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Sources of movement-related cortical potentials derived from foot, finger, and mouth movements.

Movement-related cortical potentials (MRCPs) register brain electrical activity before and during movement execution. In an attempt to delineate the components of MRCPs that reflect common sources to various movements and that are movement-specific, simple self-paced voluntary foot, finger, and mouth movements were studied. MRCPs were recorded in eight healthy volunteers with 30 electrodes placed on the scalp. Data were analyzed using Brain Electric Source Analysis software, and multiple equivalent dipole models were developed to separate spatial and temporal aspects of brain activity related to the execution of voluntary movements. Independent models were separately developed for the grand average data and for the individual subjects' data for each movement type. MRCPs derived from foot movements were accounted for using a 5-dipole model, finger movements using an 8-dipole model, and mouth movements with a 7-dipole model, yielding the grand average residual variances of 3%, 2%, and 6%, respectively. Based on individual models, intersubject variability of dipole locations was less than 10 mm (+/- SD). Overlaying the mean dipole coordinates onto the stereotaxic atlas provided proof that the sensorimotor cortical areas, supplementary motor area, and also cerebellum and thalamus were active in all three movements. Locations of the dipoles in the contralateral sensorimotor area clearly implied well-known medial to lateral somatotopic organization of foot, finger, and mouth movements. Temporal separation of the activity spread over different brain areas was demonstrated by evolution in the moments of dipole source potentials. The authors' models support the view of simultaneous activation of the primary motor cortex and supplementary motor area at the time of movement execution. Multiple equivalent dipole models developed in this study implied the activity originating in corresponding brain areas as previously detected by positron emission tomography or functional magnetic resonance imaging. However, MRCPs provided additional information regarding the temporal evolution of the brain activity related to the execution of voluntary movements. Thus, the concurrent use of MRCPs and other imaging techniques may provide complementary information not easily obtained by the other imaging techniques themselves.

Adult↗

Hemorrhage in the floor of the mouth after second-stage surgery: case report.

Placement of dental implants in the interforaminal region of the mandible is generally considered a routine, simple, and safe procedure. However, severe bleeding and hematoma in the floor of the mouth have been reported as a rare but potentially fatal complication related to the placement of an implant in this region. The following report describes a case of life-threatening hemorrhage in the floor of the mouth after second-stage surgery to place the healing abutment. The implants were forced to match with the prosthesis in a severely atrophic upper jaw, resulting in a perforation of the lingual cortex and mucosa of the floor of the mouth. Clinicians who place implants should be knowledgeable in the treatment of such a serious complication.

Aged, 80 and over↗

Conspicuous, ultraviolet-rich mouth colours in begging chicks.

There is as yet no clear consensus on the function of vivid mouth colours in begging chicks. A major obstacle to our understanding has been that no studies have measured gape colours independently of human colour perception. Here, we present the first study, to our knowledge, to use UV-VIS spectrometry to quantify the gape colour, background nest colour and nest light environment of eight European passerines. Both mouths and the surrounding flanges show striking and previously unreported peaks of reflectance in the ultraviolet, coupled with high long-wavelength reflectance responsible for the human-visible appearance of the gape. High ultraviolet reflectance is likely to have an important effect on the conspicuousness of nestling mouths, since contrast with the nest background is maximal in the ultraviolet. Furthermore, the dual-peak nature of the spectra suggests that gapes are avian non-spectral colours analogous to human purple.

Animals↗

Locomotion through use of the mouth brushes in the larva of Culex pipiens (Diptera: Culicidae).

The larva of the mosquito Culex pipiens is a filter-feeder and is able to use the feeding current generated by its mouth brushes to glide slowly through the water. The hydrodynamics of the mouth brushes, and of gliding, were investigated by visualizing the feeding current using dyes. Unlike the mouth brushes of a sessile filter-feeder such as the blackfly larva, those of C. pipiens function more like 'paddles' than 'rakes', a beneficial adaptation to life in still as opposed to running water. Technically, the Froude efficiency of gliding is very low (0.23) because the design of the feeding brushes favours delivery of water into the wake rather than forward momentum to the body. The wider implications of these findings to foraging strategy and other aspects of the behaviour of mosquito larvae are discussed.

