Tokuji Unno

Lombard reflex during PAG-induced vocalization in decerebrate cats

The Lombard reflex occurs when a speaker increases his vocal effort while speaking in the presence of ambient noise. The purpose of this study was to clarify whether the Lombard reflex can be evoked during controlled vocalization in an animal model. In decerebrate cats, repetitive electrical stimulation was applied to the midbrain periaqueductal gray (PAG) to evoke vocalization. Pure tone auditory stimulation was delivered through a loudspeaker. The activities of the laryngeal adductor muscle, diaphragm and external oblique abdominal muscle and the voice intensity were measured during PAG stimulation, in the presence and absence of the auditory stimulation. To clarify the effects of the auditory laryngeal reflex on the activity of laryngeal adductor motoneurons, the amplitude of the laryngeal reflex evoked by single shock stimulation of the superior laryngeal nerve was also measured during respiration, in the presence and absence of auditory stimulation. The sound made by the cats due to PAG-induced vocalization was augmented by exposure to auditory stimulation, and the activities of the laryngeal adductor muscle and external oblique abdominal muscle were also augmented. During respiration, auditory stimulation also increased the amplitude of the laryngeal reflex evoked in the laryngeal adductor muscle. These results demonstrate that the essential neuronal mechanisms for evoking the Lombard reflex exist within the brainstem.

Sneeze-evoking region within the brainstem

The neuronal mechanisms of sneezing were examined in precollicular-postmammillary decerebrate cats. Mechanical stimulation (frequency 20 Hz, peak-to-peak displacement 0.5 mm) of the nasal membrane evoked a series of sneezes. In the same preparation, electrical stimulation (duration 0.2 ms, frequency 10 Hz, 5-50 microA) delivered to the lower brainstem also evoked sneezes. The changes in EMG activity and subglottic pressure during brainstem-induced sneeze were similar to those recorded nasal-induced sneeze. The sneeze-evoking region was located along the ventromedial part of the spinal trigeminal nucleus and the adjacent pontine-medullary lateral reticular formation, and extended rostrocaudally from P4.0 to P14.5 according to the Horsley-Clarke coordinates. These results suggest that the sneeze-evoking region is a distinct structure of the brainstem, having a homogeneous function. This region appears to control the epipharyngeal, intrinsic laryngeal and respiratory muscles. The integrated activity of these muscles underlies the generation of a sneeze.

Spindle Cell Lipoma within the Larynx: A Case Report with Correlated Light and Electron Microscopy

A spindle cell lipoma was removed surgically from the right intralaryngeal lesion of a 68-year-old man. Laryngoscopy demonstrated a spherical protrusion with intact mucosa near the vestibular fold. CT scan examination showed a low-density mass just medial to the thyroid cartilage. Light microscopy revealed that the circumscribed tumor consisted of mature lipocytes and spindle cells. Electron microscopy revealed that the spindle cells lacked a typical basal lamina. Such tumors are more frequent in the posterior aspect of the neck and shoulder regions. To our knowledge, this is the first reported case of a spindle cell lipoma within the larynx.

Mast cells in allergic nasal epithelium and lamina propria before and after provocation. An electron microscopic study

A study of mast cells in subjects with nasal allergy was made by electron microscopy before and after provocation in three areas; the nasal epithelium, the subepithelial layer and the deep layer of the nasal lamina propria. The ration of degranulation of the mast cells in the nasal epithelium and subepithelial layer increased after provocation. The main features of exchanged granules of the mast cells in these areas were (1) swelling of lower electron density of the area enclosed by perigranular membrane, (2) lower electron density of the total area of granular substance with fibrillar and reticular changes, and (3) the disappearance of granular substance. It was, therefore, judged that the mast cells in the nasal epithelium and in the subepithelial layer play a more important part in the onset of a nasal allergic reaction than do those in the deep layer of the nasal lamina propria.

Dynamics of mast cell degranulation in human allergic nasal epithelium after provocation with allergen.

The histamine content in the nasal epithelial layer of twenty‐five patients with nasal allergy was measured before, 10 min after and 1 hr after nasal provocation with allergen. A decrease in histamine content was observed 10 min after provocation compared to the values obtained before provocation (P<0.05). There was a tendency for an increase in the histamine content of the nasal epithelium one hour after provocation when compared with the amounts present 10 min after provocation (P<0.1). Mast cells in the nasal epithelial layer of a further five patients were studied by electron microscopy 10 min and 1 hr after provocation. The rate of mast cell degranulation appeared to decrease 1 hr after provocation when compared with 10 min.

