Neural control of leg stiffness during hopping in boys and men

The purpose of the study was to investigate whether boys and men utilise different control strategies whilst hopping. Eleven boys (11–12 yr old) and ten men completed hopping at 1.5 Hz, 3.0 Hz and at their preferred frequency. A footswitch measured contact and flight times, from which leg stiffness was calculated. Simultaneously, surface electromyograms (EMGs) of selected lower limb muscles were recorded and quantified for each 30 ms period during the first 120 ms post-ground contact. At 1.5 Hz there were no differences between the groups in relative stiffness or muscle activity. At 3.0 Hz men had significantly shorter contact times (P = 0.013), longer flight times (P = 0.002), greater relative stiffness (P = 0.01) and significantly greater soleus (P = 0.012) and vastus lateralis (P < 0.001) activity during the initial 30 ms post-ground contact. At the preferred frequency men hopped significantly faster than the boys (P = 0.007), with greater leg stiffness (P < 0.01) and with more extensor activity in most time periods. Boys and men demonstrated similar control strategies when hopping at a slow frequency, but when hopping frequency increased men were able to better increase feedforward and reflex muscle activity to hop with greater relative stiffness.     

Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves

Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude.     

Intra- and interday reliability of voluntary and electrically stimulated isometric contractions of the quadriceps femoris

The reliability of voluntary and electrically stimulated isometric contractions of m. quadriceps femoris of male participants (n = 10; age 30 ± 8 years; height 1.79 ± 0.05 m; body mass 79.4 ± 8.3 kg) was investigated using ratio limits of agreement (LoA) on a time scale common to examine recovery from muscle damaging exercise. No systematic changes in reliability occurred over time (baseline versus 2, 24, 48, and 72 h). Maximal voluntary contraction (MVC) and interpolated twitch technique (ITT) showed no mean bias (P > 0.05) with 95% LoA of ±12.7 and ±5.4, respectively. Resting twitch and potentiated doublet peak force showed no mean bias (P > 0.05). However, 95% LoA were smaller for the doublet (±13.9) than the twitch (±32.0). Twitch and doublet rates showed similar trends. Ratio of low (20 Hz) to high (50 Hz) frequency forces showed no mean bias (P > 0.05) and 95% LoA of (±9.2). However, there was significant mean bias (P < 0.05) and wider 95% LoA for peak force, contraction and relaxation parameters of the low and high frequency forces. In conclusion, MVC, ITT, potentiated doublet and the ratio of low to high frequency forces are recommended to most reliably examine functional muscle recovery between 2 and 72 h after damaging exercise.     

The acute effects of local muscle vibration frequency on peak torque,rate of torque development,and EMG activity

PurposeVibratory stimuli enhance muscle activity and may be used for rehabilitation and performance enhancement. Efficacy of vibration varies with the frequency of stimulation, but the optimal frequency is unclear. The purpose of this study was to examine the effects of 30 Hz and 60 Hz local muscle vibration (LMV) on quadriceps function.MethodsTwenty healthy volunteers (age = 20.4 ± 1.4 years, mass = 68.1 ± 11.0 kg, height = 170.1 ± 8.8 cm, males = 9) participated. Isometric knee extensor peak torque (PT), rate of torque development (RTD), and electromyography (EMG) of the quadriceps were assessed followed by one of the three LMV treatments (30 Hz, 60 Hz, control) applied under voluntary contraction, and again immediately, 5, 15, and 30 min post-treatment in three counterbalanced sessions. Dependent variables were analyzed using condition by time repeated-measures ANOVA.ResultsThe condition × time interaction was significant for EMG amplitude (p = 0.001), but not for PT (p = 0.324) or RTD (p = 0.425). The increase in EMG amplitude following 30 Hz LMV was significantly greater than 60 Hz LMV and control.ConclusionsThese findings suggest that 30 Hz LMV may elicit an improvement in quadriceps activation and could be used to treat quadriceps dysfunction resulting from knee pathologies.     

