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Biomedical subjects

B Shapiro

Publications and source records attributed to B Shapiro.

At least 181 records · Page 10Linked to original sources
PubMed1989

Demonstration by iodine-131-hippurate renography of a marked sensitivity of some transplanted kidneys to volume contraction.

Incidental observations made in a canine renal transplant model in which both native and transplanted kidneys were present revealed that abnormal I-131-iodohippurate renograms were derived from some of the transplanted kidneys in the presence of mild dehydration. In these cases, the renogram normalized with fluid administration. In contrast, the renograms derived from the native kidneys were unaffected by the mild dehydration of the animals. These findings demonstrate a greater sensitivity to dehydration of some transplanted kidneys when compared to normal kidneys.

Animals↗
PubMed1989

Management of pheochromocytoma.

The fundamental principles of pheochromocytoma management are reviewed. These are a high index of clinical suspicion; biochemical confirmation of the diagnosis; preoperative localization and pharmacologic treatment with alpha-adrenergic blockers (and occasionally with beta-adrenergic blockers and/or alpha-methylparatyrosine); meticulous anesthesia and intraoperative cardiovascular monitoring; and attention to the surgical principles of wide exposure, careful dissection and complete exploration, early interruption of tumor vasculature, and delivery of the tumor with the capsule intact. For malignant lesions, the roles of pharmacologic management (alpha- and beta-adrenergic blockade, alpha-methylparatyrosine, and drugs for heart failure, diabetes, and pain), teleradiotherapy, radiopharmaceutical treatment with I-131 MIBG and chemotherapy (with cyclophosphamide, vincristine, and dacarbazine) are discussed.

Adrenal Gland Neoplasms↗
PubMed1989

Clinical features, diagnosis, and localization of carcinoid tumors and their management.

In this article, we have focused on the evolving face of neuroendocrine tumors, newer approaches to their diagnosis and localization, the importance of sophisticated immunohistochemistry, tracer scanning, and the role of peptide therapy in the management of the symptom complex as well as the tumor. With recent expansion in our understanding of the pathophysiology of these tumors have come new and innovative approaches to their management. There is, however, much that remains unsolved and that requires diligent research and evaluation if we are ultimately to include neuroendocrine tumors among the curable cancers.

Carcinoid Tumor↗
PubMed1989

Labetalol reduces iodine-131 MIBG uptake by pheochromocytoma and normal tissues.

Iodine-131 metaiodobenzylguanidine [131I]MIBG has proven to be an effective radiopharmaceutical for the scintigraphic localization of pheochromocytomas. Uptake of MIBG is inhibited by blockade of the neuronal uptake pathway for catecholamines ("uptake-1") and by depletion of catecholamine storage vesicle contents, but is not significantly affected by conventional alpha- and beta-adrenoreceptor blocking drugs. Labetalol is an antihypertensive agent with combined alpha- and beta-blocking properties that has been used to manage patients with suspected pheochromocytomas. We report eight patients in whom concurrent or recent therapy with labetalol significantly reduced the uptake of [131I]MIBG into salivary glands, liver, spleen, and general body background. Tumor uptake of MIBG was also reduced in two of the three patients who were proven to have pheochromocytomas. In one case, the effect of labetalol persisted for 36 hr after the drug had been discontinued. The inhibitory effect of labetalol on MIBG uptake in sympathomedullary tissues is likely to be a result of the drug's little-known, additional properties of uptake-1 blockade and depletion of storage vesicle contents, rather than its alpha- or beta-blocking effects. Additionally, labetalol would also appear to hasten clearance of MIBG from other tissues. Labetalol therapy should be discontinued for several days (possibly up to 1 wk) before undertaking [131I]MIBG scintigraphy. A comprehensive list of drugs that should be avoided in patients undergoing MIBG scintigraphy is appended.

3-Iodobenzylguanidine↗
PubMed1989

Alterations of iodine-131 MIBG biodistribution in an anephric patient: comparison to normal and impaired renal function.

