Localization of oral-motor rhythmogenic circuits in the isolated rat brainstem preparation.

Using an in vitro isolated brainstem preparation from neonatal rat (0-2 days), the minimal circuitry for production of rhythmical oral-motor activity was determined. In the presence of the excitatory amino acid agonist, N-methyl-D,L-aspartate (NMA), and the GABAA antagonist, bicuculline (BIC), rhythmical oral-motor activity was recorded from the motor branch of the trigeminal nerve. In preparations where the brainstem was isolated in continuity between the rostral inferior colliculus and the obex, oral-motor activity was not observed. However, when the brainstem was serially transected in the coronal plane starting at the obex and proceeding rostrally, rhythmogenic activity emerged and became more stable until the level of the rostral facial nucleus (facial colliculus, FC) was approached. Transections more rostral than the FC produced rhythms that progressively deteriorated until the trigeminal motor nucleus (MoV) was reached, at which point all activities ceased. Surgical isolation of an ipsilateral quadrant of the brainstem encompassing the tissue between the FC and inferior colliculus, rostro-caudally, and the midline to lateral brainstem, medio-laterally, exhibited oral-motor activity as well. The remaining contralateral side of brainstem was devoid of rhythmical trigeminal activity. However, further coronal transection of the remaining brainstem at the level of the FC induced rhythmical oral-motor activity in the trigeminal nerve. The data suggest the existence of bilaterally coordinated rhythmogenic circuits in each half of brainstem between the rostral trigeminal nucleus and the rostral facial nucleus, which are tonically inhibited by brainstem circuits caudal to the facial nucleus.

Effect of norepinephrine receptors on trigeminal rhythm generation in newborn rats.

N-methyl-D,L-aspartate acid and bicuculline are required to enhance the trigeminal rhythmic activities in an in vitro isolated brainstem block preparation. In this study, we analyzed the effect of norepinephrine on the trigeminal neural circuit underlying rhythmic jaw movements. Rhythmic trigeminal activity is observed in brainstem preparations (inferior colliculus to obex) only following blockade of alpha(2)-adrenoceptors with idazoxan. This observation, combined with the inhibition of rhythm by alpha(2)-adrenoceptor agonists suggests endogenous alpha(2)-adrenoceptor mediated inhibition of trigeminal networks. A complex noradrenergic modulation of trigeminal systems is further supported by the prazosin-sensitive potentiation of rhythm by bath application of the alpha(1)-adrenoceptor agonist phenylephrine.

Bilateral multiple pulmonary metastases in a patient with double advanced cancer of the head and neck.

A case of advanced gingival cancer is described. The cancer invaded into the mandible and skin of the cheek and was associated with cervical lymph node metastases, mediastinal lymph node metastases, and bilateral multiple pulmonary metastases. The patient received neoadjuvant chemoradiotherapy and local immunotherapy, followed by curative surgery for the primary and neck lesions. Histopathological examination of the primary cancer and the upper and middle cervical nodes (n = 7) indicated a diagnosis of squamous cell carcinoma. Sections of the lower cervical nodes (n = 5) revealed well-differentiated thyroid carcinoma, suggesting that the mediastinal and pulmonary lesions were of thyroid origin. After total thyroidectomy and mediastinal dissection followed by treatment with radioiodine, the multiple pulmonary nodules disappeared. There has been no evidence of recurrent tumour for 5 years.

Migration of a dental implant into the maxillary sinus. A case report.

This article reports a rare case of a displaced dental implant that migrated into the maxillary sinus.

Changes of arterial oxygen saturation (SpO2) following push-back operation.

This study showed the influence of the push-back operation on the occurrence of sleep-related apnea in cleft-palate patients with an analysis of arterial oxygen saturation (SpO2) during sleep, polygraphic analysis of nasal air flow, and chest wall movements. The postoperative SpO2 was lower than that of the presurgical period in all cases, requiring from five to nine days to recover to presurgical levels. According to polygraphic analysis this depression of SpO2 was caused by peripheral obstructive apnea, while, in spite of the cessation of nasal airflow, chest wall movement continued.

Retrospective analysis of 1502 patients with facial fractures.

