Clinical superiority of a new nonionic contrast agent (iopamidol) for cardiac angiography

The hemodynamic and electrophysiologic alterations induced by ionic contrast agents during cardiac angiography are well described. Recently nonionic contrast agents have become available for cardiac angiography. To evaluate the safety of these new agents, a double-blind randomized study was performed comparing a new nonionic agent (iopamidol) with a commonly used ionic contrast agent (Renografin-76). Eighty-one patients undergoing left ventriculography and coronary angiography were included; 41 received iopamidol and 40 received sodium meglumine diatrizoate (Renografin-76). After left ventriculography, there was a decrease in the arterial pressure with both contrast agents. However, the severity and the duration of hypotension were both significantly greater with Renografin-76 compared with the new nonionic agent (p less than 0.001). After selective injections of the coronary arteries, electrocardiographic analysis demonstrated that the increase in the QT interval (p less than 0.0002) and the changes in both the ST segment and T wave amplitude (p less than 0.001) were significantly greater in the Renografin-76 group compared with the iopamidol group. During coronary angiography, 8 of the 40 patients receiving Renografin-76 required temporary pacing for sinus pauses of 2.5 seconds or more, and 2 of the 40 also developed ventricular fibrillation. None of the 41 patients receiving iopamidol had these complications. This report demonstrates that the electrocardiographic changes, the severity and duration of hypotension and the incidence of serious arrhythmias are significantly greater with Renografin-76 than with iopamidol. Thus, this new nonionic agent appears to enhance the safety of cardiac angiography.

Long-term follow-up of solitary hemangioma of the choroid

Three cases of solitary hemangioma of the choroid are reported. One patient, followed for 22 years, was untreated, and the natural course was chronic and progressive. Although the tumor itself did not enlarge markedly, the serous detachment of the retina was extensive. Cystoid degeneration and deterioration of visual acuity was the final result. Two patients were treated with argon green laser and then followed for eight years and one year, respectively. Laser photocoagulation is the method of choice. Clinical characteristics and differential diagnosis are discussed. Early diagnosis and early treatment are important for preserving vision in an eye affected with hemangioma of the choroid.

Immunologic characterization of a granulocytic leukemia of inbred strain 13 guinea pigs: presence of Ia-positive myeloblasts

Membrane markers expressed by a transplantable granulocytic leukemia induced in inbred strain 13 guinea pigs by N-nitroso-N-butylurea have been investigated by serologic and immunochemical methods. Although the leukemic myeloblasts have no detectable surface immunoglobulin or Fc receptors, they have been found to synthesize and express membrane antigens encoded for by the I-region of the major histocompatibility complex. Despite the presence of Ia antigens, these cells do not stimulate allogeneic T lymphocytes in the mixed lymphocyte reaction nor are they able to present soluble antigen to immune T cells. The presence of Ia antigens on immature myeloid cells suggests that these proteins may be important in cellular functions beyond those identified in the cellular immune system.

Serotherapy of avian reticuloendotheliosis virus-induced tumors

Immune serum, obtained from animals that had survived sublethal challenge with RE virus, was very effective in achieving tumor cures in chickens infected with this virus. The therapeutic effect could also be obtained by the immunoglobulin fraction of immune serum. The serum did not influence the development of an unrelated malignancy. Serotherapy studies in Bx and Tx recipients indicate that the B-cell or T-cell system of the host does not significantly contribute to the curative activity of immune serum. Absorption studies show that the curative effect is mediated by antibodies to tumor-associated transplantation antigens on tumor cells, not by antiviral antibodies.

New thermooptical measurement method and a comparison with other methods

A simple and sensitive method of measuring the thermally induced index changes arising from absorption of a laser beam in a low-loss material is described. The sample is placed outside the laser cavity, but at the position of minimum radius of curvature of the wavefront, which is a confocal distance behind the waist. It is estimated that the method is sensitive enough to measure absorption coefficients of the order of 5 x 10(_6) cm(_1) and it is shown experimentally to have good accuracy on low-loss materials. A detailed comparison of sensitivity and accuracy estimates is given for the various published thermal-lens methods for measuring low absorption coefficients.Although the method is illustrated for the thermal effect, it is applicable to other nonlinear index changes induced by laser beams.