Hair snaring and molecular genetic identification for reconstructing the spatial structure of Eurasian lynx populations

Non-invasive genetic sampling (NGS) is being increasingly applied in wildlife monitoring and population genetic research. This study was designed to evaluate the use of NGS for reconstructing the spatial structure of populations of large felids. We developed a procedure for reliably genotyping individuals of Eurasian lynx (Lynx lynx) from samples obtained through a hair-trapping scheme based on a network of lynx scent-marking sites. The spatial locations of the identified genotypes were matched with the home ranges distribution of radio-tracked individuals, thus cross-checking the accuracy of the two methods. We analyzed DNA extracted from 170 hair samples and 11 blood samples from live-trapped lynx collected in 2004–2009 in the Bia?owie?a Primeval Forest, Poland. We obtained PCR products in 96 (67%) hair samples; 82 (85%) of them were reliably genotyped at 12 autosomal microsatellite loci following a multiple-tubes protocol and stringent quality-controls of the data set. The sample included 29 distinct genotypes; 18 were found only in hair samples, five were determined only in live-trapped animals, and six in both hair and blood samples. Based on linkage disequilibrium we estimated an effective population size N_e = 20.3 (90% CI = 15–28). The total population size estimated with Capwire was N_c = 32 (95% CI = 25–37) in close agreement with the observed number of genotypes. The genotypes obtained from hair samples were re-sampled on average 3.9 times and 50% of them were recorded for more than one year. The spatial distribution of six hair-genotypes was consistent with their home ranges obtained by radio-tracking in the same period. The distribution ranges of hair-trapped genotypes overlapped on average in 86.4% (mode 100%) with home ranges of the corresponding individuals. Hair-trapping and molecular identification is a reliable method for reconstructing the spatial organization of lynx population. It is likely to be also efficiently used in other rare and endangered species of felids in combination with data from other monitoring techniques, such as radio- and snow-tracking and photo-trapping.     

Stature,body mass,and brain size: A two-million-year odyssey

Physical size has been critical in the evolutionary success of the genus Homo over the past 2.4 million-years. An acceleration in the expansion of savannah grasslands in Africa from 1.6 Ma to 1.2 Ma witnessed concomitant increases in physical stature (150–170 cm), weight (50–70 kg), and brain size (750–900 cm³). With the onset of 100,000 year Middle Pleistocene glacial cycles (“ice ages”) some 780,000 years ago, large-bodied Homo groups had reached modern size and had successfully dispersed from equatorial Africa, Central, and Southeast Asia to high-latitude localities in Atlantic Europe and North East Asia. While there is support for incursions of multiple Homo lineages to West Asia and Continental Europe at this time, data does not favour a persistence of Homo erectus beyond ～400,000 years ago in Africa, west and Central Asia, and Europe. Novel Middle Pleistocene Homo forms (780,000–400,000 years) may not have been substantially taller (150–170 cm) than earlier Homo (1.6 Ma–800,000 years), yet brain size exceeded 1000 cm³ and body mass approached 80 kg in some males. Later Pleistocene Homo (400,000–138,000 years) were ‘massive’ in their height (160–190 cm) and mass (70–90 kg) and consistently exceed recent humans. Relative brain size exceeds earlier Homo, yet is substantially lower than in final glacial H. sapiens and Homo neanderthalensis. A final leap in absolute and relative brain size in Homo (300,000–138,000 years) occurred independent of any observed increase in body mass and implies a different selective mediator to that operating on brain size increases observed in earlier Homo.     

Atrial flutter and atrial tachycardia detection using Bayesian approach with high resolution time–frequency spectrum from ECG recordings

