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Objective: This study compared our program's ("InsKid") capability for measuring the infundibulopelvic angle (IPA) with existing ones. Methods: Prospectively, data from 50 patients with lower pole kidney stones with indications for retrograde intrarenal surgery (RIRS) were collected. All patients underwent computed tomography (CT)-urography. The IPA of each pelvicalyceal (PCS) unit was measured with the Elbahnasy's, Sampaio's, and "InsKid" methods. Results were compared. Finally, we compared the area under the receiver operating characteristic (ROC) curve (AUC) for predicting stone-free status after RIRS. We defined success as stone fragments ≤ 2 mm on the CT scan on the first postoperative day (POD1). The stone-free rate refers to no identifiable stone fragments on the POD1 CT. Test–retest reliability and face validity were defined to estimate psychometric properties of InsKid. Results: The success rate after first procedure was 87.5%. The average value of IPA using the Elbahnasy and Sampaio methods and our program were 85.2° ± 11.9°, 95.1° ± 10.1°, and 79.9° ± 13.0, respectively. There was a significant difference among the InsKid, Elbahnasy, and Sampaio (AUC = 0.762, 0.601, and 0.629, respectively) approaches with respect to the capability of predicting the immediate success of RIRS. Repeated measurement did not affect values of IPA (1.3° ± 0.7, p = 0.67). All specialist appreciated proposed software as highly useful (5/5). Conclusion: This new application reproduces the intraoperative aspects of the PCS more clearly than the other methods and also provides an easy solution for clearly defining the IPA without relying on the central axes. [ABSTRACT FROM AUTHOR]

We propose a camera model for cameras with hypercentric lenses. Because of their geometry, hypercentric lenses allow to image the top and the sides of an object simultaneously. This makes them useful for certain inspections tasks, for which otherwise multiple images would have to be acquired and stitched together. After describing the projection geometry of hypercentric lenses, we derive a camera model for hypercentric lenses that is intuitive for the user. Furthermore, we describe how to determine the parameter values of the model by calibrating the camera with a planar calibration object. We also apply our camera model to two example applications: in the first application, we show how two cameras with hypercentric lenses can be used for dense 3D reconstruction. For an efficient reconstruction, the images are rectified such that corresponding points occur in the same image row. Standard rectification methods would result in perspective distortions in the images that would prevent stereo matching algorithms from robustly establishing correspondences. Therefore, we propose a new rectification method for objects that are approximately cylindrical in shape, which enables a robust and efficient reconstruction. In the second application, we show how to unwrap cylindrical objects to simplify further inspection tasks. For the unwrapping, the pose of the cylinder must be known. We show how to determine the pose of the cylinder based on a single camera image and based on two images of a stereo camera setup. [ABSTRACT FROM AUTHOR]

Abstract—The effects of sensory stimulation on the model of paired Mauthner neurons of monocularly deprived goldfish have been studied by light- and electron microscopy. Three-dimensional reconstruction was performed using serial semi-thin sections in order to determine the volumes of soma and dendrites for the right and left Mauthner neurons. These data suggested that long-term stimulation of some fish caused a decrease in the volume of the lateral dendrites of neurons contralateral with respect to the side of the enucleated eye. As a result, the morphological homeostasis in the dendrites of Mauthner neurons, which was observed in the control fish, was disturbed after the effect of stimulation upon this group of fish. The main mechanism of this effect of stimulation, according to ultrastructural analysis, is the compaction of the cytoskeleton in the lateral dendrite of a neuron and a reduction in the number of synaptic vesicles in the region of afferent synapses. In contrast, stimulation of the remaining fish induced the resistance of the contralateral Mauthner neuron to prolonged stimulation, as well as the hypertrophy of its lateral and shortening of the ventral dendrites. These results suggest that the homeostasis of the dendrites of Mauthner neurons essentially depends on the state of the visual inputs, the load on which increased as a result of the doubled impact. [ABSTRACT FROM AUTHOR]

