Age and gender influence on maximal bite force and masticatory muscles thickness

The present study aimed investigate the age and gender influence on maximal molar bite force and at outlining the criteria for normal masticatory muscle development in a sample of 177 Brazilian Caucasian dentate individuals aged 7-80 years divided into five age groups: I(7-12 years), II (13-20 years), III (21-40 years), IV (41-60 years), and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided in respect to gender (20 M/20 F). Bite force was recorded with a mouth-adapted 1000 N dynamometer and the highest out of three records was regarded as the maximal bite force. The data were submitted to multivariate statistical analysis (SPSS 17.0 p < 0.05). Effects of group and gender were found, but no interactions between them. The ANOVA showed significant differences between groups bilaterally. Bonferroni`s test showed that group I had significantly lower bite force means at both sides as compared to all groups, except group V. No differences were found between the left and right sides. In all the groups, gender was found to be a significant factor associated with maximal bite force. A global comparison including all the subjects and measures showed that the means of men were approximately 30% higher than those of women, within-group comparisons yielded similar results in all groups. Muscle thickness was measured with a SonoSite Titan ultrasound tool using a high-resolution real-time 56 mm/10 MHz linear-array transducer. Three ultrasound images were obtained from the bilateral masseter and temporal muscles at rest and at maximal voluntary contraction. The means of the three measures in each clinical condition were analyzed with multivariate statistical analysis (SPSS 17.0 p < 0.05). A gradual increase in thickness of the masseter and temporal muscles was found both at rest and maximal voluntary contraction for groups I to IV, whereas a decrease in muscle thickness was observed in group V. Multivariate analysis showed that in both conditions there was an effect of group and gender. The study of the development of the stomatognathic system in relation to age and gender can provide useful data for the identification of normal and impaired functioning patterns. The results of this study indicate that age and gender are associated with structural and functional alterations in the muscles of the stomatognathic system. (C) 2010 Elsevier Ltd. All rights reserved.

Ageing and surface EMG activity patterns of masticatory muscles

P>The purpose of this study was to evaluate the influence of age on the electromyographic activity of masticatory muscles. All volunteers were Brazilian, fully dentate (except for Group I - mixed dentition), Caucasian, aged 7-80, and divided into five groups: I (7-12 years), II (13-20 years), III (21-40 years), IV (41-60 years) and V (61-80 years). Except for Group V, which comprised nine women and eight men, all groups were equally divided with respect to gender (20 M/20 F). Surface electromyographic records of masticatory muscles were obtained at rest and during maximal voluntary contraction, right and left laterality, maximal jaw protrusion and maximal clenching in the intercuspal position. Statistically significant differences (P < 0 center dot 05) were found in all clinical conditions among the different age groups. Considerably different patterns of muscle activation were found across ages, with greater electromyographic activity in children and youth, and decreasing from adults to aged people.

Electromyographic evaluation in children having rapid maxillary expansion

Introduction: The aim of this study was to analyze the electromyographic activity of the masseter and temporalis muscles of children having rapid maxillary expansion (RME) with a bonded rapid maxillary expansion appliance. Methods: The sample consisted of 27 children (mean age, 8.6 years) with posterior crossbite who required RME treatment. Electromyographic activity of the masseter and temporalis muscles was analyzed before treatment and after the appliance was removed. The mean interval between the 2 analyses was 5 months. Muscular activity was electromyographically analyzed in rest position, and with maximum voluntary dental clenching and chewing. Differences in the 2 measurements were evaluated by using paired t tests. Results and Conclusions: Electromyographic analysis showed that activity of the masseter and temporalis muscles increased significantly after the expansion appliance was removed during rest, dental clenching, and habitual chewing. (Am J Orthod Dentofacial Orthop 2009;136:355-60)

Masticatory muscle activity in children with a skeletal or dentoalveolar open bite

Forty-five children (31 boys and 14 girls), aged 6-11 years, were included in the study, 15 with a skeletal anterior open bite (SAOB), 15 with a dentoalveolar anterior open bite (DAOB), and 15 with a normal occlusion (CG), defined by clinical evaluation and lateral cephalograms. EMG recordings of the temporal and masseter muscles were performed under maximal voluntary clenching and during chewing. Analysis of variance was used for inter-group analysis, followed by the Tukey post hoc test. A Student`s t-test for paired data was used for intra-group analysis. There were statistically significant differences among the three groups (P < 0.05), with the mean EMG being highest in the CG and lowest in children with a SAOB. The percentage EMG activity during chewing in relation to that during maximal voluntary clenching was more than 100 per cent in the SAOB group. The CG and DAOB groups presented higher EMG activity during clenching compared with chewing (P < 0.001), as well as a greater difference between tasks. In the SAOB group, the neuromuscular system appeared to have a lower capacity to produce EMG activity according to the task, while that in the DAOB group suggests that their functional capacity during growth should also be carefully observed.