Contemporary methods of atrial flutter (AFL), atrial tachycardia (AT), and atrial fibrillation (AF) monitoring, although superior to the standard 12-lead ECG and symptom-based monitoring, are unable to accurately discriminate between AF, AFL and AT. Thus, there is a need to develop accurate, automated, and comprehensive atrial arrhythmia detection algorithms using standard ECG recorders. To this end, we have developed a sensitive and real-time realizable algorithm for accurate AFL and AT detection using any standard electrocardiographic recording. Our novel method for automatic detection of atrial flutter and atrial tachycardia uses a Bayesian approach followed by a high resolution time–frequency spectrum. We find the TQ interval of the electrocardiogram (ECG) corresponding to atrial activity by using a particle filter (PF), and analyze the atrial activity with a high resolution time–frequency spectral method: variable frequency complex demodulation (VFCDM). The rationale for using a high-resolution time–frequency algorithm is that our approach tracks the time-varying fundamental frequency of atrial activity, where AT is within 2.0–4.0 Hz, AFL is within 4.0–5.3 Hz and NSR is found at frequencies less than 2.0 Hz. For classifications of AFL (n = 22), AT (n = 10) and normal sinus rhythms (NSR) (n = 29), we found that our approach resulted in accuracies of 0.89, 0.87 and 0.91, respectively; the overall accuracy was 0.88.     

The interaction between body position and vibration frequency on acute response to whole body vibration

PurposeThe present study was designed to investigate the electromyographic (EMG) response in leg muscles to whole-body vibration while using different body positions and vibration frequencies.MethodsTwenty male sport sciences students voluntarily participated in this single-group, repeated-measures study in which EMG data from the vastus lateralis (VL) and the lateral gastrocnemius (LG) were collected over a total of 36 trials for each subject (4 static positions × 9 frequencies).ResultsWe found that vibration frequency, body position and the muscle stimulated had a significant effect (P-values ranged from 0.001 to 0.031) on the EMG response. Similarly, the muscle × frequency and position × muscle interactions were significant (P < 0.001). Interestingly, the frequency × positions interactions were not significant (P > 0.05).ConclusionsOur results indicate that lower frequencies of vibration (25–35 Hz) result in maximal activation of LG, whereas higher frequencies (45–55 Hz) elicit the highest responses in the VL. In addition, the position P2 (half squat position with the heels raised) is beneficial both for VL and LG, independently of the vibration frequency.     

Neuromuscular fatigue during a prolonged intermittent exercise: Application to tennis

The time course of alteration in neuromuscular function of the knee extensor muscles was characterized during a prolonged intermittent exercise. Maximal voluntary contraction (MVC) and surface EMG activity of both vastii were measured during brief interruptions before (T₀), during (30, 60, 90, 120, 150 and 180 min: T₃₀, T₆₀, T₉₀, T₁₂₀, T₁₅₀, T₁₈₀) and 30 min after (T₊₃₀) a 3 h tennis match in 12 trained players. M-wave and twitch contractile properties were analyzed following single stimuli. Short tetani at 20 Hz and 80 Hz were also applied to six subjects at T₀ and T₁₈₀. Significant reductions in MVC (P < 0.05; −9%) and electromyographic activity normalized to the M wave for both vastii (P < 0.01) occurred with fatigue at T₁₈₀. No significant changes in M-wave duration and amplitude nor in twitch contractile properties were observed. The ratio between the torques evoked by 20 Hz and 80 Hz stimulation declined significantly (P < 0.001; −12%) after exercise. Central activation failure and alterations in excitation–contraction coupling are probable mechanisms contributing to the moderate impairment of the neuromuscular function during prolonged tennis playing.     

Cercopithecoid primate postcranial fossils from Cooper's D,South Africa

Among several highly fossiliferous localities in the Bloubank Valley (Gauteng, South Africa), the Cooper's Cave System has been known since 1938 and has produced a rich fossil assemblage, including some remains of the early hominin Paranthropus robustus. In 2001, excavations began at a new locality, Cooper's D, which dates to ～1.4-1.5 Ma. Although hominins are relatively rare in the assemblage, remains of cercopithecoid primates are much more common. Craniodental fossils currently indicate the possible presence of at least three large-bodied cercopithecoid primate genera at Cooper's D: Gorgopithecus, Papio, and Theropithecus. In this study, we identify and describe > 100 cercopithecoid primate postcranial fossils representing all regions of the appendicular skeleton. The specimens come from several age classes and size morphs; more than one third of the fossils described are from sub-adult and juvenile individuals. The adult postcranial fossils vary substantially in size, with body masses estimated between 30 and 60 kg (from 16 of the better preserved specimens). The functional morphology of the postcranial remains indicate that these elements come from animals that likely utilized terrestrial substrates, but they remain difficult to definitively attribute to Gorgopithecus, Theropithecus, or Papio given the absence of associated skeletons. The smaller specimens likely belong to Papio while the larger ones can be attributed to the other two genera. Because Cooper's D has also yielded fossils of the early hominin Paranthropus robustus, this raises the question of how these four large-bodied, mostly terrestrial primates sympatrically utilized the landscape.     

