Search PubMed⌕ Search

Biomedical subjects

B Shapiro

Publications and source records attributed to B Shapiro.

At least 163 records · Page 9Linked to original sources
PubMed1990

The role of imaging tests in the diagnosis of thyroid carcinoma.

Many noninvasive high-quality imaging tests are widely available to assist in the evaluation of thyroid nodules. These include thyroid scans, computed tomography, ultrasonography, and magnetic resonance imaging. These procedures and other less commonly performed tests are reviewed. Their routine role in the diagnosis of thyroid carcinoma, however, has been, for the most part, obviated by the convenience and accuracy of fine needle aspiration cytology. Special situations in which imaging tests are most useful are discussed.

3-Iodobenzylguanidine↗
PubMed1990

Adrenal cortical adenoma causing Cushing's syndrome: correct localization by functional scintigraphy despite nonlocalizing morphological imaging studies.

A 60-year-old woman with Cushing's syndrome in whom high-dose dexamethasone failed to suppress glucocorticoids was studied by ultrasound and CT. Neither of these morphological studies was interpreted as revealing any adrenal abnormality. Functional imaging with NP-59 (131-I-beta-iodomethylnorcholesterol) revealed unequivocal, intense, unilateral uptake in the left adrenal gland and subsequent surgery removed a 2.5 cm adrenocortical adenoma from this site. Following surgery the patient was temporarily adrenocortically insufficient but later returned to normal. It is unusual for adrenocortical adenomas causing Cushing's syndrome not to be correctly located by CT. NP-59 scintigraphy in addition to being highly accurate in the location of adrenocortical adenomas also has the advantage of correctly depicting bilateral cortical nodular hyperplasia in which CT will frequently reveal only the largest nodule, which may be incorrectly designated a unilateral adenoma. Furthermore, scintigraphy provides evidence of suppression of the contralateral, normal adrenal cortical tissue in Cushing's syndrome caused by an adrenal adenoma and predicts the vulnerability of such patients to postoperative adrenocortical insufficiency.

Adenoma↗
PubMed1990

Diagnostic accuracy and pitfalls of [iodine-131]6-beta-iodomethyl-19-norcholesterol (NP-59) imaging.

NP-59 concentrates in steroid hormone synthesizing tissues, enabling scintigraphic localization and characterization of endocrine dysfunction in the adrenal cortex and ovary. Studying 108 consecutive cases from 1982 to 1985 and using clinical, biochemical, radiographic, and pathologic data, we performed a rigorous assessment of the accuracy and pitfalls of NP-59 scintigraphy. The evaluation was divided into categories of abnormal hormone secretion: Cushing's syndrome, primary aldosteronism, and hyperandrogenism. Additional categories included euadrenal tumors (without detectable hormone dysfunction) and sites of residual adrenal cortical tissue. The accuracy of NP-59 scintigraphy ranged from 71% in primary aldosteronism and 75% in euadrenal tumors, to 100% for Cushing's syndrome and hyperandrogenism. However, more than in most nuclear medicine studies, NP-59 imaging requires well-defined indications to be met for it to be efficacious, including the fulfillment of clear clinical, biochemical, and radiographic criteria. The high reproducibility of NP-59 scintigraphic interpretation was demonstrated when 40 random cases underwent interinstitutional exchange and through interobserver evaluation at the University of Michigan. Responses of 85/126 medical centers to questionnaires revealed the high level of NP-59 safety.

Adosterol↗
PubMed1990

Iodine-125-MIBG to treat neuroblastoma: preliminary report.

Three children with Stage III neuroblastoma were treated with [125I]MIBG in a phase I toxicity study. Concepts of the treatment were: in small tumors, the absorbed dose of radiation from MIBG labeled with 131I is reduced but the absorbed dose from [125I]MIBG is less affected; and many recurrences of neuroblastoma arise from small tumors. Two patients exhibited only modest thrombocytopenia and leukopenia, the most sensitive indices of radiation toxicity, after receiving 261 and 407 mCi, and 83 and 104 rad of whole-body radiation. One patient died of progressive neuroblastoma; the other two patients have stable disease over 30 mo after treatment. Per millicurie given, [125I]MIBG imparts about one-fourth the radiation dose of [131I]MIBG to the whole body. Iodine-125-MIBG can be given in doses that impart over 100 rad of whole-body radiation and that exceed 400 mCi before toxicity becomes limiting, even in small children.

