Large-scale analysis reveals populational contributions of cortical spike rate and synchrony to behavioural functions.

PubMed

Kimura, Rie; Saiki, Akiko; Fujiwara-Tsukamoto, Yoko; Sakai, Yutaka; Isomura, Yoshikazu

2017-01-01

There have been few systematic population-wide analyses of relationships between spike synchrony within a period of several milliseconds and behavioural functions. In this study, we obtained a large amount of spike data from > 23,000 neuron pairs by multiple single-unit recording from deep layer neurons in motor cortical areas in rats performing a forelimb movement task. The temporal changes of spike synchrony in the whole neuron pairs were statistically independent of behavioural changes during the task performance, although some neuron pairs exhibited correlated changes in spike synchrony. Mutual information analyses revealed that spike synchrony made a smaller contribution than spike rate to behavioural functions. The strength of spike synchrony between two neurons was statistically independent of the spike rate-based preferences of the pair for behavioural functions. Spike synchrony within a period of several milliseconds in presynaptic neurons enables effective integration of functional information in the postsynaptic neuron. However, few studies have systematically analysed the population-wide relationships between spike synchrony and behavioural functions. Here we obtained a sufficiently large amount of spike data among regular-spiking (putatively excitatory) and fast-spiking (putatively inhibitory) neuron subtypes (> 23,000 pairs) by multiple single-unit recording from deep layers in motor cortical areas (caudal forelimb area, rostral forelimb area) in rats performing a forelimb movement task. After holding a lever, rats pulled the lever either in response to a cue tone (external-trigger trials) or spontaneously without any cue (internal-trigger trials). Many neurons exhibited functional spike activity in association with forelimb movements, and the preference of regular-spiking neurons in the rostral forelimb area was more biased toward externally triggered movement than that in the caudal forelimb area. We found that a population of neuron pairs with spike synchrony does exist, and that some neuron pairs exhibit a dependence on movement phase during task performance. However, the population-wide analysis revealed that spike synchrony was statistically independent of the movement phase and the spike rate-based preferences of the pair for behavioural functions, whereas spike rates were clearly dependent on the movement phase. In fact, mutual information analyses revealed that the contribution of spike synchrony to the behavioural functions was small relative to the contribution of spike rate. Our large-scale analysis revealed that cortical spike rate, rather than spike synchrony, contributes to population coding for movement. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Computed tomography characteristics of fibrosarcoma -- a histological subtype of feline injection-site sarcoma.

PubMed

Travetti, Olga; di Giancamillo, Mauro; Stefanello, Damiano; Ferrari, Roberta; Giudice, Chiara; Grieco, Valeria; Saunders, Jimmy H

2013-06-01

Feline injection-site sarcoma (FISS) may be a consequence of subcutaneous injection. In the present study, the medical records and the computed tomography (CT) features of 22 cats with a FISS, histopathological subtype fibrosarcoma, were used. The majority of the fibrosarcomas (45%) were located in the interscapular region. All fibrosarcomas, except one with mild enhancement, showed strong contrast uptake, characterised as ring (42%), heterogeneous (36%), homogeneous (9%), heterogeneous/ring (6.5%) or mixed heterogeneous/homogeneous enhancement (6.5%). The longest axis of the mass was in a cranio-caudal (68%) or dorso-ventral (32%) direction. The median volume calculated on CT was 7.57 cm(3). Common features were a marked local invasiveness of the musculature and heterogeneity of the tissue in the periphery of the neoplasia. When the fibrosarcoma was interscapular, performing an additional post-contrast scan with the forelimbs positioned caudally along the body, in addition to the standard protocol with the forelimbs extended cranially, allowed better evaluation of the actual relationship between the tumour and the surrounding tissues. The mean number of muscles involved with the tumour was 2.09 with extended and 1.95 with flexed forelimbs. When a lower number of structures was considered infiltrated through the double positioning, a less invasive surgical approach to underlying muscles and scapula was performed.

Comparative kinematics of the forelimb during swimming in red-eared slider (Trachemys scripta) and spiny softshell (Apalone spinifera) turtles.

PubMed

Pace, C M; Blob, R W; Westneat, M W

2001-10-01

Softshell turtles (Family Trionychidae) possess extensive webbing between the digits of the manus, suggesting that the forelimb may serve as an effective thrust generator during aquatic locomotion. However, the hindlimb has previously been viewed as the dominant propulsive organ in swimming freshwater turtles. To evaluate the potential role of the forelimb in thrust production during swimming in freshwater turtles, we compared the forelimb morphology and three-dimensional forelimb kinematics of a highly aquatic trionychid turtle, the spiny softshell Apalone spinifera, and a morphologically generalized emydid turtle, the red-eared slider Trachemys scripta. Spiny softshells possess nearly twice as much forelimb surface area as sliders for generating drag-based thrust. In addition, although both species use drag-based propulsion, several aspects of forelimb kinematics differ significantly between these species. During the thrust phase of the forelimb cycle, spiny softshells hold the elbow and wrist joints significantly straighter than sliders, thereby further increasing the surface area of the limb that can move water posteriorly and increasing the velocity of the distal portion of the forelimb. These aspects of swimming kinematics in softshells should increase forelimb thrust production and suggest that the forelimbs make more substantial contributions to forward thrust in softshell turtles than in sliders. Spiny softshells also restrict forelimb movements to a much narrower dorsoventral and anteroposterior range than sliders throughout the stroke, thereby helping to minimize limb movements potentially extraneous to forward thrust production. These comparisons demonstrate considerable diversity in the forelimb kinematics of turtles that swim using rowing motions of the limbs and suggest that the evolution of turtle forelimb mechanics produced a variety of contrasting solutions for aquatic specialization.

Hot Water Extract of Leather Carp (Cyprinus carpio nudus) Improves Exercise Performance in Mice

PubMed Central

Lee, Gong-Hyeon; Harwanto, Dicky; Park, Sun-Mee; Choi, Jae-Suk; Kim, Mi-Ryung; Hong, Yong-Ki

2015-01-01

The hot water extract of leather carp (Cyprinus carpio nudus) has been used as a nourishing tonic soup and as an aid for recovery from physical fatigue. In this study, we investigated the effect of leather carp extract on exercise performance in mice. Swimming endurance and forelimb grip strength were assessed following oral administration of the extract (once per day for 7 days) at a dose of 0.5 mg/10 μL/g body weight. After 7 days, mice given the leather carp extract had significantly greater swimming endurance [105±18 s (P<0.05); 52% longer than day 0] and forelimb grip strength [1.18±0.05 Newton (P<0.01); 17% greater than day 0]. The extract increased muscle mass, but had little effect on body weight. Following the swimming exercise, blood glucose, glutathione peroxidase, and superoxide dismutase levels in extract-fed mice were significantly higher (145%, 131%, and 106%, respectively) than in the saline control group. Blood levels of high-density lipoprotein cholesterol were also significantly increased (128%) in mice given the extract compared to the controls. These results suggest that leather carp extract can improve physical exercise performance and prevent oxidative stress caused by exhaustive workouts. PMID:26770911

Muscle Dysfunction in Androgen Deprivation: Role of Ryanodine Receptor

DTIC Science & Technology

2016-11-01

undergoing ORX have reduced muscle specific force due to calcium leak through RyR1, which is caused by high levels of TGFβ released from the bone during... leak could be causing long-term effects, such as decreased muscle mass, body weight and forelimb grip strength. 15. SUBJECT TERMS Prostate Cancer...calcium leak and contractile dysfunction in chronic muscle fatigue, heart failure and muscular dystrophy (13-16). RyR1 is the skeletal muscle

Role of development in reorganization of the SI forelimb-stump representation in fetally, neonatally, and adult amputated rats.

PubMed

Pluto, Charles P; Lane, Richard D; Chiaia, Nicolas L; Stojic, Andrey S; Rhoades, Robert W

2003-09-01

Rats that sustain forelimb removal on postnatal day (P) 0 exhibit numerous multi-unit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) that also respond to hindlimb stimulation when cortical GABAA+B receptors are blocked. Most of these hindlimb inputs originate in the medial SI hindlimb representation. Although many forelimb-stump sites in these animals respond to hindlimb stimulation, very few respond to stimulation of the face (vibrissae or lower jaw), which is represented in SI just lateral to the forelimb. The lateral to medial development of SI may influence the capacity of hindlimb (but not face) inputs to "invade" the forelimb-stump region in neonatal amputees. The SI forelimb-stump was mapped in adult (>60 days) rats that had sustained amputation on embryonic day (E) 16, on P0, or during adulthood. GABA receptors were blocked and subsequent mapping revealed increases in nonstump inputs in E16 and P0 amputees: fetal amputees exhibited forelimb-stump sites responsive to face (34%), hindlimb (10%), and both (22%); neonatal amputees exhibited 10% face, 39% hindlimb, and 5% both; adult amputees exhibited 10% face, 5% hindlimb, and 0% both, with approximately 80% stump-only sites. These results indicate age-dependent differences in receptive-field reorganization of the forelimb-stump representation, which may reflect the spatiotemporal development of SI. Results from cobalt chloride inactivation of the SI vibrissae region and electrolesioning of the dysgranular cortex suggest that normally suppressed vibrissae inputs to the SI forelimb-stump area originate in the SI vibrissae region and synapse in the dysgranular cortex.

Differential expression of choline kinase isoforms in skeletal muscle explains the phenotypic variability in the rostrocaudal muscular dystrophy mouse.

PubMed

Wu, Gengshu; Sher, Roger B; Cox, Gregory A; Vance, Dennis E

2010-04-01

Choline kinase in mammals is encoded by two genes, Chka and Chkb. Disruption of murine Chka leads to embryonic lethality, whereas a spontaneous genomic deletion in murine Chkb results in neonatal forelimb bone deformity and hindlimb muscular dystrophy. Surprisingly, muscular dystrophy isn't significantly developed in the forelimb. We have investigated the mechanism by which a lack of choline kinase beta, encoded by Chkb, results in minimal muscular dystrophy in forelimbs. We have found that choline kinase beta is the major isoform in hindlimb muscle and contributes more to choline kinase activity, while choline kinase alpha is predominant in forelimb muscle and contributes more to choline kinase activity. Although choline kinase activity is decreased in forelimb muscles of Chkb(-/-) mice, the activity of CTP:phosphocholine cytidylyltransferase is increased, resulting in enhanced phosphatidylcholine biosynthesis. The activity of phosphatidylcholine phospholipase C is up-regulated while the activity of phospholipase A(2) in forelimb muscle is not altered. Regeneration of forelimb muscles of Chkb(-/-) mice is normal when challenged with cardiotoxin. In contrast to hindlimb muscle, mega-mitochondria are not significantly formed in forelimb muscle of Chkb(-/-) mice. We conclude that the relative lack of muscle degeneration in forelimbs of Chkb(-/-) mice is due to abundant choline kinase alpha and the stable homeostasis of phosphatidylcholine. 2009 Elsevier B.V. All rights reserved.

Mediolateral hoof balance in relation to the handedness of apprentice farriers.

PubMed

Ronchetti, A; Day, P; Weller, R

2011-01-15

Horses that had been trimmed and shod by apprentice farriers were sourced from the Royal School of Military Engineering, Melton Mowbray (37 horses) and from the Household Cavalry, Knightsbridge (54 horses). The lateral and medial hoof wall angles of both forelimbs were measured using a Ruidoso hoof gauge by the same operator. The difference between the lateral and medial hoof wall angles for each horse was calculated and the results were compared between right-handed and left-handed farriers using the Mann-Whitney U test (P<0.05). There was a significant difference in the mediolateral hoof balance obtained between right-handed and left-handed farriers for each forelimb (P<0.001). Right-handed farriers were shown to create an imbalance in 47 per cent of left forelimbs and 46 per cent of right forelimbs assessed, while left-handed farriers created an imbalance in 41 per cent of left forelimbs and 71 per cent of right forelimbs. The tendency was for right-handed farriers to over-trim the medial (inner) aspect of the left forelimb and the lateral (outer) aspect of the right forelimb; the reverse was demonstrated for left-handed farriers. Performing a risk ratio confirmed these findings.

Forelimb muscle function in pig-nosed turtles, Carettochelys insculpta: testing neuromotor conservation between rowing and flapping in swimming turtles

PubMed Central

Rivera, Angela R. V.; Blob, Richard W.

2013-01-01

Changes in muscle activation patterns can lead to new locomotor modes; however, neuromotor conservation—the evolution of new forms of locomotion through changes in structure without concurrent changes to underlying motor patterns—has been documented across diverse styles of locomotion. Animals that swim using appendages do so via rowing (anteroposterior oscilations) or flapping (dorsoventral oscilations). Yet few studies have compared motor patterns between these swimming modes. In swimming turtles, propulsion is generated exclusively by limbs. Kinematically, turtles swim using multiple styles of rowing (freshwater species), flapping (sea turtles) and a unique hybrid style with superficial similarity to flapping by sea turtles and characterized by increased dorsoventral motions of synchronously oscillated forelimbs that have been modified into flippers (Carettochelys insculpta). We compared forelimb motor patterns in four species of turtle (two rowers, Apalone ferox and Trachemys scripta; one flapper, Caretta caretta; and Carettochelys) and found that, despite kinematic differences, motor patterns were generally similar among species with a few notable exceptions: specifically, presence of variable bursts for pectoralis and triceps in Trachemys (though timing of the non-variable pectoralis burst was similar), and the timing of deltoideus activity in Carettochelys and Caretta compared with other taxa. The similarities in motor patterns we find for several muscles provide partial support for neuromotor conservation among turtles using diverse locomotor styles, but the differences implicate deltoideus as a prime contributor to flapping limb motions. PMID:23966596

Tensile properties in collagen-rich tissues of Quarter Horses with hereditary equine regional dermal asthenia (HERDA).

PubMed

Bowser, J E; Elder, S H; Pasquali, M; Grady, J G; Rashmir-Raven, A M; Wills, R; Swiderski, C E

2014-03-01

Hereditary equine regional dermal asthenia (HERDA) is an autosomal recessive disorder of Quarter Horses characterised by skin fragility. Horses with HERDA have a missense mutation in peptidyl-prolyl cis-trans isomerase B (PPIB), which encodes cyclophilin B and alters folding and post translational modifications of fibrillar collagen. The study aimed to test the hypothesis that tendons, ligaments and great vessels, which, like skin, are rich in fibrillar collagen, will also have abnormal biomechanical properties in horses with HERDA. Ex vivo biomechanical study comparing horses with and without a diagnosis of HERDA. Forelimb suspensory ligament, superficial and deep digital flexor tendons; withers, forelimb and abdominal skin; the main pulmonary artery and the aortic arch were harvested from 6 horses with HERDA and 6 control horses without the HERDA allele. Tissues were distracted to failure. Tensile strength (TS), elastic modulus (EM) and energy to failure (ETF) were compared. Horses with HERDA had significantly lower TS and EM in tendinoligamentous tissues and great vessels, respectively. The TS, EM and ETF were significantly lower in skin from horses with HERDA. Differences in TS and ETF were more extreme at the withers than at the forelimb or abdomen. Tendinoligamentous tissue, great vessels and skin are significantly weaker in horses with HERDA than in horses lacking the PPIB mutation, substantiating that diverse tissues with high fibrillar collagen content are abnormal in HERDA and that the HERDA phenotype is not limited to the integument. © 2013 EVJ Ltd.

Tbx5 Buffers Inherent Left/Right Asymmetry Ensuring Symmetric Forelimb Formation

PubMed Central

Nishimoto, Satoko; Kucharska, Anna; Newbury-Ecob, Ruth; Logan, Malcolm P. O.

2016-01-01

The forelimbs and hindlimbs of vertebrates are bilaterally symmetric. The mechanisms that ensure symmetric limb formation are unknown but they can be disrupted in disease. In Holt-Oram Syndrome (HOS), caused by mutations in TBX5, affected individuals have left-biased upper/forelimb defects. We demonstrate a role for the transcription factor Tbx5 in ensuring the symmetric formation of the left and right forelimb. In our mouse model, bilateral hypomorphic levels of Tbx5 produces asymmetric forelimb defects that are consistently more severe in the left limb than the right, phenocopying the left-biased limb defects seen in HOS patients. In Tbx hypomorphic mutants maintained on an INV mutant background, with situs inversus, the laterality of defects is reversed. Our data demonstrate an early, inherent asymmetry in the left and right limb-forming regions and that threshold levels of Tbx5 are required to overcome this asymmetry to ensure symmetric forelimb formation. PMID:27992425

Musculoskeletal Complications and Bone Metastases in Breast Cancer Patients Undergoing Estrogen Deprivation Therapy

DTIC Science & Technology

2015-10-01

resulting from estrogen (E2) deprivation therapy. [20% complete] Percent Fat 0 2 4 6 8 -20 0 20 40 Weeks post-surgery OVX SHAM **p = 0.0050 by 2-way...increased body fat percentage as assessed by DXA, B. decreased bone mineral density (BMD) as assessed by DXA, and C. reduced forelimb grip strength in...e.g., glucocorticoids, GnRH inhibitors, radiation, fracture , osteoporosis, etc.) could increase the homing of dormant disseminated cancer cells to

Acute inactivation of the contralesional hemisphere for longer durations improves recovery after cortical injury.

PubMed

Mansoori, Babak K; Jean-Charles, Loyda; Touvykine, Boris; Liu, Aihua; Quessy, Stephan; Dancause, Numa

2014-04-01

A rapidly growing number of studies using inhibition of the contralesional hemisphere after stroke are reporting improvement in motor performance of the paretic hand. These studies have used different treatment onset time, duration and non-invasive methods of inhibition. Whereas these results are encouraging, several questions regarding the mechanisms of inhibition and the most effective treatment parameters are currently unanswered. In the present study, we used a rat model of cortical lesion to study the effects of GABA-mediated inactivation on motor recovery. In particular, we were interested in understanding better the effect of inactivation duration when it is initiated within hours following a cortical lesion. Cortical lesions were induced with endothelin-1 microinjections. The contralesional hemisphere was inactivated with continuous infusion of the GABA-A agonist Muscimol for 3, 7 or 14days in three different groups of animals. In a fourth group, Muscimol was infused at slower rate for 14days to provide additional insights on the relation between the effects of inactivation on the non-paretic forelimb behavior and the recovery of the paretic forelimb. In spontaneously recovered animals, the lesion caused a sustained bias to use the non-paretic forelimb and long-lasting grasping deficits with the paretic forelimb. Contralesional inactivation produced a general decrease of behavioral activity, affected the spontaneous use of the forelimbs and caused a specific reduction of the non-paretic forelimb function. The intensity and the duration of these behavioral effects varied in the different experimental groups. For the paretic forelimb, increasing inactivation duration accelerated the recovery of grasping function. Both groups with 14days of inactivation had similar recovery profiles and performed better than animals that spontaneously recovered. Whereas the plateau performance of the paretic forelimb correlated with the duration of contralesional inactivation, it was not correlated with the spontaneous use of the forelimbs or with grasping performance of the non-paretic hand. Our results support that contralesional inactivation initiated within hours after a cortical lesion can improve recovery of the paretic forelimb. In our model, increasing the duration of the inactivation improved motor outcomes but the spontaneous use and motor performance of the non-paretic forelimb had no impact on recovery of the paretic forelimb. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Reducing contralateral SI activity reveals hindlimb receptive fields in the SI forelimb-stump representation of neonatally amputated rats.

PubMed

Pluto, Charles P; Chiaia, Nicolas L; Rhoades, Robert W; Lane, Richard D

2005-09-01

In adult rats that sustained forelimb amputation on the day of birth, >30% of multiunit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) also respond to cutaneous hindlimb stimulation when cortical GABA(A+B) receptors are blocked (GRB). This study examined whether hindlimb receptive fields could also be revealed in forelimb-stump sites by reducing one known source of excitatory input to SI GABAergic neurons, the contralateral SI cortex. Corpus callosum projection neurons connect homotopic SI regions, making excitatory contacts onto pyramidal cells and interneurons. Thus in addition to providing monosynaptic excitation in SI, callosal fibers can produce disynaptic inhibition through excitatory synapses with inhibitory interneurons. Based on the latter of these connections, we hypothesized that inactivating the contralateral (intact) SI forelimb region would "unmask" normally suppressed hindlimb responses by reducing the activity of SI GABAergic neurons. The SI forelimb-stump representation was first mapped under normal conditions and then during GRB to identify stump/hindlimb responsive sites. After GRB had dissipated, the contralateral (intact) SI forelimb region was mapped and reversibly inactivated with injections of 4% lidocaine, and selected forelimb-stump sites were retested. Contralateral SI inactivation revealed hindlimb responses in approximately 60% of sites that were stump/hindlimb responsive during GRB. These findings indicate that activity in the contralateral SI contributes to the suppression of reorganized hindlimb receptive fields in neonatally amputated rats.

HCN channels segregate stimulation‐evoked movement responses in neocortex and allow for coordinated forelimb movements in rodents

PubMed Central

Farrell, Jordan S.; Palmer, Laura A.; Singleton, Anna C.; Pittman, Quentin J.; Teskey, G. Campbell

2016-01-01

Key points The present study tested whether HCN channels contribute to the organization of motor cortex and to skilled motor behaviour during a forelimb reaching task.Experimental reductions in HCN channel signalling increase the representation of complex multiple forelimb movements in motor cortex as assessed by intracortical microstimulation.Global HCN1KO mice exhibit reduced reaching accuracy and atypical movements during a single‐pellet reaching task relative to wild‐type controls.Acute pharmacological inhibition of HCN channels in forelimb motor cortex decreases reaching accuracy and increases atypical movements during forelimb reaching. Abstract The mechanisms by which distinct movements of a forelimb are generated from the same area of motor cortex have remained elusive. Here we examined a role for HCN channels, given their ability to alter synaptic integration, in the expression of forelimb movement responses during intracortical microstimulation (ICMS) and movements of the forelimb on a skilled reaching task. We used short‐duration high‐resolution ICMS to evoke forelimb movements following pharmacological (ZD7288), experimental (electrically induced cortical seizures) or genetic approaches that we confirmed with whole‐cell patch clamp to substantially reduce I h current. We observed significant increases in the number of multiple movement responses evoked at single sites in motor maps to all three experimental manipulations in rats or mice. Global HCN1 knockout mice were less successful and exhibited atypical movements on a skilled‐motor learning task relative to wild‐type controls. Furthermore, in reaching‐proficient rats, reaching accuracy was reduced and forelimb movements were altered during infusion of ZD7288 within motor cortex. Thus, HCN channels play a critical role in the separation of overlapping movement responses and allow for successful reaching behaviours. These data provide a novel mechanism for the encoding of multiple movement responses within shared networks of motor cortex. This mechanism supports a viewpoint of primary motor cortex as a site of dynamic integration for behavioural output. PMID:27568501

High-order motor cortex in rats receives somatosensory inputs from the primary motor cortex via cortico-cortical pathways.

PubMed

Kunori, Nobuo; Takashima, Ichiro

2016-12-01

The motor cortex of rats contains two forelimb motor areas; the caudal forelimb area (CFA) and the rostral forelimb area (RFA). Although the RFA is thought to correspond to the premotor and/or supplementary motor cortices of primates, which are higher-order motor areas that receive somatosensory inputs, it is unknown whether the RFA of rats receives somatosensory inputs in the same manner. To investigate this issue, voltage-sensitive dye (VSD) imaging was used to assess the motor cortex in rats following a brief electrical stimulation of the forelimb. This procedure was followed by intracortical microstimulation (ICMS) mapping to identify the motor representations in the imaged cortex. The combined use of VSD imaging and ICMS revealed that both the CFA and RFA received excitatory synaptic inputs after forelimb stimulation. Further evaluation of the sensory input pathway to the RFA revealed that the forelimb-evoked RFA response was abolished either by the pharmacological inactivation of the CFA or a cortical transection between the CFA and RFA. These results suggest that forelimb-related sensory inputs would be transmitted to the RFA from the CFA via the cortico-cortical pathway. Thus, the present findings imply that sensory information processed in the RFA may be used for the generation of coordinated forelimb movements, which would be similar to the function of the higher-order motor cortex in primates. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Functional anatomy and adaptation of male gorillas (Gorilla gorilla gorilla) with comparison to male orangutans (Pongo pygmaeus).

PubMed

Zihlman, Adrienne L; McFarland, Robin K; Underwood, Carol E

2011-11-01

Great apes diversified during the Miocene in Old World forests. Two lineages, gorillas in Africa and orangutans in Asia, have sexual dimorphisms of super-sized males, though they presumably diverged from a smaller common ancestor. We test the hypothesis that they increased in body mass independently and convergently, and that their many postcranial differences reflect locomotor differences. Whole body dissections of five adult male gorillas and four adult male orangutans allowed quantification of body mass distribution to limb segments, of body composition (muscle, bone, skin, and fat relative to total body mass), and of muscle distribution and proportions. Results demonstrate that gorilla forelimb anatomy accommodates shoulder joint mobility for vertical climbing and reaching while maintaining joint stability during quadrupedal locomotion. The heavily muscled hind limbs are equipped for propulsion and weight-bearing over relatively stable substrates on the forest floor. In contrast, orangutan forelimb length, muscle mass, and joint construction are modified for strength and mobility in climbing, bridging, and traveling over flexible supports through the forest canopy. Muscles of hip, knee, and ankle joints provide rotational and prehensile strength essential for moving on unstable and discontinuous branches. We conclude that anatomical similarities are due to common ancestry and that differences in postcranial anatomy reflect powerful selection for divergent locomotor adaptations. These data further support the evolutionary conclusion that gorillas fall with chimpanzees and humans as part of the African hominoid radiation; orangutans are a specialized outlier. Copyright © 2011 Wiley-Liss, Inc.

Conditional genetic deletion of PTEN after a spinal cord injury enhances regenerative growth of CST axons and motor function recovery in mice

PubMed Central

Danilov, Camelia A.; Steward, Oswald

2015-01-01

Previous studies indicate that conditional genetic deletion of phosphatase and tensin homolog (PTEN) in neonatal mice enhances the ability of axons to regenerate following spinal cord injury (SCI) in adults. Here, we assessed whether deleting PTEN in adult neurons post-SCI is also effective, and whether enhanced regenerative growth is accompanied by enhanced recovery of voluntary motor function. PTENloxP/loxP mice received moderate contusion injuries at cervical level 5 (C5). One group received unilateral injections of adeno-associated virus expressing CRE (AAV-CRE) into the sensorimotor cortex; controls received a vector expressing green fluorescent protein (AAV-GFP) or injuries only (no vector injections). Forelimb function was tested for 14 weeks post-SCI using a grip strength meter (GSM) and a hanging task. The corticospinal tract (CST) was traced by injecting mini-ruby BDA into the sensorimotor cortex. Forelimb gripping ability was severely impaired immediately post-SCI but recovered slowly over time. The extent of recovery was significantly greater in PTEN-deleted mice in comparison to either the AAV-GFP group or the injury only group. BDA tract tracing revealed significantly higher numbers of BDA-labeled axons in caudal segments in the PTEN-deleted group compared to control groups. In addition, in the PTEN-deleted group, there were exuberant collaterals extending from the main tract rostral to the lesion, into and around the scar tissue at the injury site. These results indicate that PTEN deletion in adult mice shortly post-SCI can enhance regenerative growth of CST axons and forelimb motor function recovery. PMID:25704959

Bilateral Cervical Contusion Spinal Cord Injury in Rats

PubMed Central

Anderson, Kim D.; Sharp, Kelli G.; Steward, Oswald

2009-01-01

There is increasing motivation to develop clinically relevant experimental models for cervical SCI in rodents and techniques to assess deficits in forelimb function. Here we describe a bilateral cervical contusion model in rats. Female Sprague-Dawley rats received mild or moderate cervical contusion injuries (using the Infinite Horizons device) at C5, C6, or C7/8. Forelimb motor function was assessed using a Grip Strength Meter (GSM); sensory function was assessed by the von Frey hair test; the integrity of the corticospinal tract (CST) was assessed by biotinylated dextran amine (BDA) tract tracing. Mild contusions caused primarily dorsal column (DC) and gray matter (GM) damage while moderate contusions produced additional damage to lateral and ventral tissue. Forelimb and hindlimb function was severely impaired immediately post-injury, but all rats regained the ability to use their hindlimbs for locomotion. Gripping ability was abolished immediately after injury but recovered partially, depending upon the spinal level and severity of the injury. Rats exhibited a loss of sensation in both fore- and hindlimbs that partially recovered, and did not exhibit allodynia. Tract tracing revealed that the main contingent of CST axons in the DC was completely interrupted in all but one animal whereas the dorsolateral CST (dlCST) was partially spared, and dlCST axons gave rise to axons that arborized in the GM caudal to the injury. Our data demonstrate that rats can survive significant bilateral cervical contusion injuries at or below C5 and that forepaw gripping function recovers after mild injuries even when the main component of CST axons in the dorsal column is completely interrupted. PMID:19559699

A Three-Dimensional Analysis of Morphological Evolution and Locomotor Performance of the Carnivoran Forelimb

PubMed Central

Martín-Serra, Alberto; Figueirido, Borja; Palmqvist, Paul

2014-01-01

In this study, three-dimensional landmark-based methods of geometric morphometrics are used for estimating the influence of phylogeny, allometry and locomotor performance on forelimb shape in living and extinct carnivorans (Mammalia, Carnivora). The main objective is to investigate morphological convergences towards similar locomotor strategies in the shape of the major forelimb bones. Results indicate that both size and phylogeny have strong effects on the anatomy of all forelimb bones. In contrast, bone shape does not correlate in the living taxa with maximum running speed or daily movement distance, two proxies closely related to locomotor performance. A phylomorphospace approach showed that shape variation in forelimb bones mainly relates to changes in bone robustness. This indicates the presence of biomechanical constraints resulting from opposite demands for energetic efficiency in locomotion –which would require a slender forelimb– and resistance to stress –which would be satisfied by a robust forelimb–. Thus, we interpret that the need of maintaining a trade-off between both functional demands would limit shape variability in forelimb bones. Given that different situations can lead to one or another morphological solution, depending on the specific ecology of taxa, the evolution of forelimb morphology represents a remarkable “one-to-many mapping” case between anatomy and ecology. PMID:24454891

Forelimbs of Tyrannosaurus Rex: A pathetic vestigial organ or an integral part of a fearsome predator?

NASA Astrophysics Data System (ADS)

Lee, Scott A.; Thomas, Joshua D.

2014-12-01

In this paper, we examine a first-year torque and angular acceleration problem to address a possible use of the forelimbs of Tyrannosaurus rex. A 1/40th-scale model (see Fig. 1) is brought to the classroom to introduce the students to the quandary: given that the forelimbs of T. rex were too short to reach its mouth, what function did the forelimbs serve? This issue crosses several scientific disciplines including paleontology, ecology, and physics, making it a great starting point for thinking "outside the box." Noted paleontologist Kenneth Carpenter has suggested that the forelimbs of T. rex were an integral part of its predatory behavior. Given the large teeth of T. rex, it is assumed that they killed with their teeth. Lipkin and Carpenter1 have suggested that the forelimbs were used to hold a struggling victim (which had not been dispatched with the first bite) while the final, lethal bite was applied. If that is the case, then the forelimbs must be capable of large angular accelerations α in order to grab the animal attempting to escape. The concepts of the typical first-year physics course are sufficient to test this hypothesis by solving α =τ /I . Naturally, students love solving any problem related to Tyrannosaurus rex!

Activity-Based Therapies To Promote Forelimb Use after a Cervical Spinal Cord Injury

PubMed Central

Dai, Haining; MacArthur, Linda; McAtee, Marietta; Hockenbury, Nicole; Tidwell, J. Lille; McHugh, Brian; Mansfield, Kevin; Finn, Tom; Hamers, Frank P.T.

2009-01-01

Abstract Significant interest exists in strategies for improving forelimb function following spinal cord injury. We investigated the effect of enriched housing combined with skilled training on the recovery of skilled and automatic forelimb function after a cervical spinal cord injury in adult rats. All animals were pretrained in skilled reaching, gridwalk crossing, and overground locomotion. Some received a cervical over-hemisection lesion at C4-5, interrupting the right side of the spinal cord and dorsal columns bilaterally, and were housed in standard housing alone or enriched environments with daily training. A subset of animals received rolipram to promote neuronal plasticity. Animals were tested weekly for 4 weeks to measure reaching, errors on the gridwalk, locomotion, and vertical exploration. Biotinylated dextran amine was injected into the cortex to label the corticospinal tract. Enriched environments/daily training significantly increased the number and success of left reaches compared to standard housing. Animals also made fewer errors on the gridwalk, a measure of coordinated forelimb function. However, there were no significant improvements in forelimb use during vertical exploration or locomotion. Likewise, rolipram did not improve any of the behaviors tested. Both enriched housing and rolipram increased plasticity of the corticospinal tract rostral to the lesion. These studies indicate that skilled training after a cervical spinal cord injury improves recovery of skilled forelimb use (reaching) and coordinated limb function (gridwalk) but does not improve automatic forelimb function (locomotion and vertical exploration). These studies suggest that rehabilitating forelimb function after spinal cord injury will require separate strategies for descending and segmental pathways. PMID:19317604

Evidence toads may modulate landing preparation without predicting impact time

PubMed Central

Cox, S. M.; Gillis, Gary

2017-01-01

ABSTRACT Within anurans (frogs and toads), cane toads (Bufo marinus) perform particularly controlled landings in which the forelimbs are exclusively used to decelerate and stabilize the body after impact. Here we explore how toads achieve dynamic stability across a wide range of landing conditions. Specifically, we suggest that torques during landing could be reduced by aligning forelimbs with the body's instantaneous velocity vector at impact (impact angle). To test whether toad forelimb orientation varies with landing conditions, we used high-speed video to collect forelimb and body kinematic data from six animals hopping off platforms of different heights (0, 5 and 9 cm). We found that toads do align forelimbs with the impact angle. Further, toads align forelimbs with the instantaneous velocity vector well before landing and then track its changes until touchdown. This suggests that toads may be prepared to land well before they hit the ground rather than preparing for impact at a specific moment, and that they may use a motor control strategy that allows them to perform controlled landings without the need to predict impact time. PMID:27895052

Assessment of intensive care unit‐acquired weakness in young and old mice: An E. coli septic peritonitis model

PubMed Central

Hoogland, Inge C.M.; Wieske, Luuk; Weber, Nina C.; Verhamme, Camiel; Schultz, Marcus J.; van Schaik, Ivo N.; Horn, Janneke

2015-01-01

ABSTRACT Introduction: There are few reports of in vivo muscle strength measurements in animal models of ICU‐acquired weakness (ICU‐AW). In this study we investigated whether the Escherichia coli (E. coli) septic peritonitis mouse model may serve as an ICU‐AW model using in vivo strength measurements and myosin/actin assays, and whether development of ICU‐AW is age‐dependent in this model. Methods: Young and old mice were injected intraperitoneally with E. coli and treated with ceftriaxone. Forelimb grip strength was measured at multiple time points, and the myosin/actin ratio in muscle was determined. Results: E. coli administration was not associated with grip strength decrease, neither in young nor in old mice. In old mice, the myosin/actin ratio was lower in E. coli mice at t = 48 h and higher at t = 72 h compared with controls. Conclusions: This E. coli septic peritonitis mouse model did not induce decreased grip strength. In its current form, it seems unsuitable as a model for ICU‐AW. Muscle Nerve 53: 127–133, 2016 PMID:26015329

Vertical movement symmetry of the withers in horses with induced forelimb and hindlimb lameness at trot.

PubMed

Rhodin, M; Persson-Sjodin, E; Egenvall, A; Serra Bragança, F M; Pfau, T; Roepstorff, L; Weishaupt, M A; Thomsen, M H; van Weeren, P R; Hernlund, E

2018-04-15

The main criteria for lameness assessment in horses are head movement for forelimb lameness and pelvic movement for hindlimb lameness. However, compensatory head nod in horses with primary hindlimb lameness is a well-known phenomenon. This compensatory head nod movement can be easily misinterpreted as a sign of primary ipsilateral forelimb lameness. Therefore, discriminating compensatory asymmetries from primary directly pain-related movement asymmetries is a prerequisite for successful lameness assessment. To investigate the association between head, withers and pelvis movement asymmetry in horses with induced forelimb and hindlimb lameness. Experimental study. In 10 clinically sound Warmblood riding horses, forelimb and hindlimb lameness were induced using a sole pressure model. The horses were then trotted on a treadmill. Three-dimensional optical motion capture was used to collect kinematic data from reflective markers attached to the poll, withers and tubera sacrale. The magnitude and side (left or right) of the following symmetry parameters, vertical difference in minimum position, maximum position and range-up were calculated for head, withers, and pelvis. Mixed models were used to analyse data from induced forelimb and hindlimb lameness. For each mm increase in pelvic asymmetry in response to hindlimb lameness induction, withers movement asymmetry increased by 0.35-0.55 mm, but towards the contralateral side. In induced forelimb lameness, for each mm increase in head movement asymmetry, withers movement asymmetry increased by 0.05-0.10 mm, in agreement with the head movement asymmetry direction, both indicating lameness in the induced forelimb. Results must be confirmed in clinically lame horses trotting overground. The vertical asymmetry pattern of the withers discriminated a head nod associated with true forelimb lameness from the compensatory head movement asymmetry caused by primary hindlimb lameness. Measuring movement symmetry of the withers may, thus, aid in determining primary lameness location. © 2018 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

Local GABA receptor blockade reveals hindlimb responses in the SI forelimb-stump representation of neonatally amputated rats.

