Trachoma, antibiotics and randomised controlled trials.
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Anti-Bacterial Agents↗
Biomedical subjects
B Shapiro
Publications and source records attributed to B Shapiro.
Controversies in diagnostic approaches to the indeterminate follicular thyroid nodule.
In this paper we review the controversies in diagnostic approaches to follicular thyroid nodules with indeterminate cytology. The authors consider some of the controversies surrounding the indeterminate follicular thyroid nodule, including the definition and the postoperative outcome. Among the techniques that may improve preoperative diagnostic accuracy are large needle aspiration biopsy and immunohistochemistry for galectin-3.
Adenocarcinoma, Follicular↗
Bayesian coalescent inference of past population dynamics from molecular sequences.
We introduce the Bayesian skyline plot, a new method for estimating past population dynamics through time from a sample of molecular sequences without dependence on a prespecified parametric model of demographic history. We describe a Markov chain Monte Carlo sampling procedure that efficiently samples a variant of the generalized skyline plot, given sequence data, and combines these plots to generate a posterior distribution of effective population size through time. We apply the Bayesian skyline plot to simulated data sets and show that it correctly reconstructs demographic history under canonical scenarios. Finally, we compare the Bayesian skyline plot model to previous coalescent approaches by analyzing two real data sets (hepatitis C virus in Egypt and mitochondrial DNA of Beringian bison) that have been previously investigated using alternative coalescent methods. In the bison analysis, we detect a severe but previously unrecognized bottleneck, estimated to have occurred 10,000 radiocarbon years ago, which coincides with both the earliest undisputed record of large numbers of humans in Alaska and the megafaunal extinctions in North America at the beginning of the Holocene.
Algorithms↗
Efficient energy based modeling and experimental validation of liquid filling in planar micro-fluidic components and networks.
This paper presents a model that describes how liquid flow fills micro-fluidic components and networks. As an alternative to computational fluid dynamic (CFD) simulations, we use a constrained energy minimization approach. This approach is based on two assumptions that hold in many micro-fluidic devices: (i) The length scales are small, and we consider slow filling rates, hence fluid momentum and viscous terms are small compared to surface tension forces, consequently the liquid/gas interfaces can be viewed as a succession of quasi-steady equilibrium configurations. (ii) Any equilibrium configuration corresponds to a surface tension energy minima which is constrained by the device shape and the volume of liquid in the device. The model is developed for planar micro-fluidic devices, is based on a fundamental physical principle, and shows accurate agreement with experimental data. It takes us only a few minutes to evaluate the model for a planar component of any shape using the Surface Evolver software, and this is significantly less then the computer run time required for CFD simulations. Moreover, once a library of component models has been created (which takes less than an hour of computer time) it then takes only seconds to simulate different network architectures with thousands of components. This fast "reconfigure the network and simulate in seconds" capability is essential for the design of truly complex networks that will enable the next generation of passive, micro-fluidic, lab-on-a-chip systems.
Computer Simulation↗
'Low dose' 99mTc-Sestamibi for radioguided surgery of primary hyperparathyroidism.
AIM: In this study, we evaluated the efficacy of low dose (99m)Tc-Sestamibi administration for radioguided parathyroid surgery in patients with primary hyperparathyroidism (PHPT). METHODS: Three hundred consecutive PHPT patients were studied between September, 1999 and July, 2003. Pre-operative work-up included (99m)Tc-pertechnetate/(99m)Tc-Sestamibi subtraction scintigraphy and high resolution ultrasonography (US). 37MBq of (99m)Tc-Sestamibi was injected i.v. in the operating suite approximately 10 min prior to the beginning of the surgical procedure for intraoperative radiolocalization; quick parathyroid hormone (QPTH) assays were performed. RESULTS: Two hundred and seven of the 211 patients selected for minimally-invasive radioguided parathyroidectomy (MIRP) were successfully treated for a solitary parathyroid adenoma (PA) through a 2-2.5 cm skin incision (mean operative time 35 min, mean hospital stay 1.2 days). In the 89 patients selected for traditional bilateral neck exploration (BNE), radioguided surgery was not as successful in the identification of the PA, especially in patients with (99m)Tc-Sestamibi-avid thyroid nodules. Nevertheless, the combination of probe and QPTH measurement was very helpful in patients with multigland disease. CONCLUSIONS: Low-dose (99m)Tc-Sestamibi administered few minutes before surgery is sufficient for MIRP in patients with high likelihood of a solitary PA and without concomitant (99m)Tc-Sestamibi-avid thyroid nodules. The combination of radioguided surgery and QPTH measurements is very useful in the early identification of unanticipated multigland disease.
