Accumulation and elimination of particulate iodipamide ethyl ester in the lungs and kidneys of the rat. A morphological study.

Particulate iodipamide ethyl ester, a new hepatolienographic x-ray contrast agent, was intravenously injected into rats. Lung and kidney biopsies taken at various intervals after the injection were examined by light and electron microscopy. IDE particles could be found in the lung capillaries phagocytized by polymorphonuclear neutrophils (PMNs). There were also free particles in the alveolar capillaries in the samples taken 5 min to 4 hours after the injection. No aggregates or emboli were seen. Two days or more after the injection no intra- and extracellular particles were present. The PMNs underwent transient local hydropic degeneration; the lung cells were morphologically intact. In the kidneys, the particles first appeared in both cortical and medullary capillaries. No emboli were observed. The kidney cells did not ingest IDE, but polymorphonuclear neutrophils (PMNs) with ingested IDE were often seen loosely attached to the glomerular capillary walls. In addition, free particles were evident in the capillaries in the samples taken up to 1 hour after injection. All particles in subsequent kidney samples were located in PMNs in the glomeruli. After three or more days the renal tissue was totally devoid of particulate IDE. No morphological evidence of kidney cell injury was observed.

Uptake and dissolution of particulate iodipamide ethyl ester in the spleen. A morphologic study.

Iodipamide ethyl ester (IDE) is an experimental particulate contrast agent being developed for CT image enhancement of the liver and spleen. IDE particles are phagocytized by the reticuloendothelial cells after an intravenous injection. The uptake and dissolution of IDE particles were studied in the spleen with light and electron microscopy. Two minutes after injection, intra- and extracellular IDE particles were found in the red pulp of the spleen. Highest concentration of IDE was seen in the marginal zone surrounding the white pulp. Particles also were seen elsewhere in the red pulp but only occasionally between the outermost cells of the white pulp. The extracellular particles disappeared within 4 hours postinjection. At one day postinjection, the amount of intracellular IDE particles had begun to decrease. Electron micrographs showed that the intracellular particles dissolved gradually in the phagocytes and caused transient degenerative morphologic changes. At three days postinjection, practically all IDE particles had disappeared from the spleen. Polystyrene latex particles were used as controls. They were phagocytized like the IDE particles, but they did not disappear from the phagocytes. IDE particles caused no morphologic injuries in nonphagocytic cells of the spleen.

Response of white blood cells to iodipamide ethyl ester particles.

The effect of intravenously injected iodipamide ethyl ester (IDE) particles (150 mgl/kg) on white blood cells was studied by light and electron microscopy. The clearance of IDE from rat plasma also was determined by analyzing free IDE particles in a counting chamber. The total white blood cell count remained essentially unchanged up to 40 minutes after the IDE injection, but the polymorphonuclear (PMN) neutrophil count decreased significantly. At 5 minutes postinjection, occasional PMNs contained ingested IDE particles, but by 40 minutes no intracellular particles could be found in the peripheral circulation. In vitro incubation experiments confirmed that human PMNs ingest IDE particles. In electron microscopy, the cells and particles seemed to be morphologically intact. Of the IDE particles counted at 5 minutes postinjection, only 4% remained in plasma at 30 minutes and none at 40 minutes. The decrease in PMN count apparently reflects sequestration of phagocytic cells from the circulation.

Effect of intravenously administered iodipamide ethyl ester particles on rat liver morphology.

The effect of intravenously injected iodipamide ethyl ester (IDE) particles (150 mgI/kg) on the rat liver was studied by light and electron microscopy. IDE particles were phagocytized by Kupffer cells within a few minutes postinjection. After 4 hours particles began to dissolve in the Kupffer cells causing transient morphologic alterations resembling hydropic degeneration. The number of Kupffer cells seemed, however, to be unchanged and were ultrastructurally normal by 17 days postinjection. Hepatocytes contained large lipid droplets from one to four days after IDE injection. No changes were found in the hepatocytes from one week to one year after IDE injection. The fat-storing cells and endothelial cells remained ultrastructurally normal throughout the study.

On the microwave exposure.

During the last decades the use of microwaves has been common in the industry, medicine, household and armed forces. According to the literature microwaves may especially cause lens opacities and other serious health disturbances. The authors of this paper examined 121 radar workers, but nothing was found which could be connected to microwaves. For example, the amount of lens opacities had correlation only to the age of the patients, but not to the exposure time of microwaves. The exposure duration varied from 0 to 28 years and the age of the patients between 18 and 59 years.

Development of sexual dimorphism in the embryonic gonad.

Differentiation of gonads in embryonic pigs (ages 24 to 44 days) was studied by light and electron microscopy. Incipient short cord-like structures were seen in embryos of both sexes at the age of 24 days. The cords were ultrastructurally similar. Medullary cords appeared in the testis at 26 days and in the ovary at 28 days. The cords in the ovary degenerated gradually and new cortical cords started to develop at 34 days. The formation of cords in both sexes is difficult to explain with the H-Y antigen theory, according to which the antigen should organize cords only in the male. The present results indicate that new approaches are needed for further development of the H-Y antigen theory.