Reconstruction Of Histological Sections Research Articles

Virtual autopsy and confirmation of normal fetal heart anatomy in the first trimester using three-dimensional (3D) reconstruction of histological sections.

Objective: In this pilot study, we tested the feasibility of cardiac structures reconstruction from histological sections in 12–13 weeks normal fetuses. Conventional autopsy is hampered at this gestational age because of the small size of the heart anatomical structures, while alternative non-invasive methods for pathology examination of the fetus are expensive, rarely available and lack accuracy data regarding the confirmation of first trimester heart defects suspected by early prenatal ultrasound (US) scans. Materials and Methods: Normal hearts from fetuses aged 12–13 gestational weeks (GW) were harvested for histological preparation, virtual reconstruction, and cardiac structures analysis. The normalcy of heart structures was confirmed before pregnancy termination, using a detailed US scan protocol. The fetal heart was routinely processed for formalin fixation and paraffin embedding (FFPE) and 10 μm seriate sections have been cut until finishing the specimen. All sections have been scanned and a three-dimensional (3D) reconstruction of the whole organ has been rendered, based on computer-aided manual tracing. Using the 3D navigation software, the main cardiac structures were searched for a proper and confident visualization. Results: Five cases were investigated. Visualization of the normal heart cavities, including atrioventricular septum was very good in all fetuses. The entire course of right and left ventricle outflow tracts was confidently confirmed, along the branching pattern of aorta and pulmonary artery trunk. Regarding the veno-atrial connections, it was easy to identify the entrance of the inferior and superior caval veins into the right atrium, but a detailed review of the histological sections was necessary for the visualization of the left atrium venous openings. The inherent morphological deformation following heart block sectioning resulted in a lower resolution or quality of the “reconstructed” planes, but these distortions did not represent a significant impediment in any of the cases. The resources involved ordinary histology and information technology (IT) equipment. To further decrease the time involved by the protocol, many steps may be automated: cutting, coloring, and scanning. Conclusions: The results indicate that this method can be implemented to routine clinical practice. The use of 3D reconstruction of fetal heart histological sections in first trimester may serve as an important audit to confirm the normalcy of heart structures. Also, the histological and postprocessed information is retained, and this volume can be stored, reanalyzed, or sent online for a second opinion. The method involves relatively undemanding resources, i.e., hardware, software, competences, and time. The procedure could also benefit from refinements used in other imaging techniques to limit human–computer interactions, such as sections distortion.

COMPARISON OF HYPOSPADIAC AND NORMAL PREPUTIAL VASCULAR ANATOMY

Data about the differences between the vascularization of normal and hypospadiac prepuce are lacking. We investigated the course of the preputial arterial blood vessels in normal controls and children with hypospadias by using transillumination, arterial methylene blue injection and 3-dimensional (3-D) reconstruction of serial histological sections focusing on arterial vessels. Prepuce of 48 normal controls and 15 children with hypospadias was transilluminated by a front and back lighting technique and then photographed. All of the normal and 12 of hypospadiac prepuces not used for urethroplasty or penile body skin reconstruction were removed. The blood vessels of normal prepuce were also identified after arterial injection of methylene blue. Selected prepuce of normal controls and children with hypospadias was serially sectioned, and arterial and venous vessels were histologically distinguished. A 3-D computer reconstruction of the arterial system of normal and hypospadiac prepuces was performed. We confirmed the reliability of the transillumination technique to describe the arterial vascular anatomy of the prepuce by comparing the transillumination to methylene blue injection and 3-D reconstruction of histological sections. We classified the arterial vascular anatomy of normal prepuce as 1 artery predominant (41.67%), 2 arteries predominant (25%), H-type arching artery (12.5%) and net-like arterial system (20.83%). However, hypospadiac prepuce revealed a net-like arterial system more frequently (50%). We noted that the frequency of net-like arterial system was higher in more severe hypospadiac prepuce. Understanding the differences between normal and hypospadiac prepuce vascular anatomy is germane to hypospadias surgery. The arterial blood supply of the hypospadiac prepuce is different than normal. A better knowledge of the vascular anatomy of the hypospadiac prepuce may improve the surgical results of hypospadias repair.

Ontogenetic Torsion and Protoconch Form in the Archaeogastropod Haliotis kamtschatkana: Evolutionary Implications

AbstractOntogenetic torsion in archaeogastropods has strongly influenced theories about early gastropod evolution, but the seminal studies by Crofts (1937, 1955) remain the major source of information about tissue movements during this developmental process. Computer‐generated reconstructions of histological sections indicate that the cephalopodium of Haliotis kamtschatkanaJonas, 1845 rotates by a full 180° relative to the shell and visceral lobe during the first quarter of pre‐metamorphic development. However, a portion of pallial epithelium, including some of the shell field, accompanies the rotating cephalopodium; a process facilitated by detachment of the pallium from the apertural rim of the protoconch. Transmission electron microscopy indicates that a tract of the larval retractor muscle, which Crofts (1955) implicated in the mechanism of torsion, inserts on both pedal andpallial cells. A deep invagination of shell field epithelium is a major focus of rotational torque. As a result of pallial deformation during cephalopodial rotation, the anus and gill rudiment are restricted to the right half of the larval body for 2 days after cephalopodial rotation by 180° has been completed. Scanning and transmission electron microscopy indicate that grooves in the lateral flanks of the protoconch correspond to the deep invagination of shell field epithelium. The grooves are not created by a coiling type of accrelionary shell growth or by flexion of the protoconch. A calcareous shelf is secondarily added to the periostracal template of the protoconch along its visceral apertural rim. Morphogenetic movements during ontogenetic torsion in this species are more complex than a simple rotation between cephalopodium and visceropallium and the protoconch shows no evidence of exogastric coiling. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.

A method for determining reference points in celloidin specimens for computer graphic reconstruction

For three-dimensional computer graphic reconstruction of histological sections, it is important to determine reference points. We have developed a machine that makes reference points in a celloidin block for this purpose by drilling holes straight into the block. A sliding microtome is placed under the machine, which consists of a worktable, a stand, and a motor-driven unit. The celloidin block is sectioned on a microtome to determine a plane for serial sectioning. Several holes are then drilled in the block vertical to the plane selected. Serially sectioned specimens are next stained with hematoxylin and eosin and are mounted in the usual manner. Three-dimensional reconstructions of the specimens were next done using a PC-9801 computer and CosmoZone-S software. As an example, the reconstruction of a guinea pig stapes is described.