Adenoma↗
A rare case of paraneoplastic cerebellar degeneration discovered by whole-body F-18 FDG PET.
A rare case of paraneoplastic cerebellar degeneration (PCD) in a 36-year-old woman is reported. She developed hyposthenia of the inferior limbs, diplopia, and disequilibrium in July 2001. Routine blood tests, tumoral markers, brain MRI, evoked potentials, and cerebrospinal fluid (CSF) examination were substantially normal. The clinical syndrome rapidly worsened in the following 2 months; she was wheelchair-bound with marked limb ataxia. CSF showed an increase of the IgG index with oligoclonal bands; brain MRI remained negative. The patient's serum and CSF were analyzed to detect antineuronal antibodies; anti-Yo antibodies were found that is typical of PCD. No tumor was found until April 2003; repeated CT scan, ultrasound, and mammographic examinations were negative. A further worsening in clinical symptoms was observed with a complete loss of autonomy (Rankin score 5) despite the performance of immunosuppressive therapy. In April 2003, an F-18 FDG PET scan visualized an area of abnormal uptake in the upper outer quadrant of the left breast. Interestingly, brain F-18 FDG uptake was normal. Suspicious microcalcifications were found on a new mammography and malignant cells were disclosed at cytology. The patient was operated on and final histologic examination revealed an infiltrating ductal breast cancer. In the reported case, F-18 FDG PET played a crucial role in detecting the unknown primary tumor in a young patient with PCD.
Adult↗
Incomplete photonic band gap as inferred from the speckle pattern of scattered light waves.
Motivated by recent experiments on intensity correlations of the waves transmitted through disordered media, we demonstrate that the speckle pattern from disordered photonic crystal with incomplete band gap represents a sensitive tool for determination of the stop-band width. We establish the quantitative relation between this width and the angular anisotropy of the intensity correlation function.
Journal Article↗
Anomalously localized states in the Anderson model.
It is demonstrated that anomalously localized states (ALS) in the Anderson model, being lattice specific, are not related to any of the continuous theories. We identify the spatial structure of ALS on a lattice and calculate their likelihood. Analytical results explain peculiarities in previous numerical simulations.
Journal Article↗
Controversies on minimally invasive procedures for radio-guided surgery of parathyroid tumours.
The definitive treatment of primary hyperparathyroidism (PHPT) is the surgical approach which traditionally consists of bilateral neck exploration with visualization of at least 4 parathyroid glands and removal of the enlarged ones. However, the most frequent cause of PHPT is a solitary parathyroid adenoma so that a limited neck exploration in order to remove the solitary adenoma alone appears adequate to many surgeons. The recent significant improvements achieved in the pre-operative parathyroid localization techniques, mainly the parathyroid scintigraphy, and the introduction in surgical practice of measurement of quick parathyroid hormone, endoscopic procedures, and intra-operative gamma probes used together specific radiopharmaceuticals allowed to offer the PHPT patient a limited neck exploration as the unilateral neck exploration and the minimally invasive parathyroidectomy. The present article deals with the role of the intra-operative gamma probes used together with specific radio-pharmaceuticals, discussing the principal advantages and disadvantages of each currently used radio-guided approach.
