Relation between persistent currents and the scattering matrix.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
B Shapiro
Publications and source records attributed to B Shapiro.
Clinical significance of the large adrenal mass.
Current clinical teaching indicates that large (greater than 5 cm in diameter) adrenal masses are often malignant. In a retrospective analysis of patients studied between 1977 and 1988 with computed tomography (CT), adrenal scintigraphy, and when available, magnetic resonance imaging (MRI) 45 were found to have adrenal masses greater than 5 cm (range 5-19 cm) in diameter. Thirty were benign (16 phaeochromocytomas, six adrenocortical adenomas, four adrenal cysts, two myelolipomas, an adrenal hematoma and a ganglioneuroma). Of 15 malignant masses, there were seven adrenocortical carcinomas, five adrenal metastases and three adrenal lymphomas. With the exception of the adrenal myelolipomas, cysts, and the ganglioneuroma neither CT nor MRI demonstrated sufficient diagnostic specificity to distinguish benign from malignant lesions. Functional scintigraphy with 131I-6-beta-iodomethyl-19-norcholesterol for suspected adrenocortical lesions and 131I-metaiodobenzylguanidine for suspected phaeochromocytomas frequently provided useful information.
19-Iodocholesterol↗
Phaeochromocytoma and functioning paraganglioma in childhood and adolescence: role of iodine 131 metaiodobenzylguanidine.
Phaeochromocytomas and functioning paragangliomas are rare tumours in childhood and adolescence. We review our experience of 43 cases (24 men, 19 women) who were first diagnosed at the age of less than or equal to 18 years. All patients were evaluated at some point in their illness with iodine 131 metaiodobenzylguanidine (131I-mIBG) scintigraphy. Eight patients (19%) had bilateral adrenal tumours, 12 (28%) had solitary extra-adrenal tumours, and 8 (19%) had multiple tumours. In 10 patients (23%), the tumours were associated with a familial neurocristopathic syndrome. Thirteen of 24 (54%) unifocal tumours which were initially considered to be benign ultimately proved to be multi-focal and/or malignant. The final prevalence of malignancy was 60%--26 patients, of whom only 15 (57%) had obviously malignant tumours at the time of diagnosis. Primary tumour size greater than or equal to 5 cm was more commonly associated with a malignant course in adrenal but not extra-adrenal tumours. No other clinical, biochemical or morphological characteristic was significantly associated with malignancy. Although the high prevalence of malignancy in this series at least partly reflects referral bias, the need for lifelong follow-up of these patients is underscored. 131I-mIBG scintigraphy was positive in 36 patients (84%), with a somewhat lower false-negative rate (12%) than X-ray computed tomography (20%). Eight patients with malignant tumours received therapeutic doses of 131I-mIBG, with partial tumour responses in 3. Thus, 131I-mIBG is an efficacious, non-invasive, localising agent and may be considered as a palliative therapeutic agent when alternatives have failed.
3-Iodobenzylguanidine↗
Accumulation of Scoparone in Heat-Treated Lemon Fruit Inoculated with Penicillium digitatum Sacc.
Phytoalexin scoparone (6,7-dimethoxycoumarin) generally was not detected in noninoculated lemon fruit (Citrus limon [L.] Burm., cv Eureka) but accumulated in fruit after inoculation with Penicillium digitatum Sacc. A much greater increase in the amount of scoparone was found in fruit exhibiting an incompatible response to Penicillium after heat treatment at 36 degrees C for 3 days. Heat treatment prevented development of decay in the inoculated fruit. The concentration of the compound after inoculation continued to increase during and after the heat treatment period, reaching 178 micrograms per gram fresh weight of the flavedo 6 days after the heat treatment. Changes in scoparone concentration in fruit were closely correlated with the changes in the antifungal activity of the fruit extract. A low concentration of the phytoalexin was detected in fruit injured mechanically. Scoparone also accumulated in the fruit following ultraviolet illumination; the concentration of the compound was dose-dependent. Median effective dose values of the inhibition of germ tube elongation and spore germination of P. digitatum were 29 and 46 micrograms per milliliter, respectively. Our findings suggest that the rapid increase in scoparone concentration plays an important role in the increased resistance of heat-treated lemon fruit to infection by P. digitatum.
Journal Article↗
Radiolabelled semisolid test meal clearance in the evaluation of esophageal involvement in scleroderma and Sjogren's syndrome.