PubMed

Pluto, Charles P; Lane, Richard D; Rhoades, Robert W

2004-07-01

In adult rats that sustained forelimb amputation on the day of birth, there are numerous multi-unit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) that also respond to cutaneous stimulation of the hindlimb when cortical receptors for GABA are blocked. These normally suppressed hindlimb inputs originate in the SI hindlimb representation and synapse in the dysgranular cortex before exciting SI forelimb-stump neurons. In our previous studies, GABA (A + B) receptor blockade was achieved by topically applying a bicuculline methiodide/saclofen solution (BMI/SAC) to the cortical surface. This treatment blocks receptors throughout SI and does not allow determination of where along the above circuit the GABA-mediated suppression of hindlimb information occurs. In this study, focal injections of BMI/SAC were delivered to three distinct cortical regions that are involved in the hindlimb-to-forelimb-stump pathway. Blocking GABA receptors in the SI hindlimb representation and in the dysgranular cortex was largely ineffective in revealing hindlimb inputs ( approximately 10% of hindlimb inputs were revealed in both cases). In contrast, when the blockade was targeted at forelimb-stump recording sites, >80% of hindlimb inputs were revealed. Thus GABAergic interneurons within the forelimb-stump representation suppress the expression of reorganized hindlimb inputs to the region. A circuit model incorporating these and previous observations is presented and discussed.

Evaluation of forelimb horseshoe characteristics of thoroughbreds racing on dirt surfaces.

PubMed

Gross, Diane K; Stover, Susan M; Hill, Ashley E; Gardner, Ian A

2004-07-01

To describe forelimb horseshoe characteristics of horses racing on dirt surfaces and determine whether these characteristics vary with region of California, season, horse characteristics, and race-related factors. 5,730 Thoroughbred racehorses. From June 17, 2000, to June 16, 2001, the characteristics of 1 forelimb horseshoe of horses that raced on dirt surfaces at 5 major racetracks in California were recorded. These characteristics included shoe type; toe grab height; and presence of a rim, pad, and heel traction devices (jar caulks, heel stickers, heel blocks, and special nails). Horse and race information was obtained from commercial records. One race/horse was randomly selected. 99% of forelimb horseshoes were aluminum racing plates, 35% had a pad, 23% had a rim, and 8% had a heel traction device. A toe grab was observed on 75% of forelimb horseshoes (14% very low [< or = 2 mm], 30% low [> 2 and < or = 4 mm], 30% regular [> 4 and < or = 6 mm], and 1% high [> 6 and < or = 8 mm]). Forelimb horseshoe characteristics varied with region of California, season, age and sex of the horse, race purse and distance, and track surface condition. Log-linear modeling revealed that all of these factors were significantly interrelated. Complex interrelationships among forelimb horseshoe characteristics and region, season, age and sex of the horse, and race-related factors need to be considered when evaluating the relationships between injury and horseshoe characteristics in Thoroughbred racehorses.

Reconstruction and in vivo analysis of the extinct tbx5 gene from ancient wingless moa (Aves: Dinornithiformes)

PubMed Central

2014-01-01

Background The forelimb-specific gene tbx5 is highly conserved and essential for the development of forelimbs in zebrafish, mice, and humans. Amongst birds, a single order, Dinornithiformes, comprising the extinct wingless moa of New Zealand, are unique in having no skeletal evidence of forelimb-like structures. Results To determine the sequence of tbx5 in moa, we used a range of PCR-based techniques on ancient DNA to retrieve all nine tbx5 exons and splice sites from the giant moa, Dinornis. Moa Tbx5 is identical to chicken Tbx5 in being able to activate the downstream promotors of fgf10 and ANF. In addition we show that missexpression of moa tbx5 in the hindlimb of chicken embryos results in the formation of forelimb features, suggesting that Tbx5 was fully functional in wingless moa. An alternatively spliced exon 1 for tbx5 that is expressed specifically in the forelimb region was shown to be almost identical between moa and ostrich, suggesting that, as well as being fully functional, tbx5 is likely to have been expressed normally in moa since divergence from their flighted ancestors, approximately 60 mya. Conclusions The results suggests that, as in mice, moa tbx5 is necessary for the induction of forelimbs, but is not sufficient for their outgrowth. Moa Tbx5 may have played an important role in the development of moa’s remnant forelimb girdle, and may be required for the formation of this structure. Our results further show that genetic changes affecting genes other than tbx5 must be responsible for the complete loss of forelimbs in moa. PMID:24885927

A three-dimensional morphometric analysis of upper forelimb morphology in the enigmatic tapir (Perissodactyla: Tapirus) hints at subtle variations in locomotor ecology.

PubMed

MacLaren, Jamie A; Nauwelaerts, Sandra

2016-11-01

Forelimb morphology is an indicator for terrestrial locomotor ecology. The limb morphology of the enigmatic tapir (Perissodactyla: Tapirus) has often been compared to that of basal perissodactyls, despite the lack of quantitative studies comparing forelimb variation in modern tapirs. Here, we present a quantitative assessment of tapir upper forelimb osteology using three-dimensional geometric morphometrics to test whether the four modern tapir species are monomorphic in their forelimb skeleton. The shape of the upper forelimb bones across four species (T. indicus; T. bairdii; T. terrestris; T. pinchaque) was investigated. Bones were laser scanned to capture surface morphology and 3D landmark analysis was used to quantify shape. Discriminant function analyses were performed to reveal features which could be used for interspecific discrimination. Overall our results show that the appendicular skeleton contains notable interspecific differences. We demonstrate that upper forelimb bones can be used to discriminate between species (>91% accuracy), with the scapula proving the most diagnostic bone (100% accuracy). Features that most successfully discriminate between the four species include the placement of the cranial angle of the scapula, depth of the humeral condyle, and the caudal deflection of the olecranon. Previous studies comparing the limbs of T. indicus and T. terrestris are corroborated by our quantitative findings. Moreover, the mountain tapir T. pinchaque consistently exhibited the greatest divergence in morphology from the other three species. Despite previous studies describing tapirs as functionally mediportal in their locomotor style, we find osteological evidence suggesting a spectrum of locomotor adaptations in the tapirs. We conclude that modern tapir forelimbs are neither monomorphic nor are tapirs as conserved in their locomotor habits as previously described. J. Morphol. 277:1469-1485, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Plasticity in One Hemisphere, Control From Two: Adaptation in Descending Motor Pathways After Unilateral Corticospinal Injury in Neonatal Rats

PubMed Central

Wen, Tong-Chun; Lall, Sophia; Pagnotta, Corey; Markward, James; Gupta, Disha; Ratnadurai-Giridharan, Shivakeshavan; Bucci, Jacqueline; Greenwald, Lucy; Klugman, Madelyne; Hill, N. Jeremy; Carmel, Jason B.

2018-01-01

After injury to the corticospinal tract (CST) in early development there is large-scale adaptation of descending motor pathways. Some studies suggest the uninjured hemisphere controls the impaired forelimb, while others suggest that the injured hemisphere does; these pathways have never been compared directly. We tested the contribution of each motor cortex to the recovery forelimb function after neonatal injury of the CST. We cut the left pyramid (pyramidotomy) of postnatal day 7 rats, which caused a measurable impairment of the right forelimb. We used pharmacological inactivation of each motor cortex to test its contribution to a skilled reach and supination task. Rats with neonatal pyramidotomy were further impaired by inactivation of motor cortex in both the injured and the uninjured hemispheres, while the forelimb of uninjured rats was impaired only from the contralateral motor cortex. Thus, inactivation demonstrated motor control from each motor cortex. In contrast, physiological and anatomical interrogation of these pathways support adaptations only in the uninjured hemisphere. Intracortical microstimulation of motor cortex in the uninjured hemisphere of rats with neonatal pyramidotomy produced responses from both forelimbs, while stimulation of the injured hemisphere did not elicit responses from either forelimb. Both anterograde and retrograde tracers were used to label corticofugal pathways. There was no increased plasticity from the injured hemisphere, either from cortex to the red nucleus or the red nucleus to the spinal cord. In contrast, there were very strong CST connections to both halves of the spinal cord from the uninjured motor cortex. Retrograde tracing produced maps of each forelimb within the uninjured hemisphere, and these were partly segregated. This suggests that the uninjured hemisphere may encode separate control of the unimpaired and the impaired forelimbs of rats with neonatal pyramidotomy. PMID:29706871

Plasticity in One Hemisphere, Control From Two: Adaptation in Descending Motor Pathways After Unilateral Corticospinal Injury in Neonatal Rats.

PubMed

Wen, Tong-Chun; Lall, Sophia; Pagnotta, Corey; Markward, James; Gupta, Disha; Ratnadurai-Giridharan, Shivakeshavan; Bucci, Jacqueline; Greenwald, Lucy; Klugman, Madelyne; Hill, N Jeremy; Carmel, Jason B

2018-01-01

After injury to the corticospinal tract (CST) in early development there is large-scale adaptation of descending motor pathways. Some studies suggest the uninjured hemisphere controls the impaired forelimb, while others suggest that the injured hemisphere does; these pathways have never been compared directly. We tested the contribution of each motor cortex to the recovery forelimb function after neonatal injury of the CST. We cut the left pyramid (pyramidotomy) of postnatal day 7 rats, which caused a measurable impairment of the right forelimb. We used pharmacological inactivation of each motor cortex to test its contribution to a skilled reach and supination task. Rats with neonatal pyramidotomy were further impaired by inactivation of motor cortex in both the injured and the uninjured hemispheres, while the forelimb of uninjured rats was impaired only from the contralateral motor cortex. Thus, inactivation demonstrated motor control from each motor cortex. In contrast, physiological and anatomical interrogation of these pathways support adaptations only in the uninjured hemisphere. Intracortical microstimulation of motor cortex in the uninjured hemisphere of rats with neonatal pyramidotomy produced responses from both forelimbs, while stimulation of the injured hemisphere did not elicit responses from either forelimb. Both anterograde and retrograde tracers were used to label corticofugal pathways. There was no increased plasticity from the injured hemisphere, either from cortex to the red nucleus or the red nucleus to the spinal cord. In contrast, there were very strong CST connections to both halves of the spinal cord from the uninjured motor cortex. Retrograde tracing produced maps of each forelimb within the uninjured hemisphere, and these were partly segregated. This suggests that the uninjured hemisphere may encode separate control of the unimpaired and the impaired forelimbs of rats with neonatal pyramidotomy.

Adaptive changes in the motor cortex during and after longterm forelimb immobilization in adult rats.

PubMed

Viaro, Riccardo; Budri, Mirco; Parmiani, Pierantonio; Franchi, Gianfranco

2014-05-15

Experimental and clinical studies have attempted to evaluate the changes in cortical activity seen after immobilization-induced longterm sensorimotor restriction, although results remain controversial. We used intracortical microstimulation (ICMS), which provides topographic movement representations of the motor areas in both hemispheres with optimal spatial characterization, combined with behavioural testing to unravel the effects of limb immobilization on movement representations in the rat primary motor cortex (M1). Unilateral forelimb immobilization in rats was achieved by casting the entire limb and leaving the cast in place for 15 or 30 days. Changes in M1 were bilateral and specific for the forelimb area, but were stronger in the contralateral-to-cast hemisphere. The threshold current required to evoke forelimb movement increased progressively over the period in cast, whereas the forelimb area size decreased and the non-excitable area size increased. Casting resulted in a redistribution of proximal/distal movement representations: proximal forelimb representation increased, whereas distal representation decreased in size. ICMS after cast removal showed a reversal of changes, which remained partial at 15 days. Local application of the GABAA-antagonist bicuculline revealed the impairment of cortical synaptic connectivity in the forelimb area during the period of cast and for up to 15 days after cast removal. Six days of rehabilitation using a rotarod performance protocol after cast removal did not advance map size normalization in the contralateral-to-cast M1 and enabled the cortical output towards the distal forelimb only in sites that had maintained their excitability. These results are relevant to our understanding of adult M1 plasticity during and after sensorimotor deprivation, and to new approaches to conditions that require longterm limb immobilization. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Assessing forelimb function after unilateral cervical spinal cord injury: novel forelimb tasks predict lesion severity and recovery.

PubMed

Khaing, Zin Z; Geissler, Sydney A; Jiang, Shan; Milman, Brian D; Aguilar, Sandra V; Schmidt, Christine E; Schallert, Timothy

2012-02-10

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. Recently there has been increasing interest in cervical spinal cord injury models because the majority of spinal cord injuries are at cervical levels. Here we examined spontaneous functional recovery of adult rats with either laminectomy or lateral hemisection of the cervical spinal cord at C3-C4. Behavioral tests were carried out, including the forelimb locomotor scale (FLS), a postural instability test (PIT), a pasta-handling test that has been used to assess forepaw digit function and latency to eat, forelimb use during vertical-lateral wall exploration in a cylindrical enclosure, and vibrissae-elicited forelimb placing tests. In addition, a forelimb step-alternation test was developed to assess functional recovery at 12 weeks post-injury. All tests detected cSCI-induced deficits relative to laminectomy. Interestingly, the severity of deficits in the forelimb step-alternation test was associated with more extensive spinal damage, greater impairment, and less recovery in the FLS and other tests. For the pasta-handling test we found that rats with a milder cervical injury (alternators) were more likely to use both forepaws together compared to rats with a more severe injury (non-alternators). In addition, using the PIT, we detected enhanced function of the good limb, suggesting that neural plasticity on the unaffected side of the spinal cord may have occurred to compensate for deficits in the impaired forelimb. These outcome measures should be useful for investigating neural events associated with cSCI, and for developing novel treatment strategies.

Clawed forelimbs allow northern seals to eat like their ancient ancestors

NASA Astrophysics Data System (ADS)

Hocking, David P.; Marx, Felix G.; Sattler, Renae; Harris, Robert N.; Pollock, Tahlia I.; Sorrell, Karina J.; Fitzgerald, Erich M. G.; McCurry, Matthew R.; Evans, Alistair R.

2018-04-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name `pinniped' comes from the Latin pinna and pedis, meaning `fin-footed'. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. `Hold and tear' processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.

Grasp-Based Functional Coupling Between Reach- and Grasp-Related Components of Forelimb Muscle Activity

PubMed Central

Geed, Shashwati; van Kan, Peter L. E.

2017-01-01

How are appropriate combinations of forelimb muscles selected during reach-to-grasp movements in the presence of neuromotor redundancy and important task-related constraints? The authors tested whether grasp type or target location preferentially influence the selection and synergistic coupling between forelimb muscles during reach-to-grasp movements. Factor analysis applied to 14–20 forelimb electromyograms recorded from monkeys performing reach-to-grasp tasks revealed 4–6 muscle components that showed transport/preshape- or grasp-related features. Weighting coefficients of transport/preshape-related components demonstrated strongest similarities for reaches that shared the same grasp type rather than the same target location. Scaling coefficients of transport/preshape- and grasp-related components showed invariant temporal coupling. Thus, grasp type influenced strongly both transport/preshape- and grasp-related muscle components, giving rise to grasp-based functional coupling between forelimb muscles. PMID:27589010

Clawed forelimbs allow northern seals to eat like their ancient ancestors

PubMed Central

Sattler, Renae; Harris, Robert N.; Pollock, Tahlia I.; Sorrell, Karina J.; Fitzgerald, Erich M. G.; McCurry, Matthew R.

2018-01-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding. PMID:29765684

Clawed forelimbs allow northern seals to eat like their ancient ancestors.

PubMed

Hocking, David P; Marx, Felix G; Sattler, Renae; Harris, Robert N; Pollock, Tahlia I; Sorrell, Karina J; Fitzgerald, Erich M G; McCurry, Matthew R; Evans, Alistair R

2018-04-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name 'pinniped' comes from the Latin pinna and pedis , meaning 'fin-footed'. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. 'Hold and tear' processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos . Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.

Effects of ventrolateral thalamic nucleus cooling on initiation of forelimb ballistic flexion movements by conditioned cats.

PubMed

Bénita, M; Condé, H; Dormont, J F; Schmied, A

1979-02-15

Five cats were trained to perform a forelimb ballistic flexion on a reaction time paradigm including an upper limit of about 400 ms for reinforcement (food pellets). They were implanted with a cyrogenic probe thermically insulated, except at the tip, by a vacuum jacket (outer diameter, 1.1 mm). Four cats had the probe inserted into the ventrolateral thalamic nucleus (VL), contralateral to the moving limb. During cooling they showed increased reaction times, which remained constant throughout daily sessions performed during many weeks, independent of the foreperiod but varying from 25 to 100 ms according to the subject. The temperatures used to upset the reaction times varied from +10 decrees C to -8 degrees C, depending on the localisation of the probe and on the insulation of the silver tip used to prevent nervous tissue reaction, but for each subject the reaction times always increased when the temperature was lowered. The fifth cat, with a probe inserted between VL and the Centre Median, showed a decrease of reaction times on cooling to 0 degrees C and an increase of the reaction times for a cooling at -10 degrees C. For one of the four cats with a probe properly inserted into the VL, strain-gauges were stuck on the lever to measure the latency of the decrease of the pressure exerted by the subject when the subject initiated the forelimb flexion in response to the CS. Reaction times and latencies of pressure changes were closely correlated with the movement onset, and they were equally delayed during cooling. This result demonstrates that it is not by slowing down movement velocity that reaction times are upset during VL cooling but by delaying the movement onset.

HIGH RATES OF EVOLUTION PRECEDED THE ORIGIN OF BIRDS

PubMed Central

Puttick, Mark N; Thomas, Gavin H; Benton, Michael J; Polly, P David

2014-01-01

The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous. PMID:24471891

The comparative anatomy of the forelimb veins of primates.

PubMed Central

Thiranagama, R; Chamberlain, A T; Wood, B A

1989-01-01

One hundred and thirteen forelimbs taken from 62 individuals belonging to 17 primate genera were dissected to reveal the entire course of the superficial venous system. The course of the deep venous system was also documented in at least one forelimb of each primate genus, and the number and location of perforating veins was recorded in 18 human and 45 non-human primate limbs. In Pan, Gorilla and in about 25% of human specimens the lateral superficial vein was confined to the forearm, while in all other primates, and in the majority of humans, this vein extended from the carpus to the clavicular region. Only Pongo and humans exhibited a second main superficial vein on the medial side of the forearm. In all primates the deep veins of the forelimb usually accompanied the arteries. Thus variation in the deep venous system reflected the different arterial patterns exhibited by these primates. The number of perforating veins in the forelimb was related to the length of the limb. Primate genera with longer forelimbs had more perforators, though not as many as would be expected if the number of perforators scaled linearly with limb length. PMID:2514175

The forelimb of Tyrannosaurus rex: a pathetic vestigial organ or an integral part of a fearsome predator?

NASA Astrophysics Data System (ADS)

Lee, Scott A.; Thomas, Joshua

2014-03-01

The function of the forelimb of Tyrannosaurus rex remains a controversial topic since it was too short to transfer food directly to the mouth. Since Tyrannosaurus rex was bipedal, the forelimb was not involved in locomotion. Suggestions for its possible use include providing an initial push for a laying animal to stand or to hold position during mating. We report numerical calculations performed to determine the moment of inertia of the forearm and the torques generated by the muscles of the arm, based on three-dimensional representations of the forelimb. Our results imply that the forelimb was capable of very high angular accelerations, on the order of 130 radians/s2. This corresponds to a tangential acceleration of the manus on the order of 90 m/s2 or about 9g, indicating that the manus could be moved extremely quickly to control a struggling prey animal immediately before the death blow was delivered by the teeth of Tyrannosaurus rex. Rather than a pathetic vestigial organ, these calculations suggest that the forelimbs were an integral part of the predation tactics of Tyrannosaurus rex.

Comparison of hand use and forelimb posture during vertical climbing in mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes).

PubMed

Neufuss, Johanna; Robbins, Martha M; Baeumer, Jana; Humle, Tatyana; Kivell, Tracy L

2017-12-01

Studies on grasping and limb posture during arboreal locomotion in great apes in their natural environment are scarce and thus, attempts to correlate behavioral and habitat differences with variation in morphology are limited. The aim of this study is to compare hand use and forelimb posture during vertical climbing in wild, habituated mountain gorillas (Gorilla beringei beringei) and semi-free-ranging chimpanzees (Pan troglodytes) to assess differences in the climbing styles that may relate to variation in hand or forelimb morphology and body size. We investigated hand use and forelimb posture during both ascent and descent vertical climbing in 15 wild mountain gorillas and eight semi-free-ranging chimpanzees, using video records obtained ad libitum. In both apes, forelimb posture was correlated with substrate size during both ascent and descent climbing. While climbing, both apes used power grips and diagonal power grips, including three different thumb postures. Mountain gorillas showed greater ulnar deviation of the wrist during vertical descent than chimpanzees, and the thumb played an important supportive role when gorillas vertically descended lianas. We found that both apes generally had the same grip preferences and used similar forelimb postures on supports of a similar size, which is consistent with their overall similarity in hard and soft tissue morphology of the hand and forelimb. However, some species-specific differences in morphology appear to elicit slightly different grasping strategies during vertical climbing between mountain gorillas and chimpanzees. © 2017 Wiley Periodicals, Inc.

Computer-assisted kinematic evaluation of induced compensatory movements resembling lameness in horses trotting on a treadmill.

PubMed

Kelmer, Gal; Keegan, Kevin G; Kramer, Joanne; Wilson, David A; Pai, Frank P; Singh, Prableen

2005-04-01

To characterize compensatory movements of the head and pelvis that resemble lameness in horses. 17 adult horses. Kinematic evaluations were performed while horses trotted on a treadmill before and after shoe-induced lameness. Lameness was quantified and the affected limb determined by algorithms that measured asymmetry in vertical movement of the head and pelvis. Induced primary lameness and compensatory movements resembling lameness were assessed by the Friedman test. Association between induced lameness and compensatory movements was examined by regression analysis. Compensatory movements resembling lameness in the ipsilateral forelimb were seen with induced lameness of a hind limb. There was less downward and less upward head movement during and after the stance phase of the ipsilateral forelimb. Doubling the severity of lameness in the hind limb increased severity of the compensatory movements in the ipsilateral forelimb by 50%. Compensatory movements resembling lameness of the hind limb were seen after induced lameness in a forelimb. There was less upward movement of the pelvis after the stance phase of the contralateral hind limb and, to a lesser extent, less downward movement of the pelvis during the stance phase of the ipsilateral hind limb. Doubling the severity of lameness in the forelimb increased compensatory movements of the contralateral hind limb by 5%. Induced lameness in a hind limb causes prominent compensatory movements resembling lameness in the ipsilateral forelimb. Induced lameness in a forelimb causes slight compensatory movements resembling lameness in the ipsilateral and contralateral hind limbs.

Conditional genetic deletion of PTEN after a spinal cord injury enhances regenerative growth of CST axons and motor function recovery in mice.

PubMed

Danilov, Camelia A; Steward, Oswald

2015-04-01

Previous studies indicate that conditional genetic deletion of phosphatase and tensin homolog (PTEN) in neonatal mice enhances the ability of axons to regenerate following spinal cord injury (SCI) in adults. Here, we assessed whether deleting PTEN in adult neurons post-SCI is also effective, and whether enhanced regenerative growth is accompanied by enhanced recovery of voluntary motor function. PTEN(loxP/loxP) mice received moderate contusion injuries at cervical level 5 (C5). One group received unilateral injections of adeno-associated virus expressing CRE (AAV-CRE) into the sensorimotor cortex; controls received a vector expressing green fluorescent protein (AAV-GFP) or injuries only (no vector injections). Forelimb function was tested for 14weeks post-SCI using a grip strength meter (GSM) and a hanging task. The corticospinal tract (CST) was traced by injecting mini-ruby BDA into the sensorimotor cortex. Forelimb gripping ability was severely impaired immediately post-SCI but recovered slowly over time. The extent of recovery was significantly greater in PTEN-deleted mice in comparison to either the AAV-GFP group or the injury only group. BDA tract tracing revealed significantly higher numbers of BDA-labeled axons in caudal segments in the PTEN-deleted group compared to control groups. In addition, in the PTEN-deleted group, there were exuberant collaterals extending from the main tract rostral to the lesion and into and around the scar tissue at the injury site. These results indicate that PTEN deletion in adult mice shortly post-SCI can enhance regenerative growth of CST axons and forelimb motor function recovery. Copyright © 2015 Elsevier Inc. All rights reserved.

Cheap Labor: Myosin fiber type expression and enzyme activity in the forelimb musculature of sloths (Pilosa: Xenarthra).

PubMed

Spainhower, Kyle B; Cliffe, Rebecca N; Metz, Allan K; Barkett, Ernest M; Kiraly, Paije M; Thomas, Dylan R; Kennedy, Sarah J; Avey-Arroyo, Judy; Butcher, Michael T

2018-05-03

Sloths are canopy-dwelling inhabitants of American neotropical rainforests that exhibit suspensory behaviors. These abilities require both strength and muscular endurance to hang for extended periods of time; however, the skeletal muscle mass of sloths is reduced, thus requiring modifications to muscle architecture and leverage for large joint torque. We hypothesize that intrinsic muscle properties also are modified for fatigue resistance and predict a heterogeneous expression of slow/fast myosin heavy chain (MHC) fibers that utilize oxidative metabolic pathways for economic force production. MHC fiber type distribution and energy metabolism in the forelimb muscles of three-toed ( Bradypus variegatus, N=5) and two-toed ( Choloepus hoffmanni, N=4) sloths were evaluated using SDS-PAGE, immunohistochemistry, and enzyme activity assays. The results partially support our hypothesis by a primary expression of the slow MHC-1 isoform as well as moderate expression of fast MHC-2A fibers, while few hybrid MHC-1/2A fibers were found in both species. MHC-1 fibers were larger in cross-sectional area (CSA) than MHC-2A fibers and comprised the greatest %CSA in each muscle sampled. Enzyme assays showed elevated activity for the anaerobic enzymes creatine kinase (CK) and lactate dehydrogenase (LDH) compared to low activity for aerobic markers citrate synthase (CS) and 3- hydroxyacetyl CoA dehydrogenase (3-HAD). These findings suggest that sloth forelimb muscles may rely heavily on rapid ATP resynthesis pathways, and lactate accumulation may be beneficial. The intrinsic properties observed match well with suspensory requirements, and these modifications may have further evolved in unison with low metabolism and slow movement patterns as means to systemically conserve energy.

Effect of Coriolus versicolor Mycelia Extract on Exercise Performance and Physical Fatigue in Mice.

PubMed

Ho, Chun-Sheng; Tung, Yu-Tang; Kung, Woon-Man; Huang, Wen-Ching; Leung, Wing-Ki; Huang, Chi-Chang; Wu, Jyh-Horng

2017-01-01

In this study, Coriolus versicolor mycelia (CVM) was evaluated the ergogenic and anti-fatigue activities. Male ICR mice were divided into four groups ( n = 8/group) to receive vehicle or CVM by oral gavage for 4 weeks at 0, 615, 1230 or 3075 mg/kg/day, which were respectively designated the vehicle, CVM-1X, CVM-2X and CVM-5X groups. Forelimb grip strength, endurance swimming time, and levels of physical fatigue-associated parameters serum lactate, ammonia, glucose and creatine kinase (CK) after physical challenge were performed to evaluate exercise performance and anti-fatigue activity. Results revealed that the forelimb grip strength of mice in group CVM-1X, CVM-2X and CVM-5X were significantly increased by 1.20-, 1.18- and 1.23-fold, respectively, compared to the vehicle group. After the 15 minute swimming exercise, the levels of serum lactate of CVM-1X, CVM-2X and CVM-5X groups were significantly lower than the vehicle control group by 29%, 23% and 31%, respectively. The levels of ammonia in CVM-1X, CVM-2X and CVM-5X groups were significantly lowered by 22%, 25% and 41%, respectively, compared to the vehicle control group. In addition, the levels of serum CK in CVM-2X and CVM-5X groups were significantly lowered by 13% and 11%, respectively, compared to the vehicle control group. Accordingly, the supplementation with CVM has beneficial effects on performance improvement and anti-fatigue activity, and thus has great potential as a source for natural health products.

Effect of Coriolus versicolor Mycelia Extract on Exercise Performance and Physical Fatigue in Mice

PubMed Central

Ho, Chun-Sheng; Tung, Yu-Tang; Kung, Woon-Man; Huang, Wen-Ching; Leung, Wing-Ki; Huang, Chi-Chang; Wu, Jyh-Horng

2017-01-01

In this study, Coriolus versicolor mycelia (CVM) was evaluated the ergogenic and anti-fatigue activities. Male ICR mice were divided into four groups (n = 8/group) to receive vehicle or CVM by oral gavage for 4 weeks at 0, 615, 1230 or 3075 mg/kg/day, which were respectively designated the vehicle, CVM-1X, CVM-2X and CVM-5X groups. Forelimb grip strength, endurance swimming time, and levels of physical fatigue-associated parameters serum lactate, ammonia, glucose and creatine kinase (CK) after physical challenge were performed to evaluate exercise performance and anti-fatigue activity. Results revealed that the forelimb grip strength of mice in group CVM-1X, CVM-2X and CVM-5X were significantly increased by 1.20-, 1.18- and 1.23-fold, respectively, compared to the vehicle group. After the 15 minute swimming exercise, the levels of serum lactate of CVM-1X, CVM-2X and CVM-5X groups were significantly lower than the vehicle control group by 29%, 23% and 31%, respectively. The levels of ammonia in CVM-1X, CVM-2X and CVM-5X groups were significantly lowered by 22%, 25% and 41%, respectively, compared to the vehicle control group. In addition, the levels of serum CK in CVM-2X and CVM-5X groups were significantly lowered by 13% and 11%, respectively, compared to the vehicle control group. Accordingly, the supplementation with CVM has beneficial effects on performance improvement and anti-fatigue activity, and thus has great potential as a source for natural health products. PMID:29104465

Did saber-tooth kittens grow up musclebound? A study of postnatal limb bone allometry in felids from the Pleistocene of Rancho La Brea.

PubMed

Long, Katherine; Prothero, Donald; Madan, Meena; Syverson, Valerie J P

2017-01-01

Previous studies have demonstrated that the Pleistocene saber-toothed cat Smilodon fatalis had many forelimb adaptations for increased strength, presumably to grapple with and subdue prey. The Rancho La Brea tar pits yield large samples of juvenile limb bones forming a growth series that allow us to examine how Smilodon kittens grew up. Almost all available juvenile limb bones were measured, and reduced major axis fits were calculated to determine the allometric growth trends. Contrary to expectations based on their robust limbs, Smilodon kittens show the typical pattern of growth found in other large felids (such as the Ice Age lion, Panthera atrox, as well as living tigers, cougars, servals, and wildcats) where the limb grows longer and more slender faster than they grow thick. This adaptation is thought to give felids greater running speed. Smilodon kittens do not grow increasingly more robust with age. Instead, they start out robust and follow the ancestral felid growth pattern, while maintaining their robustness compared to other felids. Apparently, the growth of felid forelimbs is highly canalized and their ontogeny is tightly constrained.

Forelimbs of "Tyrannosaurus Rex": A Pathetic Vestigial Organ or an Integral Part of a Fearsome Predator?

ERIC Educational Resources Information Center

Lee, Scott A.; Thomas, Joshua D.

2014-01-01

In this paper, we examine a first-year torque and angular acceleration problem to address a possible use of the forelimbs of "Tyrannosaurus rex." A 1/40th-scale model (see Fig. 1) is brought to the classroom to introduce the students to the quandary: given that the forelimbs of "T. rex" were too short to reach its mouth, what…

The effect of ambient temperature on infrared thermographic images of joints in the distal forelimbs of healthy racehorses.

PubMed

Soroko, Maria; Howell, Kevin; Dudek, Krzysztof

2017-05-01

The aim of the study was to describe the dependence on ambient temperature of distal joint temperature at the forelimbs of racehorses. The study also investigated the influence of differing ambient temperatures on the temperature difference between joints: this was measured ipsilaterally (i.e. between the carpal and fetlock joints along each forelimb) and contralaterally (i.e. between the same joints of the left and right forelimbs). Sixty-four healthy racehorses were monitored over 10 months. At each session, three thermographic images were taken of the dorsal, lateral and medial aspects of the distal forelimbs. Temperature measurements were made from regions of interest (ROIs) covering the carpal and fetlock joints. There was a strong correlation between ambient temperature and absolute joint temperature at all ROIs. The study also observed a moderate correlation between ambient temperature and the ipsilateral temperature differences between joints when measured from the medial and lateral aspects. No significant correlation was noted when measured dorsally. The mean contralateral temperature differences between joints were all close to 0°C. The data support previous reports that the temperature distribution between the forelimbs of the healthy equine is generally symmetric, although some horses differ markedly from the average findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Therapeutic intraspinal microstimulation improves forelimb function after cervical contusion injury

NASA Astrophysics Data System (ADS)

Kasten, M. R.; Sunshine, M. D.; Secrist, E. S.; Horner, P. J.; Moritz, C. T.

2013-08-01

Objective. Intraspinal microstimulation (ISMS) is a promising method for activating the spinal cord distal to an injury. The objectives of this study were to examine the ability of chronically implanted stimulating wires within the cervical spinal cord to (1) directly produce forelimb movements, and (2) assess whether ISMS stimulation could improve subsequent volitional control of paretic extremities following injury. Approach. We developed a technique for implanting intraspinal stimulating electrodes within the cervical spinal cord segments C6-T1 of Long-Evans rats. Beginning 4 weeks after a severe cervical contusion injury at C4-C5, animals in the treatment condition received therapeutic ISMS 7 hours/day, 5 days/week for the following 12 weeks. Main results. Over 12 weeks of therapeutic ISMS, stimulus-evoked forelimb movements were relatively stable. We also explored whether therapeutic ISMS promoted recovery of forelimb reaching movements. Animals receiving daily therapeutic ISMS performed significantly better than unstimulated animals during behavioural tests conducted without stimulation. Quantitative video analysis of forelimb movements showed that stimulated animals performed better in the movements reinforced by stimulation, including extending the elbow to advance the forelimb and opening the digits. While threshold current to elicit forelimb movement gradually increased over time, no differences were observed between chronically stimulated and unstimulated electrodes suggesting that no additional tissue damage was produced by the electrical stimulation. Significance. The results indicate that therapeutic intraspinal stimulation delivered via chronic microwire implants within the cervical spinal cord confers benefits extending beyond the period of stimulation, suggesting future strategies for neural devices to promote sustained recovery after injury.

Therapeutic intraspinal microstimulation improves forelimb function after cervical contusion injury

PubMed Central

Kasten, M.R.; Sunshine, M.D.; Secrist, E.S.; Horner, P.J.; Moritz, C.T.

2013-01-01

Objective Intraspinal microstimulation (ISMS) is a promising method for activating the spinal cord distal to an injury. The objectives of this study were to examine the ability of chronically implanted stimulating wires within the cervical spinal cord to (1) directly produce forelimb movements, and (2) assess whether ISMS stimulation improved subsequent volitional control of paretic extremities following injury. Approach We developed a technique for implanting intraspinal stimulating electrodes within the cervical spinal cord segments C6-T1 of Long-Evans rats. Beginning 4 weeks after a severe cervical contusion injury at C4–C5, animals in the treatment condition received therapeutic ISMS 7 hours/day, 5 days/week for the following 12 weeks. Main Results Over 12 weeks of therapeutic ISMS, stimulus-evoked forelimb movements were relatively stable. We also explored whether therapeutic ISMS promotes recovery of forelimb reaching movements. Animals receiving daily therapeutic ISMS performed significantly better than unstimulated animals during behavioral tests conducted without stimulation. Quantitative video analysis of forelimb movements showed that stimulated animals performed better in the movements reinforced by stimulation, including extending the elbow to advance the forelimb and opening the digits. While threshold current to elicit forelimb movement gradually increased over time, no differences were observed between chronically stimulated and unstimulated electrodes suggesting that no additional tissue damage was produced by the electrical stimulation. Significance The results indicate that therapeutic intraspinal stimulation delivered via chronic microwire implants within the cervical spinal cord confers benefits extending beyond the period of stimulation, suggesting future strategies for neural devices to promote sustained recovery after injury. PMID:23715242

Detection of an epidermoid cyst in the foot of a horse by use of magnetic resonance imaging.