Determination of temperature variation during the individual steps of the production of hospital diets of modified consistency

Background & aim: Many disease outbreaks of food origin are caused by foods prepared in Food Service and Nutrition Units of hospitals, affecting hospitalized patients who, in most cases, are immunocompromised and therefore at a higher risk of severe worsening of their clinical status. The aim of this study was to determine the variations in temperature and the time-temperature factor of hospital diets. Methods: The time and temperature for the preparation of 4 diets of modified consistency were determined on 5 nonconsecutive days in a hospital Diet and Nutrition Unit at the end of preparation and during the maintenance period, portioning and distribution at 3 sites, i.e., the first, the middle and the last to receive the diets. Results and discussion: All foods reached an adequate temperature at the end of cooking, but temperature varied significantly from the maintenance period to the final distribution, characterizing critical periods for microorganism proliferation. During holding, temperatures that presented a risk were reached by 16.7% of the meats and 59% of the salads of the general diet, by 16.7% of the garnishes in the bland diet and by 20% of the meats and garnishes in the viscous diet. The same occurred at the end of distribution for 100% of the hot samples and of the salads and for 61% of the desserts. None of the preparations remained at risk temperature for a time exceeding that established by law. Conclusion: The exposure to inadequate temperature did not last long enough to pose risks to the patient.

The rise of multiple births in Brazil

Aim: The aim of this study was to assess the rise in multiple births and its influence on trends of low birth weight (LBW) rates in Porto Alegre, Brazil. Methods: This is a registry-based study of live births from 1994 to 2005 obtained from the national live birth information system. Chi-square tests for trends were assessed for LBW and multiple birth rates. The impact of multiple births on LBW trends was assessed by sequential modelling, including year and further adjustment for multiple births. Risk factors for multiple births were assessed using the Poisson regression. Results: A total of 263 252 live births were studied. The LBW rate increased from 9.70% to 9.88% (p < 0.001) and the multiple birth rate rose from 1.95% to 2.53% (p < 0.001). LBW rate increased among twins, from 57.14% to 63.46% (p = 0.001). The twin birth rate rose by 24.7%, while the rate of triplets or higher-order increased by 150%. Multiple births may be responsible for 23.9% of the increase in the LBW rate over the period. Mothers with higher levels of schooling, older mothers and mothers delivering in private hospitals were more likely to deliver multiple births. Conclusions: It seems that both the increase in multiple births and in the LBW among multiple births contributed to this rise in overall LBW rate.

Molecular characteristics of extended-spectrum beta-lactamase-producing Escherichia coli from Rio de Janeiro, Brazil

Twenty-five extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli clinical isolates from Rio de Janeiro, Brazil were characterized by isoelectric focusing, PCR and sequencing of bla(ESBL) genes, plasmid-mediated quinolone resistance determinants, phylogenetic groups, replicon typing, pulsed-field electrophoresis, and multilocus sequencing typing. Twenty-three (92%) ESBL-producing E. coli isolates were positive for bla(CTX-M) genes, aac(6`)-lb-cr, and qnrB. Genetic relatedness of ESBL producers clustered seven (28%) CTX-M-15-producing isolates as sequence type (ST) 410, clonal complex (CC) 23, and two (8%) as clone O25-ST131. Our results illustrate the predominance of phylo-group A (52%), ST410 (CC 23) and CTX-M-15 among ESBL-producing E. coli isolates from hospitals in Rio de Janeiro.

Assessment of two central auditory tests in elderly patients without hearing complaints

Speech understanding disorders in the elderly may be due to peripheral or central auditory dysfunctions. Asymmetry of results in dichotic testing increases with age, and may reflect on a lack of inter-hemisphere transmission and cognitive decline. Aim: To investigate auditory processing of aged people with no hearing complaints. Study design: clinical prospective. Materials and Methods: Twenty-two voluntary individuals, aged between 55 and 75 years, were evaluated. They reported no hearing complaints and had maximal auditory thresholds of 40 dB HL until 4 KHz, 80% of minimal speech recognition scores and peripheral symmetry between the ears. We used two kinds of tests: speech in noise and dichotic alternated dissyllables (SSW). Results were compared between males and females, right and left ears and between age groups. Results: There were no significant differences between genders, in both tests. Their Left ears showed worse results, in the competitive condition of SSW. Individuals aged 65 or older had poorer performances than those aged 55 to 64. Conclusion: Central auditory tests showed worse performance with aging. The employment of a dichotic test in the auditory evaluation setting in the elderly may help in the early identification of degenerative processes, which are common among these patients.