Esophageal involvement by scleroderma is frequent. Investigation by manometry or radiography is invasive and nonphysiological. Scintigraphy of the clearance of small radiolabelled liquid boluses in the supine position, while sensitive and noninvasive, may also be nonphysiological and does not allow the simultaneous determination of gastric emptying. We thus studied the esophageal clearance of a semisolid test meal ingested in the upright position. Forty-seven patients with scleroderma and 24 with Sjogren's syndrome were compared with ten normal controls and ten patients with gastric emptying abnormalities but no esophageal involvement. Results of scintigraphy were also correlated with manometry and contrast radiography. Quantitative evaluation of esophageal tracer retention at ten minutes postingestion was: (mean +/- SD), 2.8 +/- 1.0% in normals, 2.9 +/- 0.9% in gastric dysmotility, 4.8 +/- 2.9% in Sjogren's syndrome, and 22.3 +/- 25.0% in scleroderma; similar results were found at 20 and 60 minutes. The T 1/2 of gastric emptying was 47.1 +/- 5.7 minutes in normals, 95.9 +/- 25.3 minutes in gastric dysmotility, 62.9 +/- 19.5 minutes in Sjogren's syndrome, and 52.9 +/- 13.5 minutes in scleroderma. We conclude that esophageal clearance of a semisolid test meal is a sensitive index of esophageal dysmotility and correlates well with results from manometry and contrast radiography but is noninvasive and quantifiable. The simultaneous measurement of gastric emptying is also possible in many cases.
Adult↗
Absent splenic uptake of indium-111-oxine-labeled autologous leukocytes in functional asplenia.
An incidental finding of absent splenic uptake of autologous, indium-111-oxine-labeled leukocytes in an immunosuppressed renal transplant recipient was documented to be associated with functional asplenia based on absence of technetium-99m-sulfur colloid clearance by a morphologically normal spleen. The patient had recently suffered an episode of disseminated varicella infection that might have led to the development of functional asplenia.
Adult↗
Clinical significance of the solitary functioning adrenal gland.
To assess the compensatory functional and anatomic changes in the remaining adrenal cortex after unilateral adrenalectomy or in the unaffected adrenal in patients with unilateral adrenal destruction by neoplasm, 17 patients with a single, functioning adrenal gland and normal indices of adrenocortical function, nine after adrenalectomy and eight with a unilateral, destructive adrenal lesion were studied with 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy and computed tomography. Adrenal masses with a mean (+/- s.d.) diameter of 2.8 +/- 1.0 cm; (range 1-4 cm; 95% confidence interval (Cl), 2.5-3.1 cm) were identified by computed tomography in seven of nine patients in the remaining adrenal cortex at variable times (6.1 +/- 5.9 y; range 0.5-19 y) after unilateral adrenalectomy. Mean (+/- s.e.m.) NP-59 uptake was elevated (p less than 0.01) in both adrenalectomy and adrenal destruction groups, mean uptake (+/- s.e.m.) was 0.32% +/- 0.04% administered dose (95% Cl, 0.24%-0.4% administered dose) as compared to normal (0.16% +/- 0.05% administered dose, 95% Cl, 0.06%-0.26% administered dose). The remaining adrenal cortex may be anatomically abnormal after unilateral adrenalectomy and demonstrate compensatory, increased NP-59 uptake in the presence of overall, normal adrenocortical function.
Adosterol↗
A comparison of scintigraphy, thermography, ultrasound and phlebography in grading of clinical varicocele.
Varicocele, a varicosity of the pampiniform plexus, usually on the left side, is a common urologic problem. It may be associated with symptoms of local discomfort or abnormal spermatogenesis. Internal spermatic vein phlebography is the "gold standard" investigative technique, but it is invasive. Noninvasive studies include: labeled blood-pool scintigraphy, thermography and ultrasound. Two hundred sixty-three patients were investigated with various combinations of these modalities. The degree of abnormality for each modality was graded semiquantitatively and the results compared. In addition, the results of semen analysis were correlated to imaging results. Ninety-six patients were investigated with all four tests (scintigraphy, thermography, ultrasound and phlebography). The correlation of positive phlebography to positive scintigraphy was 98%, to thermography 100% and to ultrasound 98%. The concordance (grade for grade) was 71% for scintigraphy, 68% for thermography and 62% for ultrasound. There was no obvious correlation between abnormalities of semen analysis and grading of varicocele. We conclude that the diagnostic accuracy and grading of severity by noninvasive techniques (including scintigraphy) compare very favorably with that of phlebography. Moreover, scintigraphy allows the noninvasive evaluation of reflux through the internal spermatic vein, which may be useful in planning therapy.
Adult↗
Endocrine crises. Pheochromocytoma.
A rational management of pheochromocytoma is outlined, consisting of clinical suspicion, biochemical confirmation, radiologic localization, meticulous preoperative, interoperative, and postoperative monitoring, and pharmacologic intervention. The principles for achieving surgical cure (possible in 90% of cases) are described, as is the pharmacologic, chemotherapeutic, and radiotherapeutic management of malignant or inoperable tumors.
Adolescent↗
Maximizing thallium stress/redistribution scans.
Explore the source record for details and available documents.
Heart↗
Conductance distribution at the mobility edge.
Explore the source record for details and available documents.
Journal Article↗
Contributions of nuclear endocrinology to the diagnosis of adrenal tumors.
Explore the source record for details and available documents.
3-Iodobenzylguanidine↗
Health and hormonal characteristics of premenopausal women with lower bone mass.