Spiroplasmas and phytoplasmas: Microbes associated with plant hosts

This review will focus on two distinct genera, Spiroplasma and ‘Candidatus Phytoplasma,’ within the class Mollicutes (which also includes the genus Mycoplasma, a concern for animal-based cell culture). As members of the Mollicutes, both are cell wall-less microbes which have a characteristic small size (1–2 μM in diameter) and small genome size (530 Kb–2220 Kb). These two genera contain microbes which have a dual host cycle in which they can replicate in their leafhopper or psyllid insect vectors as well as in the sieve tubes of their plant hosts. Major distinctions between the two genera are that most spiroplasmas are cultivable in nutrient rich media, possess a very characteristic helical morphology, and are motile, while the phytoplasmas remain recalcitrant to cultivation attempts to date and exhibit a pleiomorphic or filamentous shape. This review article will provide a historical over view of their discovery, a brief review of taxonomical characteristics, diversity, host interactions (with a focus on plant hosts), phylogeny, and current detection and elimination techniques.     

Analysis of Actinobacteria from mould-colonized water damaged building material

Mould-colonized water damaged building materials are frequently co-colonized by actinomycetes. Here, we report the results of the analyses of Actinobacteria on different wall materials from water damaged buildings obtained by both cultivation-dependent and cultivation-independent methods. Actinobacteria were detected in all but one of the investigated materials by both methods. The detected concentrations of Actinobacteria ranged between 1.8 × 10⁴ and 7.6 × 10⁷ CFU g^?1 of investigated material. A total of 265 isolates from 17 materials could be assigned to 31 different genera of the class Actinobacteria on the basis of 16S rRNA gene sequence analyses. On the basis of the cultivation-independent approach, 16S rRNA gene inserts of 800 clones (50%) were assigned to 47 different genera. Representatives of the genera Streptomyces, Amycolatopsis, Nocardiopsis, Saccharopolyspora, Promicromonospora, and Pseudonocardia were found most frequently. The results derived from both methods indicated a high abundance and variety of Actinobacteria in water damaged buildings. Four bioaerosol samples were investigated by the cultivation-based approach in order to compare the communities of Actinobacteria in building material and associated air samples. A comparison of the detected genera of bioaerosol samples with those directly obtained from material samples resulted in a congruent finding of 9 of the overall 35 detected genera (25%), whereas four genera were only detected in bioaerosol samples.     

Acute severe male hypo-testosteronemia affects central motor command in humans

Purpose: To indirectly evaluate the effect of androgens on neuromuscular system in humans we analyzed if an induced short-term hypogonadal state (serum total testosterone-TT < 2.3 ng/ml) may affect central drive to skeletal muscle and/or muscle neuro-mechanical performance. Methods: We compared voluntary and electrically evoked muscle sEMG signals from biceps brachii in nine hypogonadal male volunteers (Hypo) and in ten healthy controls (Cont). Serum TT and dihydrotestosterone (DHT) were assayed. Results: With respect to Hypo, Cont exhibited significantly higher median frequency content (MDF) at any angular velocity; normalized MDF [95.9% (SD = 23.3) vs 73.8% (SD = 9.3)]; muscle fiber conduction velocity (CV) from lowest to highest angular velocities; initial MDF at fatigue test [91.78 Hz (SD = 22.03) vs 70.94 Hz (SD = 11.06)] as well as was the normalized slope [−0.64 (SD = 0.14 vs −0.5 (SD = 0.11)]. In the non-fatigued state, Hypo showed a slower single twitches time to peak (TTP). In Cont, half relaxation time (HRT) decreased after fatigue while increased in Hypo (p < 0.05 between groups). A significant correlation between both TT and dihydrotestosterone with MDF and CV was found during voluntary contractions only. Conclusions: A brief exposure to very low serum TT concentration in males seem to determine a reduced excitability of the NM system which, in turn, would favor a predominant recruitment of slow twitch MUs.     