PubMed

Sanz, Macarena G; Sampson, Sarah N; Schneider, Robert K; Gavin, Patrick R; Baszler, Timothy V

2006-06-15

CASE DESCRIPTION-A 4-year-old Quarter Horse stallion was evaluated because of a 10-month history of moderate (grade 3/5) left forelimb lameness (detectable during trotting over a smooth, hard surface). CLINICAL FINDINGS-No abnormalities were detected in either forelimb via palpation or application of hoof testers; however, lameness was eliminated after administration of a palmar digital nerve block in the left forelimb. Whereas radiography and ultrasonography did not identify any left forelimb foot abnormalities, magnetic resonance (MR) imaging revealed a circumscribed soft tissue mass in the distal aspect of the digital flexor tendon sheath (DFTS) dorsal to the lateral aspect of the deep digital flexor tendon. Subsequently, the left forelimb DFTS was injected with local anesthetic, which resulted in 90% improvement of the horse's lameness. TREATMENT AND OUTCOME-The distal aspect of the left forelimb DFTS was evaluated tenoscopically. The mass was removed under tenoscopic guidance, after which the distal digital annular ligament was transected. The horse received phenylbutazone orally for 10 days, and the left forelimb DFTS was injected with hyaluronic acid and methylprednisolone acetate 7 days after the surgery. Following a rehabilitation program, the horse was returned to full training at 6 months after surgery and competed successfully during a 2-year follow-up period. CLINICAL RELEVANCE-Use of MR imaging should be considered in all lame horses for which a definitive diagnosis cannot be made via radiography, ultrasonography, or other imaging techniques, especially when the lameness has been localized to a specific anatomic region by use of diagnostic anesthesia.

Causal Link between the Cortico-Rubral Pathway and Functional Recovery through Forced Impaired Limb Use in Rats with Stroke

PubMed Central

Ishida, Akimasa; Isa, Kaoru; Umeda, Tatsuya; Kobayashi, Kazuto; Kobayashi, Kenta; Hida, Hideki

2016-01-01

Intensive rehabilitation is believed to induce use-dependent plasticity in the injured nervous system; however, its causal relationship to functional recovery is unclear. Here, we performed systematic analysis of the effects of forced use of an impaired forelimb on the recovery of rats after lesioning the internal capsule with intracerebral hemorrhage (ICH). Forced limb use (FLU) group rats exhibited better recovery of skilled forelimb functions and their cortical motor area with forelimb representation was restored and enlarged on the ipsilesional side. In addition, abundant axonal sprouting from the reemerged forelimb area was found in the ipsilateral red nucleus after FLU. To test the causal relationship between the plasticity in the cortico-rubral pathway and recovery, loss-of-function experiments were conducted using a double-viral vector technique, which induces selective blockade of the target pathway. Blockade of the cortico-rubral tract resulted in deficits of the recovered forelimb function in FLU group rats. These findings suggest that the cortico-rubral pathway is a substrate for recovery induced by intensive rehabilitation after ICH. SIGNIFICANCE STATEMENT The research aimed at determining the causal linkage between reorganization of the motor pathway induced by intensive rehabilitative training and recovery after stroke. We clarified the expansion of the forelimb representation area of the ipsilesional motor cortex by forced impaired forelimb use (FLU) after lesioning the internal capsule with intracerebral hemorrhaging (ICH) in rats. Anterograde tracing showed robust axonal sprouting from the forelimb area to the red nucleus in response to FLU. Selective blockade of the cortico-rubral pathway by the novel double-viral vector technique clearly revealed that the increased cortico-rubral axonal projections had causal linkage to the recovery of reaching movements induced by FLU. Our data demonstrate that the cortico-rubral pathway is responsible for the effect of intensive limb use. PMID:26758837

Forelimb anatomy and the discrimination of the predatory behavior of carnivorous mammals: the thylacine as a case study.

PubMed

Janis, Christine M; Figueirido, Borja

2014-12-01

Carnivorous mammals use their forelimbs in different ways to capture their prey. Most terrestrial carnivores have some cursorial (running) adaptations, but ambush predators retain considerable flexibility in their forelimb movement, important for grappling with their prey. In contrast, predators that rely on pursuit to run down their prey have sacrificed some of this flexibility for locomotor efficiency, in the greater restriction of the forelimb motion to the parasagittal plane. In this article, we measured aspects of the forelimb anatomy (44 linear measurements) in 36 species of carnivorous mammals of known predatory behavior, and used multivariate analyses to investigate how well the forelimb anatomy reflects the predatory mode (ambush, pursuit, or pounce-pursuit). A prime intention of this study was to establish morphological correlates of behavior that could then be applied to fossil mammals: for this purpose, five individuals of the recently extinct thylacine (Thylacinus cynocephalus) were also included as unknowns. We show that the three different types of predators can be distinguished by their morphology, both in analyses where all the forelimb bones are included together, and in the separate analyses of each bone individually. Of particular interest is the ability to distinguish between the two types of more cursorial predators, pursuit and pounce-pursuit, which have previously been considered as primarily size-based categories. Despite a prior consideration of the thylacine as a "pounce-pursuit" or an "ambush" type of predator, the thylacines did not consistently cluster with any type of predatory carnivores in our analyses. Rather, the thylacines appeared to be more generalized in their morphology than any of the extant carnivores. The absence of a large diversity of large carnivorous mammals in Australia, past and present, may explain the thylacine's generalized morphology. © 2014 Wiley Periodicals, Inc.

Rehabilitative skilled forelimb training enhances axonal remodeling in the corticospinal pathway but not the brainstem-spinal pathways after photothrombotic stroke in the primary motor cortex.

PubMed

Okabe, Naohiko; Himi, Naoyuki; Maruyama-Nakamura, Emi; Hayashi, Norito; Narita, Kazuhiko; Miyamoto, Osamu

2017-01-01

Task-specific rehabilitative training is commonly used for chronic stroke patients. Axonal remodeling is believed to be one mechanism underlying rehabilitation-induced functional recovery, and significant roles of the corticospinal pathway have previously been demonstrated. Brainstem-spinal pathways, as well as the corticospinal tract, have been suggested to contribute to skilled motor function and functional recovery after brain injury. However, whether axonal remodeling in the brainstem-spinal pathways is a critical component for rehabilitation-induced functional recovery is not known. In this study, rats were subjected to photothrombotic stroke in the caudal forelimb area of the primary motor cortex and received rehabilitative training with a skilled forelimb reaching task for 4 weeks. After completion of the rehabilitative training, the retrograde tracer Fast blue was injected into the contralesional lower cervical spinal cord. Fast blue-positive cells were counted in 32 brain areas located in the cerebral cortex, hypothalamus, midbrain, pons, and medulla oblongata. Rehabilitative training improved motor performance in the skilled forelimb reaching task but not in the cylinder test, ladder walk test, or staircase test, indicating that rehabilitative skilled forelimb training induced task-specific recovery. In the histological analysis, rehabilitative training significantly increased the number of Fast blue-positive neurons in the ipsilesional rostral forelimb area and secondary sensory cortex. However, rehabilitative training did not alter the number of Fast blue-positive neurons in any areas of the brainstem. These results indicate that rehabilitative skilled forelimb training enhances axonal remodeling selectively in the corticospinal pathway, which suggests a critical role of cortical plasticity, rather than brainstem plasticity, in task-specific recovery after subtotal motor cortex destruction.

Rehabilitative skilled forelimb training enhances axonal remodeling in the corticospinal pathway but not the brainstem-spinal pathways after photothrombotic stroke in the primary motor cortex

PubMed Central

Himi, Naoyuki; Maruyama-Nakamura, Emi; Hayashi, Norito; Narita, Kazuhiko; Miyamoto, Osamu

2017-01-01

Task-specific rehabilitative training is commonly used for chronic stroke patients. Axonal remodeling is believed to be one mechanism underlying rehabilitation-induced functional recovery, and significant roles of the corticospinal pathway have previously been demonstrated. Brainstem-spinal pathways, as well as the corticospinal tract, have been suggested to contribute to skilled motor function and functional recovery after brain injury. However, whether axonal remodeling in the brainstem-spinal pathways is a critical component for rehabilitation-induced functional recovery is not known. In this study, rats were subjected to photothrombotic stroke in the caudal forelimb area of the primary motor cortex and received rehabilitative training with a skilled forelimb reaching task for 4 weeks. After completion of the rehabilitative training, the retrograde tracer Fast blue was injected into the contralesional lower cervical spinal cord. Fast blue-positive cells were counted in 32 brain areas located in the cerebral cortex, hypothalamus, midbrain, pons, and medulla oblongata. Rehabilitative training improved motor performance in the skilled forelimb reaching task but not in the cylinder test, ladder walk test, or staircase test, indicating that rehabilitative skilled forelimb training induced task-specific recovery. In the histological analysis, rehabilitative training significantly increased the number of Fast blue-positive neurons in the ipsilesional rostral forelimb area and secondary sensory cortex. However, rehabilitative training did not alter the number of Fast blue-positive neurons in any areas of the brainstem. These results indicate that rehabilitative skilled forelimb training enhances axonal remodeling selectively in the corticospinal pathway, which suggests a critical role of cortical plasticity, rather than brainstem plasticity, in task-specific recovery after subtotal motor cortex destruction. PMID:29095902

Intact intracortical microstimulation (ICMS) representations of rostral and caudal forelimb areas in rats with quinolinic acid lesions of the medial or lateral caudate-putamen in an animal model of Huntington's disease.

PubMed

Karl, Jenni M; Sacrey, Lori-Ann R; McDonald, Robert J; Whishaw, Ian Q

2008-09-05

Neurotoxic, cell-specific lesions of the rat caudate-putamen (CPu) have been proposed as a model of human Huntington's disease and as such impair performance on many motor tasks, including skilled forelimbs tasks such as reaching for food. Because the CPu and motor cortex share reciprocal connections, it has been proposed that the motor deficits are due in part to a secondary disruption of motor cortex. The purpose of the present study was to examine the functionality of the motor cortex using intracortical microstimulation (ICMS) following neurotoxic lesions of the CPu. ICMS maps have been shown to be sensitive indicators of motor skill, cortical injury, learning, and experience. Long-evans hooded rats received a sham, a medial, or a lateral CPu lesion using the neurotoxin, quinolinic acid (2,3-pyridinedicarboxylic acid). Two weeks later the motor cortex was stimulated under light ketamine anesthesia. Neither lateral nor medial lesions of the CPu altered the stimulation threshold for eliciting forelimb movements, the type of movements elicited, or the size of the rostral forelimb (RFA) and caudal forelimb areas (CFA) from which movements were elicited. The preservation of ICMS forelimb movement representations (the forelimb map) in rats with cell-specific CPu lesions suggests motor impairments following lesions of the lateral striatum are not due to the disruption of the motor map. Therefore, the impairments that follow striatal cell loss are due either to alterations in circuitry that is independent of motor cortex or to alterations in circuitry afferent to the motor cortex projections.

Forelimb kinematics and motor patterns of swimming loggerhead sea turtles (Caretta caretta): are motor patterns conserved in the evolution of new locomotor strategies?

PubMed

Rivera, Angela R V; Wyneken, Jeanette; Blob, Richard W

2011-10-01

Novel functions in animals may evolve through changes in morphology, muscle activity or a combination of both. The idea that new functions or behavior can arise solely through changes in structure, without concurrent changes in the patterns of muscle activity that control movement of those structures, has been formalized as the neuromotor conservation hypothesis. In vertebrate locomotor systems, evidence for neuromotor conservation is found across evolutionary transitions in the behavior of terrestrial species, and in evolutionary transitions from terrestrial species to flying species. However, evolutionary transitions in the locomotion of aquatic species have received little comparable study to determine whether changes in morphology and muscle function were coordinated through the evolution of new locomotor behavior. To evaluate the potential for neuromotor conservation in an ancient aquatic system, we quantified forelimb kinematics and muscle activity during swimming in the loggerhead sea turtle, Caretta caretta. Loggerhead forelimbs are hypertrophied into wing-like flippers that produce thrust via dorsoventral forelimb flapping. We compared kinematic and motor patterns from loggerheads with previous data from the red-eared slider, Trachemys scripta, a generalized freshwater species exhibiting unspecialized forelimb morphology and anteroposterior rowing motions during swimming. For some forelimb muscles, comparisons between C. caretta and T. scripta support neuromotor conservation; for example, the coracobrachialis and the latissimus dorsi show similar activation patterns. However, other muscles (deltoideus, pectoralis and triceps) do not show neuromotor conservation; for example, the deltoideus changes dramatically from a limb protractor/elevator in sliders to a joint stabilizer in loggerheads. Thus, during the evolution of flapping in sea turtles, drastic restructuring of the forelimb was accompanied by both conservation and evolutionary novelty in limb motor patterns.

Forelimb training drives transient map reorganization in ipsilateral motor cortex

PubMed Central

Pruitt, David T.; Schmid, Ariel N.; Danaphongse, Tanya T.; Flanagan, Kate E.; Morrison, Robert A.; Kilgard, Michael P.; Rennaker, Robert L.; Hays, Seth A.

2016-01-01

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. PMID:27392641

Forelimb training drives transient map reorganization in ipsilateral motor cortex.

PubMed

Pruitt, David T; Schmid, Ariel N; Danaphongse, Tanya T; Flanagan, Kate E; Morrison, Robert A; Kilgard, Michael P; Rennaker, Robert L; Hays, Seth A

2016-10-15

Skilled motor training results in reorganization of contralateral motor cortex movement representations. The ipsilateral motor cortex is believed to play a role in skilled motor control, but little is known about how training influences reorganization of ipsilateral motor representations of the trained limb. To determine whether training results in reorganization of ipsilateral motor cortex maps, rats were trained to perform the isometric pull task, an automated motor task that requires skilled forelimb use. After either 3 or 6 months of training, intracortical microstimulation (ICMS) mapping was performed to document motor representations of the trained forelimb in the hemisphere ipsilateral to that limb. Motor training for 3 months resulted in a robust expansion of right forelimb representation in the right motor cortex, demonstrating that skilled motor training drives map plasticity ipsilateral to the trained limb. After 6 months of training, the right forelimb representation in the right motor cortex was significantly smaller than the representation observed in rats trained for 3 months and similar to untrained controls, consistent with a normalization of motor cortex maps. Forelimb map area was not correlated with performance on the trained task, suggesting that task performance is maintained despite normalization of cortical maps. This study provides new insights into how the ipsilateral cortex changes in response to skilled learning and may inform rehabilitative strategies to enhance cortical plasticity to support recovery after brain injury. Copyright © 2016 Elsevier B.V. All rights reserved.

Load redistribution in walking and trotting Beagles with induced forelimb lameness.

PubMed

Abdelhadi, Jalal; Wefstaedt, Patrick; Galindo-Zamora, Vladimir; Anders, Alexandra; Nolte, Ingo; Schilling, Nadja

2013-01-01

To evaluate the load redistribution mechanisms in walking and trotting dogs with induced forelimb lameness. 7 healthy adult Beagles. Dogs walked and trotted on an instrumented treadmill to determine control values for peak and mean vertical force as well as vertical impulse for all 4 limbs. A small sphere was attached to the ventral pad of the right forelimb paw to induce a reversible lameness, and recordings were repeated for both gaits. Additionally, footfall patterns were assessed to test for changes in temporal gait variables. During walking and trotting, peak and mean vertical force as well as vertical impulse were decreased in the ipsilateral forelimb, increased in the contralateral hind limb, and remained unchanged in the ipsilateral hind limb after lameness was induced. All 3 variables were increased in the contralateral forelimb during trotting, whereas only mean vertical force and vertical impulse were increased during walking. Stance phase duration increased in the contralateral forelimb and hind limb during walking but not during trotting. Analysis of the results suggested that compensatory load redistribution mechanisms in dogs depend on the gait. All 4 limbs should be evaluated in basic research and clinical studies to determine the effects of lameness on the entire body. Further studies are necessary to elucidate specific mechanisms for unloading of the affected limb and to determine the long-term effects of load changes in animals with chronic lameness.

The effect of limb amputation on standing weight distribution in the remaining three limbs in dogs.

PubMed

Cole, Grayson Lee; Millis, Darryl

2017-01-16

Despite the fact that limb amputation is a commonly performed procedure in veterinary medicine, quantitative data regarding outcomes are lacking. The intention of this study was to evaluate the effect of limb amputation on weight distribution to the remaining three limbs at a stance in dogs. Ten dogs with a prior forelimb amputation and ten dogs with a prior hindlimb amputation; all of which had no history of orthopaedic or neural disease in the remaining three limbs were included in the study. Standing weight bearing was evaluated with a commercial stance analyzer in all dogs. Five valid trials were obtained and a mean percentage of weight bearing was calculated for each remaining limb. The dogs with a previous forelimb amputation, and also those with a previous hindlimb amputation, had the largest mean increase in weight bearing in the contralateral forelimb. In conclusion, proactive monitoring of orthopaedic disease in the contralateral forelimb may be advisable in dogs with a previous limb amputation. In addition, when determining candidacy for a limb amputation, disease of the contralateral forelimb should be thoroughly evaluated.

Environmental enrichment synergistically improves functional recovery by transplanted adipose stem cells in chronic hypoxic-ischemic brain injury.

PubMed

Seo, Jung Hwa; Kim, Hyongbum; Park, Eun Sook; Lee, Jong Eun; Kim, Dong Wook; Kim, Hyun Ok; Im, Sang Hee; Yu, Ji Hea; Kim, Ji Yeon; Lee, Min-Young; Kim, Chul Hoon; Cho, Sung-Rae

2013-01-01

We investigated the effects of environmental enrichment (EE) on the function of transplanted adipose stem cells (ASCs) and the combined effect of EE and ASC transplantation on neurobehavioral function in an animal model of chronic hypoxic-ischemic (HI) brain injury. HI brain damage was induced in 7-day-old mice by unilateral carotid artery ligation and exposure to hypoxia (8% O2 for 90 min). At 6 weeks of age, the mice were randomly injected with either ASCs or PBS into the striatum and were randomly assigned to either EE or standard cages (SC), comprising ASC-EE (n=18), ASC-SC (n=19), PBS-EE (n=12), PBS-SC (n=17), and untreated controls (n=23). Rotarod, forelimb-use asymmetry, and grip strength tests were performed to evaluate neurobehavioral function. The fate of transplanted cells and the levels of endogenous neurogenesis, astrocyte activation, and paracrine factors were also measured. As a result, EE and ASC transplantation synergistically improved rotarod latency, forelimb-use asymmetry, and grip strength compared to those of the other groups. The number of engrafted ASCs and βIII-tubulin(+) neurons derived from the transplanted ASCs was significantly higher in mice in EE than those in SC. EE and ASC transplantation also synergistically increased BrdU(+)βIII-tubulin(+) neurons, GFAP(+) astrocytic density, and fibroblast growth factor 2 (FGF2) level but not the level of CS-56(+) glial scarring in the striatum. In conclusion, EE and ASC transplantation synergistically improved neurobehavioral functions. The underlying mechanisms of this synergism included enhanced repair processes such as higher engraftment of the transplanted ASCs, increased endogenous neurogenesis and astrocytic activation coupled with upregulation of FGF2.

Assessing the role of dopamine in limb and cranial-oromotor control in a rat model of Parkinson’s disease

PubMed Central

Kane, Jacqueline R.; Ciucci, Michelle R.; Jacobs, Amber N.; Tews, Nathan; Russell, John A.; Ahrens, Allison M.; Ma, Sean T.; Britt, Joshua M.; Cormack, Lawrence K.; Schallert, Timothy

2012-01-01

Parkinson’s disease (PD) is a neurodegenerative disorder primarily characterized by sensorimotor dysfunction. The neuropathology of PD includes a loss of dopamine (DA) neurons of the nigrostriatal pathway. Classic signs of the disease include rigidity, bradykinesia, and postural instability. However, as many as 90% of patients also experience significant deficits in speech, swallowing (including mastication), and respiratory control. Oromotor deficits such as these are underappreciated, frequently emerging during the early, often hemi-Parkinson, stage of the disease. In this paper, we review tests commonly used in our labs to model early and hemi-Parkinson deficits in rodents. We have recently expanded our tests to include sensitive models of oromotor deficits. This paper discusses the most commonly used tests in our lab to model both limb and oromotor deficits, including tests of forelimb-use asymmetry, postural instability, vibrissae-evoked forelimb placing, single limb akinesia, dry pasta handling, sunflower seed shelling, and acoustic analyses of ultrasonic vocalizations and pasta biting strength. In particular, we lay new groundwork for developing methods for measuring abnormalities in the acoustic patterns during eating that indicate decreased biting strength and irregular intervals between bites in the hemi-Parkinson rat. Similar to limb motor deficits, oromotor deficits, at least to some degree, appear to be modulated by nigrostriatal DA. Finally, we briefly review the literature on targeted motor rehabilitation effects in PD models. Learning outcomes Readers will: (a) understand how a unilateral lesion to the nigrostriatal pathway affects limb use, (b) understand how a unilateral lesion to the nigrostriatal pathway affects oromotor function, and (c) gain an understanding of how limb motor deficits and oromotor deficits appear to involve dopamine and are modulated by training. PMID:21820129

Genetic regulation of canine skeletal traits: trade-offs between the hind limbs and forelimbs in the fox and dog

PubMed Central

Kharlamova, Anastasia V.; Trut, Lyudmila N.; Carrier, David R.; Chase, Kevin; Lark, Karl G.

2008-01-01

Synopsis Genetic variation in functionally integrated skeletal traits can be maintained over 10 million years despite bottlenecks and stringent selection. Here, we describe an analysis of the genetic architecture of the canid axial skeleton using populations of the Portuguese Water Dog Canis familiaris) and silver fox (Vulpes vulpes). Twenty-one skeletal metrics taken from radiographs of the forelimbs and hind limbs of the fox and dog were used to construct separate anatomical principal component (PC) matrices of the two species. In both species, 15 of the 21 PCs exhibited significant heritability, ranging from 25% to 70%. The second PC, in both species, represents a trade-off in which limb-bone width is inversely correlated with limb-bone length. PC2 accounts for approximately 15% of the observed skeletal variation, ~30% of the variation in shape. Many of the other significant PCs affect very small amounts of variation (e.g., 0.2–2%) along trade-off axes that partition function between the forelimbs and hind limbs. These PCs represent shape axes in which an increase in size of an element of the forelimb is associated with a decrease in size of an element of the hind limb and vice versa. In most cases, these trade-offs are heritable in both species and genetic loci have been identified in the Portuguese Water Dog for many of these. These PCs, present in both the dog and the fox, include ones that affect lengths of the forelimb versus the hind limb, length of the forefoot versus that of the hind foot, muscle moment (i.e., lever) arms of the forelimb versus hind limb, and cortical thickness of the bones of the forelimb versus hind limb. These inverse relationships suggest that genetic regulation of the axial skeleton results, in part, from the action of genes that influence suites of functionally integrated traits. Their presence in both dogs and foxes suggests that the genes controlling the regulation of these PCs of the forelimb versus hind limb may be found in other tetrapod taxa. PMID:18458753

Reorganization of Motor Cortex by Vagus Nerve Stimulation Requires Cholinergic Innervation.

PubMed

Hulsey, Daniel R; Hays, Seth A; Khodaparast, Navid; Ruiz, Andrea; Das, Priyanka; Rennaker, Robert L; Kilgard, Michael P

2016-01-01

Vagus nerve stimulation (VNS) paired with forelimb training drives robust, specific reorganization of movement representations in the motor cortex. The mechanisms that underlie VNS-dependent enhancement of map plasticity are largely unknown. The cholinergic nucleus basalis (NB) is a critical substrate in cortical plasticity, and several studies suggest that VNS activates cholinergic circuitry. We examined whether the NB is required for VNS-dependent enhancement of map plasticity in the motor cortex. Rats were trained to perform a lever pressing task and then received injections of the immunotoxin 192-IgG-saporin to selectively lesion cholinergic neurons of the NB. After lesion, rats underwent five days of motor training during which VNS was paired with successful trials. At the conclusion of behavioral training, intracortical microstimulation was used to document movement representations in motor cortex. VNS paired with forelimb training resulted in a substantial increase in the representation of proximal forelimb in rats with an intact NB compared to untrained controls. NB lesions prevent this VNS-dependent increase in proximal forelimb area and result in representations similar to untrained controls. Motor performance was similar between groups, suggesting that differences in forelimb function cannot account for the difference in proximal forelimb representation. Together, these findings indicate that the NB is required for VNS-dependent enhancement of plasticity in the motor cortex and may provide insight into the mechanisms that underlie the benefits of VNS therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

A comparative study of single-leg ground reaction forces in running lizards.

PubMed

McElroy, Eric J; Wilson, Robbie; Biknevicius, Audrone R; Reilly, Stephen M

2014-03-01

The role of different limbs in supporting and propelling the body has been studied in many species with animals appearing to have either similarity in limb function or differential limb function. Differential hindlimb versus forelimb function has been proposed as a general feature of running with a sprawling posture and as benefiting sprawled postured animals by enhancing maneuvering and minimizing joint moments. Yet only a few species have been studied and thus the generality of differential limb function in running animals with sprawled postures is unknown. We measured the limb lengths of seven species of lizard and their single-limb three-dimensional ground reaction forces during high-speed running. We found that all species relied on the hindlimb for producing accelerative forces. Braking forces were forelimb dominated in four species and equally distributed between limbs in the other three. Vertical forces were dominated by the hindlimb in three species and equally distributed between the forelimb and hindlimb in the other four. Medial forces were dominated by the hindlimb in four species and equally distributed in the other three, with all Iguanians exhibiting hindlimb-biased medial forces. Relative hindlimb to forelimb length of each species was related to variation in hindlimb versus forelimb medial forces; species with relatively longer hindlimbs compared with forelimbs exhibited medial forces that were more biased towards the hindlimbs. These results suggest that the function of individual limbs in lizards varies across species with only a single general pattern (hindlimb-dominated accelerative force) being present.

Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability?

PubMed Central

Manzano, Adriana S; Abdala, Virginia; Herrel, Anthony

2008-01-01

Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high-speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so-called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates. PMID:18565111

Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability?

PubMed

Manzano, Adriana S; Abdala, Virginia; Herrel, Anthony

2008-09-01

Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high-speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so-called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates.

Do constraints associated with the locomotor habitat drive the evolution of forelimb shape? A case study in musteloid carnivorans

PubMed Central

Fabre, Anne-Claire; Cornette, Raphael; Goswami, Anjali; Peigné, Stéphane

2015-01-01

Convergence in morphology can result from evolutionary adaptations in species living in environments with similar selective pressures. Here, we investigate whether the shape of the forelimb long bones has converged in environments imposing similar functional constraints, using musteloid carnivores as a model. The limbs of quadrupeds are subjected to many factors that may influence their shape. They need to support body mass without collapsing or breaking, yet at the same time resist the stresses and strains induced by locomotion. This likely imposes strong constraints on their morphology. Our geometric morphometric analyses show that locomotion, body mass and phylogeny all influence the shape of the forelimb. Furthermore, we find a remarkable convergence between: (i) aquatic and semi-fossorial species, both displaying a robust forelimb, with a shape that improves stability and load transfer in response to the physical resistance imposed by the locomotor environment; and (ii) aquatic and arboreal/semi-arboreal species, with both groups displaying a broad capitulum. This augments the degree of pronation/supination, an important feature for climbing as well as grasping and manipulation ability, behaviors common to aquatic and arboreal species. In summary, our results highlight how musteloids with different locomotor ecologies show differences in the anatomy of their forelimb bones. Yet, functional demands for limb movement through dense media also result in convergence in forelimb long-bone shape between diverse groups, for example, otters and badgers. PMID:25994128

Do constraints associated with the locomotor habitat drive the evolution of forelimb shape? A case study in musteloid carnivorans.

PubMed

Fabre, Anne-Claire; Cornette, Raphael; Goswami, Anjali; Peigné, Stéphane

2015-06-01

Convergence in morphology can result from evolutionary adaptations in species living in environments with similar selective pressures. Here, we investigate whether the shape of the forelimb long bones has converged in environments imposing similar functional constraints, using musteloid carnivores as a model. The limbs of quadrupeds are subjected to many factors that may influence their shape. They need to support body mass without collapsing or breaking, yet at the same time resist the stresses and strains induced by locomotion. This likely imposes strong constraints on their morphology. Our geometric morphometric analyses show that locomotion, body mass and phylogeny all influence the shape of the forelimb. Furthermore, we find a remarkable convergence between: (i) aquatic and semi-fossorial species, both displaying a robust forelimb, with a shape that improves stability and load transfer in response to the physical resistance imposed by the locomotor environment; and (ii) aquatic and arboreal/semi-arboreal species, with both groups displaying a broad capitulum. This augments the degree of pronation/supination, an important feature for climbing as well as grasping and manipulation ability, behaviors common to aquatic and arboreal species. In summary, our results highlight how musteloids with different locomotor ecologies show differences in the anatomy of their forelimb bones. Yet, functional demands for limb movement through dense media also result in convergence in forelimb long-bone shape between diverse groups, for example, otters and badgers. © 2015 Anatomical Society.

Burrowing as a novel voluntary strength training method for mice: A comparison of various voluntary strength or resistance exercise methods.

PubMed

Roemers, P; Mazzola, P N; De Deyn, P P; Bossers, W J; van Heuvelen, M J G; van der Zee, E A

2018-04-15

Voluntary strength training methods for rodents are necessary to investigate the effects of strength training on cognition and the brain. However, few voluntary methods are available. The current study tested functional and muscular effects of two novel voluntary strength training methods, burrowing (digging a substrate out of a tube) and unloaded tower climbing, in male C57Bl6 mice. To compare these two novel methods with existing exercise methods, resistance running and (non-resistance) running were included. Motor coordination, grip strength and muscle fatigue were measured at baseline, halfway through and near the end of a fourteen week exercise intervention. Endurance was measured by an incremental treadmill test after twelve weeks. Both burrowing and resistance running improved forelimb grip strength as compared to controls. Running and resistance running increased endurance in the treadmill test and improved motor skills as measured by the balance beam test. Post-mortem tissue analyses revealed that running and resistance running induced Soleus muscle hypertrophy and reduced epididymal fat mass. Tower climbing elicited no functional or muscular changes. As a voluntary strength exercise method, burrowing avoids the confounding effects of stress and positive reinforcers elicited in forced strength exercise methods. Compared to voluntary resistance running, burrowing likely reduces the contribution of aerobic exercise components. Burrowing qualifies as a suitable voluntary strength training method in mice. Furthermore, resistance running shares features of strength training and endurance (aerobic) exercise and should be considered a multi-modal aerobic-strength exercise method in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Paws for thought: comparative radiologic anatomy of the mammalian forelimb.

PubMed

Gough-Palmer, Antony L; Maclachlan, Jody; Routh, Andrew

2008-01-01

All mammals share a remarkably similar skeleton based on a common template. This commonality is particularly well illustrated by the versatile pentadactyl limb, upon which all mammalian limbs are based. For most mammals, the primary function of the forelimb is locomotion. The forelimb has been successfully adapted in mammals of all sizes and in terrestrial, arboreal, aquatic, and airborne environments. In primates, the forelimbs have developed such that speed and stamina have been sacrificed for an increased range of movement, which in turn has provided increased manual dexterity. For instance, chimpanzee hands are pronated and the fingers are flexed, and the phalanges are longer and exhibit much more robust insertion areas for flexor tendons. Ungulates (hoofed mammals), on the other hand, have evolved to maximize speed and stamina in quadrupedal locomotion. The two main orders of ungulates have elongated phalanges and metacarpals; all ungulates have lost the first metacarpal. The cat family represents some of the most highly evolved predators. Cats' forelimbs are designed for speed, power, and acceleration rather than for stamina; they maintain all five metacarpals and phalanges, although the first digit is relatively small. (c) RSNA, 2008

The evolution and anatomy of the horse manus with an emphasis on digit reduction

PubMed Central

Danowitz, Melinda; Stachtiaris, Elizabeth; Khurana, Abhilasha; Araim, Marwan; Sayegh, Marc; Natale, Jessica

2018-01-01

We revisit digit reduction in the horse and propose that all five digits are partially present in the modern adult forelimb. Osteological descriptions of selected tetradactyl, tridactyl and monodactyl equids demonstrate the evolution of the forelimb. Histological, osteological and palaeontological evidence suggest that the Equus distal forelimb is more complex than traditionally conceived. The current understanding is that the horse distal forelimb consists of one complete digit (III) and two reduced splint metacarpals (II and IV). Metacarpals II and IV each exhibit a ventral ridge, which we suggest represents the undifferentiated digits I and V. These ridges are present in the tridactyl Mesohippus, but are absent in the tetradactyl Hyracotherium. The carpal articulations of the five metacarpals match those of pentadactyl taxa. Distally, the frog, a V-shaped structure on the ventral hoof represents digits II and IV, and the wings and hoof cartilages of the distal phalanx are digits I and V. We relate this revised interpretation of the Equus forelimb to Laetoli footprints, and suggest the Hipparion side impressions are created from the hooves of I and V, rather than from II and IV. We show shades of pentadactyly within the Equus manus. PMID:29410871

Ladder beam and camera video recording system for evaluating forelimb and hindlimb deficits after sensorimotor cortex injury in rats.

PubMed

Soblosky, J S; Colgin, L L; Chorney-Lane, D; Davidson, J F; Carey, M E

1997-12-30

Hindlimb and forelimb deficits in rats caused by sensorimotor cortex lesions are frequently tested by using the narrow flat beam (hindlimb), the narrow pegged beam (hindlimb and forelimb) or the grid-walking (forelimb) tests. Although these are excellent tests, the narrow flat beam generates non-parametric data so that using more powerful parametric statistical analyses are prohibited. All these tests can be difficult to score if the rat is moving rapidly. Foot misplacements, especially on the grid-walking test, are indicative of an ongoing deficit, but have not been reliably and accurately described and quantified previously. In this paper we present an easy to construct and use horizontal ladder-beam with a camera system on rails which can be used to evaluate both hindlimb and forelimb deficits in a single test. By slow motion videotape playback we were able to quantify and demonstrate foot misplacements which go beyond the recovery period usually seen using more conventional measures (i.e. footslips and footfaults). This convenient system provides a rapid and reliable method for recording and evaluating rat performance on any type of beam and may be useful for measuring sensorimotor recovery following brain injury.

Coordination strategies for limb forces during weight-bearing locomotion in normal rats, and in rats spinalized as neonates

PubMed Central

Giszter, Simon F; Davies, Michelle R; Graziani, Virginia

2010-01-01

Some rats spinally transected as neonates (ST rats) achieve weight-supporting independent locomotion. The mechanisms of coordinated hindlimb weight support in such rats are not well understood. To examine these in such ST rats and normal rats, rats with better than 60% of weight supported steps on a treadmill as adults were trained to cross an instrumented runway. Ground reaction forces, coordination of hindlimb and forelimb forces and the motions of the center of pressure were assessed. Normal rats crossed the runway with a diagonal trot. On average hindlimbs bore about 80% of the vertical load carried by forelimbs, although this varied. Forelimbs and hindlimb acted synergistically to generate decelerative and propulsive rostrocaudal forces, which averaged 15% of body weight with maximums of 50% . Lateral forces were very small (<8% of body weight). Center of pressure progressed in jumps along a straight line with mean lateral deviations <1 cm. ST rats hindlimbs bore about 60% of the vertical load of forelimbs, significantly less compared to intact (p<0.05). ST rats showed similar mean rostrocaudal forces, but with significantly larger maximum fluctuations of up to 80% of body weight (p<0.05). Joint force-plate recordings showed forelimbs and hindlimb rostrocaudal forces in ST rats were opposing and significantly different from intact rats (p<0.05). Lateral forces were ~20% of body weight and significantly larger than in normal rats (p<0.05). Center of pressure zig-zagged, with mean lateral deviations of ~ 2cm and a significantly larger range (p<0.05). The haunches were also observed to roll more than normal rats. The locomotor strategy of injured rats using limbs in opposition was presumably less efficient but their complex gait was statically stable. Because forelimbs and hindlimbs acted in opposition, the trunk was held compressed. Force coordination was likely managed largely by the voluntary control in forelimbs and trunk. PMID:18612631

A novel approach to induction and rehabilitation of deficits in forelimb function in a rat model of ischemic stroke.