Adenoma↗
Crossover between universality classes in the statistics of rare events in disordered conductors.
The crossover from orthogonal to the unitary universality classes in the distribution of the anomalously localized states (ALS) in two-dimensional disordered conductors is traced as a function of magnetic field. We demonstrate that the microscopic origin of the crossover is the change in the symmetry of the underlying disorder configurations that are responsible for ALS. These disorder configurations are of weak magnitude (compared to the Fermi energy) and of small size (compared to the mean free path). We find their shape explicitly by means of the direct optimal fluctuation method.
Journal Article↗
Random resonators and prelocalized modes in disordered dielectric films.
We calculate the areal density of disorder-induced resonators with a high quality factor, Q>>1, in a film with fluctuating refraction index. We demonstrate that, for a given kl>1, where k is the light wave vector and l is the transport mean-free path, when on average the light propagation is diffusive, the likelihood for finding a random resonator increases dramatically with increasing the correlation radius of the disorder. Parameters of most probable resonators as functions of Q and kl are found.
Journal Article↗
Dynamics of Pleistocene population extinctions in Beringian brown bears.
The climatic and environmental changes associated with the last glaciation (90,000 to 10,000 years before the present; 90 to 10 ka B.P.) are an important example of the effects of global climate change on biological diversity. These effects were particularly marked in Beringia (northeastern Siberia, northwestern North America, and the exposed Bering Strait) during the late Pleistocene. To investigate the evolutionary impact of these events, we studied genetic change in the brown bear, Ursus arctos, in eastern Beringia over the past 60,000 years using DNA preserved in permafrost remains. A marked degree of genetic structure is observed in populations throughout this period despite local extinctions, reinvasions, and potential interspecies competition with the short-faced bear, Arctodus simus. The major phylogeographic changes occurred 35 to 21 ka B.P., before the glacial maximum, and little change is observed after this time. Late Pleistocene histories of mammalian taxa may be more complex than those that might be inferred from the fossil record or contemporary DNA sequences alone.
Animals↗
Spatial-field correlation: the building block of mesoscopic fluctuations.
The absence of self-averaging in mesoscopic systems is a consequence of long-range intensity correlations. Microwave measurements suggest, and diagrammatic calculations confirm, that the correlation function of the normalized intensity with displacement of the source and detector, Delta R and Delta r, respectively, can be expressed as the sum of three terms, with distinctive spatial dependences. Each term involves only the sum or the product of the square of the field correlation function, F identical with F(2)(E). The leading-order term is the product, F(Delta R)F(Delta r); the next term is proportional to the sum, F(Delta R)+F(Delta r); the third term is proportional to F(Delta R)F(Delta r)+[F(Delta R)+F(Delta r)]+1.
Journal Article↗
Is there a future for adrenal scintigraphy?
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Adrenal Gland Diseases↗
Scintigraphy of acute inflammatory lesions in rats with radiolabelled recombinant human neutrophil-activating peptide-2.
Radiolabelled recombinant human interleukin-8 (IL-8) with its homologue neutrophil-activating peptide-2 (NAP-2) have been compared for imaging acute sterile inflammatory lesions in rats. 125I-IL-8 and 125I-NAP-2 were prepared by reaction with chloramine-T and injected intravenously into male rats bearing subcutaneous carrageenan abscesses in their left hindlimbs. Left hindlimb and right hindlimb activities were determined from serial total-body scintigrams between 1 h and 96 h post-injection as regional per cent injected activity corrected for physical decay (%IA). Time-activity curves for 125I-IL-8 and 125I-NAP-2 in the carrageenan-containing left hindlimbs were similar in that both peaked at 1-3 h post-injection (IL-8, 4.9+/-0.5%IA; NAP-2, 4.8+/-1.9%IA) and decreased exponentially thereafter. However, while the lesioned-to-control limb activity ratio (L/C) for 125I-IL-8 only approximately doubled during the imaging period (1.7+/-0.3 at 1 h vs 3.7+/-1.0 at 24 h post-injection), L/C for 125I-NAP-2 more than tripled, rising from 1.5+/-0.4 at 1 h to 5.3+/-0.7 by 72 h post-injection. It is concluded that while both radiolabelled IL-8 and NAP-2 may prove useful for clinical imaging, radiolabelled NAP-2 may provide better discrimination of inflammatory lesions from normal tissue at later times post-injection.