The economic effects of an estrus synchronization protocol using prostaglandin in beef heifers

We estimated the effect of estrus synchronization on reproduction, production and economic outcomes in 272 beef heifers randomly allocated to a synchronized Test group or an unsynchronized Control group. The Test group received AI upon estrus detection for 6 days followed by PGF2 treatment of heifers that had not shown estrus by day 6 (PGF/6). In both groups AI was continued for 50 days, followed by a 42-day bull breeding period. Heifers were followed through their second breeding season and until they had weaned their first calves. Synchronization resulted in a reduction in median days to first insemination (8 vs. 11 in the Test and Control groups, respectively, P < 0.01) and median days to calving of calves born to AI (14 vs. 20, P = 0.04). There was no significant difference in pregnancy rate to the AI period (60.0% vs. 51.8%, P = 0.18), final pregnancy rate (82.2% vs. 83.2%, P = 0.87) or pregnancy rate to the subsequent breeding season (96.0% vs. 95.0%, P = 1.00). Although mean calf weaning mass was not significantly different (207.0 kg vs. 201.4 kg, P = 0.32), the total mass of calves weaned in this study was 14,843 kg vs. 13,060 kg and the benefit: cost ratio for synchronization was 2.8. It was therefore concluded that a PGF/6 protocol may affect the total mass of calves weaned by changing days to calving, weaning rate, the ratio of male: female calves born and/or the birth mass of calves.     

Interactions between nutritional and opioidergic pathways in the control of LH secretion in male sheep

Our aim was to determine the role of opioidergic processes in the effects of nutrition on the secretion of LH pulses in the mature male sheep. In the first of three experiments, adult Merino rams were acclimatised to a maintenance diet and then allocated to one of three dietary groups (n = 5): continuation of the maintenance diet (Group M); reduction to half of the maintenance allocation (Group HM); or supplementation of the maintenance diet with lupin grain (Group HD). An initial administration of naloxone (2 mg/kg body weight, i.v.) was followed at 40-min intervals by three further administrations (1 mg/kg). Blood was sampled every 20 min for 12 h before the initial naloxone administration and then for a further 6 h. LH pulse frequency after naloxone treatment was significantly higher in Group HD than in Group HM (P < 0.05). The second study tested whether the response to naloxone depended on calcium status. We used 22 adult Merino rams in two consecutive experiments, one in which the rams were fed a maintenance diet, and one in which the rams were fed with the maintenance diet plus 1 kg lupin grain for 5 weeks. In both experiments, rams were allocated to groups that received one of the following treatments: (a) 0.02 g/kg calcium borogluconate + 0.2 mg/kg naloxone hydrochloride (Nal + Ca²⁺; n = 6); (b) 0.2 mg/kg naloxone hydrochloride (Nal; n = 6); (c) 0.02 g/kg calcium borogluconate (Ca²⁺; n = 5); (d) 0.1 ml/kg NaCl 0.9% (Saline; n = 5). All treatments were given as a single i.v. administration daily for 5 days. Blood was sampled every 20 min for 24 h during the acclimatization period (Day 0) and on the last day (Day 5) of treatment. In the first study (under maintenance), none of the treatments affected LH pulse frequency. In the second study (the lupin-supplemented rams), LH pulse frequency was significantly increased (P < 0.05) by the administration of naloxone + Ca²⁺, naloxone alone and Ca²⁺ alone. Overall, rams on a low plane of nutrition showed the smallest response to naloxone, suggesting that an opioidergic mechanism is not involved in the suppressive effect of restricted nutrition on the gonadotrophic axis. Rather, because testosterone secretion was increased on the high plane of nutrition, the LH responses to naloxone are better explained by the effects of testosterone on opioidergic mechanisms. Finally, we failed to observe any interaction between opioids and calcium in the control of LH secretion.     

