Human Subjects Review boards: A modest proposal.

Proposes a solution to problems related to the human Ss review boards as discussed by S. J. Ceci et al (see record 1986-12806-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Easy graphical display of beam directions in three-dimensional converging radiation therapy: proposal for a radiation map

In stereotactic radiosurgery, non-coplanar isocentric beams are employed to concentrate the dose distribution on the planning target volume (PTV). However, the directions of incident beams must be determined with great care by using a digitally reconstructed beam's eye view (BEV) to prevent the irradiation of organs at risk. We present a new method of 2-dimensional graphical representation (radiation map) to facilitate the understanding of 3-dimensional relationships between incident beams and critical organs. After determining the isocenter and beam diameter, beam directions and critical organs are projected onto the imaginary sphere centered on the isocenter. The coordinate of the beam directions and the organs at risk can be expressed by latitude and longitude on the sphere. The contours of the organs at risk are displayed with a margin of the the radius of the radiation beam. Mirror images of the critical organs are also displayed to prevent irradiation by the opposing beams. The radiation map could be produced within 5 minutes using a workstation. Radiation maps, like DVH, will be very useful in the evaluation of radiation treatment planning.     

Interstate forensic psychology consultations: A call for reform and proposal of a model rule.

Forensic psychology has made important gains in professional recognition and stature in the courts, resulting in increasing demands for mobility of expertise. Current regulations regarding the interjurisdictional temporary forensic practice of psychology, however, are characterized by variability of regulations, ambiguity and inaccessibility, and continuing total barriers. A uniform, well-reasoned policy is needed. A conceptual basis for such a policy is provided by a discussion of licensing rationales and the application of these to forensic practice. Uniformity, public and professional protection, and practicability are identified as fundamental regulatory criteria. A Model Rule Regarding the Temporary Forensic Practice of Psychology is proposed for adoption by state licensing boards on a nationwide basis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apoptosis in a neonatal rat model of cerebral hypoxia-ischemia

BACKGROUND and PURPOSE: The mechanisms of excitotoxic cell death in cerebral ischemia are poorly understood. In addition to necrosis, apoptotic cell death may occur. The purpose of this study was to determine whether an established model of cerebral hypoxia-ischemia in the neonatal rat demonstrates any features of apoptosis. METHODS: Seven-day-old neonatal rats underwent bilateral, permanent carotid ligation followed by 1 hour of hypoxia, and their brains were examined 1, 3, and 4 days after hypoxia-ischemia. The severity of ischemic damage was assessed in the dentate gyrus and frontotemporal cortex by light microscopy. Immunocytochemistry was performed to detect the cleavage of actin by caspases, a family of enzymes activated in apoptosis. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) reactivity was examined in the cortical infarction bed and dentate gyrus. Neonatal rat brain DNA was run on agarose gel electrophoresis to detect DNA fragmentation. Ethidium bromide-staining and electron microscopy were used to determine whether apoptotic bodies, 1 of the hallmarks of apoptosis, were present. RESULTS: The frontotemporal cortex displayed evidence of infarction, and in most rats the dentate gyrus showed selective, delayed neuronal death. Immunocytochemistry demonstrated caspase-related cleavage of actin. TUNEL and DNA electrophoresis provided evidence of DNA fragmentation. Ethidium bromide-staining and electron microscopy confirmed the presence of chromatin condensation and apoptotic bodies. CONCLUSIONS: Features of apoptosis are present in the described model of cerebral hypoxia-ischemia. Apoptosis may represent a mode of ischemic cell death that could be the target of novel treatments that could potentially expand the therapeutic window for stroke.     

A three-dimensional mathematical model of electromagnetic casting and testing against a physical model: Part I. The mathematical model

This first of two related articles describes a mathematical model for electromagnetic casting in three dimensions,i.e., where the dependent variables are functions of all three spatial coordinates. It is shown how the method of inductances can be extended to three dimensions in order to solve Maxwell's equations for the electromagnetic field in and around the caster. The principal task here is the calculation of the inductances between loops of irregular shape, and the method by which this is done is described. The computations are self-consistent ones in that the free surface of the molten metal is adjusted in response to the supporting electromagnetic forces which are themselves dependent on the shape of that surface. The computed electromagnetic forces are input into a second phase of the calculation where melt flow is computed in three dimensions using the finite element package FIDAP.     

A national trainee advisory network: a proposal

Trainees should have a well-defined and consistent communication conduit to the authorities involved with their training. It is important that trainees are involved in the evolution of structured training programmes and for training authorities to receive feedback from individuals in each specialty. This paper proposes a structure for trainee representation on regional and national training authorities to facilitate an advisory network.     

Experimental aneurysms: proposal for a new technic

The authors present a critical analysis of the various methods of experimental production of aneurysms and report their own method in which saccular aneurysms were produced at the bifurcation of the common carotid artery in dogs with vein patch grafts. The objective point of this study was the creation of an experimental model to evaluate the efficacy of a therapeutic procedure. These aneurysms have a low incidence of thrombosis and a tendency to enlarge and to become spherical. They closely simulate the saccular aneurysms developing spontaneously in the cerebral arteries of man, and as such are useful models for experimental purposes.     

