Mary Girton

Proximal versus peripheral hepatic artery embolization experimental study in monkeys.

A case is described in which extensive embolization of the hepatic artery to reduce insulin production by a metastatic islet-cell tumor resulted in liver failure, intrahepatic abscesses, and death. The difference between proximal and peripheral hepatic artery obstruction was investigated in monkeys by embolizing hepatic arterial beds with Gelfoam and silicone. Gelfoam obstructed proximally, arterial collaterals developed rapidly, and liver function remained normal. Peripheral hepatic artery embolization with silicone produced liver infarction and severe functional abnormalities. Peripheral hepatic artery occlusion was more effective in preventing the development of collateral circulation but involved a significant risk of hepatic failure or abscess.

Bile duct cysts secondary to liver infarcts: Report of a case and experimental production by small vessel hepatic artery occlusion

Hepatic bile duct cysts were demonstrated on an abdominal CT scan and confirmed at autopsy in a patient with polyarteritis nodosa. The cysts developed in close proximity to hepatic artery aneurysms and occlusions visualized at hepatic arteriography and confirmed postmortem. The development of similar bile duct cysts following hepatic artery occlusion was demonstrated in 13 Rhesus monkeys.

Computed Tomography of the Liver and Kidneys in Glycogen Storage Disease

Glycogen, in concentrations encountered in von Gierkes disease, has computed tomography (CT) attenuation coefficients in the 50 to 70 Hounsfield unit (HU: 1,000 scale) range and accounts for the increased density of the liver. However, in eight patients with Type I glycogen storage disease, simultaneous hepatic infiltration with fat and glycogen led to a range of liver CT densities from 13 to 80 HU. Fatty infiltration may facilitate the demonstration of hepatic tumors in older patients with this disease. Half the patients showed increased attenuation coefficients of the renal cortex, indicating glycogen deposition in the kidneys.

Influence of glycogen on liver density: computed tomography from a metabolic perspective.

The liver is a metabolically active organ with a radiographic density that can be modified by its glycogen and fat content. In rhesus monkeys an increase in liver glycogen induced by glucose loading was accompanied by an increase in attenuation values on computed tomography and a decrease in total liver fat. Conversely, fasting depleted glycogen, increased fat, and decreased liver attenuation. Acute glycogen depletion without significant change in fat was induced by administration of glucagon and accompanied by a decrease in attenuation. These results along with in vitro measurements of glycogen solutions suggest that an increase of approximately 3 Hounsfield units can be expected for each percent increase in liver glycogen content.

A Novel Testis-Stimulating Factor in Familial Male Precocious Puberty

BACKGROUND Familial male precocious puberty is a gonadotropin-independent form of precocious puberty that occurs only in males. The cause of the disorder is unknown. To examine the hypothesis that the plasma of boys with familial male precocious puberty contains a novel stimulator of testicular testosterone production, we developed a bioassay using adult male cynomolgus monkeys. METHODS We collected plasma from 12 boys with familial male precocious puberty, 7 normal prepubertal boys of similar ages and with similar plasma gonadotropin levels, and 1 boy with hypogonadotropic hypogonadism and infused it into the testicular artery of adult male cynomolgus monkeys that had been pretreated with gonadotropin-releasing-hormone antagonist to inhibit the endogenous secretion of gonadotropins. Testicular venous effluent was collected at 15-minute intervals for 3 or 5 hours for the measurement of testosterone. RESULTS The mean (+/- SE) peak testosterone response, as compared with base line, was significantly greater in the monkeys infused with plasma from the 12 boys with familial male precocious puberty than in the monkeys infused with plasma from the 7 normal prepubertal boys and the boy with hypogonadotropic hypogonadism (385 +/- 51 vs. 184 +/- 25 percent, P less than 0.005) in the three-hour studies. Plasma from 92 percent of the boys with familial male precocious puberty and 12.5 percent of the normal prepubertal boys stimulated a response greater than 195 percent of base-line values. In the animals studied for five hours after receiving a second dose of antagonist, the mean peak testosterone response, as compared with base line, was significantly greater in the monkeys infused with plasma from three boys with familial male precocious puberty than in the monkeys infused with plasma from three normal prepubertal boys (363 +/- 81 vs. 115 +/- 6 percent, P less than 0.01). The mean area under the testosterone-response curve was significantly larger in the monkeys infused with plasma from the boys with familial male precocious puberty in the five-hour studies (154 +/- 34 vs. -58 +/- 10 percent, P less than 0.005), but not in the three-hour studies. CONCLUSIONS These findings support the presence of a circulating testis-stimulating factor in the plasma of boys with familial male precocious puberty. The production of such a factor would explain the biologic nature of the disorder.

