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Biomedical subjects

E C Lasser

Publications and source records attributed to E C Lasser.

18 recordsLinked to original sources
PubMed1979

Complement and contrast material reactors.

Patients showing systemic reactions to intravascular contrast media and patients receiving contrast media without reaction have significantly different mean values (p is less than 0.05) for functionally determined serum C1-esterase inhibitor (C1 INH) and total hemolytic complement (CH50). The lower concentration of these components in reactors appears in baseline serum samples (as well as after injection), and suggests that many anaphylactoid reactions to contrast media are conditioned by earlier complement consumption, and result directly from contrast-induced activation of complement, and other activation system components in the presence of inhibitor depression.

Complement C1 Inactivator Proteins↗
PubMed1979

Comparison of radiopaque perfluorocarbon and Ethiodol in lymphography.

Lymphangiography was performed on 40 adult cats, 39 dogs, 20 rabbits, and 12 rats of mixed sex using Ethiodol or radiopaque perfluorocarbon (BPC). Ethiodol was more radiodense than RPC, but imaging of lymph channels and nodes was satisfactory with the latter. RPC could be infused rapidly, while Ethiodol infusion was time consuming. RPC was biologically inert; Ethiodol produced both local and systemic inflammatory reactions. The lymph node distribution with RPC was more uniform and persisted for longer periods. It was concluded that RPC was an improvement over Ethiodol for lymphangiography.

Animals↗
PubMed1979

Complement and coagulation: causative considerations in contrast catastrophies.

Earlier studies suggest that adverse reactions to injected radiographic contrast media are idiosyncratic. In an attempt to gain a better understanding of pathophysiologic events underlying these reactions, rabbit models injected with lethal dose ranges of a cholangiographic contrast material were studied. These animals showed activation of both the complement and coagulation systems. Externally applied heat potentiated complement consumption and increased mortality. Depleting complement components C3-C9 by cobra venom factor did not prevent activation of coagulation or diminish mortality. However, depleting fibrinogen diminished complement activation and markedly diminished mortality. Heparin, administered at several hourly intervals after contrast challenge, also diminished mortality. These studies suggest that the adverse effects of contrast media in this model system are mediated chiefly by the coagulation system, and that complement, if it participates deleteriously, must involve components up to, but not including, C3. A logical role for the inhibitor of C1 esterase in adverse contrast reactions is considered.

Ancrod↗
PubMed1978

Nonimmunologic complement activation in normal human serum induced by radiographic contrast media.

Two different radiographic contrast media (RCM), iothalamate and iodipamide, induced the activation of several complement (C) components in normal, genetically C2-deficient and agammaglobulinemic human sera in vitro. This activation was dose dependent and demonstrable by a reduction in whole C as well as C4, C2, C3, and C5 hemolytic activities. C6, C8, and C9 hemolytic activities were unaffected. Concommitant with the loss of C3 hemolytic activity was the appearance of C3 proteolytic cleavage products that were identified by immunoelectrophoresis. Both the loss of C3 hemolytic activity and the production of C3 fragments occurred in the presence of 10 mM EDTA, indicating RCM-induced C3 cleavage occurred without participation of the multicomponent C3/C5 convertases of either the classical or alternative C pathways. Furthermore, loss of C3 hemolytic activity was not due to the direct alteration of the C3 molecule by RCM because purified C3 was unaffected upon incubation with RCM at a concentration that induced 80% reduction in the C3 hemolytic activity in normal human serum. Serum samples obtained from 40 patients, before and 30 min after undergoing i.v. pyelography, revealed no significant change in total hemolytic C activity; 34 patients received sodium and methylglucamine diatrizoate and six received sodium iothalamate. Hemolytic C3 levels were also determined for the six patients before and 30 min after administration of sodium iothalamate and no significant change in activity was detectable.

Agammaglobulinemia↗
PubMed1978

Tumor imaging with x-rays using macrophage uptake of radiopaque fluorocarbon emulsions.

Radiopaque fluorocarbon (RFC) emulsions were prepared with small particle size and high concentration of the fluorocarbon. When RFC emulsions were injected intravenously in hamsters, rats, and mice with eight types of malignant tumors, the tumors became radiopaque, except in the mice with spontaneous teratoma of the ovaries. Tumors as small as 3 to 4 mm could be defined radiographically using routine x-ray techniques. The tumors remained radiopaque for days to weeks after injection. Light and electron microscopy revealed characteristic fluorocarbon vacuoles primarily in the tumor macrophages. Thus RFC emulsions may be useful in detection of malignant tumors.

Animals↗
PubMed1977

Steroids: theoretical and experimental basis for utilization in prevention of contrast media reactions.