The need for an efficient method of integration of a dense normal field is inspired by several computer vision tasks, such as shape-from-shading, photometric stereo, deflectometry. Inspired by edge-preserving methods from image processing, we study in this paper several variational approaches for normal integration, with a focus on non-rectangular domains, free boundary and depth discontinuities. We first introduce a new discretization for quadratic integration, which is designed to ensure both fast recovery and the ability to handle non-rectangular domains with a free boundary. Yet, with this solver, discontinuous surfaces can be handled only if the scene is first segmented into pieces without discontinuity. Hence, we then discuss several discontinuity-preserving strategies. Those inspired, respectively, by the Mumford-Shah segmentation method and by anisotropic diffusion, are shown to be the most effective for recovering discontinuities. [ABSTRACT FROM AUTHOR]

The need for efficient normal integration methods is driven by several computer vision tasks such as shape-from-shading, photometric stereo, deflectometry. In the first part of this survey, we select the most important properties that one may expect from a normal integration method, based on a thorough study of two pioneering works by Horn and rooks (Comput Vis Graph Image Process 33(2): 174-208, 1986) and Frankot and Chellappa (IEEE Trans Pattern Anal Mach Intell 10(4): 439-451, 1988). Apart from accuracy, an integration method should at least be fast and robust to a noisy normal field. In addition, it should be able to handle several types of boundary condition, including the case of a free boundary and a reconstruction domain of any shape, i.e., which is not necessarily rectangular. It is also much appreciated that a minimum number of parameters have to be tuned, or even no parameter at all. Finally, it should preserve the depth discontinuities. In the second part of this survey, we review most of the existing methods in view of this analysis and conclude that none of them satisfies all of the required properties. This work is complemented by a companion paper entitled Variational Methods for Normal Integration, in which we focus on the problem of normal integration in the presence of depth discontinuities, a problem which occurs as soon as there are occlusions. [ABSTRACT FROM AUTHOR]

Virtually no information on the chronology of prenatal development of the human urinary tract and the sex-related differences in the emergence of urinary tract topography during embryonic development is presently available. The aim of our work was to study sex-related differences in urethra development in human embryos and early fetuses. Forty-nine preparations of human embryos and early fetuses without external signs of anatomical abnormalities were studied in order to achieve the aim and fulfill the objectives of the study. Embryos and early fetuses were divided into six groups according to gestational age and parietococcygeal length. The complex of adequate methods of morphological research used in the study included preparation and microscopy of serial histological and anatomical sections of human embryos, including female and male urinary tracts, preparation of 3D-reconstruction models, and morphometry. The formation of prostatic urethra, a derivative of the urogenital sinus, was shown to occur at the beginning of the ninth week of embryogenesis, and the primordium of the internal sphincter of the urinary tract was formed at the end of the tenth week. Formation of the terminal part of spongy urethra took place during weeks 10-11 and involved funnel-like protrusion of the ectoderm from the top of the balanus towards the urethra lumen. The secondary ventral displacement of the urethral opening does not occur in female fetuses, and, therefore, only the prostatic urethra is a homolog of the female urinary tract. The pelvic part of the urogenital sinus was transformed into the prostatic urethra and the membranous urethra of the male at the end of the first stage of fetal development. Elongation of the genital tubercle (a penis primordium) and formation of the urethral ridge walls that involved the urogenital folds occurred at the same time. [ABSTRACT FROM AUTHOR]

Isopoda (Crustacea, Peracarida) from the deep sea are relatively well studied but little is known about their lifestyles or the functional morphology and anatomy. The isopod family Macrostylidae, for example, is rather small in size, usually less than 1 cm in body length, and occurs mainly in the deep sea between 3000–6000 m. This family features a paired subepidermal structure on the posterior end of the pleotelson. It has been reported only in this family and was first mentioned by Hansen in 1916, who hypothesised that it represents a pair of statocysts. Nevertheless, neither the structure nor the function has been investigated until now. The shape of some related features, however, has already been used for species differentiation thus indicating that phylogenetically as well as systematically valuable information may be inherent in this feature. Here, the anatomy of this structure was studied based on four species of Macrostylidae from the North Pacific and Atlantic Oceans. It was digitally reconstructed from histological sections. The paired structure comprised two tergal invaginations, each with distinct muscular attachments and a modified seta that distally held a statocyst on the shaft. This resembles equilibrium organs reported from other organisms and thus the statocysts hypothesis seems reliable. Using energy-dispersive X-ray spectroscopy, the substance of the statolith could be determined as silicon dioxide. Based on these findings, the function of this organ and its potential phylogenetic and ecological implications are discussed. [ABSTRACT FROM AUTHOR]