A total of 1502 patients with facial fractures treated between 1981 and 1996 were retrospectively analysed. The male: female ratio was 2.8:1 and the largest subgroup of patients was between 10 and 29 years of age. The most common cause of injury was traffic accidents (52%) involving motorcycles, bicycles or automobiles. Other common causes included, in descending order, falls (16.6%), assaults (15.5%) and sports (9.7%). Isolated mandibular fractures were most common (56.9%), followed by isolated midface fractures (25.9%). The percentage of fractures involving both the midface and mandible was 6.7, and that of isolated alveolar fractures was 10.5.

Diagnostic imaging in two cases of recurrent maxillary ameloblastoma: comparative evaluation of plain radiographs, CT and MR images.

We report detailed clinical and imaging findings of two patients with recurrent maxillary ameloblastoma. In one patient the recurrent tumour presented at follow-up examination 5 years after the initial operation. The other patients had a far advanced recurrent tumour with maxillary destruction extending into the adjacent normal structures including the infratemporal fossa, infraorbital fissure, masticator space and the left ethmoid sinus. The findings on conventional radiography including panoramic, posteroanterior and Waters' projection, and the findings of computed tomography (CT) and magnetic resonance (MR) imaging were evaluated using the following three variables: artefact degradation, lesion detectability, and conspicuity. The results suggested that MR imaging was the best imaging method for visualization of the tumours, followed by contrast enhanced CT. These two cases show that maxillary ameloblastoma can be difficult to control when it extends to the adjacent normal structures after destroying the maxilla. MR imaging was essential to establish the exact extent of the advanced maxillary ameloblastoma.

Fiberscopic methods for assessment of velopharyngeal closure during various activities.

Fiberscope NPF, developed to observe velopharyngeal movements easily, enables a direct visualization of the soft palate, lateral and posterior pharyngeal walls under the physiological conditions. It is most useful for the diagnosis of velopharyngeal inadequacy. It is very important that a patient himself can observe velopharyngeal movements through the eyepiece of the fiberscope in order to do self exercise.

Malignant schwannoma and melanoma occurring in the maxilla.

A rare case of malignant melanoma of the hard palate following malignant schwannoma of the left maxilla in a 47-year-old woman is reported. Twenty-two months after surgical excision of malignant schwannoma with postoperative radiation and chemotherapy, malignant melanoma appeared with symptoms of gingival bleeding and swelling. Although the patient was treated by the partial maxillectomy with radical neck dissection and postoperative chemotherapy and adjuvant immunotherapy, she died of multiple distant metastases 9 months after the oral manifestation. A possible histological relationship of both tumors which are considered to be derived from the neural crest cells is also discussed.

Examination of the relationships between jaw opener and closer rhythmical muscle activity in an in vitro brainstem jaw-attached preparation.

An in vitro jaw-attached brainstem preparation was developed to investigate the relationship between jaw opener and closer muscle activity during chemically induced rhythmical jaw movements in neonatal rats. In the majority of preparations examined, where a defined region of brainstem was isolated and the neuronal innervation of the jaw opener and closer muscles was left intact, bath application of the excitatory amino acid agonist N-methyl-D,L-aspartate (NMA, 20-40 microM) in combination with bicuculline (BIC 10 microM), a GABA(A) antagonist, produced rhythmical electromyogram (EMG) activity in jaw opener and closer muscles, bilaterally, in conjunction with rhythmical jaw movements. Low concentrations of NMA (20 microM) in combination with BIC produced temporally coordinated activity between the jaw opener and closer muscles, ipsilaterally. With higher doses of NMA (40 microM), each muscle group exhibited bursting, but temporal coordination between them was difficult to establish. Similarly, NMA application in combination with the glycine antagonist strychnine (STR, 10 microM), also produced rhythmical EMG activity from both opener and closer muscles, ipsilaterally, but showed no temporal coordination between the antagonist muscle pair. However, coordination of opener and closer muscle discharge could be restored by the addition of BIC to the bath. We suggest that there exist separate, but coordinated, rhythm generator circuits for opener and closer motoneuronal discharge located in close proximity to the trigeminal motor nucleus and under GABAergic control for production of temporal coordination between rhythmogenic circuits.

The motor nerve supply of the velopharyngeal muscles.

