Opening of Small and Intermediate Calcium-Activated Potassium Channels Induces Relaxation Mainly Mediated by Nitric-Oxide Release in Large Arteries and Endothelium- Derived Hyperpolarizing Factor in Small Arteries from Rat

ABSTRACT This study was designed to investigate whether calcium-activated potassium channels of small (SK Ca or K Ca 2) and intermediate (IK Ca or K Ca 3.1) conductance activated by 6,7-dichloro-1H-indole-2,3-dione 3-oxime (NS309) are involved in both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF)-type relaxation in large and small rat mesenteric arteries. Segments of rat superior and small mesenteric arteries were mounted in myographs for functional studies. NO was recorded using NO microsensors. SK Ca and IK Ca channel currents and mRNA expression were investigated in human umbilical vein endothelial cells (HUVECs), and calcium concentrations were investigated in both HUVECs and mesenteric arterial endothelial cells. In both superior (ϳ1093 m) and small mesenteric (ϳ300 m) arteries, NS309 evoked endothelium-and concentration-dependent relaxations. In superior mesenteric arteries, NS309 relaxations and NO release were inhibited by both N G ,N G -asymmetric dimethyl-L-arginine (ADMA) (300 M), an inhibitor of NO synthase, and apamin (0.5 M) plus 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34) (1 M), blockers of SK Ca and IK Ca channels, respectively. In small mesenteric arteries, NS309 relaxations were reduced slightly by ADMA, whereas apamin plus an IK Ca channel blocker almost abolished relaxation. Iberiotoxin did not change NS309 relaxation. HUVECs expressed mRNA for SK Ca and IK Ca channels, and NS309 induced increases in calcium, outward current, and NO release that were blocked by apamin and TRAM-34 or charybdotoxin. These findings suggest that opening of SK Ca and IK Ca channels leads to endothelium-dependent relaxation that is mediated mainly by NO in large mesenteric arteries and by EDHF-type relaxation in small mesenteric arteries. NS309-induced calcium influx appears to contribute to the formation of NO

A Case of Propofol-Induced Oropharyngeal Angioedema and Bronchospasm

Propofol (2,6-diisopropylphenol) is an ultrashort-acting sedative agent with sedative and amnestic effects that is used not only for anesthesia but also for sedation during minor outpatient procedures and endoscopic examinations. Rare cases of anaphylaxis following propofol administration have been reported in the medical literature. Documentation of anaphylaxis is often lacking because the cause and effect relationship is often hard to prove. Only a minority of patients get referred for allergy testing to confirm the offending drug. Here we report a 74-year-old woman who had an anaphylactic reaction with severe oropharyngeal edema and bronchospasm for a few minutes after receiving propofol during endoscopic examination. An allergy skin test was positive for both propofol and soybean. Soybean in the intralipid is one component of propofol, and we concluded that this anaphylaxis was caused by soybean

Homomorphic encryption and secure comparison

We propose a protocol for secure comparison of integers based on homomorphic encryption.We also propose a homomorphic encryption scheme that can be used in our protocol, makes it more efficient than previous solutions, and can also be used as the basis of efficient and general secure Multiparty Computation (MPC). We show how our comparison protocol can be used to improve security of online auctions, and demonstrate that it is efficient enough to be used in practice. For comparison of 16 bits numbers with security based on 1024 bits RSA (executed by two parties), our implementation takes 0.28 sec including all computation and communication. Using precomputation, one can save a factor of roughly 10

Homomorphic encryption and secure comparison

We propose a protocol for secure comparison of integers based on homomorphic encryption.We also propose a homomorphic encryption scheme that can be used in our protocol, makes it more efficient than previous solutions, and can also be used as the basis of efficient and general secure Multiparty Computation (MPC). We show how our comparison protocol can be used to improve security of online auctions, and demonstrate that it is efficient enough to be used in practice. For comparison of 16 bits numbers with security based on 1024 bits RSA (executed by two parties), our implementation takes 0.28 sec including all computation and communication. Using precomputation, one can save a factor of roughly 10

A correction to 'efficient and secure comparison for on-line auctions'

In this paper, we describe a correction to the cryptosystem proposed in Damgard et al. from Int. J. Applied Cryptography, Vol.1, No.1. Although, the correction is small and does not affect the performance of the protocols from Damgard et al.,it is necessary,as the cryptosystem is not secure without it

A correction to 'efficient and secure comparison for on-line auctions'

In this paper, we describe a correction to the cryptosystem proposed in Damgard et al. from Int. J. Applied Cryptography, Vol.1, No.1. Although, the correction is small and does not affect the performance of the protocols from Damgard et al.,it is necessary,as the cryptosystem is not secure without it