Animals↗
Recent advances in preoperative and intraoperative nuclear medicine procedures in patients with primary hyperparathyroidism.
Although bilateral neck exploration is traditionally considered as the treatment of choice in patients with primary hyperparathyroidism (HPT), several surgical techniques of limited neck exploration have been proposed over the last 10 years in primary HPT patients with a high probability to be affected by a solitary parathyroid adenoma. The availability in recent years of highly sensitive and accurate preoperative imaging modalities, particularly the parathyroid scintigraphy with 99mTc-MIBI and high resolution neck ultrasonography, allowed to increase the rate of primary HPT patients as candidates to a selective parathyroidectomy. One of the most innovative techniques for limited surgery is the minimally invasive radio-guided parathyroidectomy that is based on the intraoperative detection of the parathyroid adenoma under the guidance of a gamma probe allowing the removal of the parathyroid adenoma through a small 2-cm skin incision. However, if a minimally invasive parathyroidectomy is taken into consideration, accurate preoperative imaging is mandatory not only to distinguish patients with a solitary parathyroid adenoma from those with multi-glandular disease but also to diagnose patients with concomitant thyroid nodule(s) that can cause false-positive results at radio-guided surgery. In the present study the most recent advances reached with preoperative localizing imaging of parathyroid adenomas are reviewed and the techniques proposed to perform a minimally invasive radio-guided surgery are discussed with particular regard to the therapeutic efficacy and cost-effectiveness analysis.
Humans↗
Clinical role of positron emission tomography (PET) in endocrine tumours.
Positron emission tomography (PET) is considered one of the most effective nuclear medicine imaging modality in oncology. In many types of malignant tumours PET has proven to be high sensitive in detecting both primary neoplasm and metastatic disease both before therapy for staging purposes and after surgery, radiotherapy and chemotherapy during follow-up. In particular, PET showed high accuracy in differentiating post-treatment scar from viable tumoural tissue and high sensitivity in visualising very small metastatic foci as those in normal-sized (less than 1 cm in diameter) lymph nodes. A large variety of positron emitter tracers have been produced for PET imaging: the most widely used tracer in clinical oncology is 18F-fluoro-2-deoxy-D-glucose (18F-FDG). Deoxy-glucose (DG) is a glucose analog that enters the cell using specific transmenbrane carrier proteins (especially GLUT-1). Once within the cytoplasm, DG is phosphorylated to FG-6-phosphate but does not appear to be further metabolised. In most malignant tumours there is an increase of the glycolityc metabolism which accounts for an increase of the FDG uptake. However, the metabolic cellular activity can be only slightly increased or even normal in well differentiated and slow growing tumours as some endocrine neoplasms. In the present review, the clinical usefulness and limits of PET imaging are discussed in the management of patients with endocrine tumors.
Adrenal Gland Neoplasms↗
Radioisotope diagnosis and therapy of malignant pheochromocytoma.
The availability of radiopharmaceuticals to depict primary malignant pheochromocytoma and its metastases has markedly changed the approach to these unusual cancers. Whole body screening afforded by scintigraphy allows remote tumor involvement to be identified and provides staging information necessary to guide subsequent therapy. The avid accumulation by malignant pheochromocytoma of some radiopharmaceuticals used for scanning has shown promise in therapeutic trials. In this paper, we discuss radiopharmaceuticals presently employed in malignant pheochromocytoma for both diagnostic and therapeutic uses and potential future compounds that may find their way into clinical practice in the approach to these and other related neoplasms.
Adrenal Medulla↗