Rapid Injection Method Research Articles

Uptake of New Lipid-coated Nanoparticles Containing Falcarindiol by Human Mesenchymal Stem Cells.

Nanoparticles are the focus of an increased interest in drug delivery systems for cancer therapy. Lipid-coated nanoparticles are inspired in structure and size by low-density lipoproteins (LDLs) because cancer cells have an increased need for cholesterol to proliferate, and this has been exploited as a mechanism for delivering anticancer drugs to cancer cells. Moreover, depending on drug chemistry, encapsulating the drug can be advantageous to avoid degradation of the drug during circulation in vivo. Therefore, in thisstudy, this design is used to fabricate lipid-coated nanoparticles of the anticancer drug falcarindiol, providing a potential new delivery system of falcarindiol in order to stabilize its chemical structure against degradation and improve its uptake by tumors. Falcarindiol nanoparticles, with a phospholipid and cholesterol monolayer encapsulating the purified drug core of the particle, were designed. The lipid monolayer coating consists of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol (Chol), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE PEG 2000) along with the fluorescent label DiI (molar ratios of 43:50:5:2). The nanoparticles are fabricated using the rapid injection method, which is a fast and simple technique to precipitate nanoparticles by good-solvent for anti-solvent exchange. It consists of a rapid injection of an ethanol solution containing the nanoparticle components into an aqueous phase. The size of the fluorescent nanoparticles is measured using dynamic light scattering (DLS) at 74.1 ± 6.7 nm. The uptake of the nanoparticles is tested in human mesenchymal stem cells (hMSCs) and imaged using fluorescence and confocal microscopy. The uptake of the nanoparticles is observed in hMSCs, suggesting the potential for such a stable drug delivery system for falcarindiol.

Colloidal Synthesis of Bulk-Bandgap Lead Selenide Nanocrystals.

Lead selenide quantum dots (QDs) are low-bandgap IV-VI semiconducting nanomaterials that have been studied for a variety of applications. Their preparation using colloidal methods can create small spherical to larger cubic nanocrystals, with an upper limit of ~17 nm reported to date. Here we describe methods for preparing cubic PbSe nanocrystals over a 20–40 nm size range using a twostep procedure. Specifically, ~10 nm PbSe QDs are generated using the rapid injection method, the products from which are overcoated with additional lead and selenium precursors. The use of two lead reagents were studied; lead oleate resulted in a maximum of 20 nm cubes, while more reactive lead hexyldecanoate resulted in much larger nanomaterials with bulk bandgaps. However, PbSe samples prepared with lead hexyldecanoate also contained agglomerates. Special care must be taken when characterizing larger strained nanomaterials with X-ray powder diffraction, for which the Scherrer equation is inadequate. A more rigorous approach using the Williamson–Hall method provides characterizations that are consistent with electron microscopy analysis.

Self-assembly of porphyrin-grafted lipid into nanoparticles encapsulating doxorubicin for synergistic chemo-photodynamic therapy and fluorescence imaging.

The limited clinical efficacy of monotherapies in the clinic has urged the development of novel combination platforms. Taking advantage of light-triggered photodynamic treatment combined together with the controlled release of nanomedicine, it has been possible to treat cancer without eliciting any adverse effects. However, the challenges imposed by limited drug loading capacity and complex synthesis process of organic nanoparticles (NPs) have seriously impeded advances in chemo-photodynamic combination therapy. In this experiment, we utilize our previously synthesized porphyrin-grafted lipid (PGL) NPs to load highly effective chemotherapeutic drug, doxorubicin (DOX) for synergistic chemo-photodynamic therapy.Methods: A relatively simple and inexpensive rapid injection method was used to prepare porphyrin-grafted lipid (PGL) NPs. The self-assembled PGL NPs were used further to encapsulate DOX via a pH-gradient loading protocol. The self-assembled liposome-like PGL NPs having a hydrophilic core were optimized to load DOX at an encapsulation efficiency (EE) of ~99%. The resultant PGL-DOX NPs were intact, highly stable and importantly these NPs successfully escaped from the endo-lysosomal compartment after laser irradiation to release DOX in the cytosol. The therapeutic efficacy of the aforementioned formulation was validated both in vitro and in vivo.Results: PGL-DOX NPs demonstrated excellent cellular uptake, chemo-photodynamic response, and fluorescence imaging ability in different cell lines. Under laser irradiation, cells treated with a low molar concentration of PGL-DOX NPs reduced cell viability significantly. Moreover, in vivo experiments conducted in a xenograft mouse model further demonstrated the excellent tumor accumulation capability of PGL-DOX NPs driven by the enhanced permeability and retention (EPR) effect. Through fluorescence imaging, the biodistribution of PGL-DOX NPs in tumor and major organs was also easily monitored in real time in vivo. The inherent ability of porphyrin to generate ROS under laser irradiation combined with the cytotoxic effect of the anticancer drug DOX significantly suppressed tumor growth in vivo.Conclusion: In summary, the PGL-DOX NPs combined chemo-photodynamic nanoplatform may serve as a potential candidate for cancer theranostics.

Supramolecular photovoltaic cells utilizing inclusion complexes composed of Li+@C60 and cyclic porphyrin dimer

We have newly constructed supramolecular photovoltaic cells using inclusion complexes of lithium-ion-encapsulated [60]fullerene ( Li +@ C 60) and cyclic porphyrin dimers (M-CPDPy, M = H 4 and Ni 2). First, supramolecular inclusion complexes of Li +@ C 60 and M-CPDPy were prepared in MeCN/PhCN (3/1, v/v) by rapid injection method. The molecular aggregates with spherical nanoparticles demonstrated a broad absorption property in the visible region. The macroscopic structures were also estimated to be ca. 200 nm in diameter by transmission electron microscope (TEM) and dynamic light scattering (DLS) measurements. The photoelectrochemical solar cells composed of these assemblies on nanostructured SnO 2 electrode were fabricated by electrophoretic deposition method. The photoelectrochemical behavior of the nanostructured SnO 2 film of supramolecular nanoassemblies of Li +@ C 60 and M-CPDPy is significantly higher than those of the single component films ( Li +@ C 60 or M-CPDPy) and supramolecular inclusion complexes of pristine C 60 and M-CPDPy.