Association of body fat percentage and heart rate variability measures of sympathovagal balance

AimsWe tested the hypothesis that body fat percentage determines cardiac sympathovagal balance in healthy subjects.Main methodsHeart rate variability (HRV) measurements were made of the standard deviation of the normal–normal RR intervals (SDNN) and the low frequency/high frequency (LF/HF) ratio, from time domain and fast Fourier transform spectral analysis of electrocardiogram RR intervals during trials of uncontrolled and controlled (paced) breathing at 0.2 Hz. Body fat percentage was measured by dual energy x-ray absorptiometric (DEXA) scanning. Significance of differences between uncontrolled and controlled (paced) breathing was determined by analysis of variance and correlations between body fat percentage and HRV measurements by Pearson's coefficient at P < 0.05.Key findingsPercent body fat was negatively correlated with LF/HF during the uncontrolled breathing (r = ? 0.56, two-tailed P < 0.05, one-tailed P < 0.01) but not during the paced breathing trial (r = ? 0.34, (P > 0.1).SignificanceWe conclude that sympathetic activity produced by paced breathing at 0.2 Hz can obscure the relationship between body fat percentage and sympathovagal balance and that high body fat percentage may be associated with low sympathetic modulation of the heart rate in healthy adolescent/young adult males.     

Frugivorous birds visit fruits of emerging alien shrub species more frequently than those of native shrub species in the South African Mediterranean climate region

We compared daily visitation frequency indices by 4 large (> 150 g), 7 medium-size (50–150 g), 5 small (30–50 g) and 8 and tiny (< 30 g) frugivorous bird species on fleshy fruits of two native shrubs (Olea europaea subsp. africana and Chrysanthemoides monilifera subsp. monilifera), two established alien shrubs (Solanum mauritianum and Lantana camara) and two emerging alien shrubs (Myoporum tenuifolium and Pittosporum undulatum) at nine different sites in the Cape Floristic Region. Large, medium-size and tiny birds as groups displayed significantly higher visitation frequency indices on fruits of both emerging alien shrub species than the other shrub species. Small birds as a group displayed insignificantly different visitation frequency indices on fruits of both emerging and established alien shrub species but significantly higher visitation frequency indices on fruits of both emerging and established alien shrub species than on fruits of the native shrub species. However, there were significant differences in foraging frequency indices of the bird species included within each of these body size groups on fruits of the different shrub species. Among the large birds, Columba guinea and among the medium size birds Sturnus vulgaris, Streptopelia senegalensis, Turdus olivaceus and Onychognathus morio all exhibited significantly higher visitation frequency indices on fruits of both emerging alien shrub species than on fruits of the other shrub species. These findings indicate that alien plant control measures should be focused on eradicating localised populations of emerging aliens to limit preferential consumption of their fruits by birds and consequent dispersal of their seeds that germinate readily into natural areas.     

Ciliogenesis in cryopreserved mammalian tracheal epithelial cells cultured at the air–liquid interface

To determine air–liquid interface (ALI) culture derived from cryopreserved mammalian tracheal ciliated cells is a viable ciliated cell model for the investigations of regulatory mechanisms of ciliary beat frequency (CBF), two studies were performed using ovine and porcine tracheae obtained from local slaughterhouses. The protease-digested tracheal ciliated cells were harvested and cultured at the ALI using collagen-coated, porous membrane inserts. In study 1, the ALI culturing protocols were established using non-cryopreserved ovine tracheal ciliated cells. Ciliogenesis was documented with immuno-histology and electron micrographs. Vigorous beating cilia were video-recorded. CBF was measured by laser light scattering. The functional integrity of the autonomic receptors of the ciliated cells was confirmed with the stimulatory responses of CBF using luminal methacholine and basolateral terbutaline. In study 2, porcine tracheal ciliated cells stored in liquid nitrogen for a minimum of 4 weeks were used. The cryopreserved cells were thawed and cultured using the ALI protocol established in study 1. After two months, cilia outgrowths were confirmed using video microscopy and scanning electron micrograph (SEM). The trans-epithelial resistances were 28.5 kΩ (n = 4). Luminal applications of 1 μM and 10 μM methacholine stimulated CBF from a baseline of 7.4 ± 0.2 Hz to 8.4 ± 0.8 Hz and 7.7 ± 0.4 Hz, respectively (n = 5). Basolateral applications of 1 μM and 10 μM terbutaline stimulated CBF from a baseline of 7.5 ± 0.3 Hz to 8.2 ± 0.4 Hz and 8.0 ± 0.4 Hz, respectively (n = 5). These data demonstrated that a ciliated cell bank can be established using cryopreserved ciliated cells for pulmonary drug discovery and toxicological screening.     

