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Biomedical subjects

J C Sisson

Publications and source records attributed to J C Sisson.

At least 127 records · Page 7Linked to original sources
PubMed1983

Inverse relationship between cardiac accumulation of meta-[131I]iodobenzylguanidine (I-131 MIBG) and circulating catecholamines in suspected pheochromocytoma.

Heart intensity (HI) in the 24- and 48-hr images of meta-[131I]iodobenzylguanidine (I-131 MIBG), a pheochromocytoma-seeking guanethidine analog, were compared with concentrations of plasma and urinary catecholamines and their metabolites in nonpheochromocytoma and pheochromocytoma patients. HI was inversely related to plasma concentrations and urinary excretion rates of the hormones. Plasma norepinephrine had the highest inverse correlation with HI (r = -0.73 at 24 hr, -0.63 at 48 hr), and urinary metanephrine the lowest (r = -0.23 at 24 hr, -0.28 at 48 hr). A similar relationship was observed in the intensity of salivary-gland visualization, but with less marked variations. HI was much higher in nonpheochromocytoma patients than in pheochromocytoma patients. HI in an I-131 MIBG image provides useful information in the diagnosis of pheochromocytoma, and may provide a tool for the study of the influence of catecholamines on the heart.

3-Iodobenzylguanidine↗
PubMed1982

The spectrum of pheochromocytoma in hypertensive patients with neurofibromatosis.

We have found an appreciable number of pheochromocytomas in patients with neurofibromatosis and concurrent hypertension (ten of 18 cases). At diagnosis, the patient age range was 15 to 62 years, the clinical appearance of the neurofibromatosis did not predict who would and who would not have pheochromocytomas, but the age at diagnosis was helpful in that our younger patients tended to have causes of hypertension other than pheochromocytoma. However, several causes of hypertension may coexist. The biochemical findings were highly diagnostic. The pheochromocytomas secreted epinephrine as well as norepinephrine and resided in or next to the adrenal gland. Where pheochromocytoma is the cause of hypertension, its resection generally results in a better control of hypertension than that obtained in patients whose BPs were elevated from other unknown causes.

3-Iodobenzylguanidine↗
PubMed1981

Scintigraphic localization of pheochromocytoma.

We used a new radiopharmaceutical agent, [131I]meta-iodobenzylguanidine ([131I]MIBG), to produce scintigraphic images of pheochromocytomas in eight patients. One day or more after injection, the only normal organ that displayed distinct concentrations of radioactivity was the urinary bladder. The [131I]MIBG was probably concentrated in adrenergic vesicles; in tissues where vesicles are numerous, such as pheochromocytomas, the radionuclide was retained for days. The spectrum of pheochromocytomas shown the scintigrams was broad: intra-adrenal and extraadrenal in location, benign and malignant in character, 0.2 to 65 g in weight, and with different hormone patterns in secretion. Tumors in four patients were not detected by computed tomography. In one patient, reoperation was undertaken only because the scintigram located the extra-adrenal tumors and thereby directed the surgeon's exploration. The method offers hope of safe and reliable localization of pheochromocytomas in their many guises.

3-Iodobenzylguanidine↗
PubMed1981

Spectrum of pheochromocytoma in multiple endocrine neoplasia. A scintigraphic portrayal using 131I-metaiodobenzylguanidine.

Six patients with multiple endocrine neoplasia (MEN) types 2a and 2b were investigated to determine the spectrum of pheochromocytoma by scintigraphy. Iodine-131-metaiodobenzylguanidine (131I-MIBG), a new imaging agent which concentrates in adrenergic neurotransmitter vesicles, was administered at 0.5 mCi/1.7m2 and scintiscans were taken at 24 and 48 hours. Two normotensive patients with normal plasma and urinary catecholamines had no adrenal tracer uptake. One patient with a modest and intermittent increase only in urinary catecholamine metabolites showed faint adrenal images. Two other patients with increased plasma and urinary catecholamines showed bilateral adrenal imaging patterns. The sixth patient who had increased norepinephrine and epinephrine secretion showed bilateral asymmetrical adrenal images, findings that were corroborated at operation. Functional as well as anatomic evidence of adrenal medullary abnormalities in patients with MEN-2 syndromes are demonstrated by 131I-MIBG scintigraphy. Therefore, the procedure can be used to define the extent of abnormalities of the adrenal medulla in these patients.

3-Iodobenzylguanidine↗
PubMed1981

Tomographic thyroid scintigraphy: comparison with standard pinhole imaging: concise communication.