PubMed

Livingston-Thomas, Jessica Mary; Hume, Andrew Wilson; Doucette, Tracy Ann; Tasker, Richard Andrew

2013-01-01

Constraint-induced movement therapy (CIMT), which forces use of the impaired arm following unilateral stroke, promotes functional recovery in the clinic but animal models of CIMT have yielded mixed results. The aim of this study is to develop a refined endothelin-1 (ET-1) model of focal ischemic injury in rats that resulted in reproducible, well-defined lesions and reliable upper extremity impairments, and to determine if an appetitively motivated form of rehabilitation (voluntary forced use movement therapy; FUMT) would accelerate post-ischemic motor recovery. Male Sprague Dawley rats (3 months old) were given multiple intracerebral microinjections of ET-1 into the sensorimotor cortex and dorsolateral striatum. Sham-operated rats received the same surgical procedure up to but not including the drill holes on the skull. Functional deficits were assessed using two tests of forelimb placing, a forelimb postural reflex test, a forelimb asymmetry test, and a horizontal ladder test. In a separate experiment ET-1 stroke rats were subjected to daily rehabilitation with FUMT or with a control therapy beginning on post-surgery d 5. Performance and post-mortem analysis of lesion volume and regional BDNF expression were measured. Following microinjections of ET-1 animals exhibited significant deficits in contralateral forelimb function on a variety of tests compared with the sham group. These deficits persisted for up to 20 d with no mortality and were associated with consistent lesion volumes. FUMT therapy resulted in a modest but significantly accelerated recovery in the forelimb function as compared with the control therapy, but did not affect lesion size or BDNF expression in the ipsilesional hemisphere. We conclude that refined ET-1 microinjection protocols and forcing use of the impaired forelimb in an appetitively motivated paradigm may prove useful in developing strategies to study post-ischemic rehabilitation and neuroplasticity.

How lizards fly: A novel type of wing in animals.

PubMed

Dehling, J Maximilian

2017-01-01

Flying lizards of the genus Draco are renowned for their gliding ability, using an aerofoil formed by winglike patagial membranes and supported by elongated thoracic ribs. It remains unknown, however, how these lizards manoeuvre during flight. Here, I present the results of a study on the aerial behaviour of Dussumier's Flying Lizard (Draco dussumieri) and show that Draco attaches the forelimbs to the leading edge of the patagium while airborne, forming a hitherto unknown type of composite wing. The attachment of the forelimbs to the patagium suggests that that aerofoil is controlled through movements of the forelimbs. One major advantage for the lizards is that the forelimbs retain their complete range of movement and functionality for climbing and running when not used as a part of the wing. These findings not only shed a new light on the flight of Draco but also have implications for the interpretation of gliding performance in fossil species.

How lizards fly: A novel type of wing in animals

PubMed Central

2017-01-01

Flying lizards of the genus Draco are renowned for their gliding ability, using an aerofoil formed by winglike patagial membranes and supported by elongated thoracic ribs. It remains unknown, however, how these lizards manoeuvre during flight. Here, I present the results of a study on the aerial behaviour of Dussumier's Flying Lizard (Draco dussumieri) and show that Draco attaches the forelimbs to the leading edge of the patagium while airborne, forming a hitherto unknown type of composite wing. The attachment of the forelimbs to the patagium suggests that that aerofoil is controlled through movements of the forelimbs. One major advantage for the lizards is that the forelimbs retain their complete range of movement and functionality for climbing and running when not used as a part of the wing. These findings not only shed a new light on the flight of Draco but also have implications for the interpretation of gliding performance in fossil species. PMID:29236777

Osteological histology of the Pan-Alcidae (Aves, Charadriiformes): correlates of wing-propelled diving and flightlessness.

PubMed

Smith, N Adam; Clarke, Julia A

2014-02-01

Although studies of osteological morphology, gross myology, myological histology, neuroanatomy, and wing-scaling have all documented anatomical modifications associated with wing-propelled diving, the osteohistological study of this highly derived method of locomotion has been limited to penguins. Herein we present the first osteohistological study of the derived forelimbs and hind limbs of wing-propelled diving Pan-Alcidae (Aves, Charadriiformes). In addition to detailing differences between wing-propelled diving charadriiforms and nondiving charadriiforms, microstructural modifications to the humeri, ulnae and femora of extinct flightless pan-alcids are contrasted with those of volant alcids. Histological thin-sections of four species of pan-alcids (Alca torda, †Alca grandis, †Pinguinus impennis, †Mancalla cedrosensis) and one outgroup charadriiform (Stercorarius longicaudus) were compared. The forelimb bones of wing-propelled diving charadriiforms were found to have significantly thicker (∼22%) cortical bone walls. Additionally, as in penguins, the forelimbs of flightless pan-alcids are found to be osteosclerotic. However, unlike the pattern documented in penguins that display thickened cortices in both forelimbs and hind limbs, the forelimb and hind limb elements of pan-alcids display contrasting microstructural morphologies with thickened forelimb cortices and relatively thinner femoral cortices. Additionally, the identification of medullary bone in the sampled †Pinguinus impennis specimen suggests that further osteohistological investigation could provide an answer to longstanding questions regarding sexual dimorphism of Great Auks. Finally, these results suggest that it is possible to discern volant from flightless wing-propelled divers from fragmentary fossil remains. Copyright © 2013 Wiley Periodicals, Inc.

Combinatorial Motor Training Results in Functional Reorganization of Remaining Motor Cortex after Controlled Cortical Impact in Rats

PubMed Central

Combs, Hannah L.; Jones, Theresa A.; Kozlowski, Dorothy A.

2016-01-01

Abstract Cortical reorganization subsequent to post-stroke motor rehabilitative training (RT) has been extensively examined in animal models and humans. However, similar studies focused on the effects of motor training after traumatic brain injury (TBI) are lacking. We previously reported that after a moderate/severe TBI in adult male rats, functional improvements in forelimb use were accomplished only with a combination of skilled forelimb reach training and aerobic exercise, with or without nonimpaired forelimb constraint. Thus, the current study was designed to examine the relationship between functional motor cortical map reorganization after experimental TBI and the behavioral improvements resulting from this combinatorial rehabilitative regime. Adult male rats were trained to proficiency on a skilled reaching task, received a unilateral controlled cortical impact (CCI) over the forelimb area of the caudal motor cortex (CMC). Three days post-CCI, animals began RT (n = 13) or no rehabilitative training (NoRT) control procedures (n = 13). The RT group participated in daily skilled reach training, voluntary aerobic exercise, and nonimpaired forelimb constraint. This RT regimen significantly improved impaired forelimb reaching success and normalized reaching strategies, consistent with previous findings. RT also enlarged the area of motor cortical wrist representation, derived by intracortical microstimulation, compared to NoRT. These findings indicate that sufficient RT can greatly improve motor function and improve the functional integrity of remaining motor cortex after a moderate/severe CCI. When compared with findings from stroke models, these findings also suggest that more intense RT may be needed to improve motor function and remodel the injured cortex after TBI. PMID:26421759

Combinatorial Motor Training Results in Functional Reorganization of Remaining Motor Cortex after Controlled Cortical Impact in Rats.

PubMed

Combs, Hannah L; Jones, Theresa A; Kozlowski, Dorothy A; Adkins, DeAnna L

2016-04-15

Cortical reorganization subsequent to post-stroke motor rehabilitative training (RT) has been extensively examined in animal models and humans. However, similar studies focused on the effects of motor training after traumatic brain injury (TBI) are lacking. We previously reported that after a moderate/severe TBI in adult male rats, functional improvements in forelimb use were accomplished only with a combination of skilled forelimb reach training and aerobic exercise, with or without nonimpaired forelimb constraint. Thus, the current study was designed to examine the relationship between functional motor cortical map reorganization after experimental TBI and the behavioral improvements resulting from this combinatorial rehabilitative regime. Adult male rats were trained to proficiency on a skilled reaching task, received a unilateral controlled cortical impact (CCI) over the forelimb area of the caudal motor cortex (CMC). Three days post-CCI, animals began RT (n = 13) or no rehabilitative training (NoRT) control procedures (n = 13). The RT group participated in daily skilled reach training, voluntary aerobic exercise, and nonimpaired forelimb constraint. This RT regimen significantly improved impaired forelimb reaching success and normalized reaching strategies, consistent with previous findings. RT also enlarged the area of motor cortical wrist representation, derived by intracortical microstimulation, compared to NoRT. These findings indicate that sufficient RT can greatly improve motor function and improve the functional integrity of remaining motor cortex after a moderate/severe CCI. When compared with findings from stroke models, these findings also suggest that more intense RT may be needed to improve motor function and remodel the injured cortex after TBI.

Sensorimotor restriction affects complex movement topography and reachable space in the rat motor cortex.

PubMed

Budri, Mirco; Lodi, Enrico; Franchi, Gianfranco

2014-01-01

Long-duration intracortical microstimulation (ICMS) studies with 500 ms of current pulses suggest that the forelimb area of the motor cortex is organized into several spatially distinct functional zones that organize movements into complex sequences. Here we studied how sensorimotor restriction modifies the extent of functional zones, complex movements, and reachable space representation in the rat forelimb M1. Sensorimotor restriction was achieved by means of whole-forelimb casting of 30 days duration. Long-duration ICMS was carried out 12 h and 14 days after cast removal. Evoked movements were measured using a high-resolution 3D optical system. Long-term cast caused: (i) a reduction in the number of sites where complex forelimb movement could be evoked; (ii) a shrinkage of functional zones but no change in their center of gravity; (iii) a reduction in movement with proximal/distal coactivation; (iv) a reduction in maximal velocity, trajectory and vector length of movement, but no changes in latency or duration; (v) a large restriction of reachable space. Fourteen days of forelimb freedom after casting caused: (i) a recovery of the number of sites where complex forelimb movement could be evoked; (ii) a recovery of functional zone extent and movement with proximal/distal coactivation; (iii) an increase in movement kinematics, but only partial restoration of control rat values; (iv) a slight increase in reachability parameters, but these remained far below baseline values. We pose the hypothesis that specific aspects of complex movement may be stored within parallel motor cortex re-entrant systems.

Sensorimotor restriction affects complex movement topography and reachable space in the rat motor cortex

PubMed Central

Budri, Mirco; Lodi, Enrico; Franchi, Gianfranco

2014-01-01

Long-duration intracortical microstimulation (ICMS) studies with 500 ms of current pulses suggest that the forelimb area of the motor cortex is organized into several spatially distinct functional zones that organize movements into complex sequences. Here we studied how sensorimotor restriction modifies the extent of functional zones, complex movements, and reachable space representation in the rat forelimb M1. Sensorimotor restriction was achieved by means of whole-forelimb casting of 30 days duration. Long-duration ICMS was carried out 12 h and 14 days after cast removal. Evoked movements were measured using a high-resolution 3D optical system. Long-term cast caused: (i) a reduction in the number of sites where complex forelimb movement could be evoked; (ii) a shrinkage of functional zones but no change in their center of gravity; (iii) a reduction in movement with proximal/distal coactivation; (iv) a reduction in maximal velocity, trajectory and vector length of movement, but no changes in latency or duration; (v) a large restriction of reachable space. Fourteen days of forelimb freedom after casting caused: (i) a recovery of the number of sites where complex forelimb movement could be evoked; (ii) a recovery of functional zone extent and movement with proximal/distal coactivation; (iii) an increase in movement kinematics, but only partial restoration of control rat values; (iv) a slight increase in reachability parameters, but these remained far below baseline values. We pose the hypothesis that specific aspects of complex movement may be stored within parallel motor cortex re-entrant systems. PMID:25565987

Grizzly bear (Ursus arctos horribilis) locomotion: forelimb joint mechanics across speed in the sagittal and frontal planes.

PubMed

Shine, Catherine L; Robbins, Charles T; Nelson, O Lynne; McGowan, Craig P

2017-04-01

The majority of terrestrial locomotion studies have focused on parasagittal motion and paid less attention to forces or movement in the frontal plane. Our previous research has shown that grizzly bears produce higher medial ground reaction forces (lateral pushing from the animal) than would be expected for an upright mammal, suggesting frontal plane movement may be an important aspect of their locomotion. To examine this, we conducted an inverse dynamics analysis in the sagittal and frontal planes, using ground reaction forces and position data from three high-speed cameras of four adult female grizzly bears. Over the speed range collected, the bears used walks, running walks and canters. The scapulohumeral joint, wrist and the limb overall absorb energy (average total net work of the forelimb joints, -0.97 W kg -1 ). The scapulohumeral joint, elbow and total net work of the forelimb joints have negative relationships with speed, resulting in more energy absorbed by the forelimb at higher speeds (running walks and canters). The net joint moment and power curves maintain similar patterns across speed as in previously studied species, suggesting grizzly bears maintain similar joint dynamics to other mammalian quadrupeds. There is no significant relationship with net work and speed at any joint in the frontal plane. The total net work of the forelimb joints in the frontal plane was not significantly different from zero, suggesting that, despite the high medial ground reaction forces, the forelimb acts as a strut in that plane. © 2017. Published by The Company of Biologists Ltd.

Exercise induces cortical plasticity after neonatal spinal cord injury in the rat

PubMed Central

Kao, T; Shumsky, JS; Murray, M; Moxon, KA

2009-01-01

Exercise-induced cortical plasticity is associated with improved functional outcome after brain or nerve injury. Exercise also improves functional outcomes after spinal cord injury, but its effects on cortical plasticity are not known. The goal of this investigation was to study the effect of moderate exercise (treadmill locomotion, 3 min/day, 5days/week) on the somatotopic organization of forelimb and hindlimb somatosensory cortex (SI) after neonatal thoracic transection. We used adult rats spinalized as neonates because some of these animals develop weight-supported stepping and, therefore, the relationship between cortical plasticity and stepping could also be examined. Acute, single-neuron mapping was used to determine the percentage of cortical cells responding to cutaneous forelimb stimulation in normal, spinalized, and exercised spinalized rats. Multiple single neuron recording from arrays of chronically implanted microwires examined the magnitude of response of these cells in normal and exercised spinalized rats. Our results show that exercise not only increased the percentage of responding cells in the hindlimb SI, but also increased the magnitude of the response of these cells. This increase in response magnitude was correlated with behavioral outcome measures. In the forelimb SI, neonatal transection reduced the percentage of responding cells to forelimb stimulation but exercise reversed this loss. This restoration in the percentage of responding cells after exercise was accompanied by an increase in their response magnitude. Therefore, the increase in responsiveness of hindlimb SI to forelimb stimulation after neonatal transection and exercise may be due, in part, to the effect of exercise on the forelimb SI. PMID:19515923

Forelimb kinematics and motor patterns of the slider turtle (Trachemys scripta) during swimming and walking: shared and novel strategies for meeting locomotor demands of water and land

PubMed Central

Rivera, Angela R. V.; W. Blob, Richard

2010-01-01

Turtles use their limbs during both aquatic and terrestrial locomotion, but water and land impose dramatically different physical requirements. How must musculoskeletal function be adjusted to produce locomotion through such physically disparate habitats? We addressed this question by quantifying forelimb kinematics and muscle activity during aquatic and terrestrial locomotion in a generalized freshwater turtle, the red-eared slider (Trachemys scripta), using digital high-speed video and electromyography (EMG). Comparisons of our forelimb data to previously collected data from the slider hindlimb allow us to test whether limb muscles with similar functional roles show qualitatively similar modulations of activity across habitats. The different functional demands of water and air lead to a prediction that muscle activity for limb protractors (e.g. latissimus dorsi and deltoid for the forelimb) should be greater during swimming than during walking, and activity in retractors (e.g. coracobrachialis and pectoralis for the forelimb) should be greater during walking than during swimming. Differences between aquatic and terrestrial forelimb movements are reflected in temporal modulation of muscle activity bursts between environments, and in some cases the number of EMG bursts as well. Although patterns of modulation between water and land are similar between the fore- and hindlimb in T. scripta for propulsive phase muscles (retractors), we did not find support for the predicted pattern of intensity modulation, suggesting that the functional demands of the locomotor medium alone do not dictate differences in intensity of muscle activity across habitats. PMID:20889832

From fish to modern humans--comparative anatomy, homologies and evolution of the pectoral and forelimb musculature.

PubMed

Diogo, R; Abdala, V; Aziz, M A; Lonergan, N; Wood, B A

2009-05-01

In a recent study Diogo & Abdala [(2007) J Morphol 268, 504-517] reported the results of the first part of a research project on the comparative anatomy, homologies and evolution of the pectoral muscles of osteichthyans (bony fish and tetrapods). That report mainly focused on actinopterygian fish but also compared these fish with certain non-mammalian sarcopterygians. This study, which reports the second part of the research project, focuses mainly on sarcopterygians and particularly on how the pectoral and forelimb muscles have evolved during the transitions from sarcopterygian fish and non-mammalian tetrapods to monotreme and therian mammals and humans. The data obtained by our own dissections of all the pectoral and forelimb muscles of representative members of groups as diverse as sarcopterygian fish, amphibians, reptiles, monotremes and therian mammals such as rodents, tree-shrews, colugos and primates, including humans, are compared with the information available in the literature. Our observations and comparisons clearly stress that, with regard to the number of pectoral and forelimb muscles, the most striking transition within sarcopterygian evolutionary history was that leading to the origin of tetrapods. Whereas extant sarcopterygian fish have an abductor and adductor of the fin and a largely undifferentiated hypaxial and epaxial musculature, extant salamanders such as Ambystoma have more than 40 pectoral and forelimb muscles. There is no clear increase in the number of pectoral and forelimb muscles within the evolutionary transition that led to the origin of mammals and surely not to that leading to the origin of primates and humans.

From fish to modern humans – comparative anatomy, homologies and evolution of the pectoral and forelimb musculature

PubMed Central

Diogo, R; Abdala, V; Aziz, M A; Lonergan, N; Wood, B A

2009-01-01

In a recent study Diogo & Abdala [(2007) JMorphol268, 504–517] reported the results of the first part of a research project on the comparative anatomy, homologies and evolution of the pectoral muscles of osteichthyans (bony fish and tetrapods). That report mainly focused on actinopterygian fish but also compared these fish with certain non-mammalian sarcopterygians. This study, which reports the second part of the research project, focuses mainly on sarcopterygians and particularly on how the pectoral and forelimb muscles have evolved during the transitions from sarcopterygian fish and non-mammalian tetrapods to monotreme and therian mammals and humans. The data obtained by our own dissections of all the pectoral and forelimb muscles of representative members of groups as diverse as sarcopterygian fish, amphibians, reptiles, monotremes and therian mammals such as rodents, tree-shrews, colugos and primates, including humans, are compared with the information available in the literature. Our observations and comparisons clearly stress that, with regard to the number of pectoral and forelimb muscles, the most striking transition within sarcopterygian evolutionary history was that leading to the origin of tetrapods. Whereas extant sarcopterygian fish have an abductor and adductor of the fin and a largely undifferentiated hypaxial and epaxial musculature, extant salamanders such as Ambystoma have more than 40 pectoral and forelimb muscles. There is no clear increase in the number of pectoral and forelimb muscles within the evolutionary transition that led to the origin of mammals and surely not to that leading to the origin of primates and humans. PMID:19438764

Step-related discharges of Purkinje cells in the paravermal cortex of the cerebellar anterior lobe in the cat.

PubMed Central

Edgley, S A; Lidierth, M

1988-01-01

1. Extracellular recordings were made of the simple spike discharges of Purkinje cells in the lateral part of the paravermal cortex of lobule V in the cerebellum of awake cats. The cells were located within the c2 and c3 zones of Oscarsson (1979). 2. The peripheral receptive fields in which light mechanical stimuli could evoke simple spikes were examined in 252 Purkinje cells. Ninety-two per cent were activated by stimulation of the ipsilateral forelimb and 52% of 113 tested cells also discharged simple spikes in response to stimulation of the contralateral forelimb. The receptive fields were concentrated on the distal parts of the limbs: 67% of the 139 cells which were examined in most detail responded to stimulation of the paw or wrist of the ipsilateral forelimb. 3. In 135 of the Purkinje cells, the discharges were recorded during locomotion. Simple spikes were discharged at a mean rate of 54.3 +/- 27.8 impulses/s (S.D., n = 135) during steady walking on a belt moving at 0.5-0.7 m/s. The discharges of each cell were rhythmically modulated in time with the movements of stepping and although the timings of the discharges were highly variable between cells, activity in the population was greatest at the times of transition between the stance and swing phases in the ipsilateral forelimb and least during mid-stance. 4. As a population Purkinje cells with simple spike receptive fields on the distal parts of the forelimb(s) exhibited two activity maxima. These occurred during early stance and during the transition from stance to swing in the ipsilateral forelimb. Cells with receptive fields on the proximal parts of the limb achieved an activity maximum during late swing, and their average discharge rate fell at the time of onset of the swing phase in the ipsilateral forelimb instead of rising as was the case for the distal group. 5. The present results are compared with those from cells located more medially in the paravermal cortex. It is shown that medially located cells tend to discharge earlier in stance (or in late flexion) than laterally located cells with similar receptive fields. PMID:3171993

Reduced bone mass and muscle strength in male 5α-reductase type 1 inactivated mice.

PubMed

Windahl, Sara H; Andersson, Niklas; Börjesson, Anna E; Swanson, Charlotte; Svensson, Johan; Movérare-Skrtic, Sofia; Sjögren, Klara; Shao, Ruijin; Lagerquist, Marie K; Ohlsson, Claes

2011-01-01

Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1⁻/⁻ mice. Four-month-old male Srd5a1⁻/⁻ mice had reduced trabecular bone mineral density (-36%, p<0.05) and cortical bone mineral content (-15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1⁻/⁻ mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1⁻/⁻ mice. Male Srd5a1⁻/⁻ mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1⁻/⁻ mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1⁻/⁻ mice, is an indirect effect mediated by elevated circulating androgen levels.

Reduced Bone Mass and Muscle Strength in Male 5α-Reductase Type 1 Inactivated Mice

PubMed Central

Windahl, Sara H.; Andersson, Niklas; Börjesson, Anna E.; Swanson, Charlotte; Svensson, Johan; Movérare-Skrtic, Sofia; Sjögren, Klara; Shao, Ruijin; Lagerquist, Marie K.; Ohlsson, Claes

2011-01-01

Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1−/− mice. Four-month-old male Srd5a1 −/− mice had reduced trabecular bone mineral density (−36%, p<0.05) and cortical bone mineral content (−15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1 −/− mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1 −/− mice. Male Srd5a1 −/− mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1 −/− mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1 −/− mice, is an indirect effect mediated by elevated circulating androgen levels. PMID:21731732

Comparative anatomy, evolution, and homologies of tetrapod hindlimb muscles, comparison with forelimb muscles, and deconstruction of the forelimb-hindlimb serial homology hypothesis.

PubMed

Diogo, Rui; Molnar, Julia

2014-06-01

For more than two centuries, the idea that the forelimb and hindlimb are serially homologous structures has been accepted without serious question. This study presents the first detailed analysis of the evolution and homologies of all hindlimb muscles in representatives of each major tetrapod group and proposes a unifying nomenclature for these muscles. These data are compared with information obtained previously about the forelimb muscles of tetrapods and the muscles of other gnathostomes in order to address one of the most central and enigmatic questions in evolutionary and comparative anatomy: why are the pelvic and pectoral appendages of gnathostomes generally so similar to each other? An integrative analysis of the new myological data, combined with a review of recent paleontological, developmental, and genetic works and of older studies, does not support serial homology between the structures of these appendages. For instance, many of the strikingly similar forelimb and hindlimb muscles found in each major extant tetrapod taxon were acquired at different geological times and/or have different embryonic origins. These similar muscles are not serial homologues, but the result of evolutionary parallelism/convergence due to a complex interplay of ontogenetic, functional, topological, and phylogenetic constraints/factors. Copyright © 2014 Wiley Periodicals, Inc.

Expression of a hindlimb-determining factor Pitx1 in the forelimb of the lizard Pogona vitticeps during morphogenesis.

PubMed

Melville, Jane; Hunjan, Sumitha; McLean, Felicity; Mantziou, Georgia; Boysen, Katja; Parry, Laura J

2016-10-01

With over 9000 species, squamates, which include lizards and snakes, are the largest group of reptiles and second-largest order of vertebrates, spanning a vast array of appendicular skeletal morphology. As such, they provide a promising system for examining developmental and molecular processes underlying limb morphology. Using the central bearded dragon (Pogona vitticeps) as the primary study model, we examined limb morphometry throughout embryonic development and characterized the expression of three known developmental genes (GHR, Pitx1 and Shh) from early embryonic stage through to hatchling stage via reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). In this study, all genes were found to be transcribed in both the forelimbs and hindlimbs of P. vitticeps. While the highest level of GHR expression occurred at the hatchling stage, Pitx1 and Shh expression was greatest earlier during embryogenesis, which coincides with the onset of the differentiation between forelimb and hindlimb length. We compared our finding of Pitx1 expression-a hindlimb-determining gene-in the forelimbs of P. vitticeps to that in a closely related Australian agamid lizard, Ctenophorus pictus, where we found Pitx1 expression to be more highly expressed in the hindlimb compared with the forelimb during early and late morphogenesis-a result consistent with that found across other tetrapods. Expression of Pitx1 in forelimbs has only rarely been documented, including via in situ hybridization in a chicken and a frog. Our findings from both RT-qPCR and IHC indicate that further research across a wider range of tetrapods is needed to more fully understand evolutionary variation in molecular processes underlying limb morphology. © 2016 The Authors.

Postnatal Maturation of the Red Nucleus Motor Map Depends on Rubrospinal Connections with Forelimb Motor Pools

PubMed Central

Williams, Preston T. J. A.; Kim, Sangsoo

2014-01-01

The red nucleus (RN) and rubrospinal tract (RST) are important for forelimb motor control. Although the RST is present postnatally in cats, nothing is known about when rubrospinal projections could support motor functions or the relation between the development of the motor functions of the rubrospinal system and the corticospinal system, the other major system for limb control. Our hypothesis is that the RN motor map is present earlier in development than the motor cortex (M1) map, to support early forelimb control. We investigated RN motor map maturation with microstimulation and RST cervical enlargement projections using anterograde tracers between postnatal week 3 (PW3) and PW16. Microstimulation and tracer injection sites were verified histologically to be located within the RN. Microstimulation at PW4 evoked contralateral wrist, elbow, and shoulder movements. The number of sites producing limb movement increased and response thresholds decreased progressively through PW16. From the outset, all forelimb joints were represented. At PW3, RST projections were present within the cervical intermediate zone, with a mature density of putative synapses. In contrast, beginning at PW5 there was delayed and age-dependent development of forelimb motor pool projections and putative rubromotoneuronal synapses. The RN has a more complete forelimb map early in development than previous studies showed for M1, supporting our hypothesis of preferential rubrospinal rather than corticospinal control for early movements. Remarkably, development of the motor pool, not intermediate zone, RST projections paralleled RN motor map development. The RST may be critical for establishing the rudiments of motor skills that subsequently become refined with further CST development. PMID:24647962

Optical study of interactions among propagation waves of neural excitation in the rat somatosensory cortex evoked by forelimb and hindlimb stimuli.

PubMed

Hama, Noriyuki; Kawai, Minako; Ito, Shin-Ichi; Hirota, Akihiko

2018-05-01

Multisite optical recording has revealed that the neural excitation wave induced by a sensory stimulation begins at a focus and propagates in the cortex. This wave is considered to be important for computation in the sensory cortex, particularly the integration of sensory information; however, the nature of this wave remains largely unknown. In the present study, we examined the interaction between two waves in the rat sensory cortex induced by hindlimb and forelimb stimuli with different interstimulus intervals. We classified the resultant patterns as follows: 1) the collision of two waves, 2) the hindlimb response being evoked while the forelimb-induced wave is passing the hindlimb focus, and 3) the hindlimb response being evoked after the forelimb-induced wave has passed the hindlimb focus. In pattern 1, the two waves fused into a single wave, but the propagation pattern differed from that predicted by the superimposition of two singly induced propagation courses. In pattern 2, the state of the interaction between the two waves varied depending on the phase of optical signals constituting the forelimb-induced wave around the hindlimb focus. Although no hindlimb-induced wave was observed in the rising phase, the propagating velocity of the forelimb-induced wave increased. At the peak, neither the hindlimb-induced response nor a modulatory effect on the forelimb-induced wave was detected. In pattern 3, the hindlimb-induced wave showed a reduced amplitude and spatial extent. These results indicate that the state of the interaction between waves was strongly influenced by the relative timing of sensory inputs. NEW & NOTEWORTHY Sensory stimulation-induced cortical excitation propagates as a wave and spreads over a wide area of the sensory cortex. To elucidate the characteristics of this relatively unknown phenomenon, we examined the interaction between two individually induced waves in the somatosensory cortex. Either the waves collided or the preceding wave affected the emergence of the following one. Our results indicate that the state of the interaction was strongly influenced by the relative timing of sensory inputs.

Forelimb preferences in quadrupedal marsupials and their implications for laterality evolution in mammals.

PubMed

Giljov, Andrey; Karenina, Karina; Malashichev, Yegor

2013-03-06

Acquisition of upright posture in evolution has been argued to facilitate manual laterality in primates. Owing to the high variety of postural habits marsupials can serve as a suitable model to test whether the species-typical body posture shapes forelimb preferences in non-primates or this phenomenon emerged only in the course of primate evolution. In the present study we aimed to explore manual laterality in marsupial quadrupeds and compare them with the results in the previously studied bipedal species. Forelimb preferences were assessed in captive grey short-tailed opossum (Monodelphis domestica) and sugar glider (Petaurus breviceps) in four different types of unimanual behaviour per species, which was not artificially evoked. We examined the possible effects of sex, age and task, because these factors have been reported to affect motor laterality in placental mammals. In both species the direction of forelimb preferences was strongly sex-related. Male grey short-tailed opossums showed right-forelimb preference in most of the observed unimanual behaviours, while male sugar gliders displayed only a slight, not significant rightward tendency. In contrast, females in both species exhibited consistent group-level preference of the left forelimb. We failed to reveal significant differences in manual preferences between tasks of potentially differing complexity: reaching a stable food item and catching live insects, as well as between the body support and food manipulation. No influence of subjects' age on limb preferences was found. The direction of sex-related differences in the manual preferences found in quadrupedal marsupials seems to be not typical for placental mammals. We suggest that the alternative way of interhemispheric connection in absence of corpus callosum may result in a fundamentally distinct mechanism of sex effect on limb preferences in marsupials compared to placentals. Our data confirm the idea that non-primate mammals differ from primates in sensitivity to task complexity. Comparison of marsupial species studied to date indicate that the vertical body orientation and the bipedalism favor the expression of individual- and population-level forelimb preferences in marsupials much like it does in primates. Our findings give the first evidence for the effect of species-typical posture on the manual laterality in non-primate mammals.

[Advances in genome editing technologies for treating muscular dystrophy.

PubMed

Makita, Yukimasa; Hozumi, Hiroyuki; Hotta, Akitsu

Recent advances in genome editing technologies have opened the possibility for treating genetic diseases, such as Duchenne muscular dystrophy(DMD), by correcting the causing gene mutations in dystrophin gene. In fact, there are several reports that demonstrated the restoration of the mutated dystrophin gene in DMD patient-derived iPS cell or functional recovery of forelimb grip strength in DMD model mice. For future clinical applications, there are several aspects that need to be taken into consideration:efficient delivery of the genome editing components, risk of off-target mutagenesis and immunogenicity against genome editing enzyme. In this review, we summarize the current status and future prospective of the research in applying genome editing technologies to DMD.

Functional anatomy of the forelimb in Promegantereon* ogygia (Felidae, Machairodontinae, Smilodontini) from the late miocene of spain and the origins of the sabre-toothed felid model.

PubMed

Salesa, Manuel J; Antón, Mauricio; Turner, Alan; Morales, Jorge

2010-03-01

We examine the functional anatomy of the forelimb in the primitive sabre-toothed cat Promegantereon ogygia in comparison with that of the extant pantherins, other felids and canids. The study reveals that this early machairodontine had already developed strong forelimbs and a short and robust thumb, a combination that probably allowed P. ogygia to exert relatively greater forces than extant pantherins. These features can be clearly related to the evolution of the sabre-toothed cat hunting method, in which the rapid killing of prey was achieved with a precise canine shear-bite to the throat. In this early sabre-toothed cat from the Late Miocene, the strong forelimbs and thumb were adapted to achieve the rapid immobilization of prey, thus decreasing the risk of injury and minimizing energy expenditure. We suggest that these were the major evolutionary pressures that led to the appearance of the sabre-toothed cat model from the primitive forms of the Middle Miocene, rather than the hunting of very large prey, although these adaptations reached their highest development in the more advanced sabre-toothed cats of the Plio-Pleistocene, such as Smilodon and Homotherium. Although having very different body proportions, these later animals developed such extremely powerful forelimbs that they were probably able to capture relatively larger prey than extant pantherins.

Extreme Modification of the Tetrapod Forelimb in a Triassic Diapsid Reptile.

PubMed

Pritchard, Adam C; Turner, Alan H; Irmis, Randall B; Nesbitt, Sterling J; Smith, Nathan D

2016-10-24

The tetrapod forelimb is one of the most versatile structures in vertebrate evolution, having been co-opted for an enormous array of functions. However, the structural relationships between the bones of the forelimb have remained largely unchanged throughout the 375 million year history of Tetrapoda, with a radius and ulna made up of elongate, paralleling shafts contacting a series of shorter carpal bones. These features are consistent across nearly all known tetrapods, suggesting that the morphospace encompassed by these taxa is limited by some sort of constraint(s). Here, we report on a series of three-dimensionally preserved fossils of the small-bodied (<1 m) Late Triassic diapsid reptile Drepanosaurus, from the Chinle Formation of New Mexico, USA, which dramatically diverge from this pattern. Along with the crushed type specimen from Italy, these specimens have a flattened, crescent-shaped ulna with a long axis perpendicular to that of the radius and hyperelongate, shaft-like carpal bones contacting the ulna that are proximodistally longer than the radius. The second digit supports a massive, hooked claw. This condition has similarities to living "hook-and-pull" digging mammals and demonstrates that specialized, modern ecological roles had developed during the Triassic Period, over 200 million years ago. The forelimb bones in Drepanosaurus represent previously unknown morphologies for a tetrapod and, thus, a dramatic expansion of known tetrapod forelimb morphospace. Copyright © 2016 Elsevier Ltd. All rights reserved.

Farewell to life on land - thoracic strength as a new indicator to determine paleoecology in secondary aquatic mammals.

PubMed

Ando, Konami; Fujiwara, Shin-Ichi

2016-12-01

Habitat shifts from land to water have occurred independently in several mammal lineages. However, because we do not know completely about the relationship between skeletal morphology and function, both reliable life reconstructions of each extinct taxon and the timing of those shifts in locomotor strategies are yet to be fully understood. We estimated the strengths of rib cages against vertical compression in 26 extant and four extinct mammal specimens including cetartiodactyls, paenungulates, and carnivorans, representing 11 terrestrial, six semi-aquatic, and nine obligate aquatic taxa. Our analyses of extant taxa showed that strengths were high among terrestrial/semi-aquatic mammals, whose rib cages are subjected to vertical compression during the support on land, whereas strengths were low among obligate aquatic mammals, whose rib cages are not subjected to antigravity force in the water. We therefore propose rib strength as a new index to estimate the ability of an animal to be supported on land while being supported by either the forelimbs or thoracic region. According to our analyses of extinct taxa, this ability to be supported on land was rejected for a basal cetacean (Cetartiodactyla: Ambulocetus) and two desmostylians (Paenungulata: Paleoparadoxia and Neoparadoxia). However, this ability was not rejected for one desmostylian species (Desmostylus). Further study of the ribs of extant/extinct semi-aquatic taxa may help in understanding the ecological shifts in these groups. © 2016 Anatomical Society.

