Kosuke Ishii

Age-related development of the arrangement of connective tissue fibers in the lamina propria of the human vocal fold.

A scanning electron microscopic study was made on the morphological changes occurring with age in collagen and elastic fibers in the lamina propria of the human vocal fold. We obtained the specimens from 32 autopsy cases ranging from 20 gestational weeks to 22 postnatal years and submitted them to digestion treatments with 10% sodium hydroxide and 90% formic acid. The vocal folds in fetuses and neonates consisted of sparse and dense areas of collagen and elastic fibers, and the vocal ligament was not found. In subjects 5 years of age, a deep dense area was found in the anterior and posterior maculae flavae, and longitudinal fibers were noted between the maculae. A structure of superficial versus deep layers appeared in children older than 10 years of age. The layered structure of the lamina propria was complete around 17 years of age. The development of the layered structure and the maturity of the fibers appeared to reflect the complexity of phonatory function during adolescence.

Ultrastructure of the lamina propria of the human vocal fold.

We studied three-dimensional arrangement of collagen fibers and elastic fibers in the human vocal fold by scanning electron microscopy after digesting cellular elements and collagen fibers with formic acid treatment and cellular elements and elastic fibers with 10% sodium hydroxide. The superficial layer consisted of clusters of collagen fibers and fine elastic fibers running straight or coiled. The intermediate layer consisted of thick bundles of collagen and elastic fibers running longitudinally and fine coiled elastic fibers. The deep layer consisted of coil elastic fibers and dense collagen bundles. Collagen fibers may have a role of maintaining the organization of vocal folds even during vibration, and elastic fibers act to rapidly restore the vocal folds to their original form. We also studied the distribution of oxytalan fibers in vocal folds by aldehyde-fucusin staining. Oxytalan fibers were distributed throughout the connective tissue of the vocal folds, and a large number of fibers was present just under the epithelial basement membrane and around the muscle fibers. If these fibers are damaged and lose their functions, vibration of the vocal folds will be impaired.

Evaluation of recurrent nerve paralysis due to thoracic aortic aneurysm and aneurysm repair

Objectives: We sought to clarify the relationship between the outcome of recurrent laryngeal nerve paralysis with the characteristics of the thoracic aortic aneurysm and the surgical procedure used in each patient.

An animal model of type-1 herpes simplex virus infection of facial nerve.

As the pathogenesis of Bells palsy, herpes simplex virus (HSV) infection has been suggested on the basis of several serological studies. To clarify and analyse the pathogenic mechanisms of this disease, guinea pigs were inoculated with type-1 HSV through natural infection routes into the peripheral areas innervated by facial nerve, and nervous tissues were examined by histopathological and immunohistochemical methods. HSV-I infection in the nasal mucosa, tongue, oral muscles and auricles brought about neither clinical facial palsy nor disturbed Preyer or corneal reflexes, but viral antigens in the inoculated peripheral areas, facial and trigeminal ganglia and pons with inflammatory cell response, hemorrhages and degeneration and necrosis. Cyclophosphamide treatment resulted in disturbed Preyer and corneal reflexes and enhanced the incidence of antigen appearance and histopathological changes.

Extracellular matrix in the rat spiral limbus

SummaryThe matrix of the spiral limbus is obviously a special form of the intercellular substance. In the present study, the rats spiral limbus was investigated by electron microscopy after fixation with ruthenium red and tannic acid and immunofluorescence to demonstrate matrix components. Collagen types I, II, V, VI, VII, IX and XI and fibronectin were not observed. Collagen type II and cartilage-specific proteoglycans, however, occurred in large quantities. The basal lamina of interdental cells and inner sulcus cells did not contain any collagen type IV. while the basal lamina of the capillaries had only minor amounts. Laminin and nidogen appeared in large amounts in the basal lamina. After fixation with tannic acid, the matrix between the interdental cells and the capillaries contained 20- to 22-nm-thick single and irregularly running fibrils as well as plaques of a fine granular material. After fixation with ruthenium red, 30-to 60-nm-thick, electron-dense granules occurred and most probably consisted of proteoglycans. These findings indicate that the composition of the matrix of the spiral limbus is similar to that of cartilage but not identical.

Experiments on herpes simplex viral infections of the facial nerve in the tympanic cavity.

SummaryAn experimental protocol was developed to study viral infection of the facial nerve. Facial palsy was induced in a guinea pig model by inoculating type 1 herpes simplex virus (HSV-1) directly onto the facial nerve in the temporal bone. Partial removal of the bony wall of the fallopian canal was effected, and virus was placed on the nerve after incising its sheath on the right side and without incision of the sheath on the left side. All animals exhibited subsequent bilateral facial palsies, but with severe changes occurring on the right side. The animals were then sacrificed sequentially following infection. Immunofluorescence and histopathological studies revealed the presence of HSV antigen, infiltration of inflammatory cells, hemorrhage, and degeneration of the right facial nerve. In the left nerves, a slight hemorrhage was recognized without cellular infiltration or HSV antigens. These results suggest that the intact facial nerve is rather resistant to HSV infection, but this defense mechanism is easily destroyed by damage to the facial nerve sheath.