Purpose: Currently, intraoperative ultrasound in brain tumor surgery is a rapidly propagating option in imaging technology. We examined the accuracy and resolution limits of different ultrasound probes and the influence of 3D-reconstruction in a phantom and compared these results to MRI in an intraoperative setting (iMRI).Methods: An agarose gel phantom with predefined gel targets was examined with iMRI, a sector (SUS) and a linear (LUS) array probe with two-dimensional images. Additionally, 3D-reconstructed sweeps in perpendicular directions were made of every target with both probes, resulting in 392 measurements. Statistical calculations were performed, and comparative boxplots were generated.Results: Every measurement of iMRI and LUS was more precise than SUS, while there was no apparent difference in height of iMRI and 3D-reconstructed LUS. Measurements with 3D-reconstructed LUS were always more accurate than in 2D-LUS, while 3D-reconstruction of SUS showed nearly no differences to 2D-SUS in some measurements. We found correlations of 3D-reconstructed SUS and LUS length and width measurements with 2D results in the same image orientation.Conclusions: LUS provides an accuracy and resolution comparable to iMRI, while SUS is less exact than LUS and iMRI. 3D-reconstruction showed the potential to distinctly improve accuracy and resolution of ultrasound images, although there is a strong correlation with the sweep direction during data acquisition. [ABSTRACT FROM AUTHOR]

We conduct a thorough study of photometric stereo under nearby point light source illumination, from modeling to numerical solution, through calibration. In the classical formulation of photometric stereo, the luminous fluxes are assumed to be directional, which is very difficult to achieve in practice. Rather, we use light-emitting diodes to illuminate the scene to be reconstructed. Such point light sources are very convenient to use, yet they yield a more complex photometric stereo model which is arduous to solve. We first derive in a physically sound manner this model, and show how to calibrate its parameters. Then, we discuss two state-of-the-art numerical solutions. The first one alternatingly estimates the albedo and the normals, and then integrates the normals into a depth map. It is shown empirically to be independent from the initialization, but convergence of this sequential approach is not established. The second one directly recovers the depth, by formulating photometric stereo as a system of nonlinear partial differential equations (PDEs), which are linearized using image ratios. Although the sequential approach is avoided, initialization matters a lot and convergence is not established either. Therefore, we introduce a provably convergent alternating reweighted least-squares scheme for solving the original system of nonlinear PDEs. Finally, we extend this study to the case of RGB images. [ABSTRACT FROM AUTHOR]

Computed tomography (CT)-angiography is routinely performed prior to catheter-based and surgical treatment in congenital heart disease. To date, little is known about the accuracy and advantage of different 3D-reconstructions in CT-data. Exact anatomical information is crucial. We analyzed 35 consecutive CT-angiographies of infants with congenital heart disease. All datasets are reconstructed three-dimensionally using volume rendering technique (VRT) and threshold-based segmentation (stereolithographic model, STL). Additionally, the two-dimensional maximum intensity projection (MIP) reconstructs two-dimensional data. In each dataset and resulting image, measurements of vascular diameters for four different vessels were estimated and compared to the reference standard, measured via multiplanar reformation (MPR). The resulting measurements obtained via the STL-images, MIP-images, and the VRT-images were compared with the reference standard. There was a significant difference ( p < 0.05) between measurements. The mean difference was 0.0 for STL-images, −0.1 for MIP-images, and −0.3 for VRT-images. The range of the differences was −0.7 to 1.0 mm for STL-images, −0.6 to 0.5 mm for MIP-images and −1.1 to 0.7 mm for VRT-images. There was an excellent correlation between the STL-, MIP-, VRT-measurements, and the reference standard. Inter-reader reliability was excellent ( p < 0.01). STL-models of cardiovascular structures are more accurate than the traditional VRT-models. Additionally, they can be standardized and are reproducible. [ABSTRACT FROM AUTHOR]

