Roxane M. Mitten

Hemodynamic effects of intravenous lecithin-based perfluorocarbon emulsions in dogs.

We evaluated and compared the acute hemodynamic effects of perfluorooctylbromide-100% (PFOB), a fluorocarbon emulsified in lecithin without pluronic-F68 (F68), to those of a standard iodinated contrast agent, renografin-76% (R76), and Fluosol-DA 20% (Fluosol), a fluorocarbon emulsified in part by F68. Five open chest dogs were instrumented to evaluate hemodynamic changes after iv injection of PFOB (1 ml.1 g/kg) and R76 (1 ml.0.37 g of iodine/kg). Fluosol (1 ml.0.2 g/kg) was given to two of the five dogs at the end of their study. Fluosol caused transient hemodynamic collapse in both dogs. R76 caused the known transient effect of hypotension (-15.4 +/- 3.3%) followed by hypertension (6.5 +/- 2.7%) and an increase in aortic flow (29.3 +/- 3.9% at 30 sec). PFOB caused minimal, clinically insignificant decrease in aortic flow (4 +/- 1% at 10 sec).

Use of perfluorooctylbromide (PFOB) to detect liver abscesses with computed tomography. Safety and efficacy.

Although perfluorooctylbromide (PFOB) is known to stimulate macrophages, particulates given intravenously (IV) can inhibit the bodys response to infection by blocking the reticuloendothelial system. Since PFOB enhances abscesses on computed tomography (CT), the authors evaluated its safety and efficacy by assessing the mortality and abscess volume in 104 rabbits with intrahepatic abscesses given either PFOB or lactated Ringers (LR), and by comparing its efficacy to that of 76% meglumine sodium diatrizoate (MSD76). Abscesses were produced by injecting a virulent strain of E. coli into the liver. Two days later, five of the rabbits had died. Of the remaining rabbits, 50 were given 5 g/kg PFOB IV, and 49 were given an equal volume of LR. All rabbits had a CT scan at four and at ten days after infusion. They were killed before the second CT scan. Thirty seconds before being killed, 28 rabbits given LR were given a bolus of 2 ml/kg MSD76 IV. Following CT, rabbits were frozen, sliced, and photographed. Abscess volumes were calculated by digitizing the photographs of the anatomic sections and the CT images. MSD76 enhanced the liver by 105 Hounsfield units (HU) more than the liquefied abscess center. The abscess wall enhanced to the same degree as liver, resulting in nonvisualization of three of six abscesses less than 3 mm in size, and a 30% underestimation of true abscess volume.(ABSTRACT TRUNCATED AT 250 WORDS)

SPECIFIC ENHANCEMENT OF INTRA-ABDOMINAL ABSCESSES WITH PERFLUOROCTYLBROMIDE FOR CT IMAGING

Perfluoroctylbromide (PFOB), a radiopaque reticuloendothelial system contrast media for computed tomography, has been shown to accumulate in macrophages. In the current study PFOB was tested in rabbits as an abscess imaging agent. Two abscesses were induced in each of 24 rabbits, one in the liver and the other in the peritoneal cavity. CT of the rabbit abdomen was performed four days later, two days after the administration of 5 gm/Kg of PFOB to 12 of these rabbits. The average enhancement of the wall of liver abscesses was by 140 Hounsfield units (HU) relative to the enhanced liver and peritoneal abscesses by 135 HU relative to the control group. This enhancement was secondary to the intense accumulation of PFOB filled macrophages in the abscess wall. In those rabbits where the liver abscess ruptured, the edges of the peritoneal collections enhanced by 147 HU. Regions of inflammation prior to liquifaction enhanced considerably. These areas could not be detected in the animals not receiving PFOB. Though the liquified center of liver abscesses could be seen in the absence of PFOB, none of the peritoneal abscesses could be detected in the animals not receiving PFOB. In contradistinction, all peritoneal abscesses enhanced considerably following PFOB allowing their prospective localization. In conclusion, PFOB accumulates in abscess walls and areas of inflammation producing marked CT enhancement of liver and peritoneal abscess collections. This enhancement allowed the differentiation of peritoneal abscess collections from adjacent bowel.

In vivo estimation of perfluorooctylbromide concentration in tissues

Currently, the only available method to measure perfluorooctylbromide (PFOB) in tissues requires its extraction with a solvent followed by gas chromatography. Not only is this method invasive, but it cannot be validated because the amount of unextracted PFOB is unknown. Using a cylindrical CT phantom with eight wells in the wall filled with bromine (Br) standards, an in vivo method to measure PFOB tissue concentration was developed. Neutron activation analysis (NAA) was used to calibrate and validate the phantom since NAA allows the quantification of Br by making Br radioactive without the need for extraction. Once NAA was validated for PFOB, the phantom was calibrated using 80 rats and tested using 20 rats relative NAA. The phantom produced linear correlation between CT number and known PFOB concentrations with r = 0.998. After its calibration with NAA, the CT method produced a linear correlation between tissue PFOB concentration determined by CT and NAA near the line of identity with an r = 0.984, thus allowing the determination of PFOB tissue content in vivo noninvasively.

Initial Preclinical Experiments with the Electropotential Differential Diagnosis of Mammary Cancer

Direct current electropotential (EP) measurements were used in studying cancers in humans and experimental animals years ago, but this practice has not been accepted in the scientific community. Some studies, such as those of Burr and his colleagues [1,2], reported outstanding results with genital cancers in humans, but these studies were not pursued. Others, such as Morris and Hirschowitz [3], reported that the results of their clinical studies were erratic, with breast cancers smaller than 3 cm being electronegative while larger cancers showed either positive or negative EPs. Nordenstrom [4], the best known investigator in the field of cancer bioelectricity, has resorted to unconventional research techniques and publishing methods which are not subjected to peer review so that the entire body of his work is generally held in disrepute.