Implant-supported prosthesis following Branemark protocol on electromyography of masticatory muscles

This research evaluated the effects of Branemark protocol on electromyography of the masseter and temporal muscles. The patients were divided into two groups: Group 1: patients who wore an implant-supported prosthesis in the mandibular arch following Branemark protocol, and maxillary removable complete dentures; Group II: dentate individuals (control). Electromyography was carried out at rest, right (RL) and left (LL) laterality, protrusion and maximum voluntary contraction (MVC). Data were compared by t-test. At rest, a higher electromyographic (EMG) activity was observed in Group I, and the values were significant in the right masseter and left temporal muscles. In RL, there were statistically significant differences for right masseter (P < 0.01), left masseter and temporal muscles and for the left temporal muscle in LL (P < 0.05). In protrusion, Group I presented a higher EMG activity, and there was a statistically significant difference for the right masseter muscle (RM) (P < 0.05). In MVC, the EMG values were higher in Group II (control), but significant just for the right temporal muscle (P < 0.05). In conclusion, individuals with mandibular fixed dentures supported according to the Branemark protocol and maxillary removable complete dentures showed a higher activity of masticatory muscles during the mandibular postural clinical conditions examined; however, in the MVC, Group I presented lower values when compared to dentate group. Despite presenting different EMG values in all of the clinical conditions, both groups showed similar EMG patterns of muscle activation which demonstrates that the proposed treatment can be considered as a good option for oral rehabilitation.

A responsible gambling strategy for older Queenslanders: Final Report

This study investigates the needs, experiences, behaviours and attitudes of older Queenslanders who participate in gambling. It aims to understand the special needs and circumstances of older Queensland gamblers which might make them particularly vulnerable to problem gambling behaviour, or other negative effects of gambling. The findings of the research will provide an evidence base for the development of initiatives and policies that can address the specific prevention, protection and rehabilitation needs of older gamblers. This is with a particular view to informing the ongoing development and implementation of the Queensland Government’s Responsible Gambling Strategy and its voluntary industry code – the Queensland Responsible Gambling Code of Practice.

Immediate Effect of the Resilient Splint Evaluated Using Surface Electromyography in Patients with TMD

The aim of this study was to analyze the immediate effect of resilient splints through surface electromyography testing and to compare the findings with the electromyographic profiles of asymptomatic subjects. The participants were 30 subjects, 15 patients with TMD (TMD Group) and 15 healthy subjects (Control Group), classified according to Research Diagnostic Criteria (RDC/TMD) Axis I. A resilient occlusal splint was made for each patient in the TMD Group from two mm thick silicon to cover all teeth. The EMG examination was performed before and immediately after installing the splint. Three tests were performed as follows: 1. Maximum Voluntary Contraction (MVC) using cotton rolls (standards test); 2. MVC in maximal intercuspation position; and 3. MVC with the splint in position. The EMG signal was recorded for five seconds. EMG indices were calculated to assess muscle symmetry, jaw torque, and impact. There was a statistically significant difference when comparing the results among the study groups. The symmetry index values in the Control Group were higher than the TMD Initial Group and similar to the TMD Group after the installation of the splint. The index values of torque were higher in TMD Initial Group when compared with the Controls. Impact values were lower than normal values in the TMD Initial Group and restored upon installation of the splint. The resilient occlusal splints may be used as complementary or adjunctive treatment of temporomandibular disorders.

Underuse of beta-blockers following myocardial infarction: a tale of two cities

Aims: To measure factors associated with underuse of beta-blocker therapy after myocardial infarction (MI). Methods: The Newcastle and Perth collaborating centres of the World Health Organization (WHO) MONICA project (to MONItor trends and determinants of Cardiovascular disease) systematically evaluated all patients admitted to hospital in their respective regions with possible MI. A total of 1766 patients in Newcastle and 4503 patients in Perth, discharged from hospital after confirmed MI from 1985 to 1993, were studied, Rates of beta-blocker use before and after hospital discharge were evaluated and correlates of beta-blocker use determined. Results: Beta-blocker use was similar in Newcastle and Perth before MI (21% of patients in each centre). During hospital admission, beta-blocker therapy was initiated nearly twice as frequently in Perth compared with Newcastle (66 vs 36%, respectively) and more patients were discharged from hospital on beta-blockers in Perth (68%) than in Newcastle (45%). The main factors associated with underuse of beta-blockers in multivariate analysis were geographical centre (odds ratio (OR) for Newcastle compared with Perth 0.3 95% confidence interval (CI) 0.3-0.3), a history of previous MI (OR 0.6, 95% CI 0.5-0.7), admission to hospital in earlier years (OR 0.4, 95% CI 0.3-0.4 for years 1985-87 compared with years 1991-93), diabetes (OR 0.6, 95% CI 0.5-0.8) and the concomitant use of diuretics (OR 0.5, 95% CI 0.4-0.6) and calcium antagonists (OR 0.6, 95% CI 0.5-0.8). Conclusions: Underuse of beta-blockers after MI was strongly related to hospital prescribing patterns and not to community use of beta-blockers. Underuse occurred in patients with diabetes and in patients with left ventricular dysfunction, patients who stand to benefit most from beta-blocker use following MI.