Bundle adjustment (BA) is the problem of refining a visual reconstruction to produce jointly optimal 3D structure and viewing parameter (camera pose and or calibration) estimates, and it is almost always used as the last step of feature-based 3D reconstruction algorithm. Generally, the result of Structure from Motion (SFM) mainly relies on the quality of BA. The problem of BA is often formulated as a nonlinear least squares problem, where the data arises from keypoints matching. For 3D reconstruction, mismatched keypoints may cause serious problems, even a single mismatch will affect the entire reconstruction. Therefore, to further impove the robustness of BA algorithm is very necessary. In this paper, we propose a robust Bundle Adjustment (RBA) algorithm to optimize the initial 3D point-clouds and camera parameters which are produced by the SFM system. In the proposed RBA algorithm, we firstly use the Huber loss function to potentially down-weight outliers. Secondly, we split a large-scale bundle adjustment problem into some small ones by making use of the sparsity between 3D points and the cameras for reducing the requirements of memory. Thirdly, according to the inherent property of the matrix after it spare decompose, we use a fast matrix factorization algorithm to solve the normal equation to avoid calculating the inverse of large-scale matrix. Finally, we evaluate the proposed RBA method and compare it with the state-of-the-art methods on the synthetic dataset, BAL benchmark and real image datasets, respectively. Experimental results show that the proposed RBA method clearly outperforms the state-of-the-art methods on both computational cost and precision. [ABSTRACT FROM AUTHOR]

Repetitive transcranial magnetic stimulation (rTMS) of the human brain can lead to long-lasting changes in cortical excitability. However, the cellular and molecular mechanisms which underlie rTMS-induced plasticity remain incompletely understood. Here, we used repetitive magnetic stimulation (rMS) of mouse entorhino-hippocampal slice cultures to study rMS-induced plasticity of excitatory postsynapses. By employing whole-cell patch-clamp recordings of CA1 pyramidal neurons, local electrical stimulations, immunostainings for the glutamate receptor subunit GluA1 and compartmental modeling, we found evidence for a preferential potentiation of excitatory synapses on proximal dendrites of CA1 neurons (2-4 h after stimulation). This rMS-induced synaptic potentiation required the activation of voltage-gated sodium channels, L-type voltage-gated calcium channels and N-methyl- d-aspartate-receptors. In view of these findings we propose a cellular model for the preferential strengthening of excitatory synapses on proximal dendrites following rMS in vitro, which is based on a cooperative effect of synaptic glutamatergic transmission and postsynaptic depolarization. [ABSTRACT FROM AUTHOR]

Estimating the shape and appearance of an object, given one or several images, is still an open and challenging research problem called 3D-reconstruction. Among the different techniques available, photometric stereo (PS) produces highly accurate results when the lighting conditions have been identified. When these conditions are unknown, the problem becomes the so-called uncalibrated PS problem, which is ill-posed. In this paper, we will show how total variation can be used to reduce the ambiguities of uncalibrated PS, and we will study two methods for estimating the parameters of the generalized bas-relief ambiguity. These methods will be evaluated through the 3D-reconstruction of real-world objects. [ABSTRACT FROM AUTHOR]