The present study attempted to clarify the motor nerve supply of the velopharyngeal muscles. Experiments were carried out on 20 anesthetized rhesus monkeys. Evoked EMG responses of the levator veli palatini, uvula, and superior constrictor pharyngeus muscles, which seem to contribute to velopharyngeal closure, were analyzed by stimulating the cranial nerves within the skull. Results were as follows: 1. Muscle action potentials (M-waves) from the selected muscles could be recognized on stimulating the facial, glossopharyngeal, and vagus nerves at the petrosal area of the temporal bone but were not noted upon accessory nerve stimulation. 2. At maximal stimulation, the vagus gave a greater increase in muscle amplitude than the other nerves studied. This was followed by the glossopharyngeal with the facial nerve producing the least increase in amplitude. 3. Also at maximal stimulation, latencies in the response of the levator veli palatini and uvula muscles were reduced to the greatest degree by stimulation of the vagus, to a lesser extent for the glossopharyngeal, and least for the facial nerve. 4. On stimulating the facial nerve below the stylomastoid foramen, M-waves could not be recognized. From the present study, it was concluded that the levator veli palatini, uvula, and superior constrictor pharyngeus muscles are double innervated by the facial nerve and branches of the pharyngeal plexus derived from the glossopharyngeal and vagus nerves and that the facial nerve plays an important role as one of the motor nerves in movements responsible for velopharyngeal closure.

Roles of the facial, glossopharyngeal and vagus nerves in velopharyngeal movement.

The present study was designed to clarify the role of the motor nerves in velopharyngeal movements. Experiments were carried out on 15 anesthetized rhesus monkeys on the assumption that their velopharyngeal structures are similar to those of human beings. The pattern and degree of velopharyngeal movements with stimulation to the facial, glossopharyngeal, and vagus nerves in the petrosal area were analyzed by means of fiberscopic observations. The results obtained were as follows: 1. Velopharyngeal movements were most active with stimulation to the vagus, then the glossopharyngeal, and, finally, the facial nerve. 2. Complete closure by unilateral stimulation was elicited only by the vagus nerve and not the facial or glossopharyngeal nerves. 3. The pattern of velopharyngeal movements observed when stimulating the facial nerve was quite different from those seen when the glossopharyngeal or the vagus nerve was stimulated. That is, movements in a plane at the upper part of the nasopharynx were observed on stimulating the facial nerve while upward movements from all of the velopharyngeal structures were seen when the glossopharyngeal or vagus nerve was stimulated. 4. Combined stimulation to the nerves sometimes resulted in additive effects on velopharyngeal movements, but these could be recognized in only a few cases. This study reveals that the motor nerves innervating the velopharyngeal muscles play different roles in velopharyngeal movements.

Abnormal cellular property of fibroblasts from congenital gingival fibromatosis.

Two strains of cultured cells were isolated and characterized from the gingiva of two siblings with congenital gingival fibromatosis. The growth rate of both fibroblast strains was slower than that of comparable cells obtained from the normal gingiva of control individuals. The amounts of substances, including collagen and glycosaminoglycans, biosynthesized by the diseased cells were much greater than those by the control cells from normal gingivae. Namely, 11.7-13.7% of the protein synthesized by diseased cells was collagen, whereas collagen accounted for only 6.1-8.5% of the total protein produced by normal cells. Moreover, the production of a large amount of extracellular substances by the diseased cells was confirmed by electron microscopic examination. These observations suggest that the fibromatosis tissues contain affected fibroblasts which have low growth activity but are active in the production of much greater amounts of collagen and other extracellular substances compared to normal fibroblasts.

[A broken needle in the pterygomandibular space].

We encountered a case where a 30 gauge disposable dental needle was accidentally broken and inoculated into pterygomandibular space by a dentist during a block anesthesia for the inferior alveolar nerve. Several approaches including use of a guide needle and roentgenograms were made but all were unsuccessful. Eleven days later, further operation was attempted monitoring the needle on X-ray TV, resulting in that the broken needle was successfully removed. This technique may be useful for removal of mandibular broken needles.

[Retrospective analysis of facial fractures related to falls in 260 Japanese patients]. / Retrospektive Analyse von Frakturen des Viszerokraniums nach Sturztraumen in einem japanischen Patientenkollektiv.