Animals↗

Buffering effect of antacids in the mouth--a new treatment of dental erosion?

Antacids are drugs of choice in the treatment of reflux esophagitis and peptic ulcer disease, where acid regurgitation may cause dental erosion. Since there are no specific preventive measures or effective treatment for erosions, the present study was made to assess whether the keeping of antacids in the mouth before swallowing would be beneficial with regard to their effect on mouth pH, after acidic challenge. Five healthy subjects formed the test panel. After measuring the acid binding capacity of all the antacid preparations in the Finnish market, the two most effective were selected for testing, one in emulsion form (Novaluzid), the other a tablet (Link). Acid regurgitation was mimicked by consuming a low-pH (3.2) drink immediately before the antacid. Control series were made with the acidic drink only. Both the antacids were found to counteract totally the pH fall caused by the drink, when measured as changes in the tongue surface pH. The Novaluzid preparation was more effective than the Link preparation but the difference was not significant. It may be anticipated that patients suffering from acid regurgitations would benefit if they are counseled to keep their antacids in the mouth for a while before swallowing.

Acids↗

Comparison of the guarding capacities of mouth protectors.

The guarding capacity of seven mouth protectors (Erkoflex 3.0 and 4.0, Erkoloc 3.0, 4.5 and 5.5, TranSheet/Perform and TranSheet/LiteLine) was tested mechanically on 20 plaster models, two or three tests on each mouth protector. Two tests on a plaster model without the protector served as control. An appliance was constructed to simulate the impact of an ice-hockey puck on the teeth, the plaster model was fixed onto the device and the minimum force needed to break the plaster teeth under the protector was recorded. The average total thickness and that of the soft and hard layers of the labial plates of each mouth protector were recorded along with the average thickness of the cervical and incisal hard and soft layers. The results showed that the best protection was achieved with the TranSheet/LiteLine model, followed by TranSheet/Perform and Erkoloc 5.5 and 4.5 mouthgards. All these had a resilient layer against the teeth, and it was shown in stepwise regression analysis that the only property having a statistically significant effect on the guarding capacity was the thickness of this cervical soft layer.

Athletic Injuries↗

The cause and management of burning mouth condition.

This paper reviews the clinical presentation and many causes of burning mouth condition. A diagnostic approach and some management procedures that include eliminating all oral irritants, correcting predisposing systemic disease, and most important of all, allaying anxiety that induces parafunctional mouth habits. The term "burning mouth condition" (BMC) is considered more appropriate than the word "syndrome" for this common and troublesome complaint.

Burning Mouth Syndrome↗

Cloned viral protein vaccine for foot-and-mouth disease: responses in cattle and swine.

A DNA sequence coding for the immunogenic capsid protein VP3 of foot-and-mouth disease virus A12, prepared from the virion RNA, was ligated to a plasmid designed to express a chimeric protein from the Escherichia coli tryptophan promoter-operator system. When Escherichia coli transformed with this plasmid was grown in tryptophan-depleted media, approximately 17 percent of the total cellular protein was found to be an insoluble and stable chimeric protein. The purified chimeric protein competed equally on a molar basis with VP3 for specific antibodies to foot-and-mouth disease virus. When inoculated into six cattle and two swine, this protein elicited high levels of neutralizing antibody and protection against challenge with foot-and-mouth disease virus.

Amino Acid Sequence↗

Effect of acyclovir on radiation- and chemotherapy-induced mouth lesions.

Several chemotherapeutic regimens and radiation therapy, if delivered to the oral mucosa, are associated with a high frequency of mouth lesions. The cause of this side effect is not known for certain, but in past studies it has sometimes been associated with the ability to culture herpes simplex virus type 1 from the mouth. In a double-blind prospective trial, patients with head and neck tumors treated with chemotherapy or radiation therapy were treated with either acyclovir or placebo. Although the frequency of culture-positive herpes simplex virus was low in the untreated group, it was significantly lower, zero, in the acyclovir-treated group. However, there were no differences in the frequency or type of mouth lesions experienced by patients receiving either radiation or chemotherapy who were taking acyclovir or placebo. These results suggest that herpes simplex virus is not a frequent cause or complication of oral lesions afflicting this patient population.

