[Osaka Daigaku shigaku zasshi] The journal of Osaka University Dental Society最新文献

The Patient was a 28-year-old woman with 8th month of her pregnancy. She had noted a swelling of her palate (6-region) about 3 years before. Incisional biopsy was done in 8th month of her pregnancy and histological diagnosis was confirmed; adenoidcystic carcinoma. After normal health baby was born with cesarean section in 34 weeks, partial maxillectomy was performed. She is now free of the disease. The baby is now 1-year-old and enjoying the good health.

In order to understand how muscle spindle afferents contribute to the control of jaw-closing muscle activity, the following two experiments were performed in the urethane anesthetized rabbits; 1) EMG activities of the masseter muscle during chewing a test strip were compared before and after the trigeminal mesencephalic tract (Mes V) lesion. The Mes V, where the ganglion cells of jaw-closing muscle spindle afferents are located, was lesioned by thermal cauterization. Since the cells lying around the Mes V may also be damaged, it is possible that the effects of lesioning may partly be ascribed to the destruction of these cells. In order to circumvent this problem, kainic acid was injected into the Mes V one week before the lesioning. 2) Unit discharges were recorded from the Mes V during passive jaw-opening and during chewing a test strip. The response of these units to suxamethonium (SCh) administration was also examined. The results were as follows; 1) In the animals with the Mes V lesion, the facilitatory response of the masseter muscle during chewing the test strip was significantly reduced on the side ipsilateral to the Mes V lesion, while the contralateral masseteric activities were not affected. 2) The Mes V units were classified as the primary and secondary spindle afferents depending on the responses to SCh administration. During chewing, the Mes V units showed discharges locked to a certain phase of a single masticatory cycle. They were classified into 4 types, depending on the time relation between unit discharges and the jaw movement; 1) those fired predominantly on the jaw-opening phase, 2) those fired on the jaw-closing phase, 3) those excited at the beginning of both-jaw opening and power phases and 4) those fired within the period of the masseteric burst. The firing frequency of the third type units increased during the jaw-closing muscle burst induced by application of the test strip between the opposing molars. They were sensitive to SCh administration and supposed to be the primary spindle afferents. It is concluded that the muscle spindles of jaw-closing muscles (presumably primary endings) contribute to the enhancement of jaw-closing muscle activities during chewing.

Chewing movements are accomplished by the harmonious function of the stomatognathic system. Therefore, TMJs play important roles in chewing movements. Recently, significant findings on TMJ abnormalities have been obtained from many studies. However, the relationship between chewing movements and TMJ abnormalities remains unclear. The purpose of this study was to examine how TMJ abnormalities were reflected in chewing movements. Incisor point movements during chewing (chewing pattern) were investigated in 150 abnormal and 25 normal subjects using Sirognathograph Analysing System. Abnormal subjects were composed of 45 patients with anterior disk displacement with reduction (reciprocal click), 20 patients with anterior disk displacement without reduction (closed lock), 50 patients with osteoarthrosis and 35 patients with MPD syndrome. Analysis of condylar movements during chewing were also performed in 9 normal and 20 abnormal subjects. The results were as follow; 1. Subjects with TMJ abnormalities tended to show abnormal chewing patterns when chewing at their non-abnormal sides. 2. TMJ abnormality of each different type tended to show its respective characteristic chewing pattern. 1) Subjects with osteoarthrosis and reciprocal click without condylar posterior dislocation tended to show deviation of the turning point to the non-chewing side, with a convex opening path in the frontal plane and a lack of anteroposterior width in the sagittal plane. This finding was associated with the limitation in movement of the abnormal-side condyle. 2) Subjects with reciprocal click with condylar posterior dislocation tended to show a concave opening path and reversed or cross-over patterns in the frontal and horizontal planes, respectively. This finding was associated with the movement of the abnormal-side condyle in the medio-anterior direction during the initial phase of opening. 3) Subjects with closed lock without condylar posterior dislocation tended to show deviation of the turning point to the non-chewing side, with a concave opening path in the frontal plane and a lack of anteroposterior width in the sagittal plane. This finding was associated with the severe limitation in movement of the abnormal-side condyle. 4) Subjects with closed lock with condylar posterior dislocation characteristically tended to show reversed or cross-over patterns in the horizontal plane. This finding was associated with the movement of the abnormal-side condyle in the medio-anterior direction during the initial phase of opening. However, this movement was smaller than that of the reciprocal click. 3. Subjects with MPD syndrome showed chewing patterns similar to those of normal subjects. From the results, close relationships were found between chewing movements and TMJ abnormalities.

