Mallinckrodt

About: Mallinckrodt is a company organization based out in Dublin, Ireland. It is known for research contribution in the topics: Aqueous solution & Alkyl. The organization has 769 authors who have published 912 publications receiving 21589 citations. The organization is also known as: Mallinckrodt & MNK.

Hydrogen sulfide is an endogenous stimulator of angiogenesis

Abstract: The goal of the current study was to investigate the role of exogenous and endogenous hydrogen sulfide (H2S) on neovascularization and wound healing in vitro and in vivo Incubation of endothelial cells (ECs) with H2S enhanced their angiogenic potential, evidenced by accelerated cell growth, migration, and capillary morphogenesis on Matrigel Treatment of chicken chorioallantoic membranes (CAMS) with H2S increased vascular length Exposure of ECs to H2S resulted in increased phosphorylation of Akt, ERK, and p38 The KATP channel blocker glibenclamide or the p38 inhibitor SB203580 abolished H2S-induced EC motility Since glibenclamide inhibited H2S-triggered p38 phosphorylation, we propose that KATP channels lay upstream of p38 in this process When CAMs were treated with H2S biosynthesis inhibitors dl-propylargylglycine or beta-cyano-L-alanine, a reduction in vessel length and branching was observed, indicating that H2S serves as an endogenous stimulator of the angiogenic response Stimulation of ECs with vascular endothelial growth factor (VEGF) increased H2S release, while pharmacological inhibition of H2S production or KATP channels or silencing of cystathionine gamma-lyase (CSE) attenuated VEGF signaling and migration of ECs These results implicate endothelial H2S synthesis in the pro-angiogenic action of VEGF Aortic rings isolated from CSE knockout mice exhibited markedly reduced microvessel formation in response to VEGF when compared to wild-type littermates Finally, in vivo, topical administration of H2S enhanced wound healing in a rat model, while wound healing was delayed in CSE−/− mice We conclude that endogenous and exogenous H2S stimulates EC-related angiogenic properties through a KATP channel/MAPK pathway

Novel receptor-targeted fluorescent contrast agents for in vivo tumor imaging.

Abstract: Achilefu S, Dorshow RB, Bugaj JE, Rajagopalan R. Novel receptor-targeted fluorescent contrast agents for in vivo tumor imaging. Invest Radiol 2000;35:479–485.RATIONALE AND OBJECTIVES.To evaluate the efficacy of a novel tumor receptor-specific small-peptide–near-infrared dye conjugate for tumor detec

Acoustic radiation force in vivo: A mechanism to assist targeting of microbubbles

Abstract: The goal of targeted imaging is to produce an enhanced view of physiological processes or pathological tissue components. Contrast agents may improve the specificity of imaging modalities through selective targeting, and this may be particularly significant when using ultrasound (US) to image inflammatory processes or thrombi. One means of selective targeting involves the attachment of contrast agents to the desired site with the use of a specific binding mechanism. Because molecular binding mechanisms are effective over distances on the order of nanometers, targeting effectiveness would be greatly increased if the agent is initially concentrated in a particular region, and if the velocity of the agent is decreased as it passes the potential binding site. Ultrasonic transmission produces a primary radiation force that can manipulate microbubbles with each acoustic pulse. Observations demonstrate that primary radiation force can displace US contrast agents from the center of the streamline to the wall of a 200-μm cellulose vessel in vitro. Here, the effects of radiation force on contrast agents in vivo are presented for the first time. Experimental results demonstrate that radiation force can displace a contrast agent to the wall of a 50-μm blood vessel in the mouse cremaster muscle, can significantly reduce the velocity of flowing contrast agents, and can produce a reversible aggregation. Acoustic radiation force presents a means to localize and concentrate contrast agents near a vessel wall, which may assist the delivery of targeted agents.

Nylon-peba copolymer catheter

Abstract: Inner and outer layers of a braided body portion of an intravascular catheter as well as a soft tip portion are formed from different proportioned blends of nylon and copolymer of ester linked polyethylene and polyamide to produce optimum mechanical properties in the catheter. One or more surfaces of the catheter are coated with a hydrogel containing a copolymer of polyurethane and polyvinylpyrrolidone to provide improved lubricity and antithrombogenicity.

Optical and acoustical observations of the effects of ultrasound on contrast agents

Abstract: Optimal use of encapsulated microbubbles for ultrasound contrast agents and drug delivery requires an understanding of the complex set of phenomena that affect the contrast agent echo and persistence. With the use of a video microscopy system coupled to either an ultrasound flow phantom or a chamber for insonifying stationary bubbles, we show that ultrasound has significant effects on encapsulated microbubbles. In vitro studies show that a train of ultrasound pulses can alter the structure of an albumin-shelled bubble, initiate various mechanisms of bubble destruction or produce aggregation that changes the echo spectrum. In this analysis, changes observed optically are compared with those observed acoustically for both albumin and lipid-shelled agents. We show that, when insonified with a narrowband pulse at an acoustic pressure of several hundred kPa, a phospholipid-shelled bubble can undergo net radius fluctuations of at least 15%; and an albumin-shelled bubble initially demonstrates constrained expansion and contraction. If the albumin shell contains air, the shell may not initially experience surface tension; therefore, the echo changes more significantly with repeated pulsing. A set of observations of contrast agent destruction is presented, which includes the slow diffusion of gas through the shell and formation of a shell defect followed by rapid diffusion of gas into the surrounding liquid. These observations demonstrate that the low-solubility gas used in these agents can persist for several hundred milliseconds in solution. With the transmission of a high-pulse repetition rate and a low pressure, the echoes from, contrast agents can be affected by secondary radiation force. Secondary radiation force is an attractive force for these experimental conditions, creating aggregates with distinct echo characteristics and extended persistence. The scattered echo from an aggregate is several times stronger and more narrowband than echoes from individual bubbles.