Up to now, the internal anatomy of representatives of only two of three recent genera of the Orbitestellidae have been described. Herein, a species of the third genus, Lurifax vitreus from hydrothermal vent sites of the North Atlantic, is examined on the basis of semi-thin sections. Data on three-dimensional (3D)-anatomy and histology are provided in order to increase knowledge of the family. In addition, the original serial sections of Orbitestella wareni and Microdiscula cf. subcanaliculata of the original paper by Ponder (Journal of Molluscan Studies 56:515-532, ) were reinvestigated and compared with Lurifax vitreus. Although Lurifax vitreus is significantly larger than the two former genera, it is again devoid of a gill but shows opponent ciliary stripes and a pallial tentacle. Most orbitestellid characters reflect plesiomorphic conditions among the Heterobranchia; autapomorphies of the family include an orthostrophic protoconch, massive jaws, a diagnostic radula type, paired posterior pedal glands with a common opening, and a pedally innervated copulatory organ. In agreement with actual molecular trees, our data suggest a placement of Orbitestellidae as basic Heterobranchia outside of Ectobranchia (Valvatoidea). [ABSTRACT FROM AUTHOR]

The relic dragonfly family Epiophlebiidae is recovered as sistergroup of Anisoptera (= Epiprocta) by most molecular and morphological analyses. However, in a recent study it was placed within Anisoptera as sister group of Cordulegastridae. In another study, several affinities to Zygoptera in the morphology of the ovipositor and the egg-laying behaviour were pointed out. Here, we present a detailed study of the outer, as well as the inner, head morphology of Epiophlebia superstes. Compared with the last detailed literature account, three additional mandibular muscles were discovered, as well as additional buccal and pharyngeal muscles. The results are compared with the anatomic features of Zygoptera and Anisoptera. A formal character evaluation focused on head characters confirms the sistergroup relationship of Epiophlebiidae and Anisoptera. [ABSTRACT FROM AUTHOR]

Research performed using animal models has assisted in the understanding of flap anatomy and physiology. Pigs’ vasculature in the skin is anatomically and physiologically similar to human, making it an ideal model for research. Until now, most vascular imaging studies are of two-dimensions. The aim of this study is to provide a three-dimensional (3D) model that reveals detailed architecture of the vascular network of the porcine, for accurate quantitative assessment. Five Guangxi Bama minipigs were anaesthetized intramuscularly and underwent whole body lead oxide–gelatin injection. Spiral computed tomography scanning was performed on the subjects and three-dimensional reconstructions were made. Another minipig was used, and underwent Cardiografin injection. 3D-reconstruction was executed in vivo. All subjects were then dissected by layers to document the individual perforators. Angiography using perfusion with lead oxide–gelatine mixture has the advantage of illustrating distinctively the vessels and their perforating branches. However, it is incapable of displaying other tissues structures. Angiography through perfusion with Cardiografin in vivo has the advantage of demonstrating the relationship between arteries and bones. Yet it could only display coarsely the vascular trunk, and is incapable of displaying the vascular network. By combining these two methods, the 3D structure, source, course, and territories of the arteries were presented distinctively. 3D modeling in combination with traditional sectional imaging of the pig model enables blood vessels to be displayed more dynamically with greater realism. The procedure described could be useful for future flap research, by offering a better visualization of the vascular structure of the skin flap, allowing for better anatomical understanding. [ABSTRACT FROM AUTHOR]

The structure and functional capabilities of a digital optical microscope-profilometer capable of operating in two modes, those of micro- and nanomeasurements, are presented. The instrument operation principle is based on measuring the phase function of the wave front of light scattered by the measured surface. Software for the microscope-profilometer and its performance characteristics are considered. [ABSTRACT FROM AUTHOR]

The first description of the presence of a utriculo-endolymphatic valve in human fetuses was given by Bast in 1928. Since then this valve-like structure is called Bast’s valve. Its exact function has not yet been established. The general opinion is that it has a protective function by having the possibility to separate the superior endolymphatic compartments of the labyrinth from the inferior compartment. Phylogenetically seen birds are the first vertebrates with a cochlear duct and a distinct inferior and superior part of the labyrinth. A structure in the pigeon inner ear, resembling Bast’s valve in mammals, is described. [ABSTRACT FROM AUTHOR]