Forced emigration, favourable outcomes

The discipline of public health and preventive medicine in Australia and New Zealand had its genesis in the advocacy of 18th and 19th century military pioneers. Military (Royal Navy and British Army) surgeons were posted to Australia as part of their non-discretionary duty. Civilian doctors emigrated variously for adventure, escapism and gold fever. One group, a particularly influential group disproportionate to their numbers, came in one sense as forced emigrants because of chronic respiratory disease in general, and tuberculosis in particular. Tuberculosis was an occupational hazard of 19th century medical and surgical practice throughout western Europe. This paper analyses six examples of such emigration which had, perhaps unforeseen at the time, significant results in the advancement of public health. Such emigration was in one sense voluntary, but in another was forced upon the victims in their quest for personal survival. In Australia, such medical individuals became leading advocates and successful catalysts for change in such diverse fields as social welfare, public health, the preventive aspects of medical practice, child health, nutrition and medical education. A number of such public health pioneers today have no physical memorials; but their influence is to be seen in the ethos of medical practice in Australia and New Zealand today. Their memory is further perpetuated in the names of Australian native wildflowers and trees that symbolise not only a healthy environment but the longterm investment, accrued with interest, of the institution of public health measures for which their advocacy achieved much success.

Reliability of the input-output properties of the cortico-spinal pathway obtained from transcranial magnetic and electrical stimulation

The purpose of this experiment was to assess the test-retest reliability of input-output parameters of the cortico-spinal pathway derived from transcranial magnetic (TMS) and electrical (TES) stimulation at rest and during muscle contraction. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous muscle of eight individuals on three separate days. The intensity of TMS at rest was varied from 5% below threshold to the maximal output of the stimulator. During trials in which the muscle was active, TMS and TES intensities were selected that elicited MEPs of between 150 and 300 X at rest. MEPs were evoked while the participants exerted torques up to 50% of their maximum capacity. The relationship between MEP size and stimulus intensity at rest was sigmoidal (R-2 = 0.97). Intra-class correlation coefficients (ICC) ranged between 0.47 and 0.81 for the parameters of the sigmoid function. For the active trials, the slope and intercept of regression equations of MEP size on level of background contraction were obtained more reliably for TES (ICC = 0.63 and 0.78, respectively) than for TMS (ICC = 0.50 and 0.53, respectively), These results suggest that input-output parameters of the cortico-spinal pathway may be reliably obtained via transcranial stimulation during longitudinal investigations of cortico-spinal plasticity. (C) 2001 Elsevier Science B.V. All rights reserved.

Changes in muscle recruitment patterns during skill acquisition

The control of movement is predicated upon a system of constraints of musculoskeletal and neural origin. The focus of the present study was upon the manner in which such constraints are adapted or superseded during the acquisition of motor skill. Individuals participated in five experimental sessions, ill which they attempted to produce abduction-adduction movements of the index finger in time with an auditory metronome. During each trial, the metronome frequency was increased in eight steps from an individually determined base frequency. Electromyographic (EMC) activity was recorded from first dorsal interosseous (FDI), first volar interosseous (FVI), flexor digitorum superficialis (FDS), and extensor digitorum communis (EDC) muscles. The movements produced on the final day of acquisition more accurately matched the required profile, and exhibited greater spatial and temporal stability, than those generated during initial performance. Tn the early stages of skill acquisition, an alternating pattern of activation in FDI and FVI was maintained, even at the highest frequencies. Tn contrast, as the frequency of movement was increased, activity in FDS and EDC was either tonic or intermittent. As learning proceeded, alterations in recruitment patterns were expressed primarily in the extrinsic muscles (EDC and FDS). These changes took the form of increases in the postural role of these muscles, shifts to phasic patterns of activation, or selective disengagement of these muscles. These findings suggest that there is considerable flexibility in the composition of muscle synergies, which is exploited by individuals during the acquisition of coordination.