Characteristics of EMG frequency bands in temporomandibullar disorders patients

The aim of the present study was to determine whether any specific frequency bands of surface electromyographic (sEMG) signals are more susceptible to alterations in patients with temporomandibular disorders (TMD), when compared with healthy subjects. Twenty-seven healthy adults (19 women and eight men; mean age: 23 ± 6.68 years) and 27 TMD patients (20 women and seven men; mean age: 24 ± 5.89 years) voluntarily participated in the experiment. sEMG data were recorded from the right and left masseter muscles (RM and LM) and the right and left anterior temporalis muscles (RT and LT) as the participants performed tests of chewing (CHW) and maximal clenching effort (MCE). Frequency domain analysis of the sEMG signal was used to analyze differences between TMD patients and healthy subjects in relation to the Power Spectral Density Function (PSDF). The analysis focused on the median frequency (MDF) of the sEMG signal and PSDF frequency bands after the EMG spectrum was divided into twenty-five frequency band of 20 Hz each. The Mann-Whitney test was used to compare MDF between TMD patients and healthy subjects and the frequency bands were analyzed using three-way ANOVA with three factors: frequency band, muscle and group. The results of the analysis confirmed that the median frequency values in TMD patients were significantly higher (p < 0.05) than those recorded for healthy subjects in the two experimental conditions (MCE and CHW), for all of the muscles assessed (RM, LM, RT and LT). In addition, frequency content between 20 and 100 Hz of the normalized PSDF range was significantly lower (p < 0.05) in TMD patients than in healthy. This study contributes to quantitatively identify TMD dysfunctions, by non-invasive sEMGs; this assessment is clinically important and still lacking nowadays.     

Effect of pain location on spatial reorganisation of muscle activity

IntroductionWe aimed to determine whether the changes in muscle activity (in terms of both gross electromyography (EMG) and motor unit (MU) discharge characteristics) observed during pain are spatially organized with respect to pain location within a muscle which is the main contributor of the task.MethodsSurface and fine-wire EMG was recorded during matched low-force isometric plantarflexion from soleus (from four quadrants with fine-wire EMG and from the medial/lateral sides with surface EMG), both gastrocnemii heads, peroneus longus, and tibialis anterior. Four conditions were tested: two control conditions that each preceded contractions with pain induced in either the lateral (Pain_L) or medial (Pain_M) side of soleus.ResultsNeither the presence (p = 0.28) nor location (p = 0.19) of pain significantly altered gross muscle activity of any location (lateral/medial side of soleus, gastrocnemii, peroneus longus and tibialis anterior). Group data from 196 MUs show redistribution of MU activity throughout the four quadrants of soleus, irrespective of pain location. The significant decrease of MU discharge rate during pain (p < 0.0001; Pain_L: 7.3 ± 0.9–6.9 ± 1.1 Hz, Pain_M: 7.0 ± 1.1 to 6.6 ± 1.1 Hz) was similar for all quadrants of the soleus (p = 0.43), regardless of the pain location (p = 0.98). There was large inter-participant variation in respect to the characteristics of the altered MU discharge with pain.ConclusionResults from both surface and fine-wire EMG recordings do not support the hypothesis that muscle activity is reorganized in a simple systematic manner with respect to pain location.