Coded-aperture imaging (CAI) and multiple-view pinhole imaging (PI) of the thyroid were compared in a prospective study in 136 consecutive patients. Following 10 mCi of pertechnetate, 200K-count pinhole images were obtained in the anterior, RAO, and LAO projections, and CAI data were obtained in the anterior position. Four coronal tomographic sections were reconstructed by computer. Five observers read the studies separately, and ROC curves were constructed. Based on 109 pairs of studies, the ROC curves revealed similar performance for all observers for both techniques. When four observers compared the studies subjectively they rated the CAI more useful in 36% of cases, the PI in 6%, and the two equal in 58%. The advantages offered by the tomograms included improved contrast, accurate size representation of the gland at all depths, freedom frm pinhole-type distortion, and faster data acquisition. The major disadvantage to tomography was the 2-hr computer-processing time required. It this can be reduced, CAI offers sufficient advantages over conventional pinhole imaging to warrant its routine use.

Adult↗
PubMed1981

What promise the preliminary tests of coronary artery disease?

For some patients with coronary artery disease (CAD), bypass operations prolong life. Angiograms, incurring some risk and considerable expense, are prerequisites to surgical therapy; they delineate the region and extent of disease. However, many people who complain of chest pain do not have disease that can be benefited by operation. Therefore, tests that will safely and economically select the appropriate individuals for angiography are most welcome. Yet, if the preliminary tests falsely declare affected people to be free of CAD, they will deny these patients angiography, and, consequently, surgical treatment that would prolong their lives. Decision analysis determines that a false-negative rate of less than 2% is necessary for tests preliminary to angiography if the average survival of patients is not to be shortened. No currently used procedure has attained this sensitivity. Radionuclide ventriculography approaches this precision, but its sensitivity must be sustained in more broadly based studies.

Angiography↗
PubMed1980

Thyroid function following neck irradiation for malignant lymphoma.

Thyroid function tests for T3 resin (T3-r), serum thyroxine (T4) and serum thyroid stimulating hormone (TSH) were measured in 70 consecutive patients who had previously undergone lymphangiography and neck irradiation for malignant lymphoma. All were in remission and clinically euthyroid. The abnormalities found were: 23 (33%) patients hypothyroid by TSH, 14 (20%) with subnormal T4, and 21 (30%) with subnormal T3-r values. None of the patients were biochemically hyperthyroid. The prevalence and magnitude of abnormalities were highest during the third year after irradiation, thereafter decreasing with time.

Adolescent↗
PubMed1980

Connective tissue activation. XVIII. Stimulation of hyaluronic acid synthetase activity.

Human synovial fibroblasts synthesize hyaluronic acid, a process that can be stimulated by a number of agents. Several steps in the synthetic pathway could be the locus at which these stimulators act; the final step, promoted by hyaluronic acid synthetase, was selectd for study. Hyaluronic acid synthetase is an enzyme system that transfers monosaccharide units to nascent hyaluronic acid chains. Activities of the enzyme were determined in lysates of cultured synovial fibroblasts by measuring incorporation of 14C-UDP-glucuronic acid into hyaluronic acid. Rates of hyaluronic acid synthesis were increased by adding CTAP-I or CTAP-III, DbcAMP, or prostaglandin E2 to the cultures. In each instance, hyaluronic acid synthetase activity was enhanced in a manner comparable to that seen in hyaluronic acid synthesis. The changes in enzyme and product were observed as early as 6 hr after cultures were exposed to CTAP-III, and both indices declined when this stimulator was withdrawn for 24 hr. Although DbcAMP incrased the hyaluronic acid synthetase activity of intact fibroblasts, it had no effect on the enzyme in lysates of cells. In the cultured cells, cycloheximide reduced basal levels of synthetase activity and hyaluronic acid synthesis of hyaluronic acid may do so by inducing hyaluronic acid synthetase.

Connective Tissue↗
PubMed1979

Iodine-131: optimal therapy for hyperthyroidism in children and adolescents?

To assess the medium- to long-term effects of I-131 therapy of hyperthyroidism in children and adolescents, we studied 51 patients (age range 6--18; boys, 43 girls) treated with I-131 for Graves' disease with hyperthyroidism at the University of Michigan Medical Center (1951--1972). Patients received total doses ranging from 3 to 81.6 mCi. The mean followup period was 14.6 +/- 7.9 yr. Hyperthyroidism was effectively treated in 49 within 1 to 12 mo. One patient failed to respond to three treatment doses, and hyperthyroidism recurred in two patients: 2 and 11 yr after initial therapy. Of these three patients, two were treated by thyroidectomy and one was retreated successfully with I-131. There were no cases of thyroid cancer, other malignancies or leukemia. The patients' reproductive histories and the health of their offspring were as in the general population. At the time of study, the prevalence of hypothyroidism was 92%, with no recurrent goiters or thyroid nodules. Iodine-131 is found to be safe and effective treatment of hyperthyroidism in children and adolescents and should be the preferred mode of therapy.

Adolescent↗
PubMed1978

MEN type IIa syndrome: dilemmas in modern management.

With the use of newer techniques, the multiple endocrine neoplasm II-A syndrome can now be diagnosed early in its evolution. This article discusses the clinical course of the syndrome, the diagnostic modalities employed, and the therapeutic interventions required. An approach to the individual patient with this syndrome is presented.

Adolescent↗