One-step synthesis of monodisperse Au–Ag alloy nanoparticles in a microreaction system

Monodisperse Au–Ag alloy nanoparticles were synthesized by a one-step rapid injection method in a capillary microreaction system with a short residence time (less than 3min). Au–Ag alloy NPs possessed homogenous composition that revealed a linear relationship with surface plasmon resonance absorption peak. The optimal size distribution of Au–Ag alloy NPs with a standard deviation of 6% could be obtained from decreasing the molar ratio of Au3+:Ag+ from 1:10 to 1:20 or enhancing the synthesis temperature from 140 to 160°C. Transmission electron micrographs showed as-obtained Au–Ag alloy nanoparticles were sphere-like with the smallest average size of only 2.7nm.

A new embolus injection method to evaluate intracerebral hemorrhage in New Zealand white rabbits

The rabbit large clot embolic stroke model has been used for over 23 years to study methods to manipulate hemorrhage and to test drugs and devices for safety, because the rabbit model is particularly sensitive to embolism-induced hemorrhage. This study refined the original embolization procedure using an automated, pump-assisted injection method to introduce large blood clots or macroscopic emboli into the middle cerebral artery (MCA) via an indwelling carotid artery catheter. The study shows that rapid injection of blood clots (3 ml/30 s) produced a model where there is a high hemorrhage incidence rate (79%) and a high stroke success rate (63%), compared to a low stroke success rate (19%) with no hemorrhages when clots were injected at a slow rate (3 ml/90 s). The rapid injection method, which produces a high hemorrhage rate, is particularly useful to study neuroprotective agents to attenuate embolism-induced hemorrhage. In addition, we show that manual injection of blood clots, which produces a lower baseline hemorrhage rate (41%) with a similar stroke success rate (65%), may allow investigators to study pharmacological agents to either up or down-regulate hemorrhage incidence. Lastly, we show that in the rabbit embolic stroke model, hemorrhages are adjacent to areas of 2,3,5-triphenyltetrazolium (TTC)-negative tissue, normally associated with infarcted or ischemic tissue. Thus, there is clear separation of ischemia and hemorrhage in the model, suggesting that therapeutics that are neuroprotective may also be useful to limit the evolution of ischemic damage associated with a hemorrhage, if not attenuate hemorrhage itself.

Rapid Injection Method of Semi-Solid Food for Pediatric Patients With Gastrostomy

Rapid Injection Method of Semi-Solid Food for Pediatric Patients With Gastrostomy

A92 Postoperative blood volume deficit after major abdominal and cardiac surgery measured by a novel and rapid injection method

A92 Postoperative blood volume deficit after major abdominal and cardiac surgery measured by a novel and rapid injection method

Immunization with plasmid DNA using a pneumatic gun

We characterize a method by which the Med-E-Jet pneumatic vaccination gun can be used to propel intact, supercoiled plasmid DNA through skin and into skeletal muscles of mice. Intramuscular injection of plasmids containing the firefly luciferase gene linked to the human cytomegalovirus promoter resulted in the expression of several hundred picograms of luciferase enzyme in quadriceps muscles. Intramuscular injections of a plasmid containing the influenza A nuclear protein gene regulated by the same promoter resulted in the generation of potent and specific anti-nuclear protein humoral and cellular immune responses. This convenient and rapid injection method would be well-suited for genetic immunization of humans.

Evaluation of Upstream Sampling Method for Quantitating Aortic Regurgitation in Man

Aortic regurgitation was measured from the dye dilution curves recorded simultaneously from the left ventricle and femoral artery following continuous injection of dye into the aortic root. In 18 cases with aortic regurgitant murmur, regurgitant fraction ranged from 7.3 to 145.0% of aortic forward flow, and no regurgitant flow was detected in 4 control patients. Comparing the results of continuous injection method with those of rapid injection method performed in succession, there was a considerable difference of the values between both methods. Reproducibility of measurement was excellent in the continuous method (r=0.98), while poor in the rapid method (r=0.38). The defect of the latter method was primarily due to the inadequate timing of dye injection in relation to the phase of the cardiac cycle. Regurgitant fraction was correlated with diastolic valve area (r=0.78), heart rate (r=-0.46), and peripheral vascular resistance (r=-0.45). There was no close correlation between regurgitant fraction and diastolic pressure gradient from aorta to left ventricle or diastolic time. It is concluded that the continuous injection method can be used as a valid means for estimating aortic regurgitant flow in man and for evaluating hemodynamics in aortic valve disease.

Administration of Fluorouracil

To the Editor: —This letter is written to challenge the conclusions drawn by Dr. Lemon and associates in their article Decreased Intoxication by Fluorouracil When Slowly Administered in Glucose ( JAMA 185 :1012 [Sept 28] 1963). Since acceptance of the conclusions of these authors could lead to widespread office practice use of this method of treatment, we felt it important that a negative view of this means of therapy be presented to your readers. Lemon and associates have implied that the slow administration of fluorouracil in glucose is comparable in therapeutic effectiveness to the more commonly employed rapid injection method. Their comments are based on their results in treatment of patients with a variety of neoplasms. In many of these patients the results are invalidated for comparative purposes by simultaneous antineoplastic therapy with radiation, hormones, or fluorouracil administered orally as well as intravenously. They compare these results of the slow intravenous