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Biomedical subjects

E C Lasser

Publications and source records attributed to E C Lasser.

102 records · Page 6Linked to original sources
PubMedDate not supplied

Changes in complement and coagulation factors in a patient suffering a severe anaphylactoid reaction to injected contrast material: some considerations of pathogenesis.

A patient, suffering a severe anaphylactoid reaction to contrast material injected for an intravenous pyelogram, developed a consumption coagulopathy and evidence of complement activation. Precontrast complement values suggested that the patient had been processing complement via the classical pathway, perhaps as a consequence of an earlier protracted Klebsiella infection. Following contrast injection, a precipitous fall in hemolytic complement (CH50) and in the concentration of the C1 esterase inhibitor (C1INH) developed, as well as a diminution in C4 and C3 with the evolution of C3 conversion products. The possible role that these changes might play in the pathogenesis of idiosyncratic reactions to contrast media is considered.

Adult↗
PubMedDate not supplied

Glucocorticoid-induced elevations of C1-esterase inhibitor: a mechanism for protection against lethal dose range contrast challenge in rabbits.

Rabbits pretreated with methylprednisolone acquired significant protection against an intravenous challenge of meglumine iodipamide. In comparison to controls, the pretreated rabbits showed moderate elevations of Factor XII, and rather striking elevations of C1-esterase inhibitor. Treated rabbits also showed significantly less granulocytosis. It is believed that the protective effect can be ascribed to the modulation of acute phase reactants by increased concentrations of C1-esterase inhibitor.

Animals↗
PubMedDate not supplied

Validation of a computer-assisted method for estimating the number and volume of gallstones visualized by cholecystography.

It is likely that in the near future there will be widespread use of medicinal therapy to dissolve gallstones. The efficacy of medicinal therapy can best be determined by attempting to relate the total surface area of a collection of gallstones to the composition of bile in patients undergoing therapy. Surface area, in turn, can be directly related to gallstone size and number. In this study, involving 48 cholecystectomized patients, we have shown that standard cholecystography, together with a computer-assisted method of metrology, can effectively monitor the above parameters. Determinations of the standard deviation of 1) replicate readings (35.8%) and 2) averaged metrology estimates compared with actual stone volumes (42.9%), as well as correlation of actual stone volumes with averaged metrology estimates (r = 0.961), indicated the magnitude of assessed change in stone volume that would be necessary to accept a roentgenographic decrease or increase in stone size with 95% confidence. Even with the increased precision found in the computer-assisted method as described, to attain a 98% certainty of some volume change it was necessary to have metrology volume change of 50% or more. Actual stone counts were without significant error in 87.5% of the determinations.

Chenodeoxycholic Acid↗
PubMedDate not supplied

Effect of elevated C1-esterase inhibitor concentrations on white blood cell-endothelium interactions: a potential mechanism for steroid protection in contrast material reactions.

Purified human C1-esterase inhibitor (C1INH) infused into the circulation of rabbits caused an immediate drop in white blood cell (WBC) count and, simultaneously, a marked decrease in WBC adhesion to the endothelium in the microcirculation. Infusion of iodipamide caused a marked "carpeting" of the venous endothelium by WBC, and this condition was reversed by subsequent infusion of C1INH. The relationship of elevated C1INH to the protective effect of prednisolone on iodipamide toxicity in the rabbit is discussed.

Animals↗
PubMedDate not supplied

Etiology of anaphylactoid responses. The promise of nonionics.

Though the precise etiology of anaphylactoid contrast media reactions is unknown, recent investigations have contributed important insight into their pathogenesis. Explorations of the complement and coagulation systems, the basophil histamine release system, and antigen-IgE interactions are summarized. Current investigations focusing on the contact system are discussed. Patients with asthma and patients who are contrast material reactors show increased prekallikrein transformation rates indicating increased contact system activity. Increased endogenous heparin-like material was found in asthmatic patients and in 50% of prechallenge citrated plasmas of patients who later developed contrast reactions, suggesting partial explanation of increased incidence of reactions in asthmatics. Elevated heparin-like material may have pathogenic significance; it may potentiate prekallikrein transformation and inhibit adenylate cyclase to induce release of inflammatory mediators and produce bronchospasm. When appropriately administered, glucocorticoids appear to protect against contrast reactions. Incidence of systemic anaphylaxis with nonionic contrast media is unknown but is expected to be less than that with ionic media. Additional experience is needed to assess this potential benefit of nonionics.

Adenylyl Cyclase Inhibitors↗
PubMedDate not supplied

Intravascular hematocrit effect in cross-sectional CT imaging.

Venous fluid-fluid levels were seen on CT or MR of three patients being evaluated for possible thrombosis. In all three cases, further investigation (by ultrasonography, venography, or surgery) revealed the cause of the fluid-fluid level to be slowly flowing blood without thrombosis. On CT done after intravenous contrast medium administration, the nondependent half of the vessel was denser than the dependent half. In an attempt to confirm this MR and CT picture and, particularly, to explain the dense upper half on CT, we conducted an in vitro study. Our study confirmed that when blood with diatrizoate sodium is not clotted and allowed to settle, a similar fluid-fluid level is observed by CT imaging. Our results indicate that an intravascular fluid-fluid level seen on cross-sectional images represents slowly flowing blood, not thrombosis.

Adult↗
PubMedDate not supplied

Tumor localization and beam monitoring--electrofluorotomography.

Methodology and instrumentation are presented which are potentially capable of presenting fluoroscopically derived transverse axial body sections for use in radiation-oncology treatment planning and beam monitoring. These combine the methods of Takahashi for generating transverse axial tomograms with electronic radiography, electrofluorotomography, and a contouring program for extracting body and tumor contours in a digital format. The system will also be capable of assuring both initial and day-to-day beam alignment.

Fluoroscopy↗
PubMedDate not supplied

Computerized system for the measurement of gallstone volume, in vivo.

Instrumentation and methodology for the determination of gallstone volume from standard roentgenographic views have been developed. Evaluation of size is made by using video viewing, an operator-set electronic window, intercept registers, and the programming of a PDP/8E for handling the data. The programming makes corrections for geometric factors arising from anatomical variations, corrections for variations in technique, roentgenographic magnification, and provides for the use of several roentgenographic views. The precision of the measuring (video) technique is approximately 0.5 mm as measured on the roentgenogram. Estimates and test data indicate that this system should be capable of an absolute accuracy within 10% of the true volume.

Cholelithiasis↗
PubMedDate not supplied

Contrast medium induced changes in granulocyte adherence in vitro and during angiography.

The effect of ioxaglate and diatrizoate on per cent granulocyte adherence to nylon fibers was investigated in blood to which contrast medium was added in vitro and in blood from patients undergoing angiography. Very high concentrations of contrast medium, added to blood in vitro, directly abolished granulocyte adherence to nylon fibers. Intraaortic bolus injections of ioxaglate, but not of saline, transiently increased granulocyte concentrations in the femoral vein. Fractional granulocyte adherence to nylon fibers increased significantly above the baseline when angiographic dosages of contrast medium were diluted by circulation within the human body. On the other hand, dilute concentrations of contrast medium had no effect on per cent granulocyte adherence when added to whole blood in vitro. This indicates that the increased adherence produced in vivo is an indirect effect, which, usually, cannot be simulated in vitro.

Adult↗