Iodine-131 metaiodobenzylguanidine (MIBG) is an effective agent for the scintigraphic portrayal of pheochromocytomas of all types. Iodine-131 MIBG is a relatively stable radiopharmaceutical that is primarily excreted in the urine. Therefore, impaired renal function would be expected to alter [131I]MIBG pharmacokinetics which would thus affect blood levels, as well as scintigraphy. An 18-yr-old anephric male presented with hypertension and suspected pheochromocytoma. We have compared the [131I]MIBG scintigraphy and blood clearance kinetics in this anephric patient, two patients with renal insufficiency and four patients with normal renal function. The degree of renal insufficiency was directly correlated to the CPM/image (an index of whole-body retention) on all 3 days of imaging and the slower clearance of radioactivity from the blood. The relative distribution of radioactivity between the plasma and cell fractions was greatest in the patients with renal insufficiency. We therefore suggest that attention be paid to plasma creatinine levels prior to the administration of [131I] MIBG to permit accurate interpretation of scintigraphy. In addition, the effect of renal insufficiency on radiation dosimetry should be considered. It may thus be prudent to reduce the administered dose of [131I]MIBG given to anephric or renally insufficient patients to decrease radiation dose.

3-Iodobenzylguanidine↗
PubMed1988

Distinguishing benign from malignant euadrenal masses.

STUDY OBJECTIVE: To determine the efficacy of 131I-6-beta-iodomethylnorcholesterol (NP-59) adrenal scintigraphy in distinguishing benign from malignant euadrenal masses. DESIGN: Case series of patients with incidentally discovered unilateral, euadrenal masses. SETTING: Referral-based nuclear medicine clinics at university and affiliated Veterans Administration medical centers. PATIENTS: Consecutive sample of 119 euadrenal patients with unilateral adrenal masses discovered on computed tomographic (CT) scans for reasons other than suspected adrenal disease. INTERVENTIONS: Adrenal scintiscans done using 1 mCi of NP-59 intravenously, and gamma camera imaging 5 to 7 days later. MEASUREMENTS AND MAIN RESULTS: Mean lesion diameter was 3.3 +/- 1.9 cm (SD) (95% CI: 2.9 to 3.6 cm). In 76 patients, NP-59 uptake lateralized to the abnormal adrenal seen on CT scans (concordant imaging), and in all of these patients, a diagnosis of adenoma was made by needle-aspiration biopsy, adrenalectomy, or extended follow-up with repeat CT scans that were unchanged at 6 months or later. Twenty-six patients had absent or markedly reduced NP-59 uptake in the glands identified as abnormal on CT scans (discordant imaging). These adrenal masses proved to be metastatic malignancies in 19 patients, primary adrenal neoplasms other than adenoma in 4, and adrenal cysts in 3. Bilateral, symmetric accumulation of NP-59 was seen in 17 patients, in whom the adrenal masses were shown to be metastatic malignancies in 2, and adenomas in 6 (the lesions in these cases being 2 cm or less in diameter), and lesions not truly involving the adrenal in the rest (periadrenal metastases in 4 and pseudoadrenal masses in 5). Sensitivity was 76% (26 of 34 patients; CI, 58% to 88%); specificity, 100% (85 of 85 patients; CI, 95% to 100%), and accuracy, 93% (111 of 119 patients: CI, 88% to 98%). CONCLUSIONS: Functional NP-59 scintigraphy can be used to accurately and noninvasively characterize many euadrenal masses; concordance of CT and NP-59 scans can be used to exclude the presence of a malignancy or other space-occupying adrenal lesion.

19-Iodocholesterol↗
PubMed1988

Adrenal localization in the adrenocorticotropic hormone-independent Cushing syndrome.

STUDY OBJECTIVE: To assess the efficacy of 131I-6-beta-iodomethylnorcholesterol scintigraphy in the adrenocorticotropic hormone-independent Cushing syndrome and to compare this with computed tomography. DESIGN: Retrospective analysis of case series from 1977 to 1987. SETTING: Referral to the Division of Nuclear Medicine at a tertiary-care university medical center. PATIENTS: Twenty-four patients with a pathologically-confirmed diagnosis of the adrenocorticotropic hormone-independent Cushing syndrome had 131I-6-beta-iodomethylnorcholesterol scintigraphy and, in most cases, computed tomography. MEASUREMENTS AND MAIN RESULTS: Using 131I-6-beta-iodomethylnorcholesterol scintigraphy, adenomas were accurately seen as focal, unilateral tracer uptake in 14 of 14 patients. In carcinoma, the classic scintigraphic pattern of bilateral nonvisualization was observed in 3 of 4 patients, with ipsilateral uptake of tracer in 1 patient with a histologically well-differentiated malignancy. Computed tomography done during the same interval depicted abnormal adrenals in all cases of adenoma and carcinoma. In cortical nodular hyperplasia, however, computed tomography identified abnormal pairs of adrenals in only one of four cases studied, whereas scintigraphy showed typical patterns of bilateral increased uptake in all of the cases. CONCLUSION: 131I-6-beta-iodomethylnorcholesterol scintigraphy accurately shows the location and nature of adrenal dysfunction in the adrenocorticotropic hormone-independent Cushing syndrome and may be particularly useful in identifying the bilateral adrenal involvement in cortical nodular hyperplasia.