This article presents a system for the automatic measurement and modelling of sewer pipes. The system recovers the interior shape of a sewer pipe from a video sequence which is acquired by a fish-eye lens camera moving inside the pipe. The approach is based on tracking interest points across successive video frames and posing the general structure-from-motion problem. It is shown that the tracked points can be reliably reconstructed despite the forward motion of the camera. This is achieved by utilizing a fish-eye lens with a wide field of view. The standard techniques for robust estimation of the two- and three-view geometry are modified so that they can be used for calibrated fish-eye lens cameras with a field of view less than 180°. The tubular arrangement of the reconstructed points allows pipe shape estimation by surface fitting. Hence, a method for modelling such surfaces with a locally cylindrical model is proposed. The system is demonstrated with a real sewer video and an error analysis for the recovered structure is presented. [ABSTRACT FROM AUTHOR]

The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast’s valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricular side is that of a flattened funnel. In the direction of the endolymphatic duct and sac this funnel runs into a very narrow duct. The valve itself has a rigid ‘arch-like’ configuration. The opposing thin, one cell-layer thick, utricular membrane is highly compliant. We propose that opening and closure of the valve occurs through movement of the flexible base/utricular membrane away from and toward the relatively rigid valve lip. [ABSTRACT FROM AUTHOR]

An approach of 3D-visualization of the temporomandibular joint (TMJ) with special focus on the articular disc based on magnetic resonance imaging (MRI) was developed for the purpose of diagnosis support. Mandibular condyle and fossa were reconstructed as 3D-surfaces. Articular disc, retrocondylar tissue, and the lateral pterygoid muscle were visualized by means of direct volume rendering. By simultaneous visualization of both, the bony surfaces and the soft tissue, anterior disc displacement could be recognized in 3D-context. Additional superposition of the 3D-visualization with the original 2D-MRI slices allowed for a combination with conventional diagnostics. The method was tested for clinical T1-, T2-, and proton density weighted MRI data from four independent medical institutions. For all cases, the skeletal anatomy could be reproduced. Applied validation approaches showed good results. Anterior disc displacement could be clearly depicted as well as the incidence of reduction of the disc. By several experienced observers, the approach was rated as significant. Although partially non-standard in the clinical routine the new method provided promising results for efficient diagnosis support. Its validity in the medical practice, namely, its impact for dislocation/deformity of the mandibular disc will be further analyzed. [ABSTRACT FROM AUTHOR]

The physical (microtomy), optical (microscopy), and radiologic (tomography) sectioning of biological objects and their digitization lead to stacks of images. Due to the sectioning process and disturbances, movement of objects during imaging for example, adjacent images of the image stack are not optimally aligned to each other. Such mismatches have to be corrected automatically by suitable registration methods. Here, a whole brain of a Sprague Dawley rat was serially sectioned and stained followed by digitizing the 20 μm thin histologic sections. We describe how to prepare the images for subsequent automatic intensity based registration. Different registration schemes are presented and their results compared to each other from an anatomical and mathematical perspective. In the first part we concentrate on rigid and affine linear methods and deal only with linear mismatches of the images. Digitized images of stained histologic sections often exhibit inhomogenities of the gray level distribution coming from staining and/or sectioning variations. Therefore, a method is developed that is robust with respect to inhomogenities and artifacts. Furthermore we combined this approach by minimizing a suitable distance measure for shear and rotation mismatches of foreground objects after applying the principal axes transform. As a consequence of our investigations, we must emphasize that the combination of a robust principal axes based registration in combination with optimizing translation, rotation and shearing errors gives rise to the best reconstruction results from the mathematical and anatomical view point. Because the sectioning process introduces nonlinear deformations to the relative thin histologic sections as well, an elastic registration has to be applied to correct these deformations. In the second part of the study a detailed description of the advances of an elastic registration after affine linear registration of the rat brain is given. We found quantitative evidence that affine linear registration is a suitable starting point for the alignment of histologic sections but elastic registration must be performed to improve significantly the registration result. A strategy is presented that enables to register elastically the affine linear preregistered~ rat brain sections and the first one hundred images of serial histologic sections through both occipital lobes of a human brain (6112 images). Additionally, we will describe how a parallel implementation of the elastic registration was realized. Finally, the computed force fields have been applied here for the first time to the morphometrized data of cells determined automatically by an image analytic framework. [ABSTRACT FROM AUTHOR]