Experimental comparison of EOE-13 and perfluoroctylbromide for the CT detection of hepatic metastases.

The relative advantages of EOE-13 and perfluoroctylbromide (PFOB) as contrast agents were evaluated using CT scanning in animals with implanted liver tumors. Three criteria were used to compare these compounds: (1)the density difference between liver and tumor, (2)the presence of opacification of intrahepatic vascular structures, and (3)the presence of ring enhancement around the tumors. All three radiographic features were superior in the scans after injection of 5 g/kg of PFOB. When a reduced dose (1.7 g/kg) of PFOB was used, however, the scans obtained with EOE-13 were of approximately equal quality. It is concluded that if toxicity problems prevent administration of PFOB in humans, then EOE-13 will probably remain the contrast agent of choice for tumor imaging in the liver.

Lipid emulsions as contrast agents for hepatic sonography: An experimental study in rabbits

An ultrasound contrast agent capable of increasing hepatic echogenicity would be useful for the detection of hepatic tumors and metastases. Fatty liver is known to produce increased liver echogenicity. Intravenously administered lipid emulsions are phagocytosed by cells of the reticuloendothelial system the liver with transient hepatic lipid accumulation. We examined the effectiveness of three lipid emulsions of differing particle size as potential ultrasound contrast agents using a rabbit liver model. None of the tested emulsions showed any consistent ability to alter liver echogenicity at maximum tolerable doses. Lipid emulsions do not appear to have potential as contrast agents for ultrasound examination of the liver.

Segmental hyperlucent defects in the liver.

When lucent defects in the liver have a segmental configuration, they may be on an ischemic basis and related to decreased vascular perfusion. Portal venous inflow, by virtue of its low pressure, is particularly susceptible to diversion by focal intrahepatic masses, intravenous thrombi, or external compression. Innovative operative techniques for tumor enucleation may also result in lucent defects that can be confused with, or conceal, pathology. A hypothesis relating such defects to diminished portal inflow and reduced glycogen content is proposed.

Computed Tomographic Demonstration of Hepatic Tumor with the Aid of Intravenous lodinated Fat Emulsion

Computed tomography showed Improved visualization of carcinogen-Induced hepatoma in monkeys following intravenous injection of an experimental contrast material, AG 60–99; selective opacification of the liver and spleen was accomplished with a dose of ≥ 0.1 mi/kg, a fraction of the dose used in conventional x-ray tomography. This marked reduction was made possible by the improved density resolution of the CT scanner. This may be the first organ-specific contrast material intended primarily for use with CT scanners.

Biodistribution study of Ethiodized Oil Emulsion 13 for computed tomography of the liver and spleen.

Biodistribution studies were conducted with a new intravenous lipoid contrast material currently undergoing clinical trials in four hospitals. The contrast material selectively opacifies the liver and spleen for computed tomographic examination. The experiments were performed on rats with 125I-labeled ethiodized oil emulsion. The study showed that the liver accumulates nearly 80% of the injected iodine within 15 min of the injection and retains a high concentration over 3 h. The second highest concentration was found in the spleen. More than 99% of the iodine is eliminated from the liver and spleen within 48 h, primarily through the kidneys.