Ultrastructural arrangement of collagen fibrils in the rat facial nerve

We studied the collagen fibril arrangement in the connective tissue sheaths (epineurium, perineurium, and endoneurium) of the intratemporal and extra-temporal portion of the rat facial nerve by transmission electron microscopy after fixing the nerves with tannic acid, and by scanning electron microscopy after digesting cellular elements by sodium hydroxide treatment. These studies revealed that the epineurium consists of thick bundles of collagen fibrils and a coarse meshwork of collagen fibrils, the perineurium consists of a lacework sheet of bundles of collagen fibrils, and the endoneurium consists of a meshwork of fine collagen fibrils in the inner layer and of longitudinally oriented bundles of collagen fibrils in the outer layer. There was little difference in the three-dimensional organization of collagen fibrils between the extra-temporal segment and vertical and horizontal segments of the facial nerve. However, the facial nerve lost the epineurium and perineurium in the central portion of the horizontal segment near the geniculate ganglion and in the labyrinthine portion, i.e. the proximal portion of the intratemporal segment. In these segments, the endoneurium consisted of a meshwork of fine collagen fibrils.

Localization of zinc in the rat submandibular gland and the effect of its deficiency on salivary secretion.

To clarify the role of zinc in the mechanism of salivary secretion, the effects of zinc deficiency on the morphologic findings and secretory function of the salivary gland were investigated with a rat model of chronic zinc deficiency, prepared by feeding a zinc-deficient diet, and a rat model of acute zinc deficiency, prepared by administration of a zinc chelator, dithizone. In rats with chronic zinc deficiency, the granule production in the granular duct cells was decreased, but the glandular epithelial cells and myoepithelial cells showed no degenerative or other destructive morphologic changes. The degranulation of the granular duct cells and acinar cells in response to acetylcholine hydrochloride seen in control rats was strongly inhibited in rats with acute and chronic zinc deficiency. The contractile response of the actin microfilament bundles in the myoepithelial cells to acetylcholine seen in the control rats was also absent in the zinc-deficient rats. Further, electron microscopy of the submandibular gland stained by Timms method disclosed prominent zinc localization at the membrane surface, granules, and vesicles of the glandular epithelial cells and in the pits of the myoepithelial cells. These findings suggest that zinc, together with many zinc-dependent enzymes, is closely involved in the production and degranulation of secretory granules in the glandular epithelial cells, and also in the contraction of the myoepithelial cells in the submandibular gland.

Giant fibrovascular polyp of the esophagus successfully treated by endoscope-assisted resection

Fibrovascular polyps of the esophagus are extremely rare. A 52-year-old woman had the sensation of food sticking in her throat for 3 weeks. Examination revealed a polypoid lesion within the esophagus that extended from the pyriform sinus to the distal esophagus above the gastric cardia. With the patient under general anesthesia, the stalk of the lesion was cut through the rigid laryngoscope; however, the tumor could not be retrieved through the mouth. Large biopsies of the lesion were taken. The remaining lesion was later passed in the fecal matter. Pathological findings were consistent with the features of fibrovascular polyps.

Involuntary expiratory phonation as a dose-related consequence of L-dopa therapy in a patient with Parkinson's disease.

We report a case of involuntary phonation caused by abnormal vocal cord movements during expiration in a patient with Parkinsons disease. A 60-year-old woman had been treated for parkinsonism at the outpatient clinic of the Department of Neurology since August 1999. She began to groan involuntarily in the daytime in September 2001. She could not eat well while groaning. Stridor was not noted during sleep at night. Endoscopic examination of the larynx revealed insufficient abduction of the bilateral vocal cords, although the glottis was not so small as to cause stridor during inspiration. During expiration, however, the vocal cords adducted, resulting in the involuntary production of voice. Electromyography showed an increase in the activity of the thyroarytenoid and lateral cricoarytenoid muscles. This muscle activity was further enhanced during inspiration. The involuntary phonation disappeared when the patients dose of l-dopa was decreased, although she had a decrease in her systemic mobility as well. When the dose of l-dopa was increased to the therapeutic level, involuntary phonation recurred, and her voluntary systemic activity improved. In the present case, it was considered that excessive dopaminergic denervation occurred in the nerve innervating the laryngeal adductors. Involuntary voice appeared to be produced by hypertonus of the laryngeal adductors because of a lowering in the threshold level for l-dopa, even though the drug was administered at the usual dose.