A system capable of performing robust live ego-motion estimation for perspective cameras is presented. The system is powered by random sample consensus with preemptive scoring of the motion hypotheses. A general statement of the problem of efficient preemptive scoring is given. Then a theoretical investigation of preemptive scoring under a simple inlier–outlier model is performed. A practical preemption scheme is proposed and it is shown that the preemption is powerful enough to enable robust live structure and motion estimation. [ABSTRACT FROM AUTHOR]

Electron tomography allows computing three-dimensional (3D) reconstructions of objects from their projections recorded at several angles. Combined with transmission electron microscopy, electron tomography has contributed greatly to the understanding of subcellular structures and organelles. Performed on frozen-hydrated samples, electron tomography has yielded useful information about complex biological structures. Combined with energy filtered transmission electron microscopy (EFTEM) it can be used to analyze the spatial distribution of chemical elements in biological or material sciences samples. In the present review, we present an overview of the requirements, applications, and perspectives of electron tomography in structural biology. [ABSTRACT FROM AUTHOR]

Intravascular brachytherapy (IVB) can significantly reduce the risk of restenosis after interventional treatment of stenotic arteries, if planned and applied correctly. In order to facilitate computer-based IVB planning, a three-dimensional reconstruction of the stenotic artery based on intravascular ultrasound (IVUS) sequences is desirable. For this purpose, the frames of the IVUS sequence are properly aligned in space, possible gaps inbetween the IVUS frames are filled by interpolation with radial basis functions known from scattered data interpolation. The alignment procedure uses additional information which is obtained from biplane X-ray angiography performed simultaneously during the capturing of the IVUS sequence. After IVUS images and biplane angiography data are acquired from the patient, the vessel-wall borders and the IVUS catheter are detected by an active contour algorithm. Next, the twist (relative orientation) between adjacent IVUS frames is determined by a sequential triangulation method. The absolute orientation of each frame is established by a stochastic analysis based on anatomical landmarks. Finally, the reconstructed 3D vessel model is visualized by methods of combined volume and polygon rendering. The reconstruction is then used for the computation of the radiation-distribution within the tissue, emitted from a β-radiation source. All these steps are performed during the percutaneous intervention. [ABSTRACT FROM AUTHOR]

The morphology of viable taste disks of the frog was explored with multi-photon microscopy. In order to identify single sensory or supporting cells within the tissue, we searched for fluorescent dyes that stained subsets of the cell population or possibly cell types. Some cell types indeed stained preferentially with certain fluorescent dyes. A subset of glia-like cells (type Ic) stained with BCECF, a H+-sensitive dye, and indo-1, a Ca2+-sensitive dye, both presented in the membrane-permeant ester form. BCECF-ester also stained the dendrites of type III receptor cells, but indo-1 ester did not. Receptor cells of type II stained with MQAE, a positively charged Cl--sensitive dye. A subset of type II cells accumulated amiloride, a positively charged fluorescent diuretic. Certain supporting cells, i.e., wing cells (type Ib) and glia-like cells (type Ic), were labeled by negatively charged dyes, e.g., calcium green-1 dextran. Mucus cells (type Ia) were stained with only two of the 19 dyes examined, and Merkel-like basal cells (type IV) were stained only with a membrane-labeling voltage-sensitive dye, presumably by endocytosis. No dye was found which would stain all types of cells or all receptor cells. This finding reveals a potential problem for future functional imaging aiming at population responses, as the responses of unstained cells then would remain unobserved. Specificity of dyes with respect to cell types was sufficient to identify supporting cells and receptor cells. Cell shape could then be reconstructed, using optical slicing and rendering techniques. Thus populations of dye-loaded elongated cells, especially types Ic, II and III, could for the first time be visualized in three dimensions. [ABSTRACT FROM AUTHOR]