Acyclovir↗

Attachment of Bacteroides melaninogenicus subsp. asaccharolyticus to oral surfaces and its possible role in colonization of the mouth and of periodontal pockets.

This investigation examined the ability of cells of Bacteroides melaninogenicus subsp. asaccharolyticus 381 to adhere to surfaces that might be important for its initial colonization of the mouth and its subsequent colonization in periodontal pockets. Of 48 asaccharolytic strains of B. melaninogenicus, 47 agglutinated human erythrocytes, whereas none of 20 fermentative strains, which included reference cultures of the subspecies intermedius and melaninogenicus, were active. Electron microscopy indicated that both asaccharolytic and fermentative strains possessed pili; hence, the presence of pili did not correlate with the hemagglutinating activities of B. melaninogenicus strains. Both asaccharolytic and fermentative B. melaninogenicus strains suspended in phosphate-buffered saline adhered in high numbers to buccal epithelial cells and to the surfaces of several gram-positive bacteria tested, including Actinomyces viscosus, A. naeslundii, A. israelii, Streptococcus sanguis, and S. mitis. B. melaninogenicus subsp. asaccharolyticus 381 also attached, but in comparatively low numbers, to untreated and to saliva-treated hydroxyapatite. Addition of clarified whole saliva to suspensions of strain 381 almost completely eliminated adherence to buccal epithelial cells and to hydroxyapatite surfaces, but saliva had no detectable effect on attachment to gram-positive plaque bacteria. Both fermentative and nonfermentative strains of B. melaninogenicus also attached in high numbers to crevicular epithelial cells derived from human periodontal pockets, but normal human serum strongly inhibited attachment. Serum also inhibited attachment of strain 381 to saliva- and serum-treated hydroxyapatite, but it had little effect upon attachment to gram-positive bacteria. These observations suggested that salivary and serum components would strongly inhibit the attachment of B. melaninogenicus cells to several oral surfaces, but not to the surfaces of certain gram-positive bacteria commonly present in human dental plaque. This was confirmed by an in vivo experiment in which streptomycin-labeled cells of B. melaninogenicus 381-R were introduced into the mouths of two volunteers. After 10 min, several hundred-fold higher numbers of the organism were recovered from preformed bacterial plaque present on teeth than from clean tooth surfaces or from the buccal mucosa and tongue dorsum. High numbers of B. melaninogenicus cells were also recovered from preformed plaque after 150 min, but virtually no cells of the organism were recovered from the other surfaces studied. These data suggest that the presence of dental plaque containing Actinomyces and other gram-positive bacteria may be essential for the attachment and colonization of B. melaninogenicus cells after their initial introduction into the mouth. Similarly, the presence of subgingival plaque containing gram-positive bacteria may be necessary for its secondary colonization in periodontal pockets.

Adult↗

Serological response of cattle to simultaneous vaccinations against foot-and-mouth disease and haemorrhagic septicaemia.

In Malaysia, where vaccination campaigns against foot-and-mouth disease and haemorrhagic septicaemia are routinely carried out, it was desirable to determine whether it was safe and efficacious to administer both vaccines simultaneously. A trial group of 104 cattle was divided into three groups; group 1 animals received both vaccines simultaneously, group 2 animals received only foot-and-mouth disease vaccine and group 3 animals received only haemorrhagic septicaemia vaccine. The serological response to vaccinations was monitored at 0, 21 and 35 days by the virus neutralisation test for foot-and-mouth disease and the mouse-protection and indirect haemagglutination tests for haemorrhagic septicaemia. The simultaneous administration of the two inactivated vaccines produced no adverse effects and the serological response did not differ from the response to either vaccine given separately, thus indicating that cattle may be safely and effectively vaccinated simultaneously in this way.