A three-dimensional mathematical model of electromagnetic casting and testing against a physical model: Part II. Results from a physical model and testing of the mathematical model

A physical model of an electromagnetic caster was constructed. The model was intended to provide measured data for comparison with the predictions of the three-dimensional (3-D) mathematical model described in part I. The physical model consisted of a molten Wood's metal pool (176×176 mm seen from above) on the top of an aluminum-bronze block. Probes were used to measure electric and magnetic fields, the deformation of the liquid surface, and the electromagnetically driven flow, at many positions within the melt, as a function of model geometry. Agreement between the measurements and the predictions of the mathematical model was generally good. The melt flow was 3-D and strongly influenced by the position of the electromagnetic screen interposed between the inductor and the metal pool.     

Multiple components in the unipolar electrogram: a simulation study in a three-dimensional model of ventricular myocardium

INTRODUCTION: For many decades, the interpretation of unipolar electrograms (EGs) and ECGs was based on simple models of the heart as a current generator, e.g., the uniform dipole layer, and, more recently, the "oblique dipole layer." However, a number of recent and old experimental data are inconsistent with the predictions of these models. To address this problem, we implemented a numerical model simulating the spread of excitation through a parallelepipedal myocardial slab, with a view to identifying the factors that affect the shape, amplitude, and polarity of unipolar EGs generated by the spreading wavefront. METHODS AND RESULTS: The numerical model represents a portion of the left ventricular wall as a parallelepipedal slab (6.5 x 6.5 x 1 cm); the myocardial tissue is represented as an anisotropic bidomain with epi-endocardial rotation of fiber direction and unequal anisotropy ratio. Following point stimulation, excitation times in the entire volume are computed by using an eikonal formulation. Potential distributions are computed by assigning a fixed shape to the action potential profile. EGs at multiple sites in the volume are computed from the time varying potential distributions. The simulations show that the unipolar QRS waveforms are the sum of a "field" component, representing the effect of an approaching or receding wavefront on the potential recorded by a unipolar electrode, and a previously unrecognized "reference" component, which reflects the drift, during the spread of excitation, of the reference potential, which moves from near the positive to near the negative extreme of the potential distribution during the spread of excitation. CONCLUSION: The drift of the reference potential explains the inconsistencies between the predictions of the models and the actual shapes of the EGs. The drift modifies the slopes of EG waveforms during excitation and recovery and can be expected to affect the assessment of excitation and recovery times and QRS and ST-T areas. Removing the drift reestablishes consistency between potential distributions and electrographic waveforms.     

Adrenal incidentaloma: proposal for a correct treatment

BACKGROUND: The incidence of unsuspected adrenal masses (incidentalomas) based on CT-scan results to be higher than in the past. The aim for our study was to establish some guidelines for an appropriate management. METHODS: From 1986 to 1995, 61 patients with no history or clinical findings suggestive of adrenal mass or adrenal hyperfunction were discovered by radiologic examination to have an incidentaloma larger than 1 cm. In each patient basal biochemical evaluations were obtained to exclude the presence of adrenal cortical or medullary dysfunction. There were 28 men and 33 (54.1%) women, with a mean age of 53 years (range 16-74). 19 patients underwent CT-guided fine-needle biopsy to exclude metastatic tumors. Furthermore in 29 patients 75-Se-selenomethyl-norcholesterol was performed and 17 were studied by MRI. RESULTS: At CT-scan mean lesion diameter was 5.48 +/- 3.76 cm (range 2-23); 32 adrenal masses were right sided and 3 (4.9%) were bilateral. 17 patients had concordant scintigraphic imaging pattern, 6 bilateral uptake and 6 had discordant imaging. CT-guided FNAB showed malignancy in 9. Adrenalectomy was performed in 45 patients according to a score calculated by 4 parameters: age of the patients, size of the mass, scintigraphic pattern, MR imaging. Twenty-four had a score greater than 9 and in the remaining 21 patients in spite of a score lower than 10 adrenalectomy was performed based on: 1) increased size at CT scan follow-up (15 pts); 2) either suspected primitive malignant neoplasm at CT-guided FNAB or history of malignancy (6 pts); 3) elevated 24-hour dopamine (4 pts). In 12 (26.7%) patients a malignant tumor was found. There were not any statistically significant differences (p > 0.05) between the age of the patients with malignant neoplasms and those with benign masses, and between the size of the masses, which were 7.58 +/- 5.93 cm (range 2-23) and 5.03 +/- 2.81 cm (range 3-17) respectively. The difference in scores between the patients with malignant masses (12.17 +/- 2.95) and those with benign ones (9.09 +/- 1.33) was statistically significant (p < 0.01). CONCLUSIONS: Since adrenal incidentaloma have a malignancy rate higher than the other adrenal tumors, it is crucial to outlinesome criteria to sort out the patients at risk for whom adrenalectomy is to be warranted. Based on our results we believe that patients with a score > 9 should undergo adrenalectomy.