Our previous study has shown that ddY mice have special patches of nasal epithelium in the posterior roof of the nasal cavity that exclusively consists of olfactory supporting cells and horizontal basal cells. Here, we extend this finding to Balb/c and DBA/2 mice, Wistar and Sprague-Dawley rats, hamsters, and guinea pigs. In the mice, rats, and hamsters studied, the patches lacked olfactory cells and their precursor, globose basal cells. In rats and hamsters, the supporting cells were arranged in a single layer, in mice as three or four layers. Horizontal basal cells were located in a single layer in these species. In the guinea pigs, the specialized roof structure was less clear and could be seen at the level of ultrastructure as an olfactory neuron-lacking area. Distinct populations of transforming growth factor (TGF)-α-like immunoreactive olfactory cells occupied an area close to the epithelial patches. In this region, the TGF-α-like immunoreactive neurons were negative for the usual olfactory markers, either OMP or protein gene product (PGP) 9.5 or β-tubulin. These cells are suggested to project to the so-called ’necklace glomeruli’ and use a different cGMP-driven, transduction pathway. Three-dimensional analysis of double- labeled (TGF-α, PGP9.5) serial sections revealed a unique relation among the epithelial patches, TGF-α-like immunoreactive neurons and olfactory epithelium. [ABSTRACT FROM AUTHOR]

Using sequential double-immunostaining and a newly-developed three-dimensional (3D-) reconstruction technique on serially cut sections from bone marrow trephines, we studied the transmural passage of megakaryocytes through the sinus wall. Biopsies derived from patients with primary (idiopathic) osteomyelofibrosis were exposed to monoclonal antibody against type IV collagen to delineate the sinus walls and also the frequently thickened basement membrane. Staining with the primary antibody was followed by Y2/51 (CD61) to identify all elements of megakaryopoiesis. In most instances serial sectioning and 3D-reconstruction revealed an amoeboid shape of megakaryocytes and a tandem-like arrangement in close spatial contact with the abluminal surface of the sinus wall. Preceded by formation of cytoplasmic processes, straight penetration of entire megakaryocytes through gaps in the sinus walls into the lumen was seen. Where collagen deposits apparently presented a barrier, a mole-like tunnelling through the basement membrane material (type IV collagen) was recognizable. Our findings are in keeping with the assumption that megakaryocyte locomotion is an essential requirement for normal thrombocytogenesis. [ABSTRACT FROM AUTHOR]

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A Drosophila visual mutant rdgA has photoreceptive cells which degenerate gradually after eclosion. Fine structure of the retinular cells of rdgAand rdgA was studied during early stages of degeneration to determine the initial morphological defects. The retinular cells of these two alleles showed the following structural abnormality within 1 day after eclosion: (1) rhabdomeres were small and irregular in shape; (2) cisternae of the rough endoplasmic reticulum were more numerous than those in normal retinular cells; (3) submicrovillar cisternae were absent; and (4) lysosomes were fewer than normal. Three-dimensional reconstruction of serial sections of the ommatidia showed that the degeneration of mutant rhabdomeres proceeds more rapidly in regions remote from the nuclei. These results suggest that the process of turnover of rhabdomeric microvilli is abnormal in rdgA. We also confirmed an increase of lysosomes and destruction of cellular organelles, as reported by previous investigators at more advanced stages of degeneration. [ABSTRACT FROM AUTHOR]

Three-dimensional MR imaging technique is not a new concept, however, there is very little experience concerning clinical trials. Especially in head and neck lesions, the accuracu of this new imaging method has not yet been tested. A pilot study was performed to evaluate the diagnostic value of demonstrating the head and neck lesions and topographical structures implemented in a three-dimensional reconstruction of the entire head. The 3D reconstruction mode is based on the ray-tracting model. The application of the contrast medium Gd-DTPA proved to be helpful. Three-dimensional reconstruction revealed clear topographic details of the lesions, including the spread of infiltration and destruction of soft tissue. Additionally, the simultaneous view of multiple slices in different orientations is an ideal method for evalauting the spread of the lesion and to visualize the relation between lesion and surrounding tissue. [ABSTRACT FROM AUTHOR]