Effects of selective injection of contrast media on coronary artery diameter

The purpose of this study was to quantify the effect of Renografin-76 on eplcardial coronary artery diameters, during selective coronary anglography. Using 105 mm-photospot angiograms taken at 0,1, and 5 min, 99 coronary segments from ten patients were measured. Comparing the anglograms at 1 and 5 min to the control anglograms, a7 ± 7% and 6 ± 7% (both p = NS) change in diameter respectively was noted. Comparing the 1 and 5 min anglograms, there was no significant change (-1 ± 7%). Measurements were found to be very reproducible. This study shows that there is a trend toward dilation of the coronary arteries during selective coronary anglography, but this did not reach statistical significance and probably is not clinically important.     

Defective neutrophil function in myotonic dystrophy

Polymorphonuclear leukocytes (PMNs), obtained from 10 patients with myotonic dystrophy and 39 age-matched controls, were tested for chemotactic activity, chemiluminescence (CL), and phagocytosis. PMNs from 8 of the 10 patients had depressed chemotactic indexes (30 +/- 23) as compared to controls (61 +/- 18) (P less than 0.0003), and 6 of the 10 patients' PMNs produced lower peaks in CL (less than 90%) than those of controls. Phagocytosis and bactericidal activity were evaluated in 7 patients and were normal. Control PMNs incubated in patient serum produced normal chemotactic activity and CL. These results indicate defects in 2 PMN membrane-associated activities in myotonic dystrophy and suggest that the PMN is affected by the generalized membrane abnormality underlying myotonic dystrophy.     

On the Theory of Ion Transport Across the Nerve Membrane, III. Potassium Ion Kinetics and Cooperativity (with x = 4, 6, 9)

The calculations of Part II of this series have been extended to square (x = 4) and octahedral (x = 6) arrangements of subunits in a potassium channel (or gate). The conclusion is the same as before: experimental induction and superposition properties of gK(t), on depolarization, seem to rule out any significant degree of interaction or cooperativity between the (protein?) subunits of K⁺ channel. Calculations for x = 4, 6, and 9 have also been made for a square lattice of interacting channels (periodic boundary conditions). Because of apparent rapid convergence with x, it seems fairly safe to conclude that this model is unsatisfactory. There is some difficulty with superposition but the principal shortcoming is a failure to produce induction behavior. Aggregation models for the K⁺ channel are also discussed briefly here. They, too, appear rather unpromising (for the same reasons as seem to exclude conformational cooperativity within a channel).