Permeant ions can have significant effects on ion channel conformational changes. To further understand the relationship between ion occupancy and gating conformational changes, we have studied macroscopic and single-channel gating of BK potassium channels with different permeant monovalent cations. While the slopes of the conductance-voltage curve were reduced with respect to potassium for all...

After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardiac catheterization. Forty patients had significant (> 50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (3...

The respective importance of flow and cellular viability in determining initial myocardial thallium uptake was studied in reperfused and nonreperfused experimental myocardial infarction. Open-chest dogs were subjected to permanent coronary artery occlusion of 70-minute (n = 3) or 5-hour duration (n = 5), or to a 3-hour temporary occlusion followed by reflow (n = 14). Thallium uptake 10 minutes ...

OBJECTIVES To study coronary artery disease (CAD) risk factors predicting positive thallium-201 single photon emission computed tomography (SPECT) indicating underlying CAD among patients of end stage renal disease. PLACE AND DESIGN: This cross-sectional (analytical) study was done at Department of Cardiology, Punjab Institute of Cardiology, from April 2004 to Dec 2007. METHODS One hundred co...

We have prepared all-biopolymer nanocomposite films using lignin as a filler and cellulose triacetate (CTA) as a polymer matrix, and characterized them by several analytical methods. Three types of lignin were tested: organosolv, hydrolytic and kraft, with or without acetylation. They were used in the form of nanoparticles incorporated at 1 wt% in CTA. Self-supported films were prepared by vapo...

The lipid peroxidation product 4-hydroxynon-2-enal (4-HNE) is cytotoxic and genotoxic at superphysiological concentrations. To characterize the mechanism of action of 4-HNE, we assessed genotoxic damage by 4-HNE and by 4-HNE triacetate [4-HNE(Ac)(3)] using the mouse lymphoma assay that measures the mutant frequency in the Tk gene. As a strong electrophile, 4-HNE reacts readily with nucleophilic...

Background. Because thallium reinjection enhances the identification of viable myocardium, many laboratories have adopted the routine practice of performing reinjection imaging instead of 3-4-hour redistribution imaging. This approach assumes that the stress-reinjection protocol provides the necessary information regarding both exercise-induced ischemia and myocardial viability. Because apparen...

Background. Thallium reinjection immediately after stress-redistribution imaging identifies ischemic but viable myocardium in as many as 50%o of the regions characterized by conventional redistribution imaging as irreversibly injured. However, we have previously shown that some regions in which irreversible defects persist despite reinjection are metabolically active, and hence viable, by posit...

OBJECTIVE To determine the sensitivity and specificity of thallium scintigraphy in detection of coronary artery disease in diabetic patients. STUDY DESIGN Cross-sectional validation study. PLACE AND DURATION OF STUDY The study was carried out from July to December 2007 in the Cardiology Department of the Pakistan Institute of Medical Sciences, Islamabad. METHODOLOGY A total of 60 diabetic...

Thallium is widely found in nature, but the only inorganic stones full of this element are crookesite and lorandit. It isalso found in pyrites of copper, lead and inorganic stones. The element and its compositions are toxic and harmful to theenvironment; therefore, its application requires caution and further research. It is important to develop sensitive andaccurate analytical methods to deter...