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Biomedical subjects

B Shapiro

Publications and source records attributed to B Shapiro.

At least 127 records · Page 7Linked to original sources
PubMed1993

Thrombocythemia and thrombosis of the adrenal vessels.

The authors describe a case of primary thrombocythemia and thrombosis of the adrenal vessels which they were able to examine by arteriography of the renal and adrenal arteries, by adrenal CT and at autopsy following the patient's death. The available research data and hypotheses concerning the pathogenesis of thrombosis and hemorrhage in thrombocythemia are reviewed, but the relationship between platelet number and function and the incidence of thrombotic and hemorrhagic complications has not yet been clearly established. Pathogenesis of thrombosis and hemorrhage in suprarenal vessels is not clear and the majority of authors postulate early venous damage.

Adrenal Glands↗
PubMed1993

Imaging of catecholamine-secreting tumours: uses of MIBG in diagnosis and treatment.

MIBG radiolabelled with 131I or 123I is a radiopharmaceutical which is concentrated in neuroendocrine tumours, particularly phaeochromocytomas and neuroblastomas. This permits non-invasive whole-body scintigraphic screening for benign and malignant, familial and sporadic, intra-adrenal and extra-adrenal phaeochromocytomas and primary and metastatic neuroblastomas, with high sensitivity (85-90%) and specificity (> 95%). MIBG is also concentrated in presynaptic terminals of adrenergic, autonomically innervated organs such as the heart, and may be used as a non-invasive in vivo probe to study this system. Large doses of 131I-MIBG and 125I-MIBG have been used experimentally to selectively deliver therapeutic doses of radiotherapy to malignant phaeochromocytomas and refractory advanced neuroblastomas.

3-Iodobenzylguanidine↗
PubMed1993

Extensive salivary contamination due to concurrent use of chewing tobacco during I-131 radioablative therapy.

Although multiple authors have reported on various causes of external I-131 contamination after administration of radioiodine, to the authors' knowledge there have been no reported cases of external contamination from salivary secretions due to expectoration of chewing tobacco. A case of extensive I-131 contamination of a hospital room, furniture, and plumbing due to indiscriminate use of chewing tobacco during an inpatient I-131 radioablative therapy is presented.

Aged↗
PubMed1993

Bone scintigraphy in blastomycotic osteomyelitis.

A case of disseminated North American blastomycosis is described in which the full extent of the multifocal osteomyelitis was depicted by Tc-99m MDP scintigraphy. Skeletal involvement by this disease is not uncommon, yet the utility of bone scintigraphy has not been reported. The efficacy with which the whole body may be examined makes this technique especially appropriate for a hematogenously disseminated and often multifocal form of osteomyelitis where radiographically occult and asymptomatic lesions may be present.

Blastomycosis↗
PubMed1993

L-thyroxine overdose: a case of marked, severe, prolonged, excess ingestion and review of the literature.

A case of a man with thyroid cancer who ingested between 0.9 and 3.3 mg l-thyroxine per day for over 10 years (the highest dose for 3 years) is reported. This had been prescribed for suppression of TSH for a well differentiated thyroid cancer. He was essentially asymptomatic and suffered no apparent ill effects from this prolonged and markedly excessive dosage of l-thyroxine. The literature lists a wide range of ill effects from both chronic and acute thyroid hormone overdosage but also records many examples of tolerance to excessive levels of exogenous thyroid hormone. The various circumstances leading to thyroid hormone overdose and potential ill-effects are reviewed.

Adult↗
PubMed1993

L-thyroxine malabsorption due to the injection of herbal remedies.

Two patients are described in whom the absorption of l-thyroxine was impaired by non-prescription herbal and nutritional remedies. The absorption of thyroid hormones is discussed and an approach to the problem of patients who appear to be unresponsive to the usual doses of thyroid hormones is suggested.

Absorption↗
PubMed1992

Single-dose pharmacokinetics of pravastatin and metabolites in patients with renal impairment.