Effect of burdock extract on physical performance and physiological fatigue in mice

PubMed Central

CHEN, Wen-Chyuan; HSU, Yi-Ju; LEE, Mon-Chien; LI, Hua Shuai; HO, Chun-Sheng; HUANG, Chi-Chang; CHEN, Fu-An

2017-01-01

Burdock (BD) is a common vegetable with many pharmacological properties. However, few studies have examined the effect of BD on exercise performance and physical fatigue. We aimed to evaluate the potential beneficial effects of BD on fatigue and ergogenic functions following physical challenge in mice. Methods: Male ICR mice were divided into four groups to receive either vehicle, or BD at 348.5, 697 or 1,742.5 mg/kg/day, by daily oral gavage for 4 weeks. Exercise performance and fatigue were evaluated from forelimb grip strength, exhaustive swimming time, and post-exercise levels of physical fatigue-related biomarkers serum lactate, ammonia, glucose, and creatine kinase (CK). Results: BD supplementation elevated endurance and grip strength in a dose-dependent manner. It also significantly decreased lactate, ammonia, and CK levels after physical challenge. In addition, BD supplementation had few subchronic toxic effects. Conclusions: Supplementation with BD has a wide spectrum of bioactive effects, including health promotion, performance improvement, and fatigue reduction. PMID:28890521

Limb Bone Structural Proportions and Locomotor Behavior in A.L. 288-1 ("Lucy").

PubMed

Ruff, Christopher B; Burgess, M Loring; Ketcham, Richard A; Kappelman, John

2016-01-01

While there is broad agreement that early hominins practiced some form of terrestrial bipedality, there is also evidence that arboreal behavior remained a part of the locomotor repertoire in some taxa, and that bipedal locomotion may not have been identical to that of modern humans. It has been difficult to evaluate such evidence, however, because of the possibility that early hominins retained primitive traits (such as relatively long upper limbs) of little contemporaneous adaptive significance. Here we examine bone structural properties of the femur and humerus in the Australopithecus afarensis A.L. 288-1 ("Lucy", 3.2 Myr) that are known to be developmentally plastic, and compare them with other early hominins, modern humans, and modern chimpanzees. Cross-sectional images were obtained from micro-CT scans of the original specimens and used to derive section properties of the diaphyses, as well as superior and inferior cortical thicknesses of the femoral neck. A.L. 288-1 shows femoral/humeral diaphyseal strength proportions that are intermediate between those of modern humans and chimpanzees, indicating more mechanical loading of the forelimb than in modern humans, and by implication, a significant arboreal locomotor component. Several features of the proximal femur in A.L. 288-1 and other australopiths, including relative femoral head size, distribution of cortical bone in the femoral neck, and cross-sectional shape of the proximal shaft, support the inference of a bipedal gait pattern that differed slightly from that of modern humans, involving more lateral deviation of the body center of mass over the support limb, which would have entailed increased cost of terrestrial locomotion. There is also evidence consistent with increased muscular strength among australopiths in both the forelimb and hind limb, possibly reflecting metabolic trade-offs between muscle and brain development during hominin evolution. Together these findings imply significant differences in both locomotor behavior and ecology between australopiths and later Homo.

Limb Bone Structural Proportions and Locomotor Behavior in A.L. 288-1 ("Lucy")

PubMed Central

Ruff, Christopher B.; Burgess, M. Loring; Ketcham, Richard A.; Kappelman, John

2016-01-01

While there is broad agreement that early hominins practiced some form of terrestrial bipedality, there is also evidence that arboreal behavior remained a part of the locomotor repertoire in some taxa, and that bipedal locomotion may not have been identical to that of modern humans. It has been difficult to evaluate such evidence, however, because of the possibility that early hominins retained primitive traits (such as relatively long upper limbs) of little contemporaneous adaptive significance. Here we examine bone structural properties of the femur and humerus in the Australopithecus afarensis A.L. 288–1 ("Lucy", 3.2 Myr) that are known to be developmentally plastic, and compare them with other early hominins, modern humans, and modern chimpanzees. Cross-sectional images were obtained from micro-CT scans of the original specimens and used to derive section properties of the diaphyses, as well as superior and inferior cortical thicknesses of the femoral neck. A.L. 288–1 shows femoral/humeral diaphyseal strength proportions that are intermediate between those of modern humans and chimpanzees, indicating more mechanical loading of the forelimb than in modern humans, and by implication, a significant arboreal locomotor component. Several features of the proximal femur in A.L. 288–1 and other australopiths, including relative femoral head size, distribution of cortical bone in the femoral neck, and cross-sectional shape of the proximal shaft, support the inference of a bipedal gait pattern that differed slightly from that of modern humans, involving more lateral deviation of the body center of mass over the support limb, which would have entailed increased cost of terrestrial locomotion. There is also evidence consistent with increased muscular strength among australopiths in both the forelimb and hind limb, possibly reflecting metabolic trade-offs between muscle and brain development during hominin evolution. Together these findings imply significant differences in both locomotor behavior and ecology between australopiths and later Homo. PMID:27902687

Influence of Muscle-Tendon Wrapping on Calculations of Joint Reaction Forces in the Equine Distal Forelimb

PubMed Central

Merritt, Jonathan S.; Davies, Helen M. S.; Burvill, Colin; Pandy, Marcus G.

2008-01-01

The equine distal forelimb is a common location of injuries related to mechanical overload. In this study, a two-dimensional model of the musculoskeletal system of the region was developed and applied to kinematic and kinetic data from walking and trotting horses. The forces in major tendons and joint reaction forces were calculated. The components of the joint reaction forces caused by wrapping of tendons around sesamoid bones were found to be of similar magnitude to the reaction forces between the long bones at each joint. This finding highlighted the importance of taking into account muscle-tendon wrapping when evaluating joint loading in the equine distal forelimb. PMID:18509485

Transcriptomic and epigenomic characterization of the developing bat wing

PubMed Central

Eckalbar, Walter L.; Schlebusch, Stephen A.; Mason, Mandy K.; Gill, Zoe; Parker, Ash V.; Booker, Betty M.; Nishizaki, Sierra; Muswamba-Nday, Christiane; Terhune, Elizabeth; Nevonen, Kimberly; Makki, Nadja; Friedrich, Tara; VanderMeer, Julia E.; Pollard, Katherine S.; Carbone, Lucia; Wall, Jeff D.; Illing, Nicola; Ahituv, Nadav

2016-01-01

Bats are the only mammals capable of powered flight, but little is known about the genetic determinants that shape their wings. Here, we generated a genome for Miniopterus natalensis and performed RNA-seq and ChIP-seq (H3K27ac, H3K27me3) on its developing forelimb and hindlimb autopods at sequential embryonic stages to decipher the molecular events that underlie bat wing development. Over 7,000 genes and several lncRNAs, including Tbx5-as1 and Hottip, were differentially expressed between forelimb, hindlimb and different stages. ChIP-seq identified thousands of regions that are differentially modified in forelimb versus hindlimb. Comparative genomics found 2,796 bat-accelerated regions within H3K27ac peaks, several of which cluster near limb-associated genes. Pathway analyses revealed multiple ribosomal proteins and known limb patterning signaling pathways as differentially regulated, and implicated increased forelimb mesenchymal condensations with differential growth. Combined, our work outlines multiple genetic components that contribute to bat wing formation, providing a genomic blueprint for this morphological innovation. PMID:27019111

First record of a pterosaur landing trackway

PubMed Central

Mazin, Jean-Michel; Billon-Bruyat, Jean-Paul; Padian, Kevin

2009-01-01

The terrestrial progression of pterosaurs, the flying reptiles of the Mesozoic Era, has been debated for over two centuries. The recent discovery of quadrupedal pterodactyloid pterosaur tracks from Late Jurassic sediments near Crayssac, France, shows that the hindlimbs moved parasagittally, as in mammals, birds and other dinosaurs, and the hypertrophied forelimbs could make tracks both close to the body wall and far outside it. Their manus tracks are unique in form, position and kinematics, which would be expected because the forelimbs were used for flight. Here, we report the first record of a pterosaur landing track, which differs substantially from typical walking trackways. The individual landed on both hind feet in parallel fashion, dragged its toes slightly as it left the track, landed again almost immediately and placed the hindfeet parallel again, then placed its forelimbs on the ground, took another short step with both hindlimbs and adjusted its forelimbs, and then began to walk off normally. The trackway shows that pterosaurs stalled to land, a reflection of their highly developed capacity for flight control and manoeuverability. PMID:19692407

The Irvine, Beatties, and Bresnahan (IBB) Forelimb Recovery Scale: An Assessment of Reliability and Validity

PubMed Central

Irvine, Karen-Amanda; Ferguson, Adam R.; Mitchell, Kathleen D.; Beattie, Stephanie B.; Lin, Amity; Stuck, Ellen D.; Huie, J. Russell; Nielson, Jessica L.; Talbott, Jason F.; Inoue, Tomoo; Beattie, Michael S.; Bresnahan, Jacqueline C.

2014-01-01

The IBB scale is a recently developed forelimb scale for the assessment of fine control of the forelimb and digits after cervical spinal cord injury [SCI; (1)]. The present paper describes the assessment of inter-rater reliability and face, concurrent and construct validity of this scale following SCI. It demonstrates that the IBB is a reliable and valid scale that is sensitive to severity of SCI and to recovery over time. In addition, the IBB correlates with other outcome measures and is highly predictive of biological measures of tissue pathology. Multivariate analysis using principal component analysis (PCA) demonstrates that the IBB is highly predictive of the syndromic outcome after SCI (2), and is among the best predictors of bio-behavioral function, based on strong construct validity. Altogether, the data suggest that the IBB, especially in concert with other measures, is a reliable and valid tool for assessing neurological deficits in fine motor control of the distal forelimb, and represents a powerful addition to multivariate outcome batteries aimed at documenting recovery of function after cervical SCI in rats. PMID:25071704

Vagus Nerve Stimulation Delivered During Motor Rehabilitation Improves Recovery in a Rat Model of Stroke

PubMed Central

Khodaparast, Navid; Hays, Seth A.; Sloan, Andrew M.; Fayyaz, Tabbassum; Hulsey, Daniel R.; Rennaker, Robert L.; Kilgard, Michael P.

2014-01-01

Neural plasticity is widely believed to support functional recovery following brain damage. Vagus nerve stimulation paired with different forelimb movements causes long-lasting map plasticity in rat primary motor cortex that is specific to the paired movement. We tested the hypothesis that repeatedly pairing vagus nerve stimulation with upper forelimb movements would improve recovery of motor function in a rat model of stroke. Rats were separated into three groups: vagus nerve stimulation during rehab, vagus nerve stimulation after rehab, and rehab alone. Animals underwent 4 training stages: shaping (motor skill learning), pre-lesion training, post-lesion training, and therapeutic training. Rats were given a unilateral ischemic lesion within motor cortex and implanted with a left vagus nerve cuff. Animals were allowed one week of recovery before post-lesion baseline training. During the therapeutic training stage, rats received vagus nerve stimulation paired with each successful trial. All seventeen trained rats demonstrated significant contralateral forelimb impairment when performing a bradykinesia assessment task. Forelimb function was recovered completely to pre-lesion levels when vagus nerve stimulation was delivered during rehab training. Alternatively, intensive rehab training alone (without stimulation) failed to restore function to pre-lesion levels. Delivering the same amount of stimulation after rehab training did not yield improvements compared to rehab alone. These results demonstrate that vagus nerve stimulation repeatedly paired with successful forelimb movements can improve recovery after motor cortex ischemia and may be a viable option for stroke rehabilitation. PMID:24553102

Forelimb kinematics during swimming in the pig-nosed turtle, Carettochelys insculpta, compared with other turtle taxa: rowing versus flapping, convergence versus intermediacy

PubMed Central

Rivera, Angela R. V.; Rivera, Gabriel; Blob, Richard W.

2013-01-01

SUMMARY Animals that swim using appendages do so by way of rowing and/or flapping motions. Often considered discrete categories, rowing and flapping are more appropriately regarded as points along a continuum. The pig-nosed turtle, Carettochelys insculpta, is unusual in that it is the only freshwater turtle to have limbs modified into flippers and swim via synchronous forelimb motions that resemble dorsoventral flapping, traits that evolved independently from their presence in sea turtles. We used high-speed videography to quantify forelimb kinematics in C. insculpta and a closely related, highly aquatic rower (Apalone ferox). Comparisons of our new data with those previously collected for a generalized freshwater rower (Trachemys scripta) and a flapping sea turtle (Caretta caretta) allow us to: (1) more precisely quantify and characterize the range of limb motions used by flappers versus rowers, and (2) assess whether the synchronous forelimb motions of C. insculpta can be classified as flapping (i.e. whether they exhibit forelimb kinematics and angles of attack more similar to closely related rowing species or more distantly related flapping sea turtles). We found that the forelimb kinematics of previously recognized rowers (T. scripta and A. ferox) were most similar to each other, but that those of C. insculpta were more similar to rowers than to flapping C. caretta. Nevertheless, of the three freshwater species, C. insculpta was most similar to flapping C. caretta. ‘Flapping’ in C. insculpta is achieved through humeral kinematics very different from those in C. caretta, with C. insculpta exhibiting significantly more anteroposterior humeral motion and protraction, and significantly less dorsoventral humeral motion and depression. Based on several intermediate kinematic parameters and angle of attack data, C. insculpta may in fact represent a synchronous rower or hybrid rower-flapper, suggesting that traditional views of C. insculpta as a flapper should be revised. PMID:23125335

Effective intracortical microstimulation parameters applied to primary motor cortex for evoking forelimb movements to stable spatial end points

PubMed Central

Van Acker, Gustaf M.; Amundsen, Sommer L.; Messamore, William G.; Zhang, Hongyu Y.; Luchies, Carl W.; Kovac, Anthony

2013-01-01

High-frequency, long-duration intracortical microstimulation (HFLD-ICMS) applied to motor cortex is recognized as a useful and informative method for corticomotor mapping by evoking natural-appearing movements of the limb to consistent stable end-point positions. An important feature of these movements is that stimulation of a specific site in motor cortex evokes movement to the same spatial end point regardless of the starting position of the limb. The goal of this study was to delineate effective stimulus parameters for evoking forelimb movements to stable spatial end points from HFLD-ICMS applied to primary motor cortex (M1) in awake monkeys. We investigated stimulation of M1 as combinations of frequency (30–400 Hz), amplitude (30–200 μA), and duration (0.5–2 s) while concurrently recording electromyographic (EMG) activity from 24 forelimb muscles and movement kinematics with a motion capture system. Our results suggest a range of parameters (80–140 Hz, 80–140 μA, and 1,000-ms train duration) that are effective and safe for evoking forelimb translocation with subsequent stabilization at a spatial end point. The mean time for stimulation to elicit successful movement of the forelimb to a stable spatial end point was 475.8 ± 170.9 ms. Median successful frequency and amplitude were 110 Hz and 110 μA, respectively. Attenuated parameters resulted in inconsistent, truncated, or undetectable movements, while intensified parameters yielded no change to movement end points and increased potential for large-scale physiological spread and adverse focal motor effects. Establishing cortical stimulation parameters yielding consistent forelimb movements to stable spatial end points forms the basis for a systematic and comprehensive mapping of M1 in terms of evoked movements and associated muscle synergies. Additionally, the results increase our understanding of how the central nervous system may encode movement. PMID:23741044

Organization of the sympathetic innervation of the forelimb resistance vessels in the cat.

PubMed

Backman, S B; Stein, R D; Polosa, C

1999-02-01

Detailed information on the outflow pathway of sympathetic vasoconstrictor fibers to the upper extremity is lacking. We studied the organization of the sympathetic innervation of the forelimb resistance vessels and of the sinoatrial (SA) node in the decerebrated, artificially respirated cat. The distal portion of sectioned individual rami T1-8 and the sympathetic chain immediately caudal to T8 on the right side were electrically stimulated while the right forelimb perfusion pressure (forelimb perfused at constant flow) and heart rate were recorded. Increases in perfusion pressure were evoked by stimulation of T2-8 (maximal response T7: 55 +/- 2.3 mm Hg). Responses were still evoked by stimulation of the sympathetic chain immediately caudal to T8 (44 +/- 15 mm Hg). Increases in heart rate were evoked by the stimulation of more rostral rami (T1-5; maximal response T3: 55.2 +/- 8 bpm). These vasoconstrictor and cardioacceleratory responses were blocked by the cholinergic antagonists hexamethonium and scopolamine. Sectioning of the vertebral nerve and the T1 ramus abolished the vasoconstrictor response. Stimulation of the vertebral nerve and of the proximal portion of the sectioned T1 ramus increased perfusion pressure (69 +/- 9 and 34 +/- 14 mm Hg, respectively), which was unaffected by ganglionic cholinergic block. These data suggest that forelimb resistance vessel control is subserved by sympathetic preganglionic neurons located mainly in the middle to caudal thoracic spinal segments. Some of the postganglionic axons subserving vasomotor function course through the T1 ramus, in addition to the vertebral nerve. Forelimb vasculature is controlled by sympathetic preganglionic neurons located in middle to caudal thoracic spinal segments and by postganglionic axons carried in the T1 ramus and vertebral nerve. This helps to provide the anatomical substrate of interruption of sympathetic outflow to the upper extremity produced by major conduction anesthesia of the stellate ganglion or spinal cord.

Were early pterosaurs inept terrestrial locomotors?

PubMed Central

2015-01-01

Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor. This is commonly justified by the absence of a non-pterodactyloid footprint record, suggestions that the expansive uropatagia common to early pterosaurs would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species. Here, these arguments are re-visited and mostly found problematic. Restriction of limb mobility is not a problem faced by extant animals with extensive fight membranes, including species which routinely utilise terrestrial locomotion. The absence of non-pterodactyloid footprints is not necessarily tied to functional or biomechanical constraints. As with other fully terrestrial clades with poor ichnological records, biases in behaviour, preservation, sampling and interpretation likely contribute to the deficit of early pterosaur ichnites. Suggestions that non-pterodactyloids have slender, mechanically weak limbs are demonstrably countered by the proportionally long and robust limbs of many Triassic and Jurassic species. Novel assessments of pterosaur forelimb anatomies conflict with notions that all non-pterodactyloids were obligated to sprawling forelimb postures. Sprawling forelimbs seem appropriate for species with ventrally-restricted glenoid articulations (seemingly occurring in rhamphorhynchines and campylognathoidids). However, some early pterosaurs, such as Dimorphodon macronyx and wukongopterids, have glenoid arthrologies which are not ventrally restricted, and their distal humeri resemble those of pterodactyloids. It seems fully erect forelimb stances were possible in these pterosaurs, and may be probable given proposed correlation between pterodactyloid-like distal humeral morphology and forces incurred through erect forelimb postures. Further indications of terrestrial habits include antungual sesamoids, which occur in the manus and pes anatomy of many early pterosaur species, and only occur elsewhere in terrestrial reptiles, possibly developing through frequent interactions of large claws with firm substrates. It is argued that characteristics possibly associated with terrestriality are deeply nested within Pterosauria and not restricted to Pterodactyloidea as previously thought, and that pterodactyloid-like levels of terrestrial competency may have been possible in at least some early pterosaurs. PMID:26157605

Forelimb preferences in quadrupedal marsupials and their implications for laterality evolution in mammals

PubMed Central

2013-01-01

Background Acquisition of upright posture in evolution has been argued to facilitate manual laterality in primates. Owing to the high variety of postural habits marsupials can serve as a suitable model to test whether the species-typical body posture shapes forelimb preferences in non-primates or this phenomenon emerged only in the course of primate evolution. In the present study we aimed to explore manual laterality in marsupial quadrupeds and compare them with the results in the previously studied bipedal species. Forelimb preferences were assessed in captive grey short-tailed opossum (Monodelphis domestica) and sugar glider (Petaurus breviceps) in four different types of unimanual behaviour per species, which was not artificially evoked. We examined the possible effects of sex, age and task, because these factors have been reported to affect motor laterality in placental mammals. Results In both species the direction of forelimb preferences was strongly sex-related. Male grey short-tailed opossums showed right-forelimb preference in most of the observed unimanual behaviours, while male sugar gliders displayed only a slight, not significant rightward tendency. In contrast, females in both species exhibited consistent group-level preference of the left forelimb. We failed to reveal significant differences in manual preferences between tasks of potentially differing complexity: reaching a stable food item and catching live insects, as well as between the body support and food manipulation. No influence of subjects’ age on limb preferences was found. Conclusions The direction of sex-related differences in the manual preferences found in quadrupedal marsupials seems to be not typical for placental mammals. We suggest that the alternative way of interhemispheric connection in absence of corpus callosum may result in a fundamentally distinct mechanism of sex effect on limb preferences in marsupials compared to placentals. Our data confirm the idea that non-primate mammals differ from primates in sensitivity to task complexity. Comparison of marsupial species studied to date indicate that the vertical body orientation and the bipedalism favor the expression of individual– and population–level forelimb preferences in marsupials much like it does in primates. Our findings give the first evidence for the effect of species-typical posture on the manual laterality in non-primate mammals. PMID:23497116

Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha)

PubMed Central

Allen, Vivian

2017-01-01

Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages, including sauropodomorph dinosaurs. We present biomechanical computer models of two locomotor extremes within Archosauria in an analysis of joint ranges of motion and the moment arms of the major forelimb muscles in order to quantify biomechanical differences between more sprawling, pseudosuchian (represented the crocodile Crocodylus johnstoni) and more erect, dinosaurian (represented by the sauropodomorph Mussaurus patagonicus) modes of forelimb function. We compare these two locomotor extremes in terms of the reconstructed musculoskeletal anatomy, ranges of motion of the forelimb joints and the moment arm patterns of muscles across those ranges of joint motion. We reconstructed the three-dimensional paths of 30 muscles acting around the shoulder, elbow and wrist joints. We explicitly evaluate how forelimb joint mobility and muscle actions may have changed with postural and anatomical alterations from basal archosaurs to early sauropodomorphs. We thus evaluate in which ways forelimb posture was correlated with muscle leverage, and how such differences fit into a broader evolutionary context (i.e. transition from sprawling quadrupedalism to erect bipedalism and then shifting to graviportal quadrupedalism). Our analysis reveals major differences of muscle actions between the more sprawling and erect models at the shoulder joint. These differences are related not only to the articular surfaces but also to the orientation of the scapula, in which extension/flexion movements in Crocodylus (e.g. protraction of the humerus) correspond to elevation/depression in Mussaurus. Muscle action is highly influenced by limb posture, more so than morphology. Habitual quadrupedalism in Mussaurus is not supported by our analysis of joint range of motion, which indicates that glenohumeral protraction was severely restricted. Additionally, some active pronation of the manus may have been possible in Mussaurus, allowing semi-pronation by a rearranging of the whole antebrachium (not the radius against the ulna, as previously thought) via long-axis rotation at the elbow joint. However, the muscles acting around this joint to actively pronate it may have been too weak to drive or maintain such orientations as opposed to a neutral position in between pronation and supination. Regardless, the origin of quadrupedalism in Sauropoda is not only linked to manus pronation but also to multiple shifts of forelimb morphology, allowing greater flexion movements of the glenohumeral joint and a more columnar forelimb posture. PMID:29188140

Locomotor function of forelimb protractor and retractor muscles of dogs: evidence of strut-like behavior at the shoulder.

PubMed

Carrier, David R; Deban, Stephen M; Fischbein, Timna

2008-01-01

The limbs of running mammals are thought to function as inverted struts. When mammals run at constant speed, the ground reaction force vector appears to be directed near the point of rotation of the limb on the body such that there is little or no moment at the joint. If this is true, little or no external work is done at the proximal joints during constant-speed running. This possibility has important implications to the energetics of running and to the coupling of lung ventilation to the locomotor cycle. To test if the forelimb functions as an inverted strut at the shoulder during constant-speed running and to characterize the locomotor function of extrinsic muscles of the forelimb, we monitored changes in the recruitment of six muscles that span the shoulder (the m. pectoralis superficialis descendens, m. pectoralis profundus, m. latissimus dorsi, m. omotransversarius, m. cleidobrachialis and m. trapezius) to controlled manipulations of locomotor forces and moments in trotting dogs (Canis lupus familiaris Linnaeus 1753). Muscle activity was monitored while the dogs trotted at moderate speed (approximately 2 m s(-1)) on a motorized treadmill. Locomotor forces were modified by (1) adding mass to the trunk, (2) inclining the treadmill so that the dogs ran up- and downhill (3) adding mass to the wrists or (4) applying horizontally directed force to the trunk through a leash. When the dogs trotted at constant speed on a level treadmill, the primary protractor muscles of the forelimb exhibited activity during the last part of the ipsilateral support phase and the beginning of swing phase, a pattern that is consistent with the initiation of swing phase but not with active protraction of the limb during the beginning of support phase. Results of the force manipulations were also consistent with the protractor muscles initiating swing phase and contributing to active braking via production of a protractor moment on the forelimb when the dogs decelerate. A similar situation appears to be true for the major retractor muscles of the forelimb. The m. pectoralis profundus and the m. latissimus dorsi were completely silent during the support phase of the ipsilateral limb when the dogs ran unencumbered and exhibited little or no increase in activity when the dogs carried added mass on their backs to increase any retraction torque during the support phase of constant-speed running. The most likely explanation for these observations is that the ground force reaction vector is oriented very close to the fulcrum of the forelimb such that the forelimb functions as a compliant strut at the shoulder when dogs trot at constant speed on level surfaces. Because the moments at the fulcrum of the pectoral girdle appear to be small during the support phase of a trotting step, a case can be made that it is the activity of the extrinsic appendicular muscles that produce the swing phase of the forelimb that explain the coupled phase relationship between ventilatory airflow and the locomotor cycle in trotting dogs.

The Effect of Lesion Size on the Organization of the Ipsilesional and Contralesional Motor Cortex

PubMed Central

Touvykine, Boris; Mansoori, Babak K.; Jean-Charles, Loyda; Deffeyes, Joan; Quessy, Stephan; Dancause, Numa

2015-01-01

Recovery of hand function following lesions in the primary motor cortex (M1) is associated with a reorganization of premotor areas in the ipsilesional hemisphere, and this reorganization depends on the size of the lesion. It is not clear how lesion size affects motor representations in the contralesional hemisphere and how the effects in the 2 hemispheres compare. Our goal was to study how lesion size affects motor representations in the ipsilesional and contralesional hemispheres. In rats, we induced lesions of different sizes in the caudal forelimb area (CFA), the equivalent of M1. The effective lesion volume in each animal was quantified histologically. Behavioral recovery was evaluated with the Montoya Staircase task for 28 days after the lesion. Then, the organization of the CFA and the rostral forelimb area (RFA)—the putative premotor area in rats—in the 2 cerebral hemispheres was studied with intracortical microstimulation mapping techniques. The distal forelimb representation in the RFA of both the ipsilesional and contralesional hemispheres was positively correlated with the size of the lesion. In contrast, lesion size had no effect on the contralesional CFA, and there was no relationship between movement representations in the 2 hemispheres. Finally, only the contralesional RFA was negatively correlated with chronic motor deficits of the paretic forelimb. Our data show that lesion size has comparable effects on motor representations in premotor areas of both hemispheres and suggest that the contralesional premotor cortex may play a greater role in the recovery of the paretic forelimb following large lesions. PMID:25967757

The Effect of Lesion Size on the Organization of the Ipsilesional and Contralesional Motor Cortex.

PubMed

Touvykine, Boris; Mansoori, Babak K; Jean-Charles, Loyda; Deffeyes, Joan; Quessy, Stephan; Dancause, Numa

2016-03-01

Recovery of hand function following lesions in the primary motor cortex (M1) is associated with a reorganization of premotor areas in the ipsilesional hemisphere, and this reorganization depends on the size of the lesion. It is not clear how lesion size affects motor representations in the contralesional hemisphere and how the effects in the 2 hemispheres compare. Our goal was to study how lesion size affects motor representations in the ipsilesional and contralesional hemispheres. In rats, we induced lesions of different sizes in the caudal forelimb area (CFA), the equivalent of M1. The effective lesion volume in each animal was quantified histologically. Behavioral recovery was evaluated with the Montoya Staircase task for 28 days after the lesion. Then, the organization of the CFA and the rostral forelimb area (RFA)--the putative premotor area in rats--in the 2 cerebral hemispheres was studied with intracortical microstimulation mapping techniques. The distal forelimb representation in the RFA of both the ipsilesional and contralesional hemispheres was positively correlated with the size of the lesion. In contrast, lesion size had no effect on the contralesional CFA, and there was no relationship between movement representations in the 2 hemispheres. Finally, only the contralesional RFA was negatively correlated with chronic motor deficits of the paretic forelimb. Our data show that lesion size has comparable effects on motor representations in premotor areas of both hemispheres and suggest that the contralesional premotor cortex may play a greater role in the recovery of the paretic forelimb following large lesions. © The Author(s) 2015.

Spinal Interneurons and Forelimb Plasticity after Incomplete Cervical Spinal Cord Injury in Adult Rats

PubMed Central

Rombola, Angela M.; Rousseau, Celeste A.; Mercier, Lynne M.; Fitzpatrick, Garrett M.; Reier, Paul J.; Fuller, David D.; Lane, Michael A.

2015-01-01

Abstract Cervical spinal cord injury (cSCI) disrupts bulbospinal projections to motoneurons controlling the upper limbs, resulting in significant functional impairments. Ongoing clinical and experimental research has revealed several lines of evidence for functional neuroplasticity and recovery of upper extremity function after SCI. The underlying neural substrates, however, have not been thoroughly characterized. The goals of the present study were to map the intraspinal motor circuitry associated with a defined upper extremity muscle, and evaluate chronic changes in the distribution of this circuit following incomplete cSCI. Injured animals received a high cervical (C2) lateral hemisection (Hx), which compromises supraspinal input to ipsilateral spinal motoneurons controlling the upper extremities (forelimb) in the adult rat. A battery of behavioral tests was used to characterize the time course and extent of forelimb motor recovery over a 16 week period post-injury. A retrograde transneuronal tracer – pseudorabies virus – was used to define the motor and pre-motor circuitry controlling the extensor carpi radialis longus (ECRL) muscle in spinal intact and injured animals. In the spinal intact rat, labeling was observed unilaterally within the ECRL motoneuron pool and within spinal interneurons bilaterally distributed within the dorsal horn and intermediate gray matter. No changes in labeling were observed 16 weeks post-injury, despite a moderate degree of recovery of forelimb motor function. These results suggest that recovery of the forelimb function assessed following C2Hx injury does not involve recruitment of new interneurons into the ipsilateral ECRL motor pathway. However, the functional significance of these existing interneurons to motor recovery requires further exploration. PMID:25625912

Use of quadrupedal step training to re-engage spinal interneuronal networks and improve locomotor function after spinal cord injury.

PubMed

Shah, Prithvi K; Garcia-Alias, Guillermo; Choe, Jaehoon; Gad, Parag; Gerasimenko, Yury; Tillakaratne, Niranjala; Zhong, Hui; Roy, Roland R; Edgerton, V Reggie

2013-11-01

Can lower limb motor function be improved after a spinal cord lesion by re-engaging functional activity of the upper limbs? We addressed this issue by training the forelimbs in conjunction with the hindlimbs after a thoracic spinal cord hemisection in adult rats. The spinal circuitries were more excitable, and behavioural and electrophysiological analyses showed improved hindlimb function when the forelimbs were engaged simultaneously with the hindlimbs during treadmill step-training as opposed to training only the hindlimbs. Neuronal retrograde labelling demonstrated a greater number of propriospinal labelled neurons above and below the thoracic lesion site in quadrupedally versus bipedally trained rats. The results provide strong evidence that actively engaging the forelimbs improves hindlimb function and that one likely mechanism underlying these effects is the reorganization and re-engagement of rostrocaudal spinal interneuronal networks. For the first time, we provide evidence that the spinal interneuronal networks linking the forelimbs and hindlimbs are amenable to a rehabilitation training paradigm. Identification of this phenomenon provides a strong rationale for proceeding toward preclinical studies for determining whether training paradigms involving upper arm training in concert with lower extremity training can enhance locomotor recovery after neurological damage.

Evaluation of different captive bolt lengths and breed influence upon post-stun hind limb and forelimb activity in fed cattle at a commercial slaughter facility.

PubMed

Martin, Miriam S; Kline, Helen C; Wagner, Dana R; Alexander, Lacey R; Edwards-Callaway, Lily N; Grandin, Temple

2018-05-03

The objective of this study was to assess the effects of captive bolt length and breed type on post-stun leg activity in cattle. A total of 2850 Holstein (HOL) and non-Holstein British/Continental bred (NHOL) steers and heifers were observed post-stunning at a large commercial slaughter facility. A pneumatically powered penetrating captive bolt stunner was used with three different bolt lengths: CON, 15.24 cm; MED, 16.51 cm; and LON, 17.78 cm. Hind limb kicking, forelimb activity, take away belt stops, carcass swing and number of knife sticks during exsanguination were recorded for each animal from video recording. Hind limb and forelimb kicks observed ranged from 0 to 25 and 0 to 8, respectively. Analysis of post-stun hind limb and forelimb activity indicated that increasing pneumatically powered penetrating captive bolt length does not decrease post-stun leg activity. There was a higher percentage of cattle experiencing take away belt stops and carcass swing in HOL as compared with NHOL. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Peripheral Nerve Injury in Developing Rats Reorganizes Representation Pattern in Motor Cortex

NASA Astrophysics Data System (ADS)

Donoghue, John P.; Sanes, Jerome N.

1987-02-01

We investigated the effect of neonatal nerve lesions on cerebral motor cortex organization by comparing the cortical motor representation of normal adult rats with adult rats that had one forelimb removed on the day of birth. Mapping of cerebral neocortex with electrical stimulation revealed an altered relationship between the motor cortex and the remaining muscles. Whereas distal forelimb movements are normally elicited at the lowest threshold in the motor cortex forelimb area, the same stimuli activated shoulder and trunk muscles in experimental animals. In addition, an expanded cortical representation of intact body parts was present and there was an absence of a distinct portion of motor cortex. These data demonstrate that representation patterns in motor cortex can be altered by peripheral nerve injury during development.

Functional specialization and ontogenetic scaling of limb anatomy in Alligator mississippiensis

PubMed Central

Allen, Vivian; Elsey, Ruth M; Jones, Nicola; Wright, Jordon; Hutchinson, John R

2010-01-01

Crocodylians exhibit a fascinating diversity of terrestrial gaits and limb motions that remain poorly described and are of great importance to understanding their natural history and evolution. Their musculoskeletal anatomy is pivotal to this diversity and yet only qualitative studies of muscle-tendon unit anatomy exist. The relative masses and internal architecture (fascicle lengths and physiological cross-sectional areas) of muscles of the pectoral and pelvic limbs of American alligators (Alligator mississippiensis Daudin 1801) were recorded for an ontogenetic series of wild specimens (n = 15, body masses from 0.5 to 60 kg). The data were analysed by reduced major axis regression to determine scaling relationships with body mass. Physiological cross-sectional areas and therefore muscle force-generating capacity were found to be greater in the extensor (anti-gravity) muscles of the pelvic limb than in the pectoral limb, reflecting how crocodylians differ from mammals in having greater loading of the hindlimbs than the forelimbs. Muscle masses and architecture were generally found to scale isometrically with body mass, suggesting an ontogenetic decrease in terrestrial athleticism. This concurs with the findings of previous studies showing ontogenetic decreases in limb bone length and the general scaling principle of a decline of strength : weight ratios with increasing size in animals. Exceptions to isometric scaling found included positive allometry in fascicle length for extensor musculature of both limbs, suggesting an ontogenetic increase in working range interpreted as increasing postural variability – in particular the major hip extensors – the interpretation of which is complicated by previous described ontogenetic increase of moment arms for these muscles. PMID:20148991

Propulsive forces of mudskipper fins and salamander limbs during terrestrial locomotion: implications for the invasion of land.

PubMed

Kawano, Sandy M; Blob, Richard W

2013-08-01

The invasion of land was a pivotal event in vertebrate evolution that was associated with major appendicular modifications. Although fossils indicate that the evolution of fundamentally limb-like appendages likely occurred in aquatic environments, the functional consequences of using early digited limbs, rather than fins, for terrestrial propulsion have had little empirical investigation. Paleontological and experimental analyses both have led to the proposal of an early origin of "hind limb-driven" locomotion among tetrapods or their ancestors. However, the retention of a pectoral appendage that had already developed terrestrial adaptations has been proposed for some taxa, and few data are available from extant functional models that can provide a foundation for evaluating the relative contributions of pectoral and pelvic appendages to terrestrial support among early stem tetrapods. To examine these aspects of vertebrate locomotor evolution during the invasion of land, we measured three-dimensional ground reaction forces (GRFs) produced by isolated pectoral fins of mudskipper fishes (Periophthalmus barbarus) during terrestrial crutching, and compared these to isolated walking footfalls by the forelimbs and hind limbs of tiger salamanders (Ambystoma tigrinum), a species with subequally-sized limbs that facilitate comparisons to early tetrapods. Pectoral appendages of salamanders and mudskippers exhibited numerous differences in GRFs. Compared with salamander forelimbs, isolated fins of mudskippers bear lower vertical magnitudes of GRFs (as a proportion of body weight), and had GRFs that were oriented more medially. Comparing the salamanders' forelimbs and hind limbs, although the peak net GRF occurs later in stance for the forelimb, both limbs experience nearly identical mediolateral and vertical components of GRF, suggesting comparable contributions to support. Thus, forelimbs could also have played a significant locomotor role among basal tetrapods that had limbs of sub-equal size. However, the salamander hind limb and mudskipper pectoral fin had a greater acceleratory role than did the salamander forelimb. Together, data from these extant taxa help to clarify how structural change may have influenced locomotor function through the evolutionary invasion of land by vertebrates.

