Portrayal of pheochromocytoma and normal human adrenal medulla by m-[123I]iodobenzylguanidine: concise communication.

The radiopharmaceutical m-[131I]iodobenzylguanidine (I-131 MIBG), which is readily taken up by adrenergic vesicles, produces scintigraphic images of pheochromocytomas in man but rarely visualizes normal adrenal glands. Iodine-123 has many potential advantages over I-131 as a radiolabel for MIBG, including shorter half-life, freedom from beta emissions, and increased gamma-camera efficiency. In this study, diagnostic doses of MIBG labeled with I-131 and I-123, with nearly equivalent radiation dosimetry, were compared as imaging agents in eight patients with known or suspected pheochromocytoma. Images of superior quality were obtained with I-123 MIBG, and lesions not visualized using I-131 MIBG were portrayed. In addition, the normal adrenal medullae were visualized on the I-123 MIBG scintigrams in six out of eight patients.

Enterohepatic circulation and distribution of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59).

The enterohepatic circulation and distribution of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) was assessed in a rabbit model to examine the relative distribution of NP-59 and its metabolites. Adrenal, bile and serum samples were obtained from seven rabbits at 48 h following NP-59 administration (240 to 570 microCi) and the distribution of 131I radioactivity examined using thin layer chromatography. In serum 71% of the radioactivity circulated as NP-59 and 20% as NP-59 esters. In contrast greater than 90% of the adrenal radioactivity was in the form of NP-59 esters while in bile 70% of the activity was NP-59 with the remainder in the form of bile acids. In another group of animals, adrenal activity was observed 5 days after intragastric administration of NP-59. Thus, we have demonstrated a significant enterohepatic circulation of NP-59 that may have the potential to influence the distribution of and resultant adrenal imaging with NP-59.

The influence of hypercholesterolaemia on the adrenal uptake and metabolic handling of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59).

The biodistribution of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) was assessed in hypercholesterolaemic patients and in a rabbit model of HC to examine the alterations in the relative distribution of NP-59 and its metabolites and to explain the changes in the patterns of adrenal cortical imaging in patients with expanded cholesterol pools. Rabbits were rendered hypercholesterolaemic with a diet supplemented with 2% cholesterol for 2 weeks prior to the intravenous administration of 240 to 570 microCi of NP-59. Adrenal, bile and serum samples were obtained from four hypercholesterolaemic rabbits at 48 h following NP-59 administration, and the distribution of 131I radioactivity was compared to that of seven rabbits maintained on a standard laboratory diet. Serum cholesterol levels were 1940 +/- 248 mg dl-1 in the hypercholesterolaemic rabbits as compared to 268 +/- 62 mg dl-1 in the controls. Adrenal cortical uptake of NP-59 was decreased in HC rabbits but no significant differences were observed in the relative proportions of NP-59 or its metabolites in the bile and adrenal tissues of hypercholesterolaemic versus control animals. Hypercholesterolaemic animals did exhibit an increase in NP-59 esters in serum as compared to controls. In three of five patients with hypercholesterolaemia, adrenal uptake of NP-59 was enhanced after successful lowering of serum cholesterol levels, while the remaining two patients who responded inadequately to cholesterol-lowering therapy showed a slight drop in NP-59 uptake.

Achilles tenodesis for calcaneus deformity in the myelodysplastic child.

Calcaneus deformity in patients with neurologic disorders leads to gait disturbances, a high incidence of osteomyelitis, cellulitis, and skin breakdown, and a major problem in the fitting of shoes of orthoses. Correction of this deformity remains a difficult challenge for the orthopedic surgeon. Twelve tenodeses of the tendo Achillis to the fibula or tibia were performed in eight patients with myelodysplasia in an attempt to control calcaneus deformity. The average age of the patients at the time of surgery was 7.4 years (range, 3.1-13.5 years) with an average follow-up period of 6.3 years (range, two to 10.9 years). The clinical examination demonstrated definite improvement in the ability to brace, prevent skin breakdown, and improve gait in all but one patient who had progressive hindfoot valgus. Roentgenographically, there was improvement in the tibiocalcaneal angle in 67%, fibular station in 58%, talar tilt in 25%, and growth of the posterior aspect of the calcaneus in 58%.

Pheochromocytoma presenting as musculoskeletal pain from bone metastases.

Six patients presented with musculoskeletal pain resulting from destructive bone lesions. These patients were ultimately shown to have metastatic pheochromocytoma. None of the cases exhibited typical symptoms of metastatic pheochromocytoma, nor was it suspected at the time of presentation. In three patients, hypertension caused pheochromocytoma to be considered as a diagnosis. The three remaining patients, all of whom had documented hypertension in the past, underwent bone biopsy. Two of these patients became markedly hypertensive in the postoperative period. Malignant pheochromocytoma may present with metastatic skeletal disease in some patients in whom the presence of hypertension as well as a carefully elicited history may suggest the diagnosis. In such patients, the possibility of pheochromocytoma should be taken into account, as biopsy may trigger a hypertensive crisis in patients not under adrenergic blockade.

Group G streptococcal arthritis and bowel disease: a rare enteropathic arthropathy.

Group G streptococci may be seen as normal flora in many parts of the body, including the gastrointestinal tract. They are rarely pathogens in humans, but they have been isolated from septic joints in debilitated patients. Three patients with group G streptococcal arthritis were further evaluated using contrast studies of the colon. Abnormalities, including an occult carcinoma and a colocutaneous fistula, were found. We conclude that group G streptococcal arthritis may be associated with gastrointestinal abnormalities that allow a portal of entry for an otherwise innocuous organism, and that this represents a rare enteropathic arthropathy.

The spontaneous release of a high-molecular-weight aggregate containing immunoglobulin G from the surface of Ehrlich ascites tumor cells.

The spontaneous release of tumor cell antigens from the cell surface into the circulation has been proposed as a mechanism whereby tumors may escape the immune response of the host. In this study we have found that Ehrlich ascites tumor cells after removal from the host (mouse) spontaneously release significant amounts of cell surface components during incubation for 1 h in cold isotonic buffer. Immunodiffusion studies revealed that immunoglobulin G (IgG) and a complement component (C3) are included in this spontaneously released material. These surface-bound humoral immune components are apparently released in the form of a high-molecular-weight aggregate (cell coat particle) as shown by ultracentrifugation and ultrafiltration experiments. Precipitation of IgG from the cell coat particle preparation with antibodies directed against mouse IgG followed by detergent gel electrophoresis of the immune precipitate revealed five major bands in addition to the heavy and light chains of IgG. These results suggest that host IgG is tightly bound to several other components at the cell surface, perhaps in the form of immune complexes. IgG is localized on the tumor cell surface in a highly heterogenous pattern with the appearance of patches and caps in some cells as shown by immunofluorescence analysis. The possibility that humoral immune components bind to the tumor cell surface and result in the shedding of high-molecular-weight aggregates of cell surface antigens into extracellular fluids is discussed.

Bone metastases in pheochromocytoma: comparative studies of efficacy of imaging.

Bone is the most common site of metastasis from pheochromocytoma. Now that the effects of hypercatecholaminemia can be adequately controlled with adrenergic blockade, pathologic fractures are becoming an increasingly significant cause of morbidity in patients with metastatic pheochromocytoma. Bone metastases from pheochromocytoma have not been extensively reevaluated since the advent of computed tomography (CT), high-resolution bone scintigraphy, and iodine 131 MIBG scintigraphy. Plain radiographs, CT scans, bone scans, and I-131 MIBG scans of 38 patients with pheochromocytoma bone metastasis were reviewed. The axial skeleton was the most common site of metastasis. Metastases typically appeared expansile and mixed lytic-sclerotic on radiographs. Bone scintigraphy was the most sensitive modality for detecting bone metastasis, with 74% of all alleged lesions being identified. In screening for bone metastasis from pheochromocytoma, bone scanning in conjunction with I-131 MIBG scanning is recommended, followed by scan- and symptom-directed radiography and - where a question still exists - CT.

Pheochromocytoma and the normal adrenal medulla: improved visualization with I-123 MIBG scintigraphy.

The radiopharmaceutical iodine 131 metaiodobenzylguanidine (I-131 MIBG) has been shown to locate pheochromocytomas scintigraphically with a false-negative rate of approximately 13%. To improve image quality and reduce the false-negative rate, I-123 was examined as a radioactive label for MIBG, as it has many advantages over I-131, including superior dosimetry and better detection efficiency. Diagnostic doses of 0.5 mCi (18.5 MBq) I-131 MIBG and 10.0 mCi (370.0 MBq) I-123 MIBG with nearly equivalent radiation dosimetries were compared in 18 patients with known or suspected pheochromocytomas. Images of superior quality were obtained with I-123 MIBG in 18 of 18 patients, and in eight cases lesions not visualized on I-131 MIBG scintigraphy were portrayed. A further advantage of I-123 MIBG is that it permits single photon emission computed tomography (SPECT). This was performed in six cases and provided additional information in three cases. The adrenal medullae were definitely visualized using I-123 scintigraphy in eight of 14 patients still possessing adrenal glands, whereas I-131 MIBG images portrayed the adrenal medulla in only one of 14 cases. Five remaining patients had multiple abdominal tumor deposits that were difficult to differentiate from normal adrenal medullae.