bone marrow mononuclear cells of rabbits using adenovirus vector enhanced by ultrasound with microbubbles in vitro. The transfection rate of the MDR1 gene was significantly increased by ultrasound microbubbles with adenovirus. After ultrasonic irradiation, there were transient holes in the cell membrane, which disappeared after irradiation by ultrasound for 24 h. The temporary swelling of the organelles was reversible. Our in vitro findings conclusively demonstrate that the exogenous MDR1 gene transfer into the mononuclear cells of rabbits with adenovirus vector was enhanced by the ultrasonic microbubbles and this transfection technique is safe.