HOXA13 and HOXD13 expression during development of the syndactylous digits in the marsupial Macropus eugenii

PubMed Central

2012-01-01

Background Kangaroos and wallabies have specialised limbs that allow for their hopping mode of locomotion. The hindlimbs differentiate much later in development but become much larger than the forelimbs. The hindlimb autopod has only four digits, the fourth of which is greatly elongated, while digits two and three are syndactylous. We investigated the expression of two genes, HOXA13 and HOXD13, that are crucial for digit patterning in mice during formation of the limbs of the tammar wallaby. Results We describe the development of the tammar limbs at key stages before birth. There was marked heterochrony and the hindlimb developed more slowly than the forelimb. Both tammar HOXA13 and HOXD13 have two exons as in humans, mice and chickens. HOXA13 had an early and distal mRNA distribution in the tammar limb bud as in the mouse, but forelimb expression preceded that in the hindlimb. HOXD13 mRNA was expressed earlier in the forelimb than the hindlimb and was predominantly detected in the interdigital tissues of the forelimb. In contrast, the hindlimb had a more restricted expression pattern that appeared to be expressed at discrete points at both posterior and anterior margins of the limb bud, and was unlike expression seen in the mouse and the chicken. Conclusions This is the first examination of HOXA and HOXD gene expression in a marsupial. The gene structure and predicted proteins were highly conserved with their eutherian orthologues. Interestingly, despite the morphological differences in hindlimb patterning, there were no modifications to the polyalanine tract of either HOXA13 or HOXD13 when compared to those of the mouse and bat but there was a marked difference between the tammar and the other mammals in the region of the first polyserine tract of HOXD13. There were also altered expression domains for both genes in the developing tammar limbs compared to the chicken and mouse. Together these findings suggest that the timing of HOX gene expression may contribute to the heterochrony of the forelimb and hindlimb and that alteration to HOX domains may influence phenotypic differences that lead to the development of marsupial syndactylous digits. PMID:22235805

Cervical intraspinal microstimulation evokes robust forelimb movements before and after injury

NASA Astrophysics Data System (ADS)

Sunshine, Michael D.; Cho, Frances S.; Lockwood, Danielle R.; Fechko, Amber S.; Kasten, Michael R.; Moritz, Chet T.

2013-06-01

Objective. Intraspinal microstimulation (ISMS) is a promising method for reanimating paralyzed limbs following neurological injury. ISMS within the cervical and lumbar spinal cord is capable of evoking a variety of highly-functional movements prior to injury, but the ability of ISMS to evoke forelimb movements after cervical spinal cord injury is unknown. Here we examine the forelimb movements and muscles activated by cervical ISMS both before and after contusion injury. Approach. We documented the forelimb muscles activated and movements evoked via systematic stimulation of the rodent cervical spinal cord both before injury and three, six and nine weeks following a moderate C4/C5 lateralized contusion injury. Animals were anesthetized with isoflurane to permit construction of somatotopic maps of evoked movements and quantify evoked muscle synergies between cervical segments C3 and T1. Main results. When ISMS was delivered to the cervical spinal cord, a variety of responses were observed at 68% of locations tested, with a spatial distribution that generally corresponded to the location of motor neuron pools. Stimulus currents required to achieve movement and the number of sites where movements could be evoked were unchanged by spinal cord injury. A transient shift toward extension-dominated movements and restricted muscle synergies were observed at three and six weeks following injury, respectively. By nine weeks after injury, however, ISMS-evoked patterns were similar to spinally-intact animals. Significance. The results demonstrate the potential for cervical ISMS to reanimate hand and arm function following spinal cord injury. Robust forelimb movements can be evoked both before and during the chronic stages of recovery from a clinically relevant and sustained cervical contusion injury.

Effect of unfocused extracorporeal shock wave therapy on growth factor gene expression in wounds and intact skin of horses.

PubMed

Link, Kaitlyn A; Koenig, Judith B; Silveira, Andressa; Plattner, Brandon L; Lillie, Brandon N

2013-02-01

To compare the effect of extracorporeal shock wave therapy (ESWT) on expression of fibroblast growth factor-7 (FGF-7), transforming growth factor-β1 (TGF-β1), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-A (PDGF), and vascular endothelial growth factor-A (VEGF) in skin with surgically created skin wounds and intact skin in horses. 14 healthy horses. 8 horses were treated with ESWT at 6 locations along the neck at 36, 24, 12, 6, 2, or 1 hour prior to collection of full-thickness biopsy specimens from each location; a control specimen was collected from a sham-treated location. In 6 horses, 5 full-thickness wounds were created in each forelimb. Wounds in 1 forelimb/horse received ESWT immediately after creation and subsequently on days 7, 14, and 21; wounds in the contralateral forelimb remained untreated. Biopsy specimens were collected from 1 wound on each forelimb on days 7, 14, 21, 28, and 35. Expression levels of FGF-7, TGF-β1, IGF-1, PDGF, and VEGF were assessed in tissue samples from the horses' necks and forelimbs. In surgically created wounds, ESWT treatment was associated with reduced TGF-β1 expression, compared with expression in control wounds, during the entire study period. At 28 days following wound creation, IGF-1 expression was significantly increased for treated and untreated wounds, compared with findings on days 7, 14, 21, and 35. There was no significant effect of treatment on FGF-7, TGF-β1, IGF-1, PDGF, or VEGF expression in intact skin. Intervention with ESWT to suppress TGF-β1 may decrease granulation tissue production, resulting in improved wound healing on the distal portion of horses' limbs.

Characteristic findings of magnetic resonance imaging (MRI) and computed tomography (CT) for severe chronic laminitis in a Thoroughbred horse

PubMed Central

YAMADA, Kazutaka; INUI, Tomohiro; ITOH, Megumi; YANAGAWA, Masashi; SATO, Fumio; TOMINARI, Masataka; MIZOBE, Fumiaki; KISHIMOTO, Miori; SASAKI, Naoki

2017-01-01

ABSTRACT A Thoroughbred horse with severe chronic laminitis of both forelimbs was evaluated on the same day with magnetic resonance imaging (MRI) and computed tomography (CT). Both MRI and CT revealed loss of the dorsal aspect of the cortical bone of the 3rd phalanx and sclerosis. CT reflected the status of the horny layer and bone of the affected feet, while MRI depicted inflammation of the laminar corium, together with tendon edema. On the 3-dimensional CT venogram, vessels were visualized in both the right and left forelimbs, although there was a difference in the vasculature of the coronary plexus and circumflex vessels between the right and left forelimbs. A combination of both MRI and CT provides detailed information regarding pathological conditions. PMID:28955162

Potential ecotoxic effects of polychlorinated biphenyls on Xenopus laevis.

PubMed

Qin, Zhan-Fen; Zhou, Jing-Ming; Cong, Lin; Xu, Xiao-Bai

2005-10-01

We examined potential ecotoxic effects of polychlorinated biphenyl (PCB)3, PCB5, Aroclor 1254, and Aroclor 1242 on Xenopus laevis. Tadpoles were exposed to PCBs from stage 46/47 (system of Nieuwkoop and Faber) to the completion of metamorphosis. We demonstrated, to our knowledge for the first time, forelimb malformations caused by PCBs (malformation rate, > 70%). The malformed forelimbs were fixed in the adduction-backward rotation position and could not move. Therefore, malformed male frogs were destined to have no offspring, because they could not grasp the females with their forelimbs to mate. Alcian blue-alizarin red double-staining indicated that the forelimb malformation resulted from the shoulder abnormality. Compared with the normal shoulder joint, the proximal humerus with the humerus inter-rotated 90 degrees in the abnormal shoulder joint. Moreover, testes from more than a third of male frogs with exposed to PCBs exhibited feminization to different degrees at gross morphology and histology, with fewer or abnormal spermatogonia and oocytes. Gonadal abnormalities would lead directly to reproductive dysfunction and population decline. These results suggest that PCBs have potentially ecotoxic effects on amphibian populations. We infer that PCBs could play roles in amphibian malformations and population declines, at least at sites that are polluted heavily with PCBs.

The phylogeny of the red panda (Ailurus fulgens): evidence from the forelimb

PubMed Central

Fisher, Rebecca E; Adrian, Brent; Barton, Michael; Holmgren, Jennifer; Tang, Samuel Y

2009-01-01

Within the order Carnivora, the phylogeny of the red panda (Ailurus fulgens) is contentious, with morphological and molecular studies supporting a wide range of possible relationships, including close ties to procyonids, ursids, mustelids and mephitids. This study provides additional morphological data, including muscle maps, for the forelimb of Ailurus, based on the dissection of four cadavers from the National Zoological Park, Washington, DC, USA. The red panda forelimb is characterized by a number of primitive features, including the lack of m. rhomboideus profundus, a humeral insertion for m. cleidobrachialis, the presence of mm. brachioradialis, articularis humeri and coracobrachialis, a single muscle belly for m. extensor digitorum lateralis with tendons to digits III–V, four mm. lumbricales, and the presence of mm. flexor digitorum brevis manus, adductores digiti I, II and V, and abductor digiti I and V. Red pandas resemble Ailuropoda, mustelids and some procyonids in possessing a soft tissue origin of m. flexor digitorum superficialis. In addition, red pandas are similar to ursids and procyonids in having a variable presence of m. biceps brachii caput breve. Furthermore, Ailurus and some ursids lack m. rhomboideus capitis. The forelimb muscle maps from this study represent a valuable resource for analyzing the functional anatomy of fossil ailurids and some notes on the Miocene ailurid, Simocyon batalleri, are presented. PMID:19930516

Rhythmic motor activity and interlimb co-ordination in the developing pouch young of a wallaby (Macropus eugenii).

PubMed Central

Ho, S M

1997-01-01

1. The forelimb motor behaviour of developing wallaby was studied. A clock-like alternating movement was reactivated whenever the animal was removed from the pouch. 2. Forelimb stepping frequency increased during the first 3 weeks of development, while the phase relationship remained constant. Forelimb activity could be affected by altering the afferent feedback from the contralateral limb, or an increase in ambient temperature. 3. In vitro experiments were performed using an isolated brainstem-spinal cord preparation from animals up to 6 weeks postnatal. Fictive locomotor activity could be evoked by electrical stimulation or bath-applied NMDA (< 10 microM). 4. Bath-applied strychnine (10-25 microM) and bicuculline (10-50 microM) disrupted the phase relationship between motor pools, while rhythmic motor discharge remained in the absence of these inhibitory pathways. 5. The present findings indicate that the pattern generator that underlies the robust forelimb movement during the first journey to the pouch is retained for different motor functions during in-pouch development. The neural network that underlies such behaviour can be divided into two major components, a rhythm generator within each hemicord, and a pattern co-ordinating pathway which involve both glycinergic and GABAergic interneurones. PMID:9218221

The phylogeny of the red panda (Ailurus fulgens): evidence from the forelimb.

PubMed

Fisher, Rebecca E; Adrian, Brent; Barton, Michael; Holmgren, Jennifer; Tang, Samuel Y

2009-12-01

Within the order Carnivora, the phylogeny of the red panda (Ailurus fulgens) is contentious, with morphological and molecular studies supporting a wide range of possible relationships, including close ties to procyonids, ursids, mustelids and mephitids. This study provides additional morphological data, including muscle maps, for the forelimb of Ailurus, based on the dissection of four cadavers from the National Zoological Park, Washington, DC, USA. The red panda forelimb is characterized by a number of primitive features, including the lack of m. rhomboideus profundus, a humeral insertion for m. cleidobrachialis, the presence of mm. brachioradialis, articularis humeri and coracobrachialis, a single muscle belly for m. extensor digitorum lateralis with tendons to digits III-V, four mm. lumbricales, and the presence of mm. flexor digitorum brevis manus, adductores digiti I, II and V, and abductor digiti I and V. Red pandas resemble Ailuropoda, mustelids and some procyonids in possessing a soft tissue origin of m. flexor digitorum superficialis. In addition, red pandas are similar to ursids and procyonids in having a variable presence of m. biceps brachii caput breve. Furthermore, Ailurus and some ursids lack m. rhomboideus capitis. The forelimb muscle maps from this study represent a valuable resource for analyzing the functional anatomy of fossil ailurids and some notes on the Miocene ailurid, Simocyon batalleri, are presented.

Does the Morphology of the Forelimb Flexor Muscles Differ Between Lizards Using Different Habitats?

PubMed

Lowie, Aurélien; Herrel, Anthony; Abdala, Virginia; Manzano, Adriana S; Fabre, Anne-Claire

2018-03-01

Lizards are an interesting group to study how habitat use impacts the morphology of the forelimb because they occupy a great diversity of ecological niches. In this study, we specifically investigated whether habitat use impacts the morphology of the forelimb flexor muscles in lizards. To do so, we performed dissections and quantified the physiological cross sectional area (PCSA), the fiber length, and the mass of four flexor muscles in 21 different species of lizards. Our results show that only the PCSA of the m. flexor carpi radialis is different among lizards with different ecologies (arboreal versus non-arboreal). This difference disappeared, however, when taking phylogeny into account. Arboreal species have a higher m. flexor carpi radialis cross sectional area likely allowing them to flex the wrist more forcefully which may allow them climb and hold on to branches better. In contrast, other muscles are not different between arboreal and non-arboreal species. Further studies focusing on additional anatomical features of the lizard forelimb as well as studies documenting how lizards use the arboreal niche are needed to fully understand how an arboreal life style may constrain limb morphology in lizards. Anat Rec, 301:424-433, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Elbow joint adductor moment arm as an indicator of forelimb posture in extinct quadrupedal tetrapods

PubMed Central

Fujiwara, Shin-ichi; Hutchinson, John R.

2012-01-01

Forelimb posture has been a controversial aspect of reconstructing locomotor behaviour in extinct quadrupedal tetrapods. This is partly owing to the qualitative and subjective nature of typical methods, which focus on bony articulations that are often ambiguous and unvalidated postural indicators. Here we outline a new, quantitatively based forelimb posture index that is applicable to a majority of extant tetrapods. By determining the degree of elbow joint adduction/abduction mobility in several tetrapods, the carpal flexor muscles were determined to also play a role as elbow adductors. Such adduction may play a major role during the stance phase in sprawling postures. This role is different from those of upright/sagittal and sloth-like creeping postures, which, respectively, depend more on elbow extensors and flexors. Our measurements of elbow muscle moment arms in 318 extant tetrapod skeletons (Lissamphibia, Synapsida and Reptilia: 33 major clades and 263 genera) revealed that sprawling, sagittal and creeping tetrapods, respectively, emphasize elbow adductor, extensor and flexor muscles. Furthermore, scansorial and non-scansorial taxa, respectively, emphasize flexors and extensors. Thus, forelimb postures of extinct tetrapods can be qualitatively classified based on our quantitative index. Using this method, we find that Triceratops (Ceratopsidae), Anhanguera (Pterosauria) and desmostylian mammals are categorized as upright/sagittally locomoting taxa. PMID:22357261

Neural Plasticity and Neurorehabilitation Following Traumatic Brain Injury

DTIC Science & Technology

2011-04-01

produces a decrease in the number of adjustments of the impaired forelimb and unimpaired limb and an increase in abnormal behaviors during pasta eating...eat uncooked vermicelli pasta . In unilateral stroke and Parkinson’s models, animals show deficits in the way they use their paws to manipulate the... pasta as it is eaten. This test has never been used to examine forelimb function in animal models of traumatic brain injury (TBI). The current study

Recovery of Breathing and Forelimb Function after Prolonged Exposure to Repetitive Acute Intermittent Hypoxia

DTIC Science & Technology

2017-03-01

breathing capacity (Aim 1) and forelimb function (Aim 2), without systemic hypertension or hippocampal pathology (Aim 3). SPECIFIC AIMS Aim 1 (Florida...benefits. On the other hand, there was no evidence for pathology ( hypertension or hippocampal pathology). We were not able to perform time-series... hypertension or hippocampal (CA1) pathology. However, we did see striking (and surprising) preliminary evidence that prolonged rAIH: 1) reduced volume of the

Distinct cortical circuit mechanisms for complex forelimb movement and motor map topography.

PubMed

Harrison, Thomas C; Ayling, Oliver G S; Murphy, Timothy H

2012-04-26

Cortical motor maps are the basis of voluntary movement, but they have proven difficult to understand in the context of their underlying neuronal circuits. We applied light-based motor mapping of Channelrhodopsin-2 mice to reveal a functional subdivision of the forelimb motor cortex based on the direction of movement evoked by brief (10 ms) pulses. Prolonged trains of electrical or optogenetic stimulation (100-500 ms) targeted to anterior or posterior subregions of motor cortex evoked reproducible complex movements of the forelimb to distinct positions in space. Blocking excitatory cortical synaptic transmission did not abolish basic motor map topography, but the site-specific expression of complex movements was lost. Our data suggest that the topography of movement maps arises from their segregated output projections, whereas complex movements evoked by prolonged stimulation require intracortical synaptic transmission. Copyright © 2012 Elsevier Inc. All rights reserved.

Dynamic gene expression of Lin-28 during embryonic development in mouse and chicken.

PubMed

Yokoyama, Shigetoshi; Hashimoto, Megumi; Shimizu, Hirohito; Ueno-Kudoh, Hiroe; Uchibe, Kenta; Kimura, Ichiro; Asahara, Hiroshi

2008-02-01

The Caenorhabditis elegans heterochronic gene lin-28 regulates developmental timing in the nematode trunk. We report the dynamic expression patterns of Lin-28 homologues in mouse and chick embryos. Whole mount in situ hybridization revealed specific and intriguing expression patterns of Lin-28 in the developing mouse and chick limb bud. Mouse Lin-28 expression was detected in both the forelimb and hindlimb at E9.5, but disappeared from the forelimb at E10.5, and finally from the forelimb and hindlimb at E11.5. Chicken Lin-28, which was first detected in the limb primordium at stage 15/16, was also downregulated as the stage proceeded. The amino acid sequences of mouse and chicken Lin-28 genes are highly conserved and the similar expression patterns of Lin-28 during limb development in mouse and chicken suggest that this heterochronic gene is also conserved during vertebrate limb development.

Distinct Laterality in Forelimb-Movement Representations of Rat Primary and Secondary Motor Cortical Neurons with Intratelencephalic and Pyramidal Tract Projections.

PubMed

Soma, Shogo; Saiki, Akiko; Yoshida, Junichi; Ríos, Alain; Kawabata, Masanori; Sakai, Yutaka; Isomura, Yoshikazu

2017-11-08

Two distinct motor areas, the primary and secondary motor cortices (M1 and M2), play crucial roles in voluntary movement in rodents. The aim of this study was to characterize the laterality in motor cortical representations of right and left forelimb movements. To achieve this goal, we developed a novel behavioral task, the Right-Left Pedal task, in which a head-restrained male rat manipulates a right or left pedal with the corresponding forelimb. This task enabled us to monitor independent movements of both forelimbs with high spatiotemporal resolution. We observed phasic movement-related neuronal activity (Go-type) and tonic hold-related activity (Hold-type) in isolated unilateral movements. In both M1 and M2, Go-type neurons exhibited bias toward contralateral preference, whereas Hold-type neurons exhibited no bias. The contralateral bias was weaker in M2 than M1. Moreover, we differentiated between intratelencephalic (IT) and pyramidal tract (PT) neurons using optogenetically evoked spike collision in rats expressing channelrhodopsin-2. Even in identified PT and IT neurons, Hold-type neurons exhibited no lateral bias. Go-type PT neurons exhibited bias toward contralateral preference, whereas IT neurons exhibited no bias. Our findings suggest a different laterality of movement representations of M1 and M2, in each of which IT neurons are involved in cooperation of bilateral movements, whereas PT neurons control contralateral movements. SIGNIFICANCE STATEMENT In rodents, the primary and secondary motor cortices (M1 and M2) are involved in voluntary movements via distinct projection neurons: intratelencephalic (IT) neurons and pyramidal tract (PT) neurons. However, it remains unclear whether the two motor cortices (M1 vs M2) and the two classes of projection neurons (IT vs PT) have different laterality of movement representations. We optogenetically identified these neurons and analyzed their functional activity using a novel behavioral task to monitor movements of the right and left forelimbs separately. We found that contralateral bias was reduced in M2 relative to M1, and in IT relative to PT neurons. Our findings suggest that the motor information processing that controls forelimb movement is coordinated by a distinct cell population. Copyright © 2017 the authors 0270-6474/17/3710904-13$15.00/0.

Nomenclatural review of long digital forelimb flexors in carnivores.

PubMed

Spoor, C F; Badoux, D M

1986-12-01

A hitherto-unknown atavistic muscle in the dog initiated a review of the literature on the homologies and nomenclature of the forelimb flexors in carnivores and man. A consequence is that we recommend a revision of the nomenclature in the Nomina Anatomica Veterinaria (Ithaca, New York, 1983) so that it is in agreement with the Nomina Anatomica (Wilkins, Baltimore, 1983). This revision mainly consists of the incorporation of the terms M. palmaris longus and Mm. flexores breves manus.

Preliminary Validation and Reliability Testing of the Montreal Instrument for Cat Arthritis Testing, for Use by Veterinarians, in a Colony of Laboratory Cats.

PubMed

Klinck, Mary P; Rialland, Pascale; Guillot, Martin; Moreau, Maxim; Frank, Diane; Troncy, Eric

2015-12-02

Subtle signs and conflicting physical and radiographic findings make feline osteoarthritis (OA) challenging to diagnose. A physical examination-based assessment was developed, consisting of eight items: Interaction, Exploration, Posture, Gait, Body Condition, Coat and Claws, (joint) Palpation-Findings, and Palpation-Cat Reaction. Content (experts) and face (veterinary students) validity were excellent. Construct validity, internal consistency, and intra- and inter-rater reliability were assessed via a pilot and main study, using laboratory-housed cats with and without OA. Gait distinguished OA status in the pilot ( p = 0.05) study. In the main study, no scale item achieved statistically significant OA detection. Forelimb peak vertical ground reaction force (PVF) correlated inversely with Gait (Rho s = -0.38 ( p = 0.03) to -0.41 ( p = 0.02)). Body Posture correlated with Gait, and inversely with forelimb PVF at two of three time points (Rho s = -0.38 ( p = 0.03) to -0.43 ( p = 0.01)). Palpation (Findings, Cat Reaction) did not distinguish OA from non-OA cats. Palpation-Cat Reaction (Forelimbs) correlated inversely with forelimb PVF at two time points (Rho s = -0.41 ( p = 0.02) to -0.41 ( p = 0.01)), but scores were highly variable, and poorly reliable. Gait and Posture require improved sensitivity, and Palpation should be interpreted cautiously, in diagnosing feline OA.

Motor deficits, impaired response inhibition, and blunted response to methylphenidate following neonatal exposure to decabromodiphenyl ether.

PubMed

Markowski, Vincent P; Miller-Rhodes, Patrick; Cheung, Randy; Goeke, Calla; Pecoraro, Vincent; Cohen, Gideon; Small, Deena J

2017-09-01

Decabromodiphenyl ether (decaBDE) is an applied brominated flame retardant that is widely-used in electronic equipment. After decades of use, decaBDE and other members of its polybrominated diphenyl ether class have become globally-distributed environmental contaminants that can be measured in the atmosphere, water bodies, wildlife, food staples and human breastmilk. Although it has been banned in Europe and voluntarily withdrawn from the U.S. market, it is still used in Asian countries. Evidence from epidemiological and animal studies indicate that decaBDE exposure targets brain development and produces behavioral impairments. The current study examined an array of motor and learning behaviors in a C57BL6/J mouse model to determine the breadth of the developmental neurotoxicity produced by decaBDE. Mouse pups were given a single daily oral dose of 0 or 20mg/kg decaBDE from postnatal day 1 to 21 and were tested in adulthood. Exposed male mice had impaired forelimb grip strength, altered motor output in a circadian wheel-running procedure, increased response errors during an operant differential reinforcement of low rates (DRL) procedure and a blunted response to an acute methylphenidate challenge administered before DRL testing. With the exception of altered wheel-running output, exposed females were not affected. Neither sex had altered somatic growth, motor coordination impairments on the Rotarod, gross learning deficits during operant lever-press acquisition, or impaired food motivation. The overall pattern of effects suggests that males are more sensitive to developmental decaBDE exposure, especially when performing behaviors that require effortful motor output or when learning tasks that require sufficient response inhibition for their successful completion. Copyright © 2017 Elsevier Inc. All rights reserved.

Primary intraosseous fibrosarcoma in a cat.

PubMed

Levitt, L; Doige, C E

1989-06-01

A primary intraosseous fibrosarcoma was diagnosed in a 1.5-year-old cat. Clinical signs included nonweight-bearing lameness of the right forelimb and signs of pain on palpation of the right elbow. Radiography of the right elbow revealed a well-circumscribed osteolytic lesion of the olecranon. The right fore-limb was amputated, and histologic examination revealed tumor invasion into local veins and metastasis to the axillary lymph nodes. The cat had no signs of tumor redevelopment or pulmonary metastatic disease one year after amputation.

A Method for Immobilizing the Forelimbs of Rabbits.

PubMed

Thunder, Richard M.; Chang, James; Broome, Rosemary L.; Most, Daniel

1998-09-01

Immobilizing the forelimbs of rabbits after surgical procedures is necessary to allow healing, yet it often can be difficult, because rabbits are often able to pull the repaired limb from its cast soon after surgery and well before adequate tissue repair has taken place. We describe here a method of immobilization that uses 3 layers of cast material combined with flexion of the radiocarpal and radiohumeral joints. This method resulted in successful immobilization in 97% of the rabbits on which it was used.

The effect of perineural anesthesia on infrared thermographic images of the forelimb digits of normal horses

PubMed Central

Holmes, Layne C.; Gaughan, Earl M.; Gorondy, Denise A.; Hogge, Steve; Spire, Mark F.

2003-01-01

Infrared thermography is an imaging modality gaining popularity as a diagnostic aid in the evaluation of equine lameness. Anecdotal reports of skin hyperthermia induced by local anesthesia, detected by thermography, have been made; however, no controlled studies have been reported. The purpose of this study was to examine the effects of perineural anesthesia on infrared thermographic images of the forelimb digits in normal horses. After environmental acclimation, infrared thermographs were made at intervals of 0, 5, 10, 15, 30, and 45 min from administration of mepivacaine hydrochloride or phosphate buffered saline in 6 adult horses with no clinical evidence of abnormality of the forelimb digits. The mean limb surface temperatures were compared by 2-factor ANOVA. Results indicated no significant difference between treatments, time after injection, or an interaction of time and treatment. Infrared thermographic imaging apparently can be performed within 45 min of perineural mepivacaine hydrochloride anesthesia without risk of artifactual changes in limb surface temperature. PMID:12757130

Humeral loads during swimming and walking in turtles: implications for morphological change during aquatic reinvasions.

PubMed

Young, Vanessa K H; Wienands, Charlotte E; Wilburn, Brittany P; Blob, Richard W

2017-11-01

During evolutionary reinvasions of water by terrestrial vertebrates, ancestrally tubular limb bones often flatten to form flippers. Differences in skeletal loading between land and water might have facilitated such changes. In turtles, femoral shear strains are significantly lower during swimming than during walking, potentially allowing a release from loads favoring tubular shafts. However, flipper-like morphology in specialized tetrapod swimmers is most accentuated in the forelimbs. To test whether the forelimbs of turtles also experience reduced torsional loading in water, we compared strains on the humerus of river cooters ( Pseudemys concinna ) between swimming and terrestrial walking. We found that humeral shear strains are also lower during swimming than during terrestrial walking; however, this appears to relate to a reduction in overall strain magnitude, rather than a specific reduction in twisting. These results indicate that shear strains show similar reductions between swimming and walking for forelimb and hindlimb, but these reductions are produced through different mechanisms. © 2017. Published by The Company of Biologists Ltd.

Directional Asymmetry in the Limbs, Skull and Pelvis of the Silver Fox (V. vulpes)

PubMed Central

Kharlamova, Anastasia V.; Trut, Lyudmila N.; Chase, Kevin; Kukekova, Anna V.; Lark, Karl G.

2011-01-01

Directional asymmetry (DA) is a characteristic of most vertebrates, most strikingly exhibited by the placement of various organs (heart, lungs, liver, etc.) but also noted in small differences in the metrics of skeletal structures such as the pelvis of certain fish or sauropsids. We have analyzed DA in the skeleton of the fox (V. vulpes), using ~1,000 radiographs of foxes from populations used in the genetic analysis of behavior and morphology. Careful measurements from this robust data base demonstrate that: 1) DA occurs in the limb bones, the ileum, and ischium and in the mandible; 2) regardless of the direction of the length asymmetry vector of a particular skeletal unit, the vectorial direction of length is always opposite to that of width; 3) with the exception of the humerus and radius, there is no correlation or inverse correlation between vectorial amplitudes or magnitudes of bone asymmetries. 4) Postnatal measurements on foxes demonstrate that the asymmetry increases after birth and continues to change (increasing or decreasing) during postnatal growth. 5) A behavior test for preferential use of a specific forelimb exhibited fluctuating asymmetry but not DA. None of the skeletal asymmetries were significantly correlated with a preferential use of a specific forelimb. We suggest that for the majority of fox skeletal parameters, growth on the right and left side of the fox are differentially biased resulting in fixed differences between the two sides in either the rate of growth or the length of the period during which growth occurs. Random effects around these fixed differences perturb the magnitude of the effects such that the magnitudes of length and width asymmetries are not inversely correlated at the level of individual animals. PMID:20862692

Directional asymmetry in the limbs, skull and pelvis of the silver fox (V. vulpes).

PubMed

Kharlamova, Anastasia V; Trut, Lyudmila N; Chase, Kevin; Kukekova, Anna V; Lark, Karl G

2010-12-01

Directional asymmetry (DA) is a characteristic of most vertebrates, most strikingly exhibited by the placement of various organs (heart, lungs, liver, etc.) but also noted in small differences in the metrics of skeletal structures such as the pelvis of certain fish or sauropsids. We have analyzed DA in the skeleton of the fox (V. vulpes), using ∼1,000 radiographs of foxes from populations used in the genetic analysis of behavior and morphology. Careful measurements from this robust data base demonstrate that: 1) DA occurs in the limb bones, the ileum, and ischium and in the mandible; 2) regardless of the direction of the length asymmetry vector of a particular skeletal unit, the vectorial direction of length is always opposite to that of width; 3) with the exception of the humerus and radius, there is no correlation or inverse correlation between vectorial amplitudes or magnitudes of bone asymmetries. 4) Postnatal measurements on foxes demonstrate that the asymmetry increases after birth and continues to change (increasing or decreasing) during postnatal growth. 5) A behavior test for preferential use of a specific forelimb exhibited fluctuating asymmetry but not DA. None of the skeletal asymmetries were significantly correlated with a preferential use of a specific forelimb. We suggest that for the majority of fox skeletal parameters, growth on the right and left side of the fox are differentially biased resulting in fixed differences between the two sides in either the rate of growth or the length of the period during which growth occurs. Random effects around these fixed differences perturb the magnitude of the effects such that the magnitudes of length and width asymmetries are not inversely correlated at the level of individual animals. © 2010 Wiley-Liss, Inc.

Effect of Curcumin Supplementation on Physiological Fatigue and Physical Performance in Mice

PubMed Central

Huang, Wen-Ching; Chiu, Wan-Chun; Chuang, Hsiao-Li; Tang, Deh-Wei; Lee, Zon-Min; Wei, Li; Chen, Fu-An; Huang, Chi-Chang

2015-01-01

Curcumin (CCM) is a well-known phytocompound and food component found in the spice turmeric and has multifunctional bioactivities. However, few studies have examined its effects on exercise performance and physical fatigue. We aimed to evaluate the potential beneficial effects of CCM supplementation on fatigue and ergogenic function following physical challenge in mice. Male ICR mice were divided into four groups to receive vehicle or CCM (180 μg/mL) by oral gavage at 0, 12.3, 24.6, or 61.5 mL/kg/day for four weeks. Exercise performance and anti-fatigue function were evaluated after physical challenge by forelimb grip strength, exhaustive swimming time, and levels of physical fatigue-associated biomarkers serum lactate, ammonia, blood urea nitrogen (BUN), and glucose and tissue damage markers such as aspartate transaminase (AST), alanine transaminase (ALT), and creatine kinase (CK). CCM supplementation dose-dependently increased grip strength and endurance performance and significantly decreased lactate, ammonia, BUN, AST, ALT, and CK levels after physical challenge. Muscular glycogen content, an important energy source for exercise, was significantly increased. CCM supplementation had few subchronic toxic effects. CCM supplementation may have a wide spectrum of bioactivities for promoting health, improving exercise performance and preventing fatigue. PMID:25647661

Progressive motor cortex functional reorganization following 6-hydroxydopamine lesioning in rats.

PubMed

Viaro, Riccardo; Morari, Michele; Franchi, Gianfranco

2011-03-23

Many studies have attempted to correlate changes of motor cortex activity with progression of Parkinson's disease, although results have been controversial. In the present study we used intracortical microstimulation (ICMS) combined with behavioral testing in 6-hydroxydopamine hemilesioned rats to evaluate the impact of dopamine depletion on movement representations in primary motor cortex (M1) and motor behavior. ICMS allows for motor-effective stimulation of corticofugal neurons in motor areas so as to obtain topographic movements representations based on movement type, area size, and threshold currents. Rats received unilateral 6-hydroxydopamine in the nigrostriatal bundle, causing motor impairment. Changes in M1 were time dependent and bilateral, although stronger in the lesioned than the intact hemisphere. Representation size and threshold current were maximally impaired at 15 d, although inhibition was still detectable at 60-120 d after lesion. Proximal forelimb movements emerged at the expense of the distal ones. Movement lateralization was lost mainly at 30 d after lesion. Systemic L-3,4-dihydroxyphenylalanine partially attenuated motor impairment and cortical changes, particularly in the caudal forelimb area, and completely rescued distal forelimb movements. Local application of the GABA(A) antagonist bicuculline partially restored cortical changes, particularly in the rostral forelimb area. The local anesthetic lidocaine injected into the M1 of the intact hemisphere restored movement lateralization in the lesioned hemisphere. This study provides evidence for motor cortex remodeling after unilateral dopamine denervation, suggesting that cortical changes were associated with dopamine denervation, pathogenic intracortical GABA inhibition, and altered interhemispheric activity.

The effects of Kinesio Taping on the trajectory of the forelimb and the muscle activity of the Musculus brachiocephalicus and the Musculus extensor carpi radialis in horses

PubMed Central

Zellner, Antonia; Bockstahler, Barbara; Peham, Christian

2017-01-01

Background information The present study aimed to investigate the effects of Kinesio Taping on the trajectory of the forelimb and the muscle activity of the M. brachiocephalicus and the M. extensor carpi radialis in horses. 19 horses and ponies of different breeds (body weight: 496±117 kg), gender (8 mares, 10 geldings and 3 stallions) and ages (14.9±6.9 years old) were analysed without Kinesio Tape (“no tape”), with Kinesio Tape (muscle facilitation application on both muscles of both sides, “with tape”) and immediately after Kinesio Taping (“post tape”) through kinematic motion analysis and surface electromyography on a treadmill at the walk (speed: 1.5±0.1 m/s) and trot (speed: 3.1±0.3 m/s). Results The results of the surface electromyography (maximum muscle activity at the walk and trot) and the kinematic motion analysis (maximum stride length and maximum height of the forelimbs flight arc at the walk and trot) showed that there were no significant differences between "no tape", "with tape" and "post tape". Conclusion To sum up, Kinesio Taping on the M. brachiocephalicus and the M. extensor carpi radialis does not affect (in a positive or negative manner) the trajectory of the forelimb or the muscle activity of the M. brachiocephalicus and the M. extensor carpi radialis in horses. PMID:29166657

Mammalian spinal biomechanics: postural support in seated macaques.