Brain stem neural mechanisms for vocalization in decerebrate cats.

In order to characterize the brain stem circuitry that produces vocalization, the activities of brain stem respiratory neurons were recorded extracellularly during vocalization induced by electrical stimulation of the periaqueductal gray in decerebrate cats. After the onset of stimulation, the respiratory rhythm ceases, and a preparatory inspiration is induced. Following this initial inspiration, vocalization characterized by increased activities of the intrinsic laryngeal adductor and the major expiratory muscles is induced. During vocalization, most of the dorsal respiratory group inspiratory neurons increase their firing rates in phase with an increase of diaphragm activity. Inspiratory neurons with a continuous discharge pattern in the rostral ventral respiratory group increase their firing rates to augment intrinsic laryngeal abductor motoneurons and bulbospinal inspiratory neurons in the dorsal respiratory group. On the other hand, most of the bulbospinal augmenting expiratory neurons in the Bötzinger complex cease firing just after the onset of periaqueductal gray stimulation for the remainder of the stimulation period. These results indicate that at least some part of the coordinated activations of intrinsic laryngeal and respiratory muscles during vocalization are mediated via the central respiratory neurons that produce breathing.

Association between HLA Antigens and Birch Pollen Allergy in Japanese Subjects

Birch pollen is a very common cause of nasal allergy (pollinosis) not only in Scandinavia, Europe, Canada, and the northern part of the United States but also in Hokkaido, Japan. Although there are many papers describing the association of HLA antigens and pollinosis caused by many other allergens, there is no report about the association of HLA antigens and birch pollen allergy. In this paper, we performed an HLA population study of birch pollen-allergic patients in Japan and their pattern analysis of HLA-DRB and HLA-DQB gene by the Southern blot hybridization technique. Our population study data indicated that the HLA-DR9 and HLA-DQw3 phenotypes strongly associated with the development of birch pollen allergy in Japanese subjects. By restriction fragment length polymorphism pattern analysis, some restriction fragments of the HLA-DQB gene were detected only in the patient group. These data suggested that there was a significant association between HLA class II antigens and the development of birch pollen allergy in Japanese subjects.

The Effects of Nasal Flow Stimulation on Central Respiratory Pattern

The purpose of this study was to analyze the functional role of nasal afferents on central respiratory mechanisms. The electromyographic activity of the diaphragm and the neuronal activities of respiratory neurons within the brainstem were recorded during nasal flow stimulation, using decerebrate cats. Flow stimulation delivered to the nose prolonged the respiratory cycle time and decreased the amplitude of diaphragmatic activity. The respiratory cycle time was prolonged due to prolongation of expiratory phase. Cool air flow stimulation was more effective for changing the respiratory pattern than was warm air. All recorded inspiratory neurons of the dorsal respiratory group decreased their firing rate during stimulation, but more than half of expiratory neurons of the ventral respiratory group did not change. These results suggest that nasal afferents which respond to temperature can modulate the central respiratory pattern and have a stronger suppressive effect on the activity of inspiratory neurons than that of expiratory neurons.

Deposition of Sprayed Particles in the Nasal Cavity

Therapeutic effects of topically applied steroids is closely related to the deposition of sprayed particles. To clarify deposition in the nasal cavity, model experiments were undertaken using the gas and powder sprays. Deposits on the moistened filter paper which covered the surface of a nose model were assessed by absorbance of the extracts. The influence of the shape and the effect of continuous suction from the posterior outlet were also studied. When the nasal cavity was kept straight without any abnormal protrusions, the gas spray deposited more than 90% of particles. The amount was significantly lowered in the model of a concave septum with hypertrophic turbinates. The powder spray deposited approximately 75% of the original dose. This amount was more than 90% of actually sprayed particles because some loss was inevitable in spraying the powder. In general, the shape of the cavity more affected the deposition of the gas spray than the powder spray. This difference was probably due to the spray angle and to the size and speed of the aerosol particles. It was concluded that the powder spray was preferable to the gas spray with regard to the deposition in the nasal cavity.

Primary position upbeat nystagmus localizing value.

Primary position upbeat nystagmus has been associated predominantly with lesions of the midbrain, midline cerebellum, and lower brainstem. However, the precise localization still remains unclear. We report one case of primary position upbeat nystagmus in which magnetic resonance imaging showed probable bilateral lesions of the prepositus hypoglossi nuclei. Morphological and physiological studies have shown that this nucleus plays important roles in vertical eye movements. We conclude that the dysfunction of bilateral prepositus hypoglossi nuclei causes the upbeat nystagmus in our patient.