19-Iodocholesterol↗
PubMed1988

Toxicity from treatment of neuroblastoma with 131I-meta-iodobenzylguanidine.

Toxic effects from 131I-meta-iodobenzylguanidine (131I-MIBG) treatments of neuroblastoma in six patients were recorded. The toxicity was largely confined to the hematologic system where circulating leukocytes and platelets regularly declined after each dose of 131I-MIBG; the values reached nadirs between three and seven weeks and recovered slowly over subsequent weeks. Prior bone marrow transplantation and infiltration of bone marrow by neuroblastoma appeared to make the hematologic system more vulnerable to the radiation. Dosimetry revealed greater absorbed radiation by the whole body than by the blood and bone marrow. These observations are explained by a relatively rapid exit of 131I-MIBG from the blood to other tissues (but not to the bone marrow). Since treatment of an aggressive and lethal tumor such as neuroblastoma should be pushed to a degree of toxicity, careful dosimetry in each case will be necessary as a guide to reach the point of maximally tolerable toxicity.

3-Iodobenzylguanidine↗
PubMed1988

Laparoscopic and transvaginal ova recovery: the effect on ova quality.

Transvaginal follicle aspiration guided by transvaginal ultrasound for ova recovery is rapidly gaining popularity in many centers practicing in vitro fertilization and embryo transfer (IVF-ET). Cycle outcome following this new method has not been directly compared to the traditional, laparoscopic recovery technique. To this end, the authors evaluated multiple parameters in 66 laparoscopic (group A), and 44 transvaginal ova recovery procedures (group B) in patients undergoing IVF-ET. No statistically significant differences could be demonstrated between the groups in all but the rate of ova fertilization. The rate of fertilization was higher in the ova recovered by transvaginal follicle aspiration (59.6 versus 69.2%; P less than 0.01). No difference could be demonstrated between the groups in the other parameters examined, which included the number of ova recovered (5.7 +/- 0.4 versus 6.0 +/- 0.7), ova maturity (87 versus 84% intermediate ova), rate of polyspermic fertilization (3.9 versus 5%), rate of cleavage (88 versus 91%), cleavage stage at transfer (3.7 +/- 0.8 versus 3.5 +/- 0.4 cells per embryo), number of embryos transferred per patient (2.7 +/- 0.1 versus 3.3 +/- 0.2), and pregnancy rates. The potential detrimental effects of general anesthesia and CO2 pneumoperitoneum present during laparoscopy but not ultrasound guided recovery on ova quality may underlie the observed difference in fertilization between the groups.

Embryo Transfer↗
PubMed1988

Adrenal masses in oncologic patients: functional and morphologic evaluation.

The role of adrenocortical scintigraphy in the evaluation of unilateral adrenal masses detected with computed tomography (CT) in 28 oncologic patients with normal adrenal function was studied prospectively with the use of NP-59 (iodine-131-6-iodomethyl-19-norcholesterol). The diagnosis was proved by means of percutaneous fine-needle aspiration cytologic examination in 20 patients, surgical biopsy in one, and clinical and CT follow-up in seven. In 14 of the 28 patients, there was increased uptake of the NP-59 on the side of the adrenal mass detected at CT (concordant uptake). Thirteen of the 14 masses with concordant uptake were greater than 2 cm in diameter, and one was 1.5 cm; all were found to be adenomas. In 11 of 28 patients there was decreased uptake on the side of the mass detected at CT (discordant uptake). None of these 11 masses were adenomas; nine were metastases and two were adrenal cysts. Uptake was indeterminate (symmetric) in three patients, two of whom had adrenal adenomas and one an adrenal metastasis; each mass with indeterminate uptake was less than 2 cm in diameter.

Adosterol↗
PubMed1988

Effects of secretin on the normal and pathological beta-cell.

Secretin is a gastrointestinal hormone that stimulates insulin secretion and enhances the insulin response to glucose. The mechanism by which secretin acts on the beta-cell has not been extensively studied. The plasma insulin responses to secretin (2 U/kg), expressed as the percent increase relative to basal plasma insulin concentrations, were similar in normal (n = 23) and obese subjects with normal glucose tolerance (n = 12), but were decreased in obese subjects with abnormal glucose tolerance (n = 11). The insulin response to secretin was directly proportional to the basal insulin concentration in these three groups. The effects of secretin on beta-cell function was not altered by propranolol (n = 6), atropine (n = 8), or surgical vagotomy (n = 10). Patients with single islet cell tumors secreting insulin (n = 18) had no plasma insulin response to secretin, whereas patients with noninsulin-secreting pancreatic tumors (gastrinomas; n = 6) and patients in whom single insulinomas had been removed (n = 7) responded normally. Two adult patients with multiple B-cell adenomas and hyperplasia (not associated with multiple endocrine neoplasia type I) hyperresponded to secretin, whereas patients with multiple endocrine neoplasia, type I, without hyperinsulinism responded normally. One patient with nesidioblastosis had no response to secretin, indicating that the pathophysiology of this entity is distinct from that of other forms of islet hyperplasia. These data suggest that secretin stimulates beta-cells directly rather than through cholinergic, adrenergic, or vagal peptidergic neural mechanisms. In addition, the ability to respond to secretin appears to be lost in patients with single insulinomas and nesidioblastosis, but not in those with multiple B-cell adenomas and hyperplasia. The lack of a plasma insulin response in patients with single insulinomas and the high normal or exaggerated response in patients with multiple B-cell adenomas and hyperplasia may prove useful in differentiating these entities.

Adenoma↗
PubMed1988

Unilateral absence of the diaphragm in an asymptomatic adult.

An asymptomatic 22-year-old man was evaluated for a persistent left lower lobe infiltrate. Barium enema and upper gastrointestinal series revealed colon and small bowel freely mobile in the left thorax. CT confirmed absence of the left hemidiaphragm. This is the first reported case of total absence of a hemidiaphragm in an adult, and extends the clinical spectrum of diaphragmatic defects where strangulation of hernia contents may occur , the asymptomatic presentation of complete absence of the hemidiaphragm with the unimpeded movement of abdominal contents suggests that no treatment is necessary.

Adult↗
PubMed1988

Sarcoidosis of the thyroid presenting as a painful nodule.

A patient, known to have sarcoidosis, developed a painful, enlarging right thyroid mass. Thyroid lobectomy was performed revealing sarcoidosis involving the thyroid. A review of the literature shows sporadic reports of involvement of the thyroid with sarcoidosis. There were no previous reports of this entity presenting as painful thyroid enlargement. Thyroid lobectomy was curative.

Adult↗
PubMed1988

Scintigraphic localization of ovarian dysfunction.

To assess the potential role of scintigraphy in the evaluation of clinically and biochemically suspect ovarian hyperandrogenism (HA), dexamethasone suppression 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scans were performed to characterize ovarian function in nine patients. Pelvic ultrasound and/or computed tomography (CT) identified anatomic abnormalities in the adnexal region in six women in whom there was discernible pelvic accumulation(s) of NP-59. In the remaining three patients testosterone levels were normal or only slightly elevated and the NP-59 scan did not demonstrate abnormal adrenal or pelvic uptake. CT and/or ultrasound studies failed to demonstrate an abnormality in the pelvis suggesting excessive peripheral conversion or abnormal end organ sensitivity of androgen precursors as potential etiologies of their HA. In three women with androgen secreting lipoid tumors of the ovary, unilateral, pelvic NP-59 activity was noted; these tumors were subsequently resected. Two women with bilateral pelvic NP-59 uptake were later shown to have hyperthecosis with markedly asymmetric and enlarged ovaries. In one woman the extent of asymmetric NP-59 uptake was anticipated by the asymmetry of ovarian vein androgen levels at selective venous catheterization. In another woman with markedly asymmetric polycystic ovary disease, intense focal uptake of NP-59 localized to the side of the anatomically abnormal, enlarged ovary. Thus, our preliminary study reviews our experience to date and suggests that NP-59 scintigraphy may be used to localize both tumorous and nontumorous ovarian dysfunction in states of HA and virilization.

Adosterol↗