3-Iodobenzylguanidine↗
PubMed1989

Scintigraphic studies in adrenal hypertension.

Endocrine hypertension secondary to disorders of the adrenal glands is uncommon, but by no means rare. The importance of correct biochemical diagnosis and subsequent localization of the responsible lesion(s) lie in the fact that many of these syndromes occur in younger patients, may exhibit familial patterns of inheritance and are frequently amenable to surgical cure. The radiopharmaceuticals (131)1-6 beta-iodomethyl-19-norcholesterol (NP-59), a marker of adrenocortical cholesterol uptake, and (131)1- and (123)1-metaiodobenzylguanidine (MIBG), a norepinephrine (NE) analog and marker of energy-dependent NE storage vesicle accumulation, can be shown to accurately localize adrenal cortex and sympathoadrenal dysfunction, respectively. In Cushing's syndrome (CS) not only does the pattern of NP-59 uptake depict the adrenal dysfunction and its pathophysiologic basis, but the level of NP-59 accumulation reflects the degree of adrenocortical hyperfunction. Adrenocorticotrophin-independent CS is uniformly and accurately localized, especially in bilateral cortical nodular hyperplasia where even high resolution computed tomography (CT) may fail to depict the often subtle, asymmetric anatomic abnormalities. Dexamethasone suppression NP-59 adrenal scintigraphy has been shown to be highly sensitive and specific, and exceeds the efficacy of CT in the differentiation of adenoma and bilateral hyperplasia in primary aldosteronism. MIBG is useful as a sympathoadrenal imaging agent whose clinical utility has been demonstrated in the localization of pheochromocytoma, especially as a modality to screen the body for multiple and extraadrenal, recurrent, or metastatic lesions. Moreover, the extent of metastatic involvement from neuroblastoma can also be accurately depicted using MIBG. In this review we will examine the role of adrenal scintigraphy in the characterization of hypersecretory disorders of the adrenal cortex, medulla, and related conditions that produce hypertension as part of their symptom(s) complex. This approach, which is complementary to other anatomical modalities of imaging, can be used to advantage in the localization of functioning cortical and medulla adrenal diseases and other neoplasms of adrenergic origin.

3-Iodobenzylguanidine↗
PubMed1989

RNA secondary structures: comparison and determination of frequently recurring substructures by consensus.

A method for assessing the preserved stem-loops of RNA secondary structures is presented. Frequently recurring helical stems in a set of secondary structures resulting from the simulated folding process of a given RNA are assessed and consensus structural motifs can then be selected to construct a secondary structure of the RNA. Alternatively, it can be applied to a series of 'optimal' and 'suboptimal' secondary structures computed using the dynamic program developed by Williams and Tinoco. To demonstrate the power and the usefulness of the program we give examples of this procedure.

Algorithms↗
PubMed1989

Iodine-131 metaiodobenzylguanidine uptake in infantile myofibromatosis.

I-131 MIBG scintigraphy was performed on a neonate who presented with a left neck mass and brachial palsy. Increased uptake of the tracer was apparent in the mass, initially suspected as being a neuroblastoma, but later diagnosed as infantile myofibromatosis. Since MIBG is principally taken up by neuroendocrine tumors, this finding suggests caution be used when interpreting studies in this age group.

3-Iodobenzylguanidine↗
PubMed1989

Scintigraphic depiction of an insulinoma by I-131 metaiodobenzylguanidine.

Scintigraphy with I-131 metaiodobenzylguanidine (MIBG) was effective in depicting a pancreatic insulinoma in a patient suffering from intermittent hypoglycemia. This observation widens the range of neuroendocrine tumors that take up to I-131 MIBG and supports the concept that many tumors of the amine precursor uptake and decarboxylation system may be imaged in this way.

3-Iodobenzylguanidine↗
PubMed1989

Uterine junctional zone: MR study of water content and relaxation properties.