Animals↗

Foot-and-mouth disease: the risk for Great Britain after 1992.

Mass annual vaccination against foot-and-mouth disease, previously applied by eight member states in the European Community (EC), was progressively phased out during 1990-91. The other four member states (the United Kingdom, Denmark, the Republic of Ireland and Greece) either never have vaccinated or ceased to do so several years ago. The EC should increase its international competitiveness if it maintains its present foot-and-mouth disease-free, non-vaccinating status. Freedom from disease and a harmonised disease control policy will also permit unrestricted movement of livestock and animal products throughout the EC when the single market is completed in 1992. Vaccination against foot-and-mouth disease on continental Europe has greatly reduced the number of outbreaks during the last 30 years and this reduction has been of indirect benefit to Great Britain. However, the cessation of vaccination will result in a higher proportion of fully susceptible cattle and in the event of outbreaks will increase the likelihood of the rapid dissemination of virus and increase the risk that the infection will enter Great Britain. The main risks of entry are likely to be associated with live animals in which the disease can be mild or inapparent, ie, sheep and goats, and with airborne virus originating from pigs on the nearby continent especially in Brittany and the Benelux countries where they are present in very high densities.

Animals↗

Airway area by acoustic reflections measured at the mouth.

We tested the hypothesis that features of upper airway and tracheal geometry can be inferred from acoustic reflection data recorded at the mouth. In six subjects we computed inferences of airway cross-sectional area vs. distance and compared them with measurements obtained from orthogonal radiographic projections of the trachea. The acoustic data show local area maxima at the uvula and hypopharynx and local minima at the oropharynx and the glottis. With subjects breathing air the inferred tracheal areas markedly exceeded the radiographic measurements. With subjects breathing 80% He-20% O2 there was good intrasubject agreement between acoustic and radiographic data in spite of large intersubject variability. The average coefficient of variation of tracheal area determinations for five trials in all subjects was 0.16. These studies suggest that features of airway geometry between the mouth and carina can be determined accurately and noninvasively in individual subjects from high-frequency reflection data measured at the mouth.

Acoustics↗

Pattern of simulated snoring is different through mouth and nose.

Cineradiography of the pharynx during simulated snoring was done in 6 healthy volunteers, and supraglottic pressure and flow rate were recorded in 12 others. We observed, immediately before snoring, a decrease in the sagittal diameter of the oropharynx followed, during snoring, by high-frequency oscillations of soft palate and pharyngeal walls. The pattern of soft palate oscillations was different while snoring through the nose or mouth. During inspiratory snoring through the nose, the soft palate remained in close contact with the back of the tongue and only the uvula presented high-frequency oscillations. Snoring through the mouth resulted in ample high-frequency oscillations of the whole soft palate. Frequency of airflow and supraglottic pressure oscillations was less (P less than 0.05) during mouth (28.2 +/- 7.5 Hz) than during nasal snoring (77.8 +/- 36.7 Hz). This difference may be related to the smaller oscillating mass (i.e., uvula) during nasal snoring. At variance with our previous data, which showed that snoring during sleep, in both heavy (nonapneic) snorers and obstructive sleep apnea patients, was systematically preceded by flow limitation, this was not true during simulated snoring.

Adult↗

Retention of glucose in oral fluid at different sites in the mouth.

Using glucose as a marker, a detailed study of retention at 5 different sites in the mouth of 1 subject and a less detailed examination of 4 selected sites in the mouths of 10 other subjects revealed site-specific differential patterns of oral retention (or clearance). These patterns seemed independent of sometimes large, absolute day-to-day variations in oral retention which occur in all subjects but appeared to vary somewhat between subjects, probably reflecting slight differences in the anatomy and physiology of the individual mouth. In general, the patterns resembled those recently derived from studies of other oral phenomena such as rates of diffusion out of plaque, fluoride uptake by mineral and hydrogen ion concentrations in plaque. They will dictate the concentrations and thereby influence the activity of all extraneous substances in different regions of the oral cavity and may relate to the site-specific patterns of oral disease.

