Hyperactivity from fluorescent lighting--fact or fancy: a commentary on the report by O'Leary, Rosenbaum, and Hughes.

The following commentary is designed to explain the experimental differences between the foregoing negative article by O'Leary, Rosenbaum, and Hughes and the original articles in this field, whose results were positive. These differences fall under the general categories of subjects, lights, measurements, and design.

The use of chromium-51 sodium chromate for the detection of food and chemical sensitivities.

Both antibody mediated lysis of human RBC's and toxic hemolysis were found to occur with chemicals used as coloring agents for foods, drugs and cosmetics. Because of the strong chromaticity of these dyes, chromium-51 sodium chromate was bound to the hemoglobin of target human RBC's and its efflux was used as an indicator of lysis instead of spectrophotometry, which had been used with food antigens. The major antibody effect was noted when treatment of the target RBC's with antiIgG resulted in a marked inhibition of lysis, indicating that IgG is a lysis-promoting factor (LPF) in this system. Weaker effects were noted by treatment of the target RBC's with monospecific antisera for the other four classes of immunoglobulin and for alpha2-macroglobulin. No neutralizing effects were observed by pre-incubation of the dyes with autologous serum prior to the addition of RBC's.

Definition of myocardial perfusion by continuous infusion of krypton-81m.

Krypton-81m, a radionuclide emitting a 190 kev gamma ray, has a half-life of 13 seconds. It is a radioisotope of an inert water-soluble noble gas and is produced at a constant rate by spontaneous decay of rubidium-81 in an 81Rb-81mKr generator-delivery system. Delivery is through a minibore Teflon catheter that can be threaded through a standard no. 7 or 8F angiographic catheter. The generator is eluted by 5 percent dextrose-in-water, delivered by infusion pump at 1.5 ml/min, and the eluate is infused intraarterially directly into any organ. Delivery and decay reach equilibrium within 2 minutes, producing a heterogeneous distribution that is proportional to the perfusibility of the tissue concerned and the time required to reach it. The ultrashort halflife of the radionuclide rapidly eliminates activity when delivery ceases; thus, experiments can be sequentially repeated at brief intervals. The radiation hazard for easily imaged doses is negligible. Preliminary studies in open chest dogs were visualized by scintillation camera, stored on digital data disk, processed, and displayed in dual channel, dual color mode on a video system. Images of myocardial perfusion defined relative levels of perfusion, collateral circulation between coronary arterial branches, equilibrium time of diffusible perfusion of the myocardium, focal defects in induced occlusion, collateral circulation to occlusion, and reactive hyperemia after release of induced coronary occlusion. The system and technique appear applicable to human subjects.

Evaluation of perfusion with the 81Rb-81mKr generator.

The development of the 81Rb-81mKr generator-delivery system has made available an ultrashort (13-sec) half-life radionuclide for continuous, constant-rate delivery as a gas, or as an isotonic, nonionic solution in 5% dextrose and water. This system has been evaluated and applied to the scintigraphic imaging of various organs and anatomic regions by intravenous and intraarterial infusion and by inhalation and deglutition. This diffusible, noble gas is inert chemically and biologically. When the gas is administered intraarterially, the volume of tissue being perfused may be defined with the scintillation camera. The 13-sec half-life is of a similar magnitude to the rate of capillary exchange, producing a heterogeneous image with steady-state administration in which the intensity of detectable radioactivity is proprotional to the time of diffusion into the tissue. This system appears capable of defining the rate of capillary exchange and the moment-to-moment changes brought about by vasoactive stimuli in specific organs.

Dual-channel facilitation of the 99mTc radiocardiogram.

A refinement of the radionuclide-angiocardiogram is described using a low deadtime scintillation camera and hardwire data storage, processing, and display system for the purpose of anatomic definition of the passage of a radioactive bolus through the carciopulmonary circulation by dual-channel, dual-color, subtraction methodology. The summation of the bolus pathway is displayed as a static frame of reference for the sequential kinetic image. The technique is noninvasive and employs 15 mCi of 99mTc pertechnetate. This procedure may be employed as the conventional bolus study for determining the cardiac kinetics ordinarily obtained by the method. The opportunity of viewing the bolus position in relation to its entire pathway significantly facilitates defining the multiple areas of interest the observer may wish to study.

Opsonic characteristics of chylomicron-bound protein.

A blood protein in complex with native chylomicrons was labeled with radiogold colloid, thus indirectly identifying the protein material in the complex as opsonin and suggesting the possibility that native chylomicrons may utilize the opsonin system for its clearance from the circulation. The protein in question has been shown to be at least divalent, in that the protein in combination with one type of particle could still react with another. It is felt that these studies provide further insight into the complex surface events that result during the process of opsonization.