In vitro and in vivo studies were done to examine the effects of methylprednisolone on the adverse reactions induced by contrast media. At very high concentrations, the steroid potentiated the complement-activating effect produced in vitro by iodipamide, but inhibited the immune and nonimmune mechanisms of hemolysis. Rabbits pretreated for 3 days with intramuscular methylprednisolone (at high or low dosages) were significantly protected against an LD47 challenging dose of iodipamide. Those treated once with a low intravenous dose immediately prior to iodipamide challenge were protected to a lesser degree. Rabbits treated once with a very high intravenous dose of steroid evidenced no protection. A hyper-responsive dog was consistently protected against adverse reactions to injected sodium iothalamate by a 3-day steroid pretreatment.

Animals↗
PubMed1976

Development of contrast media idiosyncrasy in the dog.

A laboratory dog exhibited an altered response to injections of sodium iothalamate. This idiosyncratic response may have been predicated on an earlier series of iothalamate injections. The overt manifestations of the reactions in this dog were vomiting, hypotension, and hyperreflexia. Significant changes in several electrolyte components and serum complement levels were noted when the dog reacted to the contrast material.

Animals↗
PubMed1975

Preliminary evaluation of di-iodo-triglucosyl benzene. An approach to the design of nonionic water-soluble radiographic contrast media.

A new compound, di-iodo-triglucosyl benzene (DTB), was synthesized and tested for contrast medium potential. It is stable and soluble in water, with a molecular weight of 864 and a viscosity of 33.3 cps at 40degrees C for a 66.6% w/v solution. It is rapidly excreted unchanged by the kidneys. Its estimated LD50 in mice at an intravenous injection rate of 330 mg l/min is 34.0 g/kg. It is highly hydrophilic and not epileptogenic, but its low iodine content (29.4%) makes it unfavorable for clinical use.

Animals↗
PubMedDate not supplied

Contrast and electrolyte dynamics of the intravenous pyelogram. I. Urinary pH and volume changes in the canine I. V. P.

Canine peripheral venous or suprarenal aortic injections of sodium or meglumine iothalamate produced a significant swing towards an alkaline urine only in individual dogs injected with meglumine salts. When mean values were compared for the sodium or meglumine groups as a whole, however, no significant differences could be established for pH change or induced diuresis. With both salts, ATPase inhibition could play a role in urinary electrolyte excretion. Carbonic anhydrase inhibition does not seem to play a significant role in urinary pH changes induced by contrast media.

Acetazolamide↗
PubMedDate not supplied

Contrast and electrolyte dynamics of the intravenous pyelogram. II. Disparities in serum and urine concentrations of meglumine and anion.

Intravenous or intra-aortic injections of meglumine iothalamate in dogs indicate a slightly different tissue distribution and excretory pattern of the meglumine cation and the iothalamate anion. Differences in serum and urinary concentrations of these ions suggest some cellular penetration of the meglumine anion. In addition, there seems to be some evidence for both tubular absorption and tubular excretion of meglumine as a minor component in the renal excretion of this ion. No significant differences could be demonstrated for either urinary load or concentration when the sodium salts of iothalamate were compared to the methylglucamine salts.

Animals↗
PubMedDate not supplied

Inhibition of adenosine triphosphatase and carbonic anhydrase by contrast media.

In vitro inhibition of adenosine triphosphatase and carbonic anhydrase by several radiographic contrast media and other compounds was measured. The concentrations required for 50% inhibition were, in general, similar to those obtained for other enzymes. The effect of methylglucamine could not be determined for either enzyme because of interference with the assays.

Acetazolamide↗
PubMedDate not supplied

Activation of serum complement by contrast media.

Evidence is presented for the activation of serum complement by contrast media, in vitro and in vivo. Activation as a function of concentration was measured and the increasing order of effectiveness was found to be metrizamide, iothalamate, diatrizoate, acetrizoate, iodipamide and iopanoate. This order is the same as for protein binding and enzyme inhibition. The activation mechanism for iodipamide, and by inference for the other compounds, does not involve gamma-globulin aggregation. Serial daily injections in normal dogs resulted in substantial declines in serum complement over several days. Guinea pigs which were depleted of serum complement with cobra venom factor were found to be no less sensitive to lethal doses of iodipamide than those with normal complement. Implications of these findings are discussed.

Acetrizoic Acid↗
PubMedDate not supplied

Effect of endotoxemia on contrast media reactions.

Since complement activation is sharply temperature-dependent, we have examined the effects of fever produced by a very small dose of endotoxin on contrast media lethality in rabbits. After the injection of 8.2 ml/kg of 52% methylglucamine iodipamide, a group of rabbits exhibiting an average temperature elevation of 1.5 degrees C had a 100% mortality rate. This was contrasted to a 30% mortality in control rabbits receiving contrast alone, and no mortality in rabbits receiving endotoxin alone. The rabbits with fever and increased mortality exhibited increased activation of serum complement. From this preliminary data it appears that caution should be observed in performing a contrast examination in a patient with endotoxemia and/or a fever.

Animals↗
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↗