A study of clinical renal and endocrinologic status was undertaken to determine whether the lowest maximal bone mass observed in premenopausal women, aged 20-40 years, was a result of undiagnosed disease or represented a continuum of measurement in young adult women. A clinical sample (n = 53) was generated from an epidemiologic cross-sectional study (n = 535) designed to characterized correlates of maximal bone mass. Cases were 28 premenopausal women whose femoral bone mass as in the lowest 5th percentile of the distribution, less than 0.75 g/cm2 at the femoral neck. Controls were 25 randomly selected premenopausal women whose femoral bone mass was within 1 SD of the mean of the femoral bone mass distribution. There was no indication of increased frequency of disease among the cases as compared with the controls. No occult hypogonadism, thyrotoxicosis, hyperparathyroidism, myeloma, or renal insufficiency was observed to explain lower bone mass measurement. However, cases had significantly lower estradiol levels (75 versus 106 pg/ml, P less than 0.05) and higher luteinizing hormone levels (3.8 versus 3.1 mIU/ml, P less than 0.07) than controls. Though preliminary, these findings suggest that lower estradiol levels may contribute to significant differences in bone mass even among healthy women at the time of maximal bone accumulation.
Adult↗
Speeding up the dynamic algorithm for planar RNA folding.
The simplest dynamic algorithm for planar RNA folding searches for the maximum number of base pairs. The algorithm uses O(n3) steps. The more general case, where different weights (energies) are assigned to stacked base pairs and to the various types of single-stranded region topologies, requires a considerably longer computation time because of the partial backtracking involved. Limiting the loop size reduces the running time back to O(n3). Reduction in the number of steps in the calculations of the various RNA topologies has recently been suggested, thereby improving the time behavior. Here we show how a "jumping" procedure can be used to speed up the computation, not only for the maximal number of base pairs algorithm, but for the minimal energy algorithm as well.
Algorithms↗
A computational procedure for assessing the significance of RNA secondary structure.
In our recent series of papers, we have used the structures of statistical significance from Monte Carlo simulations to improve the predictions of secondary structure of RNA and to analyze the possible role of locally significant structures in the life cycle of human immunodeficiency virus. Because of intensive computational requirements for Monte Carlo simulation, it becomes impractical even using a supercomputer to assess the significance of a structure with a window size greater than 200 along an RNA sequence of 1000 bases or more. In this paper, we have developed a new procedure that drastically reduces the time needed to assess the significance of structures. In fact, the efficiency of this new method allows us to assess structures on the VAX as well as the CRAY.
Biometry↗
Late presentation of metastatic pheochromocytoma: a problem case solved by I-131 MIBG scintigraphy.
A patient presented with recurrent pheochromocytoma 10 years following the apparently successful surgical cure of a right adrenal pheochromocytoma. Conventional medical imaging techniques, (chest radiograph, abdominal ultrasound, and abdominal CT) suggested local recurrence for which surgery was planned. I-131 MIBG scintigraphy revealed disseminated metastatic disease that rendered attempts at surgical cure futile. The patient was treated with three therapeutic doses of I-131 MIBG with good symptomatic palliation and improvement of some biochemical parameters.
3-Iodobenzylguanidine↗
Scintigraphic endocrine mimicry.
The control of hormone secretion and substrate uptake by the thyroid and inner adrenal cortex is similar because both glands undergo hypothalamic-pituitary trophic hormone modulation and negative feedback by their respective major secretory products: thyroid hormone and cortisol, respectively. As a result of these parallel mechanisms of endocrine function, thyroidal accumulation of radioiodine or Tc-99m pertechnetate and adrenal cortical accumulation of I-131-6 beta-iodomethylnorcholesterol (NP-59) and other radiocholesterol analogs are strikingly similar. The patterns of imaging of these glands are thus functional maps of the process(es) of substrate accumulation and depict the endocrine pathophysiology of these glands in a variety of dysfunctional states. The well-recognized patterns of thyroid imaging can be shown analogous to those of the adrenal cortex.
Adosterol↗
Morphine-augmented hepatobiliary scintigraphy in the severely ill: caution is in order.
Morphine augmentation in hepatobiliary scintigraphy has been reported as a useful tool to shorten imaging time. The technique has not been extensively evaluated in patients who are severely ill and receiving total parenteral nutrition, although the study of these patients with non-morphine-augmented hepatobiliary scintigraphy is problematic. The authors retrospectively analyzed 51 morphine-augmented hepatobiliary studies performed in a tertiary referral center on a population with a high proportion of severe intercurrent illness (18 patients, 14 of whom were receiving total parenteral nutrition) and hepatocellular dysfunction (eight patients). The overall sensitivity was 94%, specificity was 69%, and the false-positive rate was 40% for the diagnosis of acute cholecystitis. The majority of the false-positive cases occurred in the severely ill subgroup (false-positive rate, 60%). Morphine-augmented hepatobiliary studies may be advantageous because of shortened imaging time. However, patients who have severe intercurrent illness, whether or not they are receiving total parenteral nutrition, have a higher frequency of false-positive morphine-augmented hepatobiliary studies, and positive findings at scintigraphy in this patient group should be interpreted with caution.
Acute Disease↗