OBJECTIVE: Numerous epidemiological studies concerning fall-related injuries have been performed in the geriatric and orthopedic field to clarify the relation between the type of fall and fracture patterns. Although falls are a common cause of facial fractures, there is no study describing these relations. This study thus investigates the relationship between the type of fall and fracture pattern. MATERIALS AND METHODS: We analyzed 260 patients with fall-related facial fractures treated between 1995 and 2000 at the First Department of Oral and Maxillofacial Surgery, Osaka University Dental Hospital, Japan. These patients were classified into two groups: (1) those who suffered fractures by a fall from a standing position or lower and (2) those who suffered fractures by a fall from a level higher than the standing position. RESULTS: Fractures caused by falling from a standing position or lower was more common in older patients, especially in women beyond 70 years. The localization of mandibular fractures was not significantly different between the two groups. However, a high incidence of midface fractures was observed in the patients who fell from a higher position. These patients tended to suffer from central midface or dislocated fractures. CONCLUSION: The results were consistent with recent orthopedic studies, which suggest a relation between fractures in old patients and osteoporosis. A strong force caused by falls from a high position tends to act on the high portion of the midface. Our classification based on the height of the falls was able to demonstrate clearly the relation between etiological factors and fracture patterns. Therefore, it seemed reasonable to analyze patients treated in the Department of Oral and Maxillofacial Surgery, Heidelberg University, Germany, according to the same classification in order to compare both collectives.

Effects of human fibroblasts on invasiveness of oral cancer cells in vitro: isolation of a chemotactic factor from human fibroblasts.

Oral fibroblasts stimulated invasion of oral-carcinoma cells into the collagen matrix. The mechanisms of the fibroblast-induced stimulation of invasiveness was further investigated by examining cell motility and proteolytic activity of tumor cells, using mainly an adenoid-cystic-carcinoma cell line (ACCS) and normal fibroblasts from gingival tissues. Conditioned medium from the fibroblasts grown in serum-free medium was fractionated on a Superdex 200 pg column, and Peak 1 eluted at 200 to 300 kDa and Peak 2 eluted at 50 to 100 kDa were found to contain different specific activity. Treatment of ACCS cells with Peak 1 resulted in an increase in the production of proteolytic enzymes. Peak 2 stimulated both chemotaxis and chemokinesis of ACCS cells. A chemotactic factor was purified from the heparin-unbound fraction of Peak 2 by anion exchange and hydrophobic chromatography, and was named "fibroblast-derived motility factor (FDMF)". At 1 microg/ml, FDMF stimulated chemotaxis of ACCS cells by 4-fold compared with unstimulated controls. Characterization of the physicochemical properties of FDMF suggested that it might be different from any known motility factors. Exposure of ACCS cells to FDMF resulted in reduced amounts of actin stress fiber in the cytoplasm and induction of tyrosine phosphorylation of several cellular proteins detectable 30 to 60 min after treatment. These FDMF-induced changes were blocked by pre-treatment either with genistein or with pertussis toxin. These findings suggest that FDMF may be a novel protein which stimulates cell motility via a signaling pathway mediated by a pertussis-toxin-sensitive G protein and tyrosine phosphorylation.

Factor VII deficiency first observed at preoperative routine clotting test.

Factor VII deficiency was first observed in a 24-year-old female in the routine clotting test for tooth extraction. Her factor VII was 22%, mildly below normal limits. Factor IX complex was not administered as replacement therapy when her impacted tooth was extracted. There was no sign of abnormal postoperative bleeding. As this disease was a rare disorder, the minimum safe level of factor VII for tooth extraction was unknown. We had a opportunity to study a patient with this disorder observed in the preoperative routine clotting test for tooth extractions.

Breast feeding for cleft lip and palate patients, using the Hotz-type plate.

OBJECTIVE: Oral-cavity feeding movements were analyzed during sucking and used to modify a Hotz-type plate to facilitate sucking in infants with cleft lip and palate. DESIGN: Sucking movements were analyzed using lateral view cine radiography as three adults fed from a bottle. A Hotz-type plate was then modified to better isolate the oral cavity and to occlude the oral airway. The plate was then utilized in direct breast feeding by 10 babies. OUTCOME MEASURES: Sucking rate, amount of milk taken, and duration of use of the plate were assessed. RESULTS: Wearing this plate, four babies with cleft lip and palate could suck their mother's breast, drinking about 22 g/trial. CONCLUSIONS: Although supplemental bottle feeding was required to provide enough nourishment, this is the first step to reaching ideal breast feeding situation for these patients.