Weighted samples of uterine myometrium, junctional zone, and endometrium were excised for determination of T1 and T2 in a 20-MHz spectrometer and then dried for determination of water content. The remainder of each uterus, examined with special histopathologic stains, demonstrated no significant difference in the number of blood vessels, smooth muscle cells, fibroblasts, elastin, iron, collagen, mucin, polysaccharide, or amyloid. The junctional zone water content (79.28%) was significantly lower than that of endometrium (82.88%, P = .004) and myometrium (81.05%, P = .005). The T1 of the junctional zone (ie, 643) was significantly lower than that of endometrium (ie, 836; P = .004) and myometrium (ie, 709; P = .01). The T2 of the junctional zone (ie, 58) was significantly lower than that of endometrium (ie, 87; P = .003) and myometrium (ie, 67; P = .006). The low signal intensity of the junctional zone on T2-weighted MR images is accounted for by its lower water content and T2, while the brightness on T1-weighted images is due to its reduced T1.

Adult↗
PubMed1989

Radiochemical diagnosis of adrenal disease.

The adrenal gland consists of cortical and medullary components, both of which may be functionally imaged using radiopharmaceuticals designed to take advantage of the specialized physiology of each tissue. Radiolabeled cholesterol derivatives are taken up by normal and abnormal adrenal cortex and provide an in vitro map of adrenocortical function in Cushing's Syndrome, hyperaldosteronism, and hyperadrenogenism. Quantification of uptake shows strong correlation with biochemical parameters of adrenocortical hyperfunction. In the case of incidentally discovered euadrenal masses scintigraphy may help to distinguish between benign, nonfunctional cortical adenomas, and destructive, potentially malignant lesions. Radiolabeled metaiodobenzylguanidine (MIBG) is a tracer of type I uptake and intracellular storage capacity for catecholamines in sympathomedullary tissues and tumors derived from this system. This permits the location of pheochromocytomas of all types (benign and malignant, intra- and extra-adrenal, sporadic and familial) as well as neuroblastomas in all stages. Other neuroendocrine tumors with type I uptake capacity may also be imaged. In suitable cases preliminary data suggests the administration of large doses of MIBG may permit internal radiotherapy of otherwise untreatable neuroendocrine tumors.

Adrenal Gland Diseases↗
PubMed1989

The effect of thyroidectomy on bone mineral content in perimenopausal women.

To examine the effects of total thyroidectomy on skeletal mineral content we performed dual photon densitometry of the spine and hip in 18 patients with well differentiated thyroid cancer treated with total thyroidectomy and post-thyroidectomy 131-I thyroid remnant ablation. Study subjects were 18 Caucasian females, 45-55 years old, no more than 3 years post-menopausal, 4-20 years (mean 9.7) post-thyroidectomy and 131-I ablation. All subjects were free of disease by all criteria and receiving slightly supra-physiological doses of thyroxine. These subjects were compared with 16 carefully age and sex matched controls without thyroid disease. Patients and controls did not differ significantly in: age (mean-range) 50.2 (45-55) vs 48.7 (45-54) years, height 165.1 (152.4-177.8) vs 164.6 (157.5-172.7) cm, or weight 76.7 (49.1-122.7) vs 71.3 (54.5-104.5) kg. Neither did they differ in (mean +/- SEM): serum calcium 9.45 +/- 0.44 vs 9.49 +/- 0.36 mg/dl, serum inorganic phosphate 3.51 +/- 0.67 vs 3.60 +/- 0.43 mg/dl, serum creatinine 0.84 +/- 0.14 vs 0.91 +/- 0.11 mg/dl or PTH 151.7 +/- 71.0 vs 162.4 +/- 52.0 pg/ml. The T12 index was significantly greater in patients on exogenous thyroxine, 12.0 +/- 2.3 vs 8.7 +/- 1.3 (p less than 0.005) although TSH values performed with a standard sensitivity rather than a super sensitive TSH assay were not significantly different 1.8 +/- 0.9 vs 3.2 +/- 1.6 microU/ml. Lumbar vertebral (L2-4) mineral content was not different between patients and controls, 1.245 +/- 0.900 g/cm2 vs. 1.238 +/- 0.166 g/cm2.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗
PubMed1989

Unusual complications of antithyroid drug therapy: four case reports and review of literature.

Two cases of propylthiouracil-associated acute hepatitis, one case of fatal methimazole-associated hepatocellular necrosis and one case of propylthiouracil-associated lupus-like syndrome are described. The literature related to antithyroid drug side effects and the mechanisms for their occurrence are reviewed and the efficacy and complications of thyroidectomy and radioiodine compared to those of antithyroid drugs. It is concluded that in most circumstances 131I is the therapy of choice for hyperthyroidism.

Adult↗