The disposition of a single 20-mg oral dose of pravastatin was assessed in subjects with various degrees of renal function. Sixteen subjects (13 males, 3 females) with creatinine clearance values ranging from 15 to 112 mL/min/1.73 m2 completed the study. Area under the serum concentration-time curve, maximum serum concentration, time to maximum serum concentration, terminal serum elimination half-life, apparent clearance, and apparent volume of distribution for pravastatin were not affected by renal impairment, whereas the renal clearance of pravastatin decreased as creatinine clearance decreased (r2 = 0.697, P less than .001). The area under the serum concentration-time curve and time to maximum serum concentration of SQ 31,945 (a hepatic metabolite) increased in patients with renal impairment, whereas the terminal elimination rate constant and renal clearance of SQ 31,945 significantly decreased as a function of creatinine clearance. The renal clearance of another metabolite (SQ 31,906) also significantly declined with decreasing renal function. This single-dose study demonstrates that pravastatin pharmacokinetics were not affected in patients with renal impairment, probably because of its dual route of elimination.

Administration, Oral↗
PubMed1992

131-I-metaiodobenzylguanidine treatment in patients with refractory advanced neuroblastoma.

Fourteen patients with refractory advanced neuroblastoma were treated with 131-I-metaiodobenzylguanidine (131-I-MIBG); all had evidence of progressive disease or recurrent disease following combination chemotherapy. One patient without gross evidence of disease, following surgical resection of recurrent neuroblastoma before therapy with 131-I-MIBG, remains healthy without regrowth of tumor 3.5 years later. Two other patients had minor responses, and one had a mixed response. Two patients remain alive 1,212 and 1,926 days following the initial 131-I-MIBG treatment; the remaining 12 patients died of progressive disease. Moderate myelosuppression was the most notable toxicity observed; mild nausea and vomiting and transient mild liver enzyme elevation were also encountered. Treatment with 131-I-MIBG produced antineoplastic activity in patients with neuroblastoma and was well tolerated. To evaluate dose escalation, alternative dosage schedules, and alternative MIBG-radioconjugates, additional trials of radiolabeled MIBG are indicated.

3-Iodobenzylguanidine↗
PubMed1992

Bilateral testicular neuroblastoma. Scintigraphic depiction and therapy with I-131 MIBG.

The authors describe a 29-year-old man who had a 16-year history of neuroblastoma and uncommon manifestations. At age 13, he was diagnosed with stage III retroperitoneal ganglioneuroblastoma that was resected. Ten years later, bilateral testicular enlargement and a pelvic mass from infiltration of the neuroblastoma became palpable. Metastatic involvement was depicted with MIBG, a radiotracer that concentrates in tissues of the sympathetic nervous system. Using I-131 MIBG, the tumors were treated with therapeutic doses of radiation and a partial response was obtained. This case is unique because of the massive degree of bilateral testicular infiltration and its occurrence as a late manifestation of neuroblastoma in early adulthood.

3-Iodobenzylguanidine↗
PubMed1992

Distribution of [32P]-chromic phosphate colloid in cystic brain tumors.

To suppress cyst formation in 42 brain tumors, 32P has been stereotactically instilled in doses calculated to deliver 20,000-40,000 rad to the cyst wall, assuming uniform dispersal of the radioisotope. However, samples of cyst fluid obtained at varying intervals after injection showed lower than expected activity levels, suggesting early 'plating' of 32P. To accommodate this phenomenon, a surface-area-dependent dosimetric calculation is compared with a volume-dependent calculation which assumes uniform dispersal. These two approaches represent lower and upper extremes. It appears that in small cysts there is less difference in the required administered dose, but in larger cysts potentially very large differences exist and caution should be exercised if uniform suspension is assumed.

Brain Neoplasms↗
PubMed1992

Iodine-131-metaiodobenzylguanidine and bone scintigraphy for the detection of neuroblastoma.