PubMed

Gal, Julianna

2002-06-01

The aim of this study was to investigate whether the ligamentous lumbar vertebral column of a macaque could potentially provide passive mechanical support to the weight of the head, upper body and forelimbs during upright sitting. The seated flexed curvature of the lumbar spine of Macaca sylvana was estimated from a photograph and was partitioned equally among the lumbar-lumbar intervertebral joints. This flexed curvature was compared with the hyper-extended profile of the unloaded excised ligamentous spine of a related species (Macaca fascicularis) and used to calculate changes in intervertebral angle from the unloaded excised state to the loaded in vivo state. Changes in intervertebral angle were then used to calculate the net flexion moment required to bend the spine from the unloaded curvature to the seated curvature. The moment arm of the ventrally displaced weight of the head, upper body and forelimbs was estimated and used to calculate a corresponding net force. It was found that this force corresponded to approximately 18 % of the total body weight of the 2.34 kg sample animal. This compares with a likely fractional body weight of approximately 30-40 % for the head, upper body and forelimbs of these primates. Therefore, approximately half of the ventral flexion moment associated with the combined weight of the head, upper body and forelimbs during sitting in these animals may be supported by the passive mechanical properties associated with the ligamentous lumbar spine. This represents a potential means of relieving muscular effort and saving metabolic energy.

Inferring the use of forelimb suspensory locomotion by extinct primate species via shape exploration of the ulna.

PubMed

Rein, Thomas R; Harvati, Katerina; Harrison, Terry

2015-01-01

Uncovering links between skeletal morphology and locomotor behavior is an essential component of paleobiology because it allows researchers to infer the locomotor repertoire of extinct species based on preserved fossils. In this study, we explored ulnar shape in anthropoid primates using 3D geometric morphometrics to discover novel aspects of shape variation that correspond to observed differences in the relative amount of forelimb suspensory locomotion performed by species. The ultimate goal of this research was to construct an accurate predictive model that can be applied to infer the significance of these behaviors. We studied ulnar shape variation in extant species using principal component analysis. Species mainly clustered into phylogenetic groups along the first two principal components. Upon closer examination, the results showed that the position of species within each major clade corresponded closely with the proportion of forelimb suspensory locomotion that they have been observed to perform in nature. We used principal component regression to construct a predictive model for the proportion of these behaviors that would be expected to occur in the locomotor repertoire of anthropoid primates. We then applied this regression analysis to Pliopithecus vindobonensis, a stem catarrhine from the Miocene of central Europe, and found strong evidence that this species was adapted to perform a proportion of forelimb suspensory locomotion similar to that observed in the extant woolly monkey, Lagothrix lagothricha. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of the pseudothumb in frogs

PubMed Central

Tokita, Masayoshi; Iwai, Noriko

2010-01-01

Frogs have highly conserved hand and foot morphology, possessing four fingers and five toes. As an exception, two Japanese ranid frog species, the Otton frog Babina subaspera and the dagger frog Babina holsti, possess a unique thumb-like structure (the pseudothumb) in the forelimb, giving an appearance of a total of five fingers on the hand. To obtain insights into the developmental mechanisms that generate this novel character, we investigated the hand morphogenesis of the Otton frog. The unique morphological pattern of the pseudothumb was already established in juveniles. Surprisingly, the bud-like structure, which is similar to the area of inductive activity (e.g. feather buds in birds and the carapacial ridge in turtles), was detected over the site where the future prepollex develops in larvae. By contrast, this bud-like structure was not found in larvae of other ranid species. We discuss possible scenarios that would favour the evolution of this very unusual trait in frogs. PMID:20147308

Clinical, microscopic, and molecular aspects of canine leproid granuloma in the United States.

PubMed

Foley, J E; Borjesson, D; Gross, T L; Rand, C; Needham, M; Poland, A

2002-03-01

Leproid granulomas from seven dogs in the United States were evaluated. Gross characteristics included nodular and ulcerated dermal and subcutaneous lesions primarily on the caudal aspects of the pinnae and to a lesser extent on the muzzle, face, and forelimbs. In all except one dog, there was complete regression of the lesions within 6 months, either with no therapy or after surgical resection. Cytology or histopathology revealed pyogranulomatous inflammation with few to many acid-fast mycobacterial bacilli within macrophages. The organisms could not be cultivated in vitro. DNA sequencing of part of the 16S ribosomal RNA gene region revealed 99-100% homology among fragments from five of these dogs and fragments from dogs in the south Pacific. This syndrome occurs in dogs in North America and the prognosis is excellent, in contrast to the prognosis for rapid-growing or tuberculous mycobacteriosis.

An in vitro biomechanical comparison of two fixation methods for transverse osteotomies of the medial proximal forelimb sesamoid bones in horses.

PubMed

Wilson, D A; Keegan, K G; Carson, W L

1999-01-01

This study compared the mechanical properties of the normal intact suspensory apparatus and two methods of fixation for repair of transverse, midbody fractures of the proximal sesamoid bones of adult horses: transfixation wiring (TW) and screws placed in lag fashion (LS). An in vitro, paired study using equine cadaver limbs mounted in a loading apparatus was used to test the mechanical properties of TW and LS. Seventeen paired (13 repaired, 4 normal) equine cadaver limbs consisting of the suspensory apparatus third metacarpal bone, and first and second phalanges. The two methods of repair and normal intact specimens were evaluated in single cycle-to-failure loading. Yield failure was defined to occur at the first notable discontinuity (>50 N) in the load-displacement curve, the first visible failure as evident on the videotape, or a change in the slope of the moment-fetlock angle curve. Ultimate failure was defined to occur at the highest load resisted by the specimen. Corresponding resultant force and force per kg of body weight on the suspensory apparatus, fetlock joint moment, and angle of fetlock dorsiflexion were calculated by use of specimen dimensions and applied load. These were compared along with specimen stiffness, and ram displacement. Load on the suspensory apparatus, load on the suspensory apparatus per kg of body weight, moment, applied load, and angle of fetlock dorsiflexion at yield failure were significantly greater for the TW-repaired than for the LS-repaired specimens. A 3 to 5 mm gap was observed before yield failure in most TW-repaired osteotomies. Transfixation wiring provided greater strength to yield failure than screws placed in lag fashion in single cycle load-to-failure mechanical testing of repaired transverse osteotomized specimens of the medial proximal forelimb sesamoid bone.

Retinoic acid-independent expression of Meis2 during autopod patterning in the developing bat and mouse limb.

PubMed

Mason, Mandy K; Hockman, Dorit; Curry, Lyle; Cunningham, Thomas J; Duester, Gregg; Logan, Malcolm; Jacobs, David S; Illing, Nicola

2015-01-01

The bat has strikingly divergent forelimbs (long digits supporting wing membranes) and hindlimbs (short, typically free digits) due to the distinct requirements of both aerial and terrestrial locomotion. During embryonic development, the morphology of the bat forelimb deviates dramatically from the mouse and chick, offering an alternative paradigm for identifying genes that play an important role in limb patterning. Using transcriptome analysis of developing Natal long-fingered bat (Miniopterus natalensis) fore- and hindlimbs, we demonstrate that the transcription factor Meis2 has a significantly higher expression in bat forelimb autopods compared to hindlimbs. Validation by reverse transcriptase and quantitative polymerase chain reaction (RT-qPCR) and whole mount in situ hybridisation shows that Meis2, conventionally known as a marker of the early proximal limb bud, is upregulated in the bat forelimb autopod from CS16. Meis2 expression is localised to the expanding interdigital webbing and the membranes linking the wing to the hindlimb and tail. In mice, Meis2 is also expressed in the interdigital region prior to tissue regression. This interdigital Meis2 expression is not activated by retinoic acid (RA) signalling as it is present in the retained interdigital tissue of Rdh10 (trex/trex) mice, which lack RA. Additionally, genes encoding RA-synthesising enzymes, Rdh10 and Aldh1a2, and the RA nuclear receptor Rarβ are robustly expressed in bat fore- and hindlimb interdigital tissues indicating that the mechanism that retains interdigital tissue in bats also occurs independently of RA signalling. Mammalian interdigital Meis2 expression, and upregulation in the interdigital webbing of bat wings, suggests an important role for Meis2 in autopod development. Interdigital Meis2 expression is RA-independent, and retention of interdigital webbing in bat wings is not due to the suppression of RA-induced cell death. Rather, RA signalling may play a role in the thinning (rather than complete loss) of the interdigital tissue in the bat forelimb, while Meis2 may interact with other factors during both bat and mouse autopod development to maintain a pool of interdigital cells that contribute to digit patterning and growth.

Distinct Functional Modules for Discrete and Rhythmic Forelimb Movements in the Mouse Motor Cortex.

PubMed

Hira, Riichiro; Terada, Shin-Ichiro; Kondo, Masashi; Matsuzaki, Masanori

2015-09-30

Movements of animals are composed of two fundamental dynamics: discrete and rhythmic movements. Although the movements with distinct dynamics are thought to be differently processed in the CNS, it is unclear how they are represented in the cerebral cortex. Here, we investigated the cortical representation of movement dynamics by developing prolonged transcranial optogenetic stimulation (pTOS) using awake, channelrhodopsin-2 transgenic mice. We found two domains that induced discrete forelimb movements in the forward and backward directions, and these sandwiched a domain that generated rhythmic forelimb movements. The forward discrete movement had an intrinsic velocity profile and the rhythmic movement had an intrinsic oscillation frequency. Each of the forward discrete and rhythmic domains possessed intracortical synaptic connections within its own domain, independently projected to the spinal cord, and weakened the neuronal activity and movement induction of the other domain. pTOS-induced movements were also classified as ethologically relevant movements. Forepaw-to-mouth movement was mapped in a part of the forward discrete domain, while locomotion-like movement was in a part of the rhythmic domain. Interestingly, photostimulation of the rhythmic domain resulted in a nonrhythmic, continuous lever-pull movement when a lever was present. The motor cortex possesses functional modules for distinct movement dynamics, and these can adapt to environmental constraints for purposeful movements. Significance statement: Animal behavior has discrete and rhythmic components, such as reaching and locomotion. It is unclear how these movements with distinct dynamics are represented in the cerebral cortex. We investigated the dynamics of movements induced by long-duration transcranial photostimulation on the dorsal cortex of awake channelrhodopsin-2 transgenic mice. We found two domains causing forward and backward discrete forelimb movements and a domain for rhythmic forelimb movements. A domain for forward discrete movement and a domain for rhythmic movement mutually weakened neuronal activity and movement size. The photostimulation of the rhythmic domain also induced nonrhythmic, lever-pull movement, when the lever was present. Thus, the motor cortex has functional modules with distinct dynamics, and each module retains flexibility for adaptation to different environments. Copyright © 2015 the authors 0270-6474/15/3513311-12$15.00/0.

Electrical stimulation of motor cortex in the uninjured hemisphere after chronic unilateral injury promotes recovery of skilled locomotion through ipsilateral control.

PubMed

Carmel, Jason B; Kimura, Hiroki; Martin, John H

2014-01-08

Partial injury to the corticospinal tract (CST) causes sprouting of intact axons at their targets, and this sprouting correlates with functional improvement. Electrical stimulation of motor cortex augments sprouting of intact CST axons and promotes functional recovery when applied soon after injury. We hypothesized that electrical stimulation of motor cortex in the intact hemisphere after chronic lesion of the CST in the other hemisphere would restore function through ipsilateral control. To test motor skill, rats were trained and tested to walk on a horizontal ladder with irregularly spaced rungs. Eight weeks after injury, produced by pyramidal tract transection, half of the rats received forelimb motor cortex stimulation of the intact hemisphere. Rats with injury and stimulation had significantly improved forelimb control compared with rats with injury alone and achieved a level of proficiency similar to uninjured rats. To test whether recovery of forelimb function was attributable to ipsilateral control, we selectively inactivated the stimulated motor cortex using the GABA agonist muscimol. The dose of muscimol we used produces strong contralateral but no ipsilateral impairments in naive rats. In rats with injury and stimulation, but not those with injury alone, inactivation caused worsening of forelimb function; the initial deficit was reinstated. These results demonstrate that electrical stimulation can promote recovery of motor function when applied late after injury and that motor control can be exerted from the ipsilateral motor cortex. These results suggest that the uninjured motor cortex could be targeted for brain stimulation in people with large unilateral CST lesions.

Comparison of the temporal kinematics of the canter pirouette and collected canter.

PubMed

Burns, T E; Clayton, H M

1997-05-01

The objectives were to compare the temporal characteristics of canter pirouette strides with collected canter strides in elite dressage horses, and to determine whether the stride kinematics of the canter pirouettes fulfilled the requirements specified in the Federation Equestre Internationale Rules for Dressage Events. Eleven horses were videotaped (60 fields/s) during the individual medal competition at the 1992 Olympic Games. Temporal variables were extracted from the videotapes using standard methods. Two strides were analysed on each of the left and right leads and these were pooled to give mean values for the collected canter and the pirouettes. The pirouettes were completed in 4-9 strides, (mean of 6.4). In the collected canter strides, mean duration of the suspension was 0.013 s. There was no suspension in any of the pirouette strides, instead the stance phases of the leading forelimb and trailing hindlimb overlapped by a mean of 0.163 s. In 9 horses the trailing forelimb contacted the ground before the diagonal leading hindlimb in the collected canter, whereas in the pirouettes the leading hindlimb always made contact before the trailing forelimb (mean dissociation 0.164 s), giving the strides a distinct 4 beat rhythm. Due to increases in advanced placement between the diagonal limb pair and between the 2 forelimbs, the stride duration was longer in the pirouette (0.879 s) than the collected canter (0.629 s). It is concluded that the canter pirouette strides did not maintain the rhythm and timing of the the collected canter strides in any of the 11 horses.

Protection from ethanol-induced limb malformations by the superoxide dismutase/catalase mimetic, EUK-134.

PubMed

Chen, Shao-Yu; Dehart, Deborah B; Sulik, Kathleen K

2004-08-01

Based on previous in vitro studies that have illustrated prevention of ethanol-induced cell death by antioxidants, using an in vivo model, we have tested the anti-teratogenic potential of a potent synthetic superoxide dismutase plus catalase mimetic, EUK-134. The developing limb of C57BL/6J mice, which is sensitive to ethanol-induced reduction defects, served as the model system. On their ninth day of pregnancy, C57BL/6J mice were administered ethanol (two intraperitoneal doses of 2.9 g/kg given 4 h apart) alone or in combination with EUK-134 (two doses of 10 mg/kg). Pregnant control mice were similarly treated with either vehicle or EUK-134, alone. Within 15 h of the initial ethanol exposure, excessive apoptotic cell death was observed in the apical ectodermal ridge (AER) of the newly forming forelimb buds. Forelimb defects, including postaxial ectrodactyly, metacarpal, and ulnar deficiencies, occurred in 67.3% of the ethanol-exposed fetuses that were examined at 18 days of gestation. The right forelimbs were preferentially affected. No limb malformations were observed in control fetuses. Cell death in the AER of embryos concurrently exposed to ethanol and EUK-134 was notably reduced compared with that in embryos from ethanol-treated dams. Additionally, the antioxidant treatment reduced the incidence of forelimb malformations to 35.9%. This work illustrates that antioxidants can significantly improve the adverse developmental outcome that results from ethanol exposure in utero, diminishing the incidence and severity of major malformations that result from exposure to this important human teratogen.

Planar Covariation of Hindlimb and Forelimb Elevation Angles during Terrestrial and Aquatic Locomotion of Dogs

PubMed Central

Catavitello, Giovanna; Ivanenko, Yuri P.; Lacquaniti, Francesco

2015-01-01

The rich repertoire of locomotor behaviors in quadrupedal animals requires flexible inter-limb and inter-segmental coordination. Here we studied the kinematic coordination of different gaits (walk, trot, gallop, and swim) of six dogs (Canis lupus familiaris) and, in particular, the planar covariation of limb segment elevation angles. The results showed significant variations in the relative duration of rearward limb movement, amplitude of angular motion, and inter-limb coordination, with gait patterns ranging from a lateral sequence of footfalls during walking to a diagonal sequence in swimming. Despite these differences, the planar law of inter-segmental coordination was maintained across different gaits in both forelimbs and hindlimbs. Notably, phase relationships and orientation of the covariation plane were highly limb specific, consistent with the functional differences in their neural control. Factor analysis of published muscle activity data also demonstrated differences in the characteristic timing of basic activation patterns of the forelimbs and hindlimbs. Overall, the results demonstrate that the planar covariation of inter-segmental coordination has emerged for both fore- and hindlimbs and all gaits, although in a limb-specific manner. PMID:26218076

Development of a universal measure of quadrupedal forelimb-hindlimb coordination using digital motion capture and computerised analysis.

PubMed

Hamilton, Lindsay; Franklin, Robin J M; Jeffery, Nick D

2007-09-18

Clinical spinal cord injury in domestic dogs provides a model population in which to test the efficacy of putative therapeutic interventions for human spinal cord injury. To achieve this potential a robust method of functional analysis is required so that statistical comparison of numerical data derived from treated and control animals can be achieved. In this study we describe the use of digital motion capture equipment combined with mathematical analysis to derive a simple quantitative parameter - 'the mean diagonal coupling interval' - to describe coordination between forelimb and hindlimb movement. In normal dogs this parameter is independent of size, conformation, speed of walking or gait pattern. We show here that mean diagonal coupling interval is highly sensitive to alterations in forelimb-hindlimb coordination in dogs that have suffered spinal cord injury, and can be accurately quantified, but is unaffected by orthopaedic perturbations of gait. Mean diagonal coupling interval is an easily derived, highly robust measurement that provides an ideal method to compare the functional effect of therapeutic interventions after spinal cord injury in quadrupeds.

Record-Breaking Pain: The Largest Number and Variety of Forelimb Bone Maladies in a Theropod Dinosaur.

PubMed

Senter, Phil; Juengst, Sara L

2016-01-01

Bone abnormalities are common in theropod dinosaur skeletons, but before now no specimen was known with more than four afflicted bones of the pectoral girdle and/or forelimb. Here we describe the pathology of a specimen of the theropod dinosaur Dilophosaurus wetherilli with eight afflicted bones of the pectoral girdle and forelimb. On its left side the animal has a fractured scapula and radius and large fibriscesses in the ulna and the proximal thumb phalanx. On its right side the animal has abnormal torsion of the humeral shaft, bony tumors on the radius, a truncated distal articular surface of metacarpal III, and angular deformities of the first phalanx of the third finger. Healing and remodeling indicates that the animal survived for months and possibly years after its ailments began, but its right third finger was permanently deformed and lacked the capability of flexion. The deformities of the humerus and the right third finger may be due to developmental osteodysplasia, a condition known in extant birds but unreported in non-avian dinosaurs before now.

Skeletal, cardiac, and respiratory muscle function and histopathology in the P448Lneo- mouse model of FKRP-deficient muscular dystrophy.

PubMed

Yu, Qing; Morales, Melissa; Li, Ning; Fritz, Alexander G; Ruobing, Ren; Blaeser, Anthony; Francois, Ershia; Lu, Qi-Long; Nagaraju, Kanneboyina; Spurney, Christopher F

2018-04-06

Fukutin-related protein (FKRP) mutations are the most common cause of dystroglycanopathies known to cause both limb girdle and congenital muscular dystrophy. The P448Lneo- mouse model has a knock-in mutation in the FKRP gene and develops skeletal, respiratory, and cardiac muscle disease. We studied the natural history of the P448Lneo- mouse model over 9 months and the effects of twice weekly treadmill running. Forelimb and hindlimb grip strength (Columbus Instruments) and overall activity (Omnitech Electronics) assessed skeletal muscle function. Echocardiography was performed using VisualSonics Vevo 770 (FujiFilm VisualSonics). Plethysmography was performed using whole body system (ADInstruments). Histological evaluations included quantification of inflammation, fibrosis, central nucleation, and fiber size variation. P448Lneo- mice had significantly increased normalized tissue weights compared to controls at 9 months of age for the heart, gastrocnemius, soleus, tibialis anterior, quadriceps, and triceps. There were no significant differences seen in forelimb or hindlimb grip strength or activity monitoring in P448Lneo- mice with or without exercise compared to controls. Skeletal muscles demonstrated increased inflammation, fibrosis, central nucleation, and variation in fiber size compared to controls (p < 0.05) and worsened with exercise. Plethysmography showed significant differences in respiratory rates and decreased tidal and minute volumes in P448Lneo- mice (p < 0.01). There was increased fibrosis in the diaphragm compared to controls (p < 0.01). Echocardiography demonstrated decreased systolic function in 9-month-old mutant mice (p < 0.01). There was increased myocardial wall thickness and mass (p < 0.001) with increased fibrosis in 9-month-old P448Lneo- mice compared to controls (p < 0.05). mRNA expression for natriuretic peptide type A (Nppa) was significantly increased in P448Lneo- mice compared to controls at 6 months (p < 0.05) and for natriuretic peptide type B (Nppb) at 6 and 9 months of age (p < 0.05). FKRP-deficient P448Lneo- mice demonstrate significant deficits in cardiac and respiratory functions compared to control mice, and this is associated with increased inflammation and fibrosis. This study provides new functional outcome measures for preclinical trials of FKRP-related muscular dystrophies.

How the embryo makes a limb: determination, polarity and identity

PubMed Central

Tickle, Cheryll

2015-01-01

The vertebrate limb with its complex anatomy develops from a small bud of undifferentiated mesoderm cells encased in ectoderm. The bud has its own intrinsic polarity and can develop autonomously into a limb without reference to the rest of the embryo. In this review, recent advances are integrated with classical embryology, carried out mainly in chick embryos, to present an overview of how the embryo makes a limb bud. We will focus on how mesoderm cells in precise locations in the embryo become determined to form a limb and express the key transcription factors Tbx4 (leg/hindlimb) or Tbx5 (wing/forelimb). These Tbx transcription factors have equivalent functions in the control of bud formation by initiating a signalling cascade involving Wnts and fibroblast growth factors (FGFs) and by regulating recruitment of mesenchymal cells from the coelomic epithelium into the bud. The mesoderm that will form limb buds and the polarity of the buds is determined with respect to both antero-posterior and dorso-ventral axes of the body. The position in which a bud develops along the antero-posterior axis of the body will also determine its identity – wing/forelimb or leg/hindlimb. Hox gene activity, under the influence of retinoic acid signalling, is directly linked with the initiation of Tbx5 gene expression in the region along the antero-posterior axis of the body that will form wings/forelimbs and determines antero-posterior polarity of the buds. In contrast, Tbx4 expression in the regions that will form legs/hindlimbs is regulated by the homeoprotein Pitx1 and there is no evidence that Hox genes determine antero-posterior polarity of the buds. Bone morphogenetic protein (BMP) signalling determines the region along the dorso-ventral axis of the body in which both wings/forelimbs and legs/hindlimbs develop and dorso-ventral polarity of the buds. The polarity of the buds leads to the establishment of signalling regions – the dorsal and ventral ectoderm, producing Wnts and BMPs, respectively, the apical ectodermal ridge producing fibroblast growth factors and the polarizing region, Sonic hedgehog (Shh). These signals are the same in both wings/forelimbs and legs/hindlimbs and control growth and pattern formation by providing the mesoderm cells of the limb bud as it develops with positional information. The precise anatomy of the limb depends on the mesoderm cells in the developing bud interpreting positional information according to their identity – determined by Pitx1 in hindlimbs – and genotype. The competence to form a limb extends along the entire antero-posterior axis of the trunk – with Hox gene activity inhibiting the formation of forelimbs in the interlimb region – and also along the dorso-ventral axis. PMID:26249743

How the embryo makes a limb: determination, polarity and identity.

PubMed

Tickle, Cheryll

2015-10-01

The vertebrate limb with its complex anatomy develops from a small bud of undifferentiated mesoderm cells encased in ectoderm. The bud has its own intrinsic polarity and can develop autonomously into a limb without reference to the rest of the embryo. In this review, recent advances are integrated with classical embryology, carried out mainly in chick embryos, to present an overview of how the embryo makes a limb bud. We will focus on how mesoderm cells in precise locations in the embryo become determined to form a limb and express the key transcription factors Tbx4 (leg/hindlimb) or Tbx5 (wing/forelimb). These Tbx transcription factors have equivalent functions in the control of bud formation by initiating a signalling cascade involving Wnts and fibroblast growth factors (FGFs) and by regulating recruitment of mesenchymal cells from the coelomic epithelium into the bud. The mesoderm that will form limb buds and the polarity of the buds is determined with respect to both antero-posterior and dorso-ventral axes of the body. The position in which a bud develops along the antero-posterior axis of the body will also determine its identity - wing/forelimb or leg/hindlimb. Hox gene activity, under the influence of retinoic acid signalling, is directly linked with the initiation of Tbx5 gene expression in the region along the antero-posterior axis of the body that will form wings/forelimbs and determines antero-posterior polarity of the buds. In contrast, Tbx4 expression in the regions that will form legs/hindlimbs is regulated by the homeoprotein Pitx1 and there is no evidence that Hox genes determine antero-posterior polarity of the buds. Bone morphogenetic protein (BMP) signalling determines the region along the dorso-ventral axis of the body in which both wings/forelimbs and legs/hindlimbs develop and dorso-ventral polarity of the buds. The polarity of the buds leads to the establishment of signalling regions - the dorsal and ventral ectoderm, producing Wnts and BMPs, respectively, the apical ectodermal ridge producing fibroblast growth factors and the polarizing region, Sonic hedgehog (Shh). These signals are the same in both wings/forelimbs and legs/hindlimbs and control growth and pattern formation by providing the mesoderm cells of the limb bud as it develops with positional information. The precise anatomy of the limb depends on the mesoderm cells in the developing bud interpreting positional information according to their identity - determined by Pitx1 in hindlimbs - and genotype. The competence to form a limb extends along the entire antero-posterior axis of the trunk - with Hox gene activity inhibiting the formation of forelimbs in the interlimb region - and also along the dorso-ventral axis. © 2015 Anatomical Society.

A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny.

PubMed

Scheyer, Torsten M; Neenan, James M; Bodogan, Timea; Furrer, Heinz; Obrist, Christian; Plamondon, Mathieu

2017-06-30

Recently it was suggested that the phylogenetic clustering of Mesozoic marine reptile lineages, such as thalattosaurs, the very successful fish-shaped ichthyosaurs and sauropterygians (including plesiosaurs), among others, in a so-called 'superclade' is an artefact linked to convergent evolution of morphological characters associated with a shared marine lifestyle. Accordingly, partial 'un-scoring' of the problematic phylogenetic characters was proposed. Here we report a new, exceptionally preserved and mostly articulated juvenile skeleton of the diapsid reptile, Eusaurosphargis dalsassoi, a species previously recovered within the marine reptile 'superclade', for which we now provide a revised diagnosis. Using micro-computed tomography, we show that besides having a deep skull with a short and broad rostrum, the most outstanding feature of the new specimen is extensive, complex body armour, mostly preserved in situ, along its vertebrae, ribs, and forelimbs, as well as a row of flat, keeled ventrolateral osteoderms associated with the gastralia. As a whole, the anatomical features support an essentially terrestrial lifestyle of the animal. A review of the proposed partial character 'un-scoring' using three published data matrices indicate that this approach is flawed and should be avoided, and that within the marine reptile 'superclade' E. dalsassoi potentially is the sister taxon of Sauropterygia.

Prenatal alcohol exposure reduces the size of the forelimb representation in motor cortex in rat: an intracortical microstimulation (ICMS) mapping study.

PubMed

Xie, Ni; Yang, Qiuhong; Chappell, Tyson D; Li, Cheng-Xiang; Waters, Robert S

2010-03-01

Children with fetal alcohol spectrum disorder (FASD) often exhibit sensorimotor dysfunctions that include deficits in motor coordination and fine motor control. Although the underlying causes for these motor abnormalities are unknown, they likely involve interactions between sensory and motor systems. Rodent animal models have been used to study the effects of prenatal alcohol exposure (PAE) on skilled reaching and on the development and organization of somatosensory barrel field cortex. To this end, PAE delayed the development of somatosensory cortex, reduced the size of whisker and forelimb representations in somatosensory barrel field cortex, and delayed acquisition time to learn a skilled reaching task. However, whether PAE also affects the motor cortex (MI) remains to be determined. In the present study, we investigated the effect of PAE on the size of the forelimb representation in rat MI, thresholds for activation, and the overlap between motor and sensory cortical forelimb maps in sensorimotor cortex. Pregnant Sprague-Dawley rats were assigned to alcohol (Alc), pair-fed (PF), and chow-fed (CF) groups on gestation day 1 (GD1). Rats in the Alc group (n=4) were chronically intubated daily with binge doses of alcohol (6g/kg body weight) from GD1 to GD20 that resulted in averaged blood alcohol levels measured on GD10 (mean=191.5+/-41.9mg/dL) and on GD17 (mean=247.0+/-72.4mg/dL). PF (n=2) and CF (n=3) groups of pregnant rats served as controls. The effect of PAE on the various dependent measures was obtained from multiple male offspring from each dam within treatment groups, and litter means were compared between the groups from alcohol-treated and control (Ct: CF and PF) dams. At approximately 8 weeks of age, rats were anesthetized with ketamine/xylazine and the skull opened over sensorimotor cortex. A tungsten microelectrode was then inserted into the depths of layer V and intracortical microstimulation was used to deliver trains of pulses to evoke muscle contractions and/or movements; maximum stimulating < or =100microA. When a motor response was observed, the threshold for movement was measured and the motor receptive field projected to the cortical surface to serve as representative point for that location. A motor map for the forelimb representation was generated by systematically stimulating at adjacent sites until current thresholds reached the maximum and/or motor responses were no longer evoked. The major findings in this study were as follows: (1) PAE significantly reduced the area of the forelimb representation in the Alc offspring (6.01mm(2), standard error of the mean=+/-0.278) compared with the Ct offspring (8.03mm(2)+/-0.586), (2) PAE did not significantly reduce the averaged threshold for activation of movements between groups, (3) PAE significantly reduced the percent overlap (Alc=31.1%, Ct=55.4%) between the forelimb representation in sensory and motor cortices, and (4) no significant differences were observed in averaged body weight, hemisphere weight, or age of animal between treatment groups. These findings suggest that the effects of PAE are not restricted to somatosensory barrel field cortex but also involve the MI and may underlie deficits in motor control and sensorimotor integration observed among children with FASD. 2010. Published by Elsevier Inc.

Use-Dependent Dendritic Regrowth Is Limited after Unilateral Controlled Cortical Impact to the Forelimb Sensorimotor Cortex

PubMed Central

Jones, Theresa A.; Liput, Daniel J.; Maresh, Erin L.; Donlan, Nicole; Parikh, Toral J.; Marlowe, Dana

2012-01-01

Abstract Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3–28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI. PMID:22352953

Effect of short-term hyperinsulinemia on the localization and expression of endothelin receptors A and B in lamellar tissue of the forelimbs of horses

PubMed Central

Gauff, Felicia C.; Patan-Zugaj, Bianca; Licka, Theresia F.

2014-01-01

Objective To determine the effect of short-term hyperinsulinemia on the localization and expression of endothelin receptor (ETR)-A and ETR-B in lamellar tissue of the forelimbs of horses. Samples Distal portion of 15 cadaveric forelimbs from healthy adult horses (1 limb/horse) obtained immediately after slaughter at an abattoir. Procedures Each forelimb was assigned to 1 of 3 treatment groups (perfused with autologous blood for 10 hours [control perfusion; n = 5], perfused with an insulin [142 ± 81 μU/mL] perfusate for 10 hours [insulinemic perfusion; 5], or not perfused [unperfused control; 5]). Immunohistochemical evaluation of lamellar tissue was performed to assess localization of ETR-A and ETR-B. Expression of ETR-A and ETR-B was measured semiquantitatively on a scale of 0 to 3 (0 = none, 1 = mild, 2 = moderate, and 3 = high-intensity staining) and quantitatively by means of gray value analysis with imaging software. Results In all specimens, ETR-A and ETR-B were localized in endothelium, smooth muscle cells, axons, and keratinocytes. Quantitative expression of ETR-A in the midportion of the primary epidermal lamellae for the insulinemic perfusion group (149 ± 16) was lower than that for the control perfusion group (158 ± 15). Expression of ETR-B in the primary epidermal lamellae tips for the insulinemic perfusion group (140 ± 29) was higher than that for the control perfusion group (114 ± 8). Conclusions and Clinical Relevance Hyperinsulinemia caused significant changes in endothelin receptor expression, which suggested that ETR antagonists might be beneficial for treatment of laminitis in horses. PMID:24669922

Effect of hoof boots and toe-extension shoes on the forelimb kinetics of horses during walking.

PubMed

Amitrano, Fernando N; Gutierrez-Nibeyro, Santiago D; Schaeffer, David J

2016-05-01

OBJECTIVE To determine and compare the effect of hoof boots (HBs) and shoes with a toe extension on stance duration, ground reaction force, and sole length in contact with the ground in nonlame horses during walking. ANIMALS 6 nonlame Standardbreds. PROCEDURES Force plate gait analyses of the forelimbs were performed while the horses were walking barefoot before manipulation of feet (baseline), while the horses were walking fitted with HBs, while the horses were walking shod with toe-extension shoes, and while the horses were walking barefoot after shoe removal. Horses underwent radiography of both forelimb feet to determine the sole length in contact with the ground when barefoot, wearing HBs, and shod with toe-extension shoes. Stance duration, ground reaction force, and sole length were compared among the various walking sessions. RESULTS Compared with baseline findings, stance duration increased significantly when horses were fitted with HBs (7%) or toe-extension shoes (5%). Peak forelimb ground reaction force was similar among walking sessions; however, time of braking force peak was significantly greater during the stance phase only when horses wore HBs. Also, the sole length in contact with the ground was significantly longer in horses fitted with HBs (14.3 cm) or shod with the toe-extension shoes (17.6 cm), compared with that for one of the barefoot hooves (12.7 cm). CONCLUSIONS AND CLINICAL RELEVANCE In nonlame horses, use of HBs prolonged the stance time and time of braking force peak, which is indicative of a slower deceleration phase during limb impact with the ground. Also, the use of HBs prolonged the deceleration phase of the stride and increased the sole length in contact with the ground.

Early and late changes in the distal forelimb representation of the supplementary motor area after injury to frontal motor areas in the squirrel monkey.

PubMed

Eisner-Janowicz, Ines; Barbay, Scott; Hoover, Erica; Stowe, Ann M; Frost, Shawn B; Plautz, Erik J; Nudo, Randolph J

2008-09-01

Neuroimaging studies in stroke survivors have suggested that adaptive plasticity occurs following stroke. However, the complex temporal dynamics of neural reorganization after injury make the interpretation of functional imaging studies equivocal. In the present study in adult squirrel monkeys, intracortical microstimulation (ICMS) techniques were used to monitor changes in representational maps of the distal forelimb in the supplementary motor area (SMA) after a unilateral ischemic infarct of primary motor (M1) and premotor distal forelimb representations (DFLs). In each animal, ICMS maps were derived at early (3 wk) and late (13 wk) postinfarct stages. Lesions resulted in severe deficits in motor abilities on a reach and retrieval task. Limited behavioral recovery occurred and plateaued at 3 wk postinfarct. At both early and late postinfarct stages, distal forelimb movements could still be evoked by ICMS in SMA at low current levels. However, the size of the SMA DFL changed after the infarct. In particular, wrist-forearm representations enlarged significantly between early and late stages, attaining a size substantially larger than the preinfarct area. At the late postinfarct stage, the expansion in the SMA DFL area was directly proportional to the absolute size of the lesion. The motor performance scores were positively correlated to the absolute size of the SMA DFL at the late postinfarct stage. Together, these data suggest that, at least in squirrel monkeys, descending output from M1 and dorsal and ventral premotor cortices is not necessary for SMA representations to be maintained and that SMA motor output maps undergo delayed increases in representational area after damage to other motor areas. Finally, the role of SMA in recovery of function after such lesions remains unclear because behavioral recovery appears to precede neurophysiological map changes.

[The comparative characteristics of crystalline lens and limb regeneration in newts operated on before and after the completion of an orbital space flight].