Hypercalcemia is one of well-recognized paraneoplastic syndromes and occurs occasionally in patients with oral cancers. Because bone is the richest source of calcium in the body, it has been proposed that humoral bone resorbing factors which are released by tumors are responsible for the pathogenesis of hypercalcemia. In the present study, partial purification and identification of bone resorbing humoral factors were carried out employing VX2 squamous cell carcinoma which has been known to induce hypercalcemia in rabbits. In addition, extra- and intra-cellular mechanisms which are operating to confer autonomous growth on VX2 cancer cells were also studied. VX2 carcinoma induced marked hypercalcemia not only in rabbits but also in nude mice in parallel with tumor enlargement. Administration of indomethacin (INDO), a prostaglandin (PG) synthesis inhibitor, before onset of the hypercalcemia prevented an elevation of serum calcium levels and growth of the tumor. INDO, however, failed to decrease serum calcium levels and tumor growth when administered after development of the hypercalcemia and tumor enlargement. These results indicate that not only PGs but other humoral factors are involved in the pathogenesis of the hypercalcemia seen in VX2 cancer-bearing animals. VX2 cancer cells in culture retained their cancerous phenotypic properties, synthesized PGE2, PGF2 alpha and 6-keto PGF1 alpha and secreted highly levels of PGE2, a powerful bone resorber, into the culture medium in a time- and cell density-dependent manner. The culture supernatants also contained a trypsin- and heat-sensitive bone risorbing factor (BRF) with a molecular weight of approximately 20kD. BRF was presumed to be similar to parathyroid hormone related protein (PTHrP) from its biological and biochemical behaviors. Both PGE2 and PTHrP promoted VX2 cell growth, thus suggesting that these two substances are autocrine growth factors for VX2 cells. Calcium stimulated VX2 cell growth and secretion of PGE2 and BRF (PTHrP) in a concentration-dependent fashion. Stimulation of VX2 cell proliferation by PGE2 and PTHrP was closely correlated with a transient elevation of intracellular free calcium ion ([Ca2+]i). [Ca2+]i elevated transiently in response to PGE2 and PTHrP was shown to be supplied by influx of extracellular free calcium ion ([Ca2+]e) through calcium channel present in plasma membrane. Involvement of protein kinase C in autocrine growth stimulation of VX2 cells by PGE2 and PTHrP was unclear. These results demonstrate that PGE2 and PTHrP secreted by VX2 cancer cells not only induce hypercalcemia but promote VX2 cell growth as autocrine growth factors.(ABSTRACT TRUNCATED AT 400 WORDS)

To investigate the effects of mechanical forces on the growth of cartilages of the craniofacial complex, chondrocytes isolated from nasal septal cartilage (NSC), spheno-occipital synchondrosis (SOS), and mandibular condylar cartilage (MCC) were cultured and exposed to hydrostatic pressure in vitro. Following results were obtained. 1. By application of the pressure, DNA synthesis increased in NSC and SOS (150% of control by 50 g/cm2, 1 min), but not so much in MCC in the medium containing 10% fetal calf serum (FCS). On the other hand, GAG synthesis increased in SOS (140% of control by 50 g/cm2, 2 min.) and MCC (160% of control by 100 g/cm2, 5 min), but decreased slightly in NSC in the same condition. The stimulations in DNA and GAG syntheses reached maxima 20-22 hr and 24-27 hr respectively after the application of the pressure. These stimulatory effects of the hydrostatic pressure on DNA and GAG syntheses could be found when cultured chondrocytes were in a multilayer stage. 2. It has been reported that addition of FCS at a concentration of 10% increases DNA synthesis in these chondrocytes preincubated in medium containing 0.3% FCS. The application of the pressure 2 min before the addition of 10% FCS potentiated the increase by FCS of DNA synthesis in NSC (130% of control), but not so much that in SOS and little that in MCC. 3. When the pressure was applied on these cells 2 min before addition of parathyroid hormone (PTH; 10(-7) M), this mechanical stimulation potentiated the increase by PTH of GAG synthesis in MCC (130% of control), but not so much that in SOS, and little that in NSC. Moreover, the intracellular cAMP level which was increased just after the addition of PTH also became higher by the application of the pressure. 4. These potentiation by the hydrostatic pressure in the cases of the addition of FCS and PTH diminished when intervals between application of pressure and addition of these factors were more than 10 min. These findings suggested that mechanical forces have influences on the growth of cartilages in craniofacial complex and that these effects are mediated by factors contained in serum.

The noise generated by the metal air turbine handpiece employed in dental practice is considerable and attended with predominant high frequency components. Therefore, investigation of the noise generation mechanism and development of a silent air turbine handpiece was only a matter of course. In addition, the metal air turbine hardpiece is comparatively heavy and its production cost is high. From this point of view as well, production of a light air turbine handpiece at low cost is also desirable. In order to overcome the objections to the metal air turbine handpiece, appropriate plastics materials were employed wherever possible. In this study, the number of revolutions, noise level, frequency analysis, start pressure and weight of newly produced plastics handpieces and metal handpieces were examined and compared. The following results were obtained: 1. The number of revolutions of single-nozzle type air turbine handpieces encased in plastics housings and fitted with metal turbine rotors was higher than that of all-metal air turbine handpieces. The noise level of the former tended to be lower. 2. The number of revolutions of multi-nozzle type air turbine handpieces encased in plastics housings and fitted with turbine rotors with plastics turbine blades was almost equal to that of similar metal handpieces, with the noise level tending to be lower. 3. In the case of handpieces fitted with turbine rotors with dynamic balance, the number of revolutions was high and the noise level was low. This indicated that dynamic balance was a factor affecting the number of revolutions and noise level. 4. Narrow band sound frequency analysis of single-nozzle type air turbine handpieces showed a sharp peak at the fundamental frequency which was the same as the number of revolutions multiplied by the number of rotor turbine blades. It is thought that the noise from air turbine handpieces was aerodynamic in origin, being generated by the periodical interruption of steady air flow by rotor turbine blades. 5. The start pressure of plastics handpieces was almost equal to that of metal handpieces. 6. The weight of plastics handpieces was 20%-50% of that of metal handpieces. The present results indicate that it is possible to produce a new type of light, silent and aesthetical air turbine handpiece.

