Three-dimensional reconstruction of the feline larynx with serial histologic sections

Robot-Guided Atomic Force Microscopy for Mechano-Visual Phenotyping of Cancer Specimens

Atomic force microscopy (AFM) and other forms of scanning probe microscopy have been successfully used to assess biomechanical and bioelectrical characteristics of individual cells. When extending such approaches to heterogeneous tissue, there exists the added challenge of traversing the tissue while directing the probe to the exact location of the targeted biological components under study. Such maneuvers are extremely challenging owing to the relatively small field of view, limited availability of reliable visual cues, and lack of context. In this study we designed a system that leverages the visual topology of the serial tissue sections of interest to help guide robotic control of the AFM stage to provide the requisite navigational support. The process begins by mapping the whole-slide image of a stained specimen with a well-matched, consecutive section of unstained section of tissue in a piecewise fashion. The morphological characteristics and localization of any biomarkers in the stained section can be used to position the AFM probe in the unstained tissue at regions of interest where the AFM measurements are acquired. This general approach can be utilized in various forms of microscopy for navigation assistance in tissue specimens.

Three-dimensional reconstruction of immunolabeled neuromuscular junctions in the human thyroarytenoid muscle

OBJECTIVES/HYPOTHESIS

The objective was to reveal the location of the neuromuscular junctions in a three-dimensional reconstruction of the human thyroarytenoid muscle within the true vocal fold.

STUDY DESIGN

Immunohistochemical analysis of serially sectioned human true vocal folds was performed, followed by reconstruction in three dimensions using computer imaging software.

METHODS

Six fresh human larynges from autopsy were harvested, fixed in formalin, and embedded in paraffin. Eight vocal cords were studied from these six larynges. Five-micron serial sections were collected throughout the entire vocal cord in an axial plane at 500-microm intervals. Immunohistochemical analysis was performed with anti-synaptophysin antibody. A computer-controlled imaging and reconstruction system was used to create a three-dimensional reconstruction from the serial sections and to represent the location of the clustered band of neuromuscular junctions within each true vocal fold. The vocal cord was divided into equal thirds from anterior to posterior for statistical analysis.

RESULTS

The most neuromuscular junctions (74%) were located in the middle third, and the least (7%) were found in the anterior third. The difference in anterior-to-posterior distribution was statistically significant in all eight specimens by chi2 analysis (P <.001).

CONCLUSION

The distribution of neuromuscular junctions is not random within the human thyroarytenoid muscle. Because neuromuscular junctions are most highly concentrated in a band within the mid belly of the muscle, botulinum toxin type A (Botox) injection in patients with spasmodic dysphonia should be targeted to this region.

Three-dimensional computer-reconstructed image for studying cancer extension within the hypopharynx

Hypopharyngeal cancer is one of the head and neck cancers with poor prognosis. This is due to the unpredictable extension of the local disease and the high ratio of distant metastasis. To verify the morphological behavior of hypopharyngeal cancer, whole-mount horizontal serial sections were developed using the larynges obtained from total pharyngolaryngoesophagotomy. The technique of processing high-resolution three-dimensional (3D) images of the larynges using Nikon Cosmozone 2SA software is presented. Two representative surgical specimens were used and 3D images reconstructed. In these two particular cases, the cancer infiltrated superiorly through submucosal lymphatic ducts and formed separate daughter nests under the intact mucosal epithelium far above the main tumor. 3D images enhanced the morphological features of these cases. These cases also suggested the difficulty of defining the upper resecting limit in the operation of hypopharyngeal cancer. 3D reconstruction is and will be a crucial modality for studying the morphological behavior of hypopharyngeal cancer.

Subglottic branch of the superior laryngeal nerve in the dog penetrates the cricoid cartilage

The topographic anatomical study on the distribution pattern of the superior laryngeal nerve (SLN) in the larynx was studied in thirteen adult dogs. The ramus posterior of the SLN divides into two branches; the interarytenoid branch (IA) and the pharyngoesophageal branch (PE). The IA on both sides connect to the cricoid ganglion (CG) in the midline at the cranial border of the cricoid cartilage. Posterior glottic branches arise from the IA, run over the cricoid cartilage, and distribute fibers to the posterior wall of the glottis. Every specimen observed in the present study possessed the CG and the posterior glottic branches. The subglottic branch derives from the IA near the cricoid ganglion, and passes through the cricoid foramen (CF) (Yoshida, 1986). The subglottic branch distributes fibers to the subglottic mucous membrane covering the cricothyreoid ligament. The CF and the subglottic branch were observed on both sides of seven specimens out of thirteen dogs. They were also observed on only one side in three specimens, and were not detectable on either side in the three remaining specimens. The silver impregnation applied in the semimicroscopic dissection facilitated identification of the precise localization and the topographic arrangement of ganglia and nerve bundles.