Administration, Oral↗

Effects of flow-resistive loading on mouth occlusion pressure during CO2 rebreathing.

To evaluate mouth occlusion pressure as an index of neural drive to the respiratory muscles that is independent of lung mechanics, the occlusion pressure response to rebreathing was studied in 7 normal subjects under control conditions and during flow-resistive loading. Inspiratory, expiratory, and combined inspiratory-expiratory flow resistances of 5 and 17 cm H2O per liter per sec were studied in 7 normal subjects. Pressure at the mouth was measured 150 msec after the onset of inspiration against the occluded airway. In all subjects, the ventilatory response to CO2 rebreathing was consistenly decreased by the 3 types of resistive loads, and this decrease was often greater with the higher load. In contrast, the occlusion pressure response was usually increased with inspiratory and inspiratory-expiratory resistance, indicating increased inspiratory muscle output due to these loads. With expiratory resistance, the occlusion pressure response was decreased in most of the subjects, suggesting a decrease in muscular output with expiratory loading. The inspiratory muscle pressure response to resistive loading could have been mediated by neural reflex and/or intrinsic muscle mechanisms. Occlusion pressure, therefore, appears to reflect over-all inspiratory neuromuscular output of the respiratory system during CO2 rebreathing, even with the addition of flow-resistive loads. Measures of mouth occlusion pressure provide a distinct advantage over ventilatory parameters in studies of respiratory control mechanisms during mechanical loading.

Adult↗

Impact velocities of the teeth after a sudden unloading at various initial bite forces, degrees of mouth opening, and distances of travel.

A potentially dangerous situation arises when an individual bites on hard and brittle food which suddenly breaks, since the impact velocity of the lower teeth onto the upper teeth after the food is broken can be high and may cause dental damage. The present experiments were designed to study the magnitude of the impact velocity after a sudden unloading at various initial bite forces, degrees of mouth opening, and distances of travel. Subjects were asked to perform a static biting task during which the resistance to the bite was suddenly removed. The upward mandible movement was arrested after a certain distance. The velocity of the lower teeth at impact was calculated just before the mandible came to a standstill in combinations of 4 different bite forces (100, 80, 60, and 40 N), 4 different initial degrees of mouth opening (33.5, 30.5, 27.5, and 24.5 mm), and 3 different distances of travel of the mandible (4.5, 3.0, and 1.5 mm). We found that the bite force rapidly declined after the unloading, resulting in a small impact velocity of the lower front teeth. This impact velocity largely depended on the magnitude of the initial bite force and the distance traveled; it was barely sensitive to variations in degree of initial mouth opening. The maximal velocity of the lower teeth was 0.43 m/s (at an initial bite force of 100 N). This maximum was reached after a distance of travel of about 4 mm in 12 ms. The data suggest that the rapid decline in bite force coupled with a limitation of impact velocity is due to the force-velocity properties of the active jaw muscles and is not caused by neural control.

Biomechanical Phenomena↗

Epidemiology of mouth cancer in 1989: a review.

The oral cavity and pharynx combined is the sixth commonest site of cancer in both sexes. In many countries the mortality rate is increasing among younger men born since approximately 1910-1920. A causal role in the aetiology of mouth cancer has been established for tobacco use, both smoking and chewing, separately and in conjunction with betel-quid chewing; with alcohol consumption and, less certainly, with other factors such as poor oral hygiene, nutritional factors and certain occupational exposures. In Western countries, there is convincing evidence that a large attributable risk can be ascribed to the joint habits of cigarette smoking and alcohol consumption. In Asian societies, a high attributable risk can be ascribed to cigarette smoking and betel chewing. Mouth cancer is at the same time an important form of cancer, and one for which practical prospects for prevention already exist. Against this background of a continually increasing trend among younger persons, it seems essential to engage upon programmes of prevention, including increasing awareness for early detection, against mouth cancer at the present time.

Areca↗