Primary afferent fibers from the sternocleidomastoid and trapezius muscles were transganglionically labeled with HRP, using rats anesthetized with urethane. All labelings were found ipsilaterally; retrogradely labeled cells were located in the C2 to C4 spinal ganglia, and transganglionic labelings in the C1 to the rostral C6 spinal segments and in the medulla oblongata. Labeled terminal fields were the lamina VI, the central cervical nucleus and the ventral horn in the cervical spinal cord, and in the medulla oblongata, many labeled fibers projected to the lateral (Cul) and medial cuneate nuclei (Cum), with a few of them projecting to the vestibular nucleus and the intermediate nucleus of Cajal. In the lateral cuneate nucleus, the terminal field was located in the medial portion at rostral levels, but it gradually shifted laterally as traced caudally; in the medial cuneate nucleus, the terminal field was located rostrally in the dorsolateral portion, but caudally in the ventrolateral portion. Although the sternocleidomastoid and trapezius muscles displayed a similar afferent projection pattern, the projection from the former muscle differed from that of the latter in the following respects: 1) Levels of projections to the spinal ganglia and the cervical spinal cord were located slightly more rostrally. 2) The terminal field in the lamina VI was located slightly more medially. 3) In the ventral horn, the sternocleidomastoid muscle afferents projected rostrally to the dorsomedial portion and caudally to the ventrolateral portion, but the trapezius muscle afferents projected solely to the ventrolateral portion at more caudal levels. 4) The terminal fields in the external cuneate nucleus were more extensive. 5) The projection area in the rostral medial cuneate nucleus was located slightly more medially, and projection to the ventromedial portion of the caudal medial cuneate nucleus and that to the intermediate nucleus were considerably fewer.

Mapping of evoked potentials on the cortical surface following electrical stimulation of the chorda tympani and the glossopharyngeal nerve, and anodal D.C. stimulation of the tongue indicated that the cortical taste area (CTA) was located in the dysgranular insular cortex just dorsal to the rhinal fissure near the middle cerebral artery in the hamster. Bilateral lesion of the CTA attenuated or disrupted the conditioned taste aversion that had been acquired preoperatively. This fact suggests that the CTA plays a role in some cognitive processes of taste. Experiments using anterograde and retrograde axonal transport of wheat-germ agglutinin conjugated horseradish peroxidase showed that the CTA received inputs from the contralateral CTA, amygdala, thalamic taste area and the pontine taste area, and that neurons in the CTA (chiefly in layer V) sent axons to the contralateral CTA, amygdala, and the thalamic, pontine and bulbar taste areas. Responses of 87 CTA neurons to the four basic taste stimuli were recorded in urethane-anesthetized hamsters. Majority of the CTA neurons (85%) existed in the dysgranular insular cortex. Neurons responding best to sucrose tended to be located rostrally, those to NaCl caudally, and those to HCl were distributed evenly in the CTA. Judging from the breadth of responses to the four tastes and across-neuron correlation coefficients, responsiveness of neurons in layer V is more narrowly tuned than in layers II-IV and VI.

The present study investigates the nature of tensor veli palatini muscle (TVP) and levator veli palatini muscle (LVP) as accessory respiratory muscles. In the first part of the study, the relation between the muscles' activities as revealed by EMG activities and respiration rhythm was analysed under various combinations of partial pressures of O2 and CO2 in the arterial blood. Furthermore, the effect of sodium cyanide (NaCN) perfused through the carotid sinus was examined. During resting breathing, no EMG activity was recorded from either muscle. In hypercapnic or hypoxemic conditions produced by rebreathing, TVP exhibited a phasic EMG activity during inspiration. LVP showed a phasic EMG activity during expiration in hypoxic conditions (PaO2 less than 40 mmHg). NaCN perfused bilaterally through the carotid sinus induced the phasic EMG activities similar to those observed in hypercapnia and/or hypoxemia. TVP was more sensitive to NaCN than LVP. The second part of the study examined specific roles of the muscles in altered states of breathing. At the time of onset of LVP activity induced by rebreathing, the oral proportion of airflow markedly increased. On the other hand, TVP activity greatly increased in amplitude when negative pressure was applied to the upper airway. The results suggest that both muscles are accessory respiratory muscles and are regulated by chemogenic inputs including those from the carotid body; TVP is an accessory inspiratory muscle that contributes to the maintenance of upper airway patency, and LVP is an accessory expiratory muscle that increases the portion of expiratory airflow through the oral cavity.