PubMed

Tuchkova, S Ia; Brushlinskaia, N V; Grigorian, E N; Mitashov, V I

1994-01-01

It has been already established that a tendency towards synchronization and acceleration of the forelimb and lens regeneration is observed in Pleurodeles waltlii under the effect of space flight factors. Here we present the results obtained after 16-day space flight of two groups of newts. In animals of group I forelimbs were amputated and lenses were removed 14 and 7 days before the space flight, respectively. Intact animals of group II were operated on the day of the sputnik landing. Regenerates of the flight and corresponding control animals were fixed at the same time after the operation. For evaluation of the regeneration rate morphological criteria were used: morphological stages of regeneration were compared in the experiment and the control. For quantitative assay of the regeneration rate we determined the index of nuclei labelled with 3H-thymidine in the blastema and lens rudiment cells and used morphometry of the lens regenerates. Acceleration of forelimb and lens regeneration was observed in both groups of animals. In group II more than two-fold increase of the index of labelled nuclei was found in the blastema cells at the comparable stages of development. The size of lens regenerates in flight groups I and II exceeded reliably those in the control animals. The results obtained suggest a prolonged effect of the space flight factors on forelimb and lens regeneration. Under the conditions of space flight the lens regenerates reached more advanced stages of regeneration, as compared with the control animals operated after the space flight. These results also suggest acceleration of regeneration in lower vertebrates.

D-(/sup 3/H)aspartate retrograde labelling of callosal and association neurons of somatosensory areas I and II of cats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbaresi, P.; Fabri, M.; Conti, F.

Experiments were carried out on cats to ascertain whether corticocortical neurons of somatosensory areas I (SI) and II (SII) could be labelled by retrograde axonal transport of D-(/sup 3/H)aspartate (D-(/sup 3/H)Asp). This tritiated enantiomer of the amino acid aspartate is (1) taken up selectively by axon terminals of neurons releasing aspartate and/or glutamate as excitatory neurotransmitter, (2) retrogradely transported and accumulated in perikarya, (3) not metabolized, and (4) visualized by autoradiography. A solution of D-(/sup 3/H)Asp was injected in eight cats in the trunk and forelimb zones of SI (two cats) or in the forelimb zone of SII (six cats).more » In order to compare the labelling patterns obtained with D-(/sup 3/H)Asp with those resulting after injection of a nonselective neuronal tracer, horseradish peroxidase (HRP) was delivered mixed with the radioactive tracer in seven of the eight cats. Furthermore, six additional animals received HRP injections in SI (three cats; trunk and forelimb zones) or SII (three cats; forelimb zone). D-(/sup 3/H)Asp retrograde labelling of perikarya was absent from the ipsilateral thalamus of all cats injected with the radioactive tracer but a dense terminal plexus of anterogradely labelled corticothalamic fibers from SI and SII was observed, overlapping the distribution area of thalamocortical neurons retrogradely labelled with HRP from the same areas. D-(/sup 3/H)Asp-labelled neurones were present in ipsilateral SII (SII-SI association neurones) in cats injected in SI. In these animals a bundle of radioactive fibres was observed in the rostral portion of the corpus callosum entering the contralateral hemisphere. There, neurones retrogradely labelled with silver grains were present in SI (SI-SI callosal neurons).« less

Distinct Patterns of Desynchronized Limb Regression in Malagasy Scincine Lizards (Squamata, Scincidae)

PubMed Central

Miralles, Aurélien; Hipsley, Christy A.; Erens, Jesse; Gehara, Marcelo; Rakotoarison, Andolalao; Glaw, Frank; Müller, Johannes; Vences, Miguel

2015-01-01

Scincine lizards in Madagascar form an endemic clade of about 60 species exhibiting a variety of ecomorphological adaptations. Several subclades have adapted to burrowing and convergently regressed their limbs and eyes, resulting in a variety of partial and completely limbless morphologies among extant taxa. However, patterns of limb regression in these taxa have not been studied in detail. Here we fill this gap in knowledge by providing a phylogenetic analysis of DNA sequences of three mitochondrial and four nuclear gene fragments in an extended sampling of Malagasy skinks, and microtomographic analyses of osteology of various burrowing taxa adapted to sand substrate. Based on our data we propose to (i) consider Sirenoscincus Sakata & Hikida, 2003, as junior synonym of Voeltzkowia Boettger, 1893; (ii) resurrect the genus name Grandidierina Mocquard, 1894, for four species previously included in Voeltzkowia; and (iii) consider Androngo Brygoo, 1982, as junior synonym of Pygomeles Grandidier, 1867. By supporting the clade consisting of the limbless Voeltzkowia mira and the forelimb-only taxa V. mobydick and V. yamagishii, our data indicate that full regression of limbs and eyes occurred in parallel twice in the genus Voeltzkowia (as hitherto defined) that we consider as a sand-swimming ecomorph: in the Voeltzkowia clade sensu stricto the regression first affected the hindlimbs and subsequently the forelimbs, whereas the Grandidierina clade first regressed the forelimbs and subsequently the hindlimbs following the pattern prevalent in squamates. Timetree reconstructions for the Malagasy Scincidae contain a substantial amount of uncertainty due to the absence of suitable primary fossil calibrations. However, our preliminary reconstructions suggest rapid limb regression in Malagasy scincids with an estimated maximal duration of 6 MYr for a complete regression in Paracontias, and 4 and 8 MYr respectively for complete regression of forelimbs in Grandidierina and hindlimbs in Voeltzkowia. PMID:26042667

Resting Orientations of Dinosaur Scapulae and Forelimbs: A Numerical Analysis, with Implications for Reconstructions and Museum Mounts.

PubMed

Senter, Phil; Robins, James H

2015-01-01

The inclination of the scapular blade and the resting pose of the forelimb in dinosaurs differ among reconstructions and among skeletal mounts. For most dinosaurian taxa, no attempt has previously been made to quantify the correct resting positions of these elements. Here, we used data from skeletons preserved in articulation to quantify the resting orientations of the scapula and forelimb in dinosaurs. Specimens were included in the study only if they were preserved lying on their sides; for each specimen the angle between forelimb bones at a given joint was included in the analysis only if the joint was preserved in articulation. Using correlation analyses of the angles between the long axis of the sacrum, the first dorsal centrum, and the scapular blade in theropods and Eoraptor, we found that vertebral hyperextension does not influence scapular orientation in saurischians. Among examined taxa, the long axis of the scapular blade was found to be most horizontal in bipedal saurischians, most vertical in basal ornithopods, and intermediate in hadrosauroids. We found that in bipedal dinosaurs other than theropods with semilunate carpals, the resting orientation of the elbow is close to a right angle and the resting orientation of the wrist is such that the hand exhibits only slight ulnar deviation from the antebrachium. In theropods with semilunate carpals the elbow and wrist are more flexed at rest, with the elbow at a strongly acute angle and with the wrist approximately at a right angle. The results of our study have important implications for correct orientations of bones in reconstructions and skeletal mounts. Here, we provide recommendations on bone orientations based on our results.

Distinct patterns of desynchronized limb regression in malagasy scincine lizards (squamata, scincidae).

PubMed

Miralles, Aurélien; Hipsley, Christy A; Erens, Jesse; Gehara, Marcelo; Rakotoarison, Andolalao; Glaw, Frank; Müller, Johannes; Vences, Miguel

2015-01-01

Scincine lizards in Madagascar form an endemic clade of about 60 species exhibiting a variety of ecomorphological adaptations. Several subclades have adapted to burrowing and convergently regressed their limbs and eyes, resulting in a variety of partial and completely limbless morphologies among extant taxa. However, patterns of limb regression in these taxa have not been studied in detail. Here we fill this gap in knowledge by providing a phylogenetic analysis of DNA sequences of three mitochondrial and four nuclear gene fragments in an extended sampling of Malagasy skinks, and microtomographic analyses of osteology of various burrowing taxa adapted to sand substrate. Based on our data we propose to (i) consider Sirenoscincus Sakata & Hikida, 2003, as junior synonym of Voeltzkowia Boettger, 1893; (ii) resurrect the genus name Grandidierina Mocquard, 1894, for four species previously included in Voeltzkowia; and (iii) consider Androngo Brygoo, 1982, as junior synonym of Pygomeles Grandidier, 1867. By supporting the clade consisting of the limbless Voeltzkowia mira and the forelimb-only taxa V. mobydick and V. yamagishii, our data indicate that full regression of limbs and eyes occurred in parallel twice in the genus Voeltzkowia (as hitherto defined) that we consider as a sand-swimming ecomorph: in the Voeltzkowia clade sensu stricto the regression first affected the hindlimbs and subsequently the forelimbs, whereas the Grandidierina clade first regressed the forelimbs and subsequently the hindlimbs following the pattern prevalent in squamates. Timetree reconstructions for the Malagasy Scincidae contain a substantial amount of uncertainty due to the absence of suitable primary fossil calibrations. However, our preliminary reconstructions suggest rapid limb regression in Malagasy scincids with an estimated maximal duration of 6 MYr for a complete regression in Paracontias, and 4 and 8 MYr respectively for complete regression of forelimbs in Grandidierina and hindlimbs in Voeltzkowia.

Non-decoupled morphological evolution of the fore- and hindlimb of sabretooth predators.

PubMed

Martín-Serra, Alberto; Figueirido, Borja; Palmqvist, Paul

2017-10-01

Specialized organisms are useful for exploring the combined effects of selection of functional traits and developmental constraints on patterns of phenotypic integration. Sabretooth predators are one of the most interesting examples of specialization among mammals. Their hypertrophied, sabre-shaped upper canines and their powerfully built forelimbs have been interpreted as adaptations to a highly specialized predatory behaviour. Given that the elongated and laterally compressed canines of sabretooths were more vulnerable to fracture than the shorter canines of conical-tooth cats, it has been long hypothesized that the heavily muscled forelimbs of sabretooths were used for immobilizing prey before developing a quick and precise killing bite. However, the effect of this unique adaptation on the covariation between the fore- and the hindlimb has not been explored in a quantitative fashion. In this paper, we investigate if the specialization of sabretooth predators decoupled the morphological variation of their forelimb with respect to their hindlimb or, in contrast, both limbs vary in the same fashion as in conical-tooth cats, which do not show such extreme adaptations in their forelimb. We use 3D geometric morphometrics and different morphological indices to compare the fore- and hindlimb of conical- and sabretooth predators. Our results indicate that the limb bones of sabretooth predators covary following the same trend of conical-tooth cats. Therefore, we show that the predatory specialization of sabretooth predators did not result in a decoupling of the morphological evolution of their fore- and hindlimbs. The role of developmental constraints and natural selection on this coordinate variation between the fore- and the hindlimb is discussed in the light of this new evidence. © 2017 Anatomical Society.

Use-dependent dendritic regrowth is limited after unilateral controlled cortical impact to the forelimb sensorimotor cortex.

PubMed

Jones, Theresa A; Liput, Daniel J; Maresh, Erin L; Donlan, Nicole; Parikh, Toral J; Marlowe, Dana; Kozlowski, Dorothy A

2012-05-01

Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3-28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI.

A new scenario of the evolutionary derivation of the mammalian diaphragm from shoulder muscles

PubMed Central

Hirasawa, Tatsuya; Kuratani, Shigeru

2013-01-01

The evolutionary origin of the diaphragm remains unclear, due to the lack of a comparable structure in other extant taxa. However, recent researches into the developmental mechanism of this structure have yielded new insights into its origin. Here we summarize current understanding regarding the development of the diaphragm, and present a possible scenario for the evolutionary acquisition of this uniquely mammalian structure. Recent developmental analyses indicate that the diaphragm and forelimb muscles are derived from a shared cell population during embryonic development. Therefore, the embryonic positions of forelimb muscle progenitors, which correspond to the position of the brachial plexus, likely played an important role in the evolution of the diaphragm. We surveyed the literature to reexamine the position of the brachial plexus among living amniotes and confirmed that the cervico-thoracic transition in ribs reflects the brachial plexus position. Using this osteological correlate, we concluded that the anterior borders of the brachial plexuses in the stem synapsids were positioned at the level of the fourth spinal nerve, suggesting that the forelimb buds were laid in close proximity of the infrahyoid muscles. The topology of the phrenic and suprascapular nerves of mammals is similar to that of subscapular and supracoracoid nerves, respectively, of the other amniotes, suggesting that the diaphragm evolved from a muscle positioned medial to the pectoral girdle (cf. subscapular muscle). We hypothesize that the diaphragm was acquired in two steps: first, forelimb muscle cells were incorporated into tissues to form a primitive diaphragm in the stem synapsid grade, and second, the diaphragm in cynodonts became entrapped in the region controlled by pulmonary development. PMID:23448284

Paleomagnetic and structural evidence for oblique slip in a fault-related fold, Grayback monocline, Colorado

USGS Publications Warehouse

Tetreault, J.; Jones, C.H.; Erslev, E.; Larson, S.; Hudson, M.; Holdaway, S.

2008-01-01

Significant fold-axis-parallel slip is accommodated in the folded strata of the Grayback monocline, northeastern Front Range, Colorado, without visible large strike-slip displacement on the fold surface. In many cases, oblique-slip deformation is partitioned; fold-axis-normal slip is accommodated within folds, and fold-axis-parallel slip is resolved onto adjacent strike-slip faults. Unlike partitioning strike-parallel slip onto adjacent strike-slip faults, fold-axis-parallel slip has deformed the forelimb of the Grayback monocline. Mean compressive paleostress orientations in the forelimb are deflected 15??-37?? clockwise from the regional paleostress orientation of the northeastern Front Range. Paleomagnetic directions from the Permian Ingleside Formation in the forelimb are rotated 16??-42?? clockwise about a bedding-normal axis relative to the North American Permian reference direction. The paleostress and paleomagnetic rotations increase with the bedding dip angle and decrease along strike toward the fold tip. These measurements allow for 50-120 m of fold-axis-parallel slip within the forelimb, depending on the kinematics of strike-slip shear. This resolved horizontal slip is nearly equal in magnitude to the ???180 m vertical throw across the fold. For 200 m of oblique-slip displacement (120 m of strike slip and 180 m of reverse slip), the true shortening direction across the fold is N90??E, indistinguishable from the regionally inferred direction of N90??E and quite different from the S53??E fold-normal direction. Recognition of this deformational style means that significant amounts of strike slip can be accommodated within folds without axis-parallel surficial faulting. ?? 2008 Geological Society of America.

Contralesional Axonal Remodeling of the Corticospinal System in Adult Rats After Stroke and Bone Marrow Stromal Cell Treatment

PubMed Central

Liu, Zhongwu; Li, Yi; Zhang, Xueguo; Savant-Bhonsale, Smita; Chopp, Michael

2008-01-01

Background and Purpose Motor recovery after stroke is associated with neuronal reorganization in bilateral hemispheres. We investigated contralesional corticospinal tract remodeling in the brain and spinal cord in rats after stroke and treatment of bone marrow stromal cells. Methods Adult male Wistar rats were subjected to permanent right middle cerebral artery occlusion. Phosphate-buffered saline or bone marrow stromal cells were injected into a tail vein 1 day postischemia. An adhesive removal test was performed weekly to monitor functional recovery. Threshold currents of intracortical microstimulation on the left motor cortex for evoking bilateral forelimb movements were measured 6 weeks after stroke. When intracortical microstimulation was completed, biotinylated dextran amine was injected into the left motor cortex to anterogradely label the corticospinal tract. At 4 days before euthanization, pseudorabies virus-152-EGFP and 614-mRFP were injected into left or right forelimb extensor muscles, respectively. All animals were euthanized 8 weeks after stroke. Results In normal rats (n=5), the corticospinal tract showed a unilateral innervation pattern. In middle cerebral artery occlusion rats (n=8), our data demonstrated that: 1) stroke reduced the stimulation threshold evoking ipsilateral forelimb movement; 2) EGFP-positive pyramidal neurons were increased in the left intact cortex, which were labeled from the left stroke-impaired forelimb; and 3) biotinylated dextran amine-labeled contralesional axons sprouted into the denervated spinal cord. Bone marrow stromal cells significantly enhanced all 3 responses (n=8, P<0.05). Conclusions Our data demonstrated that corticospinal tract fibers originating from the contralesional motor cortex sprout into the denervated spinal cord after stroke and bone marrow stromal cells treatment, which may contribute to functional recovery. PMID:18617661

Sake Protein Supplementation Affects Exercise Performance and Biochemical Profiles in Power-Exercise-Trained Mice

PubMed Central

Chen, Yi-Ming; Lin, Che-Li; Wei, Li; Hsu, Yi-Ju; Chen, Kuan-Neng; Huang, Chi-Chang; Kao, Chin-Hsung

2016-01-01

Exercise and fitness training programs have attracted the public’s attention in recent years. Sports nutrition supplementation is an important issue in the global sports market. Purpose: In this study, we designed a power exercise training (PET) program with a mouse model based on a strength and conditional training protocol for humans. We tested the effect of supplementation with functional branched-chain amino acid (BCAA)-rich sake protein (SP) to determine whether the supplement had a synergistic effect during PET and enhanced athletic performance and resistance to fatigue. Methods: Male ICR mice were divided into three groups (n = 8 per group) for four-week treatment: sedentary controls with vehicle (SC), and PET and PET groups with SP supplementation (3.8 g/kg, PET + SP). Exercise performance was evaluated by forelimb grip strength and exhaustive swimming time as well as changes in body composition and anti-fatigue activity levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after a 15-min swimming exercise. The biochemical parameters were measured at the end of the experiment. Results: four-week PET significantly increased grip strength and exhaustive swimming time and decreased epididymal fat pad (EFP) weight and area. Levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and uric acid (UA) were significantly increased. PET + SP supplementation significantly decreased serum lactate, ammonia and CK levels after the 15-min swimming exercise. The resting serum levels of AST, ALT, CREA and UA were all significantly decreased with PET + SP. Conclusion: The PET program could increase the exercise performance and modulate the body composition of mice. PET with SP conferred better anti-fatigue activity, improved biochemical profiles, and may be an effective ergogenic aid in strength training. PMID:26907336

Sake Protein Supplementation Affects Exercise Performance and Biochemical Profiles in Power-Exercise-Trained Mice.

PubMed

Chen, Yi-Ming; Lin, Che-Li; Wei, Li; Hsu, Yi-Ju; Chen, Kuan-Neng; Huang, Chi-Chang; Kao, Chin-Hsung

2016-02-20

Exercise and fitness training programs have attracted the public's attention in recent years. Sports nutrition supplementation is an important issue in the global sports market. In this study, we designed a power exercise training (PET) program with a mouse model based on a strength and conditional training protocol for humans. We tested the effect of supplementation with functional branched-chain amino acid (BCAA)-rich sake protein (SP) to determine whether the supplement had a synergistic effect during PET and enhanced athletic performance and resistance to fatigue. Male ICR mice were divided into three groups (n = 8 per group) for four-week treatment: sedentary controls with vehicle (SC), and PET and PET groups with SP supplementation (3.8 g/kg, PET + SP). Exercise performance was evaluated by forelimb grip strength and exhaustive swimming time as well as changes in body composition and anti-fatigue activity levels of serum lactate, ammonia, glucose, and creatine kinase (CK) after a 15-min swimming exercise. The biochemical parameters were measured at the end of the experiment. four-week PET significantly increased grip strength and exhaustive swimming time and decreased epididymal fat pad (EFP) weight and area. Levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and uric acid (UA) were significantly increased. PET + SP supplementation significantly decreased serum lactate, ammonia and CK levels after the 15-min swimming exercise. The resting serum levels of AST, ALT, CREA and UA were all significantly decreased with PET + SP. The PET program could increase the exercise performance and modulate the body composition of mice. PET with SP conferred better anti-fatigue activity, improved biochemical profiles, and may be an effective ergogenic aid in strength training.

Pumpkin (Cucurbita moschata) fruit extract improves physical fatigue and exercise performance in mice.

PubMed

Wang, Shih-Yi; Huang, Wen-Ching; Liu, Chieh-Chung; Wang, Ming-Fu; Ho, Chin-Shan; Huang, Wen-Pei; Hou, Chia-Chung; Chuang, Hsiao-Li; Huang, Chi-Chang

2012-10-09

Pumpkin (Cucurbita moschata) is a popular and nutritious vegetable consumed worldwide. The overall purpose of this study was to evaluate the effects of C. moschata fruit extract (CME) on anti-fatigue and ergogenic functions following physiological challenges. Male ICR mice from four groups designated vehicle, CME-50, CME-100 and CME-250, respectively (n = 8 per group in each test) were orally administered CME for 14 days at 0, 50, 100 and 250 mg/kg/day. The anti-fatigue activity and exercise performance were evaluated using exhaustive swimming time, forelimb grip strength, as well as levels of plasma lactate, ammonia, glucose, and creatine kinase after an acute swimming exercise. The resting muscular and hepatic glycogen was also analyzed after 14-day supplementation with CME. Trend analysis revealed that CME treatments increased grip strength. CME dose-dependently increased 5% body weight loaded swimming time, blood glucose, and muscular and hepatic glycogen levels. CME dose-dependently decreased plasma lactate and ammonia levels and creatine kinase activity after a 15-min swimming test. The mechanism was relevant to the increase in energy storage (as glycogen) and release (as blood glucose), and the decrease of plasma levels of lactate, ammonia, and creatine kinase. Therefore, CME may be potential for the pharmacological effect of anti-fatigue.

Effects of microRNA-21 on Nerve Cell Regeneration and Neural Function Recovery in Diabetes Mellitus Combined with Cerebral Infarction Rats by Targeting PDCD4.

PubMed

Guo, Yun-Bao; Ji, Tie-Feng; Zhou, Hong-Wei; Yu, Jin-Lu

2018-03-01

We aimed to determine the effect and mechanism of microRNA-21 (miR-21) on nerve cell regeneration and nerve functional recovery in diabetes mellitus combined with cerebral infarction (DM + CI) rats by targeting PDCD4. A total of 125 male Wistar rats were selected for DM + CI rat model construction and assigned into the blank, miR-21 mimics, mimics control, miR-21 inhibitor, inhibitor control, miR-21 inhibitor + si-PDCD4 and si-PDCD4 groups. And, 20 healthy rats were selected for the normal group. Triphenylterazolium chloride (TTC) staining and HE staining were used for determination of the area of CI and pathological changes, respectively. Behaviors of rats in the eight groups were determined by forelimb placement test and balance beam walking test. Immunohistochemical staining, double immunofluorescence staining assay, Western blotting, and qRT-PCR were used to detect expressions of miR-21, PDCD4, HNA, Nestin, NeuN, β-III-Tub, PTEN, FasL, and GFAP. DNA laddering and TUNEL staining was used for cell apoptosis. TTC and HE staining confirmed that 87.5% rats were induced into CI + DM models successfully. Results of forelimb placement test and balance beam walking test showed that miR-21 mimics, and si-PCDC4 improved the nerve defect of model rats. Comparing with the blank group at the same time, rats in the miR-21 inhibitor group displayed significant decrease in the forelimb placement test score, significant increase in the balance beam walking test score, and exacerbation of nerve defect, while rats in the miR-21 mimics and si-PCDC4 groups displayed significant increase in forelimb placement test score and significant decrease in the balance beam walking test score and improvement of nerve defect situation. The HNA, Nestin, and PDCD4 expressions were decreased and the NeuN, β-III-Tub, and GFAP expressions were increased in the miR-21 mimics and si-PDCD4 groups comparing with the blank group. The results of miR-21 inhibitor group were on the contrary. In comparison to the blank group, the miR-21 mimics group and the si-PDCD4 had lower miR-21 expressions and higher expressions of PDCD4, PTEN, and FasL, while the miR-21 inhibitor group was in the opposite trend. The results of qRT-PCR were the same with Western blotting. The expressions of fluorescence in other groups were higher than the normal group; compared with the blank group, the miR-21 mimics group and the si-PDCD4 group had lower fluorescence expression and DNA ladder. However, the fluorescence expressions and DNA ladder of miR-21 inhibitor group increased markedly in contrast with the blank group. Comparing with the blank group, BrdU + /DEX + fluorescence intensity significantly enhanced in the miR-21 mimics and si-PDCD4 groups and significantly reduced in the miR-21 inhibitor group. And, comparing with the blank group, in the miR-21 mimics group, the signal strength of luciferase carrying the wild-type PDCD4 was reduced by 25%. The present studies demonstrated that miR-21 could promote the nerve cell regeneration, suppress apoptosis of nerve cells in DM + CI rats and improves the nerve defect situation of DM + CI rats by inhibiting PDCD4.

Three-dimensional skeletal kinematics of the shoulder girdle and forelimb in walking Alligator

PubMed Central

Baier, David B; Gatesy, Stephen M

2013-01-01

Crocodylians occupy a key phylogenetic position for investigations of archosaur locomotor evolution. Compared to the well-studied hindlimb, relatively little is known about the skeletal movements and mechanics of the forelimb. In this study, we employed manual markerless XROMM (X-ray Reconstruction Of Moving Morphology) to measure detailed 3-D kinematics of the shoulder girdle and forelimb bones of American alligators (Alligator mississippiensis) walking on a treadmill. Digital models of the interclavicle, scapulocoracoid, humerus, radius and ulna were created using a 3-D laser scanner. Models were articulated and aligned to simultaneously recorded frames of fluoroscopic and standard light video to reconstruct and measure joint motion. Joint coordinate systems were established for the coracosternal, glenohumeral and elbow joints. Our analysis revealed that the limb joints only account for about half of fore/aft limb excursion; the remaining excursion results from shoulder girdle movements and lateral bending of the vertebral column. Considerable motion of each scapulocoracoid relative to the vertebral column is consistent with coracosternal mobility. The hemisellar design of the glenohumeral joint permits some additional translation, or sliding in the fore-aft plane, but this movement does not have much of an effect on the distal excursion of the bone. PMID:24102540

Diversion of the urine stream by surgical modification of the preputial ostium in a dog.

PubMed

Pavletic, Michael M; Brum, Douglas E

2009-11-01

A 1.4-year-old sexually intact male Standard Poodle was evaluated with a history of urinating on its left forelimb and lower portion of the thorax. Physical examination revealed that the dog had an unusually elevated (tucked) abdominal wall and prominent dome-shaped thoracic wall. These anatomic changes altered the angle of the urine stream, resulting in the dog's soiling the xiphoid region of the thorax and left forelimb. The dorsal half of the preputial ostium was closed surgically to divert the urine stream in a ventral direction. The ventral portion of the ostium was reciprocally enlarged. Postoperatively, the dog urinated in a downward direction, eliminating urine contact with the body. The preputial orifice (ostium) plays an important role in the shape and direction of the urine stream exiting the penile urethra. Dogs with an elevated abdominal wall and prominent dome-shaped thorax may be prone to contamination of the lower portion of the thorax and forelimbs with urine during normal micturition. Partial closure of the dorsal preputial ostium, with reciprocal enlargement of the lower half of the orifice, can create a deflective barrier that effectively diverts the urine stream in a ventral direction.

Targeted, activity-dependent spinal stimulation produces long-lasting motor recovery in chronic cervical spinal cord injury

PubMed Central

McPherson, Jacob G.; Miller, Robert R.; Perlmutter, Steve I.

2015-01-01

Use-dependent movement therapies can lead to partial recovery of motor function after neurological injury. We attempted to improve recovery by developing a neuroprosthetic intervention that enhances movement therapy by directing spike timing-dependent plasticity in spared motor pathways. Using a recurrent neural–computer interface in rats with a cervical contusion of the spinal cord, we synchronized intraspinal microstimulation below the injury with the arrival of functionally related volitional motor commands signaled by muscle activity in the impaired forelimb. Stimulation was delivered during physical retraining of a forelimb behavior and throughout the day for 3 mo. Rats receiving this targeted, activity-dependent spinal stimulation (TADSS) exhibited markedly enhanced recovery compared with animals receiving targeted but open-loop spinal stimulation and rats receiving physical retraining alone. On a forelimb reach and grasp task, TADSS animals recovered 63% of their preinjury ability, more than two times the performance level achieved by the other therapy groups. Therapeutic gains were maintained for 3 additional wk without stimulation. The results suggest that activity-dependent spinal stimulation can induce neural plasticity that improves behavioral recovery after spinal cord injury. PMID:26371306

[Tenotomy of carpal and digital flexor tendons for correction of congenital neuromyodysplasia in a calf].

PubMed

Sohrt, J T; Heppelmann, M; Rehage, J; Staszyk, C

2013-01-01

In a 7-day-old heifer calf, a bilateral flexural deformity of the forelimbs involving the digital flexor tendons, the suspensory ligament and the ulnar and radial carpal flexor tendons was diagnosed. After 2 weeks of conservative treatment consisting of manual stretching of the legs and the application of splints and wooden blocks, which were glued to the soles and extended beyond the tip of the claws, the right forelimb could be extended sufficiently to allow weight bearing, whereas the left forelimb could be passively extended to only approximately 120°. Therefore, tenotomy of the ulnar carpal flexor tendon, the digital flexor tendons and the suspensory ligament was carried out in the left leg. A support bandage was then applied to the leg for 8 weeks, after which the carpus and fetlock could be completely extended passively. Flexural deformity of the carpus caused by contracture of the carpal flexor tendons was treated by means of a tenotomy of the ulnar carpal flexor tendon proximal to the accessory carpal bone, which allowed preservation of the carpal tunnel and avoided the risk of iatrogenic damage to nerves and the carpal joint capsule.

Ultrasonographic assessment of the proximal digital annular ligament in the equine forelimb.

PubMed

Dik, K J; Boroffka, S; Stolk, P

1994-01-01

Ultrasonography was used with 6 normal cadaver forelimbs of Dutch Warmblood horses to delineate the ultrasonographic anatomy of the palmar pastern region, with emphasis on the proximal digital annular ligament. Using a 5.5 MHz sector scanner, the thin proximal digital annular ligament was not visible on offset sonograms. Only if the digital sheath in the normal limb was distended was the distal border of this ligament outlined. In all normal limbs the palmarodistal thickness of the combined skin-proximal digital annular ligament layer in the mid-pastern region was 2 mm. The flexor tendons and distal sesamoidean ligaments were easily identified as hyperechoic structures. Distension of the digital sheath in the normal limbs clearly outlined the anechoic digital sheath pouches. In 4 lame horses ultrasonography aided the diagnosis of functional proximal digital annular ligament constriction. In all 4 diseased forelimbs ultrasonography demonstrated thickening of the skin-proximal digital annular ligament layer and distension of the digital sheath. In one of these limbs the distended digital sheath was also thickened. The flexor tendons and distal sesamoidean ligaments were normal. There was no radiographic evidence of additional bone or joint lesions.

Heterochrony in the regulation of the developing marsupial limb.

PubMed

Chew, Keng Yih; Shaw, Geoffrey; Yu, Hongshi; Pask, Andrew J; Renfree, Marilyn B

2014-02-01

At birth, marsupial neonates have precociously developed forelimbs. The development of the tammar wallaby (Macropus eugenii) hindlimbs lags significantly behind that of the forelimbs. This differs from the grey short-tailed opossum, Monodelphis domestica, which has relatively similar fore- and hindlimbs at birth. This study examines the expression of the key patterning genes TBX4, TBX5, PITX1, FGF8, and SHH in developing limb buds in the tammar wallaby. All genes examined were highly conserved with orthologues from opossum and mouse. TBX4 expression appeared earlier in development than in the mouse, but later than in the opossum. SHH expression is restricted to the zone of polarising activity, while TBX5 (forelimb) and PITX1 (hindlimb) showed diffuse mRNA expression. FGF8 is specifically localised to the apical ectodermal ridge, which is more prominent than in the opossum. The most marked divergence in limb size in marsupials occurs in the kangaroos and wallabies. The faster development of the fore limb compared to that of the hind limb correlates with the early timing of the expression of the key patterning genes in these limbs. Copyright © 2013 Wiley Periodicals, Inc.

Neuronal Correlates of Functional Coupling between Reach- and Grasp-Related Components of Muscle Activity

PubMed Central

Geed, Shashwati; McCurdy, Martha L.; van Kan, Peter L. E.

2017-01-01

Coordinated reach-to-grasp movements require precise spatiotemporal synchrony between proximal forelimb muscles (shoulder, elbow) that transport the hand toward a target during reach, and distal muscles (wrist, digit) that simultaneously preshape and orient the hand for grasp. The precise mechanisms through which the redundant neuromuscular circuitry coordinates reach with grasp, however, remain unclear. Recently, Geed and Van Kan (2016) demonstrated, using exploratory factor analysis (EFA), that limited numbers of global, template-like transport/preshape- and grasp-related muscle components underlie the complexity and variability of intramuscular electromyograms (EMGs) of up to 21 distal and proximal muscles recorded while monkeys performed reach-to-grasp tasks. Importantly, transport/preshape- and grasp-related muscle components showed invariant spatiotemporal coupling, which provides a potential mechanism for coordinating forelimb muscles during reach-to-grasp movements. In the present study, we tested whether ensemble discharges of forelimb neurons in the cerebellar nucleus interpositus (NI) and its target, the magnocellular red nucleus (RNm), a source of rubrospinal fibers, function as neuronal correlates of the transport/preshape- and grasp-related muscle components we identified. EFA applied to single-unit discharges of populations of NI and RNm neurons recorded while the same monkeys that were used previously performed the same reach-to-grasp tasks, revealed neuronal components in the ensemble discharges of both NI and RNm neuronal populations with characteristics broadly similar to muscle components. Subsets of NI and RNm neuronal components were strongly and significantly crosscorrelated with subsets of muscle components, suggesting that similar functional units of reach-to-grasp behavior are expressed by NI and RNm neuronal populations and forelimb muscles. Importantly, like transport/preshape- and grasp-related muscle components, their NI and RNm neuronal correlates showed invariant spatiotemporal coupling. Clinical and lesion studies have reported disruption of coupling between reach and grasp following cerebellar damage; the present results expand on those studies by identifying a neuronal mechanism that may underlie cerebellar contributions to spatiotemporal coordination of distal and proximal limb muscles during reaching to grasp. We conclude that finding similar functional units of behavior expressed at multiple levels of information processing along interposito-rubrospinal pathways and forelimb muscles supports the hypothesis that functionally related populations of NI and RNm neurons act synergistically in the control of complex coordinated motor behaviors. PMID:28270752

The effect of airflow on thermographically determined temperature of the distal forelimb of the horse.

PubMed

Westermann, S; Stanek, C; Schramel, J P; Ion, A; Buchner, H H F

2013-09-01

Current literature suggests that thermographic imaging of horses should be performed in a draught-free room. However, studies on the effect of airflow on determined temperature have not been published. To investigate effects of airflow on thermographically determined temperature of horses' forelimbs; to assess the relationship of wind velocity, rectal temperature, ambient temperature and humidity. Thermographic images were obtained for the forelimbs of 6 horses in a draught-free room. Three replicates (R) with defined wind velocities (R1, 0.5-1.0 m/s; R2, 1.3-2.6 m/s; and R3, 3.0-4.0 m/s) were conducted. Each replicate consisted of a baseline image, a 15 min phase with the wind on and a 15 min phase with the wind off. We exposed only the right leg to airflow and determined the temperature by thermography with the wind on and wind off. Temperature differences between baseline and wind on, between wind on and wind off and between different wind velocities were analysed by a general linear model, Student's paired t test and ANOVA. After the onset of wind, the temperature on the right forelimb decreased within 1-3 min (by approximately 0.6°C at R1, 1.5°C at R2 and 2.1°C at R3). With the wind off, the temperature increased within 3 min (by approximately 1.2°C at R1, 1.7°C at R2 and 2.1°C at R3). With increasing wind velocity, the temperature differences between baseline and wind on and between wind on and wind off increased significantly. Barely noticeable wind velocities caused a decrease in thermographically determined temperatures of the forelimbs of the horse. Further research is required to assess the influence of airflow on other parts of the body and at different ambient temperatures, as well as the effect on horses with inflammatory lesions, especially of the distal limbs. It is essential for practitioners to perform thermography on horses in a draught-free environment in order to avoid false-positive or -negative diagnoses. © 2012 EVJ Ltd.

THE RESPONSE OF X-IRRADIATED LIMBS OF ADULT URODELES TO NORMAL TISSUE GRAFTS. I. EFFECTS OF AUTOGRAFTS OF SIXTY-DAY FOREARM REGENERATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stinson, B.D.

1963-06-01

Results are reported of autoplastic transplantation of parts of nonirradiated, regenerated forelimb to the contralateral x-irradiated forelimb in adult Triturus viridescens. The right forelimbs were exposed to various doses of localized irradiation (1000 to 5000 r) followed by amputation of both left and right forelimbs through the mid forearm. Left limbs regenerated normally, but irradiated right limbs failed to exhibit any significant degree of regenerative activity over a 3-month period. Both forelimbs were reamputated through the distal humerus and observed for an additional two months. Left limbs produced normal regenerates, but irradiated right limbs gave no gross evidence of regenerationmore » at any of the radiation dose levels. Normal left regenerates were reamputated immediately distal to the elbow on the 60th day after the second amputation; the severed forearm was trimmed with scissors along anterior and posterior borders and denuