Search PubMed⌕ Search

Biomedical subjects

J C Sisson

Publications and source records attributed to J C Sisson.

At least 109 records · Page 6Linked to original sources
PubMed1985

Surgical treatment of cardiac pheochromocytomas.

The development at our institution of the radiopharmaceutical 131-I-metaiodobenzylguanidine has permitted for the first time scintigraphic localization of pheochromocytomas. By the use of this scan in combination with contrast-enhanced computed tomography, intrapericardial pheochromocytomas have been demonstrated in eight patients at our hospital during the past 2 years. Four of these patients have been operated upon by us, and each was found to have a pheochromocytoma arising from the heart (left atrium in three and interventricular groove at the aortic root in one). While in one patient it was possible to "shell" the tumor away from the left atrial wall without cardiopulmonary bypass, in the remaining patients, bypass and cardioplegia were required to resect the pheochromocytomas without inducing life-threatening intraoperative hypertension and cardiac arrhythmias. One patient required coronary artery reconstruction and two, excision of the posterior left atrial wall with pericardial replacement. One of these latter two patients died intraoperatively of uncontrollable hemorrhage. The three remaining patients are well and normotensive after more than 1 year of follow-up. Cardiac pheochromocytomas should not be approached as typical posterior mediastinal tumors, or as they are in the abdomen, with the expectation that they will "shell away" from contiguous structures. Cardiopulmonary bypass should be available, and resection of involved myocardium may be necessary for complete removal.

3-Iodobenzylguanidine↗
PubMed1985

Iodine-131 metaiodobenzylguanidine scintigraphy for the location of neuroblastoma: preliminary experience in ten cases.

Ten patients with histologically proven neuroblastoma were studied by [131I]MIBG scintigraphy. Tumor uptake of the radiopharmaceutical showed a spectrum varying from no uptake in one case, to slight uptake in two, moderate uptake in two and intense uptake in five cases. Iodine-131 MIBG scintigraphy was more effective in demonstrating the extent of neuroblastoma spread than were conventional bone scan and CT in one patient, equal to these modalities in four cases, almost equal in two cases and significantly inferior in three cases. These preliminary results suggest that [131I]MIBG scintigraphy is useful in detecting the presence and delineating the distribution of neuroblastoma and may, in certain cases, have therapeutic potential.

3-Iodobenzylguanidine↗
PubMed1984

Bilateral pheochromocytomas.

Bilateral pheochromocytomas most often occur as components of well-described syndromes: multiple endocrine neoplasia types 2a and 2b, von Hippel-Lindau disease and neurofibromatosis. We describe 4 patients with isolated bilateral pheochromocytomas; their tumors arose in the absence of stigmata and family history of the syndromes. The manifestations of these 4 individuals are compared with those of 14 other patients who developed pheochromocytomas in both adrenal glands as part of the syndromes. The 4 patients with the isolated pheochromocytomas manifest more rapidly progressing disease: they were 10-14 yrs of age, distinctly younger than those with the syndrome. Three of the 4 exhibited adrenal medullas that were composed entirely of tumor in contrast to the hyperplasia that usually accompanies other bilateral pheochromocytomas. However, malignant transformation of pheochromocytomas was seen both in a non-syndrome patient and in a patient with Lindau's disease.

Adolescent↗
PubMed1984

Malignant phaeochromocytoma: clinical, biochemical and scintigraphic characterization.

We have evaluated thirty patients with malignant metastatic phaeochromocytoma with regard to clinical features, indices of catecholamine secretion, histology of lesions and a number of imaging procedures including scintigraphy with the recently developed sympathetic tissue-seeking radiopharmaceutical 131I-metaiodobenzylguanidine (131I-MIBG). The primary tumour was extra-adrenal in 13 cases. The commonest site of metastases was the axial skeleton (20 cases), followed by liver (four cases), lymph nodes (four cases), peritoneum (two cases) and lung (three cases). The malignancies were indolent, the mean time following the initial diagnosis was 9.18 years (range 0 to 33 years) and the mean duration of known metastases 3.71 years (range 0 to 18 years). There was a wide range of abnormalities in plasma and urinary catecholamines which did not correlate with the extent of tumour spread, histological pattern (mitotic index, Zellballen pattern, capsular or vascular invasion pleomorphism or necrosis) or 131I-MIBG uptake by tumour deposits. 131I-MIBG scintigraphy was found to be a useful technique for determining the extent of metastatic disease in most cases (26 of 30) and in some patients (16 of 30) was more sensitive than other radiological procedures. No false positive scans were encountered.

3-Iodobenzylguanidine↗
PubMed1984

Patterns of prolactin secretion in the syndrome of general resistance to thyroid hormones.

The dynamics of TSH and PRL secretion were studied in three patients with incomplete generalized resistance to thyroid hormones. Results in the first patient differed from those in the other two. The first patient had been treated previously with radioiodine but was clinically euthyroid when subsequently treated with supraphysiological quantities of T3 and T4. Increasing doses of T4 from 0.2-0.3 mg/day caused a decline in serum TSH levels and lesser increments in TSH to injected TRH in this patient. The other two patients had not been treated, but had basal TSH levels and TSH responses to TRH similar to those in the first patient. However, the TSH response to injected metoclopramide in the first patient was substantially higher than the responses in the other two patients. The basal levels of PRL in the first patient were elevated at both T4 doses; also, her PRL responses to TRH and metoclopramide were exaggerated and, compared to normal values, disproportionate to her TSH responses to these provocative agents. In contrast, the other two patients had normal basal PRL concentrations and normal or near-normal PRL responses to TRH and metoclopramide. We conclude that within the syndrome of resistance to thyroid hormones, there are heterogeneous patterns of PRL secretion. Dopaminergic tone on thyrotrophs and lactotrophs also differs among patients with the syndrome.

Adolescent↗
PubMed1984

Plasma catecholamines in pheochromocytoma: effect of urographic contrast media.

Hypertensive crises have been provoked in pheochromocytoma patients by the injection of contrast media during angiography and venography. Fear of similar reactions to intravenous urographic contrast medium injection during computed tomography has led to studies without contrast enhancement when pheochromocytoma is suspected. With extraadrenal pheochromocytomas, intravenous contrast enhancement may be essential for tumor location by computed tomography. The catecholamine responses to injection of urographic contrast medium were examined in eight patients with pheochromocytoma and in 12 undergoing computed tomography for other reasons. Plasma norepinephrine concentrations fell in nonpheochromocytoma patients (p less than 0.005), while in pheochromocytoma patients the response was unpredictable, rising in six individuals, although the mean response was not significant (p greater than 0.35). In five patients the magnitude of the increase in norepinephrine concentrations was large enough to have led to a pressor effect had alpha adrenergic blockade not been used. It was concluded that intravenous urographic contrast medium may elevate plasma catecholamines in a significant proportion of patients with pheochromocytoma, but that with adequate alpha adrenergic blockade this should pose no threat.

Contrast Media↗
PubMed1984

An immunohistochemical study of pheochromocytomas.

Twenty -six adrenal pheochromocytomas and four normal adrenal medullae were studied immunohistochemically. These included four malignant tumors with proven metastases, six tumors in patients with neurofibromatosis, nine tumors in patients with multiple endocrine neoplasia type 2, and seven sporadic nonfamilial pheochromocytomas. Immunohistochemical localization of neuron-specific enolase (NSE) was seen in all tumors and in the four normal adrenals. Methionine enkephalin-like immunoreactivity was present in tumors from all four groups and in the normal adrenals. Corticotropinlike immunoreactivity was found focally in two normal adrenal medullae and in four benign pheochromocytomas. Our results indicated that NSE was present in all four major groups of pheochromocytomas, including benign and malignant tumors. This marker aided in distinguishing between adrenal cortical and medullary tumors in unusually difficult cases, since all normal adrenal cortex and adrenal cortical tumors had negative test results for NSE.

14-3-3 Proteins↗
PubMed1984

Diagnosis of adrenal tumors with radionuclide imaging.

The development of radiolabeled cholesterols in 1969 as precursors of adrenocortical steroid production allowed the first noninvasive imaging of the adrenal cortices. FDA-NDA approval in 1984 should allow routine use of these agents in most hospitals. NP-59 is most commonly used in the diagnosis and management of Cushing syndrome; the second most common use is in the diagnosis of primary aldosteronism. It is also helpful in the differential diagnosis of adrenal and ovarian hyperandrogenism and hirsutism, and is the only noninvasive method of detecting unilateral adrenocortical hypofunction. The newest and most popular use is in the differential diagnosis of asymptomatic masses in the region of the adrenal gland discovered incidentally with CT scan ("incidentalomas"). In this situation, the NP-59 scan can define whether the tumor is in the adrenal gland and if it is functional or nonfunctional. We believe that, in the future, radiolabeled enzyme inhibitors might offer better diagnostic imaging of the adrenal cortex, although these agents will probably not be available for routine use for some time. Our development of a radioiodinated guanethidine analog, 131I-MIBG, has allowed differentiation of normal adrenal medullary function from bilateral adrenal medullary hyperplasia before the development of hypertension or tachycardia, diagnostic increases in plasma or urinary catecholamines, or abnormal CT scans. The search for a pheochromocytoma should begin with 131I-MIBG scintigraphy. While over 90% of primary pheochromocytomas occur in the abdomen, neither a survey of the abdomen nor the finding of a single tumor should conclude the search. Whereas the CT scan can only detect a mass, the MIBG scan not only detects the mass but proves whether the mass is a pheochromocytoma. We have detected small or recurrent pheos when all other localizing studies were normal. Present drug and X-ray therapy is relatively ineffective in treating metastatic cancer of the adrenal medulla. Preliminary results in five patients indicate that, for the first time, a complex organic molecule can carry 131I into adrenal neoplasms reproducibly and in therapeutically effective doses of irradiation. We may also be able to select which patients will respond to therapeutic doses of 131I-MIBG and which patients will not respond.

Adenoma↗
PubMed1984

Comparison of the sodium dependency of uptake of meta-lodobenzylguanidine and norepinephrine into cultured bovine adrenomedullary cells.

Radioiodinated meta-iodobenzylguanidine (MIBG), a scintigraphic agent used for the detection of human pheochromocytomas, is thought to utilize the same uptake and retention mechanism(s) as norepinephrine (NE). Using cultured bovine adrenomedullary cells, we compared the mechanism(s) of uptake of MIBG to that of NE. Two different uptake systems were identified. NE and MIBG were taken up by a sodium-dependent system that was characterized by: 1) temperature dependency; 2) high affinity: Km of 1.22 +/- 0.12 microM for MIBG and 1.41 +/- 0.50 microM for NE; 3) low capacity: Vm (picomoles/10(6) cells/10 min) of 64.3 +/- 3.3 for MIBG and 36.6 +/- 7.2 for NE; 4) saturability; 5) ouabain sensitivity; and 6) energy dependency. However, NE and MIBG also were taken up by a temperature-dependent, sodium-independent, apparently unsaturable, and energy-independent system. The sodium-dependent uptake system fulfills many of the criteria for Uptake1 whereas the sodium-independent uptake system is most likely a passive diffusion process. NE uptake proceeded predominantly by the sodium-dependent process. Uptake of MIBG occurred by both pathways at low concentrations, but at high concentrations (greater than 10 microM) uptake was predominantly (75 to 100%) by the sodium-independent process. Inhibition studies suggest that MIBG and NE are transported by the same carrier involved in the sodium-dependent system. Scintiscans of the human adrenals and pheochromocytomas appear to reflect uptake of [131I]MIBG by the sodium-dependent system.

3-Iodobenzylguanidine↗
PubMed1984

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.

3-Iodobenzylguanidine↗
PubMed1984

Salivary gland accumulation of meta-[131I]iodobenzylguanidine.

Intense uptake of m-[131I] iodobenzylguanidine (I-131 MIBG ) has been observed in the salivary glands of patients undergoing scintigraphy for the location of suspected pheochromocytomas. This uptake of radioactivity was not due to free I-131 derived from the I-131 MIBG but rather to uptake of I-131 MIBG by sympathetic neuronal elements in the salivary glands. In keeping with this, administration of tricyclic antidepressants reversibly blocked salivary uptake of I-131 MIBG . Furthermore, I-131 MIBG uptake was markedly diminished by the ipsilateral salivary glands in a patient with Horner's syndrome, and was bilaterally diminished in a patient with severe idiopathic sympathetic autonomic neuropathy. The salivary gland uptake of I-131 MIBG may provide a means for the study of sympathetic innervation of these organs, and thus for the study of generalized disorders of autonomic innervation.

3-Iodobenzylguanidine↗
PubMed1984

Radiopharmaceutical treatment of malignant pheochromocytoma.

Apart from relieving effects of secreted catecholamines, treatments of malignant pheochromocytoma have achieved little success. When the radiopharmaceutical, meta-[131I] iodobenzylguanidine (I-131 MIBG ), was found to concentrate in some malignant pheochromocytomas, we calculated that this agent could impart therapeutic doses of radiation to these tumors. We therefore treated five patients with two to four doses of I-131 MIBG prepared in high specific activity, 8-11 Ci/mmol. Individual doses were given at 3- to 10-mo intervals and in 97- to 197-mCi amounts. Two patients exhibited subjective and objective benefits. Their tumors declined in size (to 28% and 30% of original volumes) and in hormone secretion (to 50% or less of baseline rates). The other three patients manifested few symptoms before treatment and showed few or no objective improvement afterward. The tumors of the patients who responded to I-131 MIBG (a) appeared to be more rapidly growing, (b) received more cumulative rads, and (c) were more predominantly in soft tissues (in contrast to bone) than those in the patients who obtained little benefit. No toxic effects were encountered during the treatments, and only minor and temporary untoward responses were seen later.

3-Iodobenzylguanidine↗
PubMed1983

Calcitonin, carcinoembryonic antigen and neuron-specific enolase in medullary thyroid carcinoma.

Calcitonin, carcinoembryonic antigen (CEA) and neuron specific enolase (NSE) were studied in the thyroid glands of patients with multiple endocrine neoplasia (MEN) type 2a, 2b, and with sporadic thyroid carcinomas (MTC). Calcitonin, CEA and NSE were localized in normal C-cells, hyperplastic C-cells, and in MTC. While the distribution of calcitonin and CEA was quite similar in most cases, a smaller proportion of cases were positive for NSE. C-cell hyperplasia was identified in all nine patients with MEN 2a and in four of six patients with MEN 2b. None of the four patients with sporadic MTC had C-cell hyperplasia. These results indicate that C-cell hyperplasia is present in patients with MEN 2a and 2b and that NSE in addition to calcitonin and CEA is a useful marker for the thyroid C-cells.

Adolescent↗
PubMed1983

Early diagnosis and thyroidectomy in multiple endocrine neoplasia, type 2b.

Medullary thyroid carcinoma is a feature of multiple endocrine neoplasia, type 2b (MEN 2b). The cancer frequently gives rise to metastases in early life and is therefore often incurable by age 4 years. Because MEN 2b frequently appears as a spontaneous mutation, and because the characteristic phenotypic features are absent in the early life of most affected patients, both MEN 2b and its medullary thyroid cancer may elude diagnosis for years. Total thyroidectomy is the only established treatment for medullary thyroid carcinoma. The timing of thyroidectomy must take into account risks and benefits in small children, but the operation may well not cure after age 4 years. Thyroidectomies in two of our patients were accomplished at ages 2 and 2 1/2 years; no complications were encountered, and no metastatic disease was found in either child. Feeding difficulties--poor suck to the point of failure to thrive--were present in the neonatal periods of seven of our nine patients who had MEN 2b. Infants with feeding difficulties should be examined periodically for the onset of pathognomonic features of MEN 2b, particularly the ganglioneuromas, which usually appear before age three years.

Adolescent↗
PubMed1983

Complementary roles of CT and 131I-MIBG scintigraphy in diagnosing pheochromocytoma.

Recently 131I-MIBG (metaiodobenzylguanidine), an adrenergic tissue-localizing radiopharmaceutical, has been used for diagnosis of pheochromocytoma. In a retrospective study of 32 patients with pathologically proved primary, metastatic, or recurrent pheochromocytoma, the roles of 131I-MIBG scintigraphy and computed tomography (CT) in pheochromocytoma detection were compared. The two methods were equally accurate in the identification of primary and recurrent pheochromocytoma. 131I-MIBG scanning was more accurate as the initial examination in patients with extraadrenal tumors. In patients with metastatic disease, scintigraphy was preferable to CT because of its nontomographic nature, which permitted imaging of the entire body. Although a positive MIBG scan is diagnostic of pheochromocytoma, CT of extraadrenal tumors (particularly in the chest) has been very useful in planning appropriate surgical intervention. Furthermore, the roles of 131I-MIBG scintigraphy and CT in the detection of pheochromocytoma are complementary because each method has certain limitations.

3-Iodobenzylguanidine↗
PubMed1983

The normal and abnormal distribution of the adrenomedullary imaging agent m-[I-131]iodobenzylguanidine (I-131 MIBG) in man: evaluation by scintigraphy.

The scintigraphic distribution of m-[131I]iodobenzylguanidine (I-131 MIBG), an adrenal medullary imaging agent, was studied to determine the patterns of uptake of this agent in man. The normal distribution of I-131 MIBG includes clear portrayal of the salivary glands, liver, spleen, and urinary bladder. The heart, middle and lower lung zones, and colon were less frequently or less clearly seen. The upper lung zones and kidneys were seldom visualized. The thyroid appeared only in cases of inadequate thyroidal blockade. The "normal" adrenal glands were seldom seen and faintly imaged in 2% at 24 hr after injection and in 16% at 48 hr, in patients shown not to have pheochromocytomas, whereas intra-adrenal, extraadrenal, and malignant pheochromocytomas usually appeared as intense focal areas of I-131 MIBG uptake at 24 through 72 hr.

3-Iodobenzylguanidine↗