The purpose of this study was to compare the utility of bone and metaiodobenzylguanidine (MIBG) scintigraphy for the detection of primary and metastatic deposits of neuroblastoma. 99mTc methylene diphosphonate (MDP) bone and 131I-MIBG scans performed within 1 mo of each other in 85 patients with known or suspected neuroblastoma were evaluated for evidence of skeletal and extraskeletal disease. In 77 of 77 patients with confirmed neuroblastoma, the MDP and MIBG scans were concordant for the presence or absence of skeletal disease. A nearly twofold greater number of skeletal lesions were evident on MIBG scanning. No patients with normal bone scans had MIBG studies indicating bone involvement. In patients with histologic evidence of bone marrow involvement, each study suggested skeletal lesions in approximately 70%. In patients with extraskeletal disease demonstrated by CT, there was soft-tissue uptake of MIBG in 80% and MDP in 39%. We conclude that both MIBG and MDP are useful for the detection of skeletal neuroblastoma. MIBG is the better agent for characterizing the extent of disease, and MDP is a valuable adjunctive agent that provides skeletal landmarks for comparison. MIBG is clearly superior for the detection of extraskeletal neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1992

Bone mineral density of the axial skeleton in acromegaly.

Acromegaly is characterized by growth hormone (GH) hypersecretion and insulin-like growth factor-I (IGF-I) excess, both of which stimulate osteoblast proliferation. At diagnosis, GH excess has usually been present for years. Furthermore, impaired gonadotropin secretion with hypogonadism is frequent. To date, studies of changes in bone mineral density (BMD) in acromegaly have been limited and the available data inconsistent. To investigate the effects of GH excess on proximal femur and lumbar spine BMD, a case series of 25 patients with acromegaly (8 eugonadal, 17 hypogonadal) documented by high plasma GH and IGF-I concentrations was studied. BMD was measured using dual-photon absorptiometry, hormonal and biochemical measurements, which included GH, IGF-I, serum calcium, phosphate, alkaline phosphatase, 1,25 dihydroxy vitamin D and urinary calcium and hydroxyproline excretion. Seven patients were re-studied after IGF-I was suppressed for six months by the somatostatin analog 201-995 (five patients) or pituitary adenomectomy (two patients). BMD was normal in 22 patients and was decreased at one site each in one eugonadal and two hypogonadal patients. BMD was similar between the eugonadal and hypogonadal groups at all sites. Urinary hydroxyproline excretion was equally increased in both groups. There was no correlation between any of the hormonal or biochemical parameters and the age, sex, race and body mass index matched Z-scores of BMD at any site. Following normalization of IGF-I for 6 mo in seven patients, there was no significant change of BMD. We conclude that proximal femoral and lumbar spine BMD is normal in most patients with active acromegaly, including those who are hypogonad. Successful treatment of acromegaly does not result in major short-term changes in BMD.

Absorptiometry, Photon↗
PubMed1992

PET scanning with hydroxyephedrine: an approach to the localization of pheochromocytoma.

Pheochromocytomas are potentially curable causes of hypertension. These tumors are currently located by functional imaging with meta-iodobenzylguanidine (MIBG), usually labeled with 131I, or anatomic imaging (computed tomography, magnetic resonance). Hydroxyephedrine (HED) is a newly developed radiotracer that concentrates in adrenergic nerve terminals. When HED is labeled with 11C, its distribution can be mapped in vivo using PET. The purposes of this investigation were to characterize the uptake of 11C-HED in pheochromocytoma and to determine the feasibility and advantages of utilizing this compound as a tumor imaging agent. Ten patients with known or suspected pheochromocytoma were studied. Each patient underwent PET scanning with 11C-HED and conventional scintigraphy with MIBG. Pheochromocytomas were localized by PET scanning in 9 of the 10 patients. Image quality was excellent and superior to that obtained from planar and tomographic MIBG studies. The uptake of 11C-HED into pheochromocytomas was rapid; tumors were evident within 5 min following intravenous injection. All lesions within the field of view that were identified by MIBG scintigraphy were readily apparent. PET scanning with 11C-HED localizes pheochromocytoma using a specifically designed radiotracer and advanced imaging technology. The method has promise for locating the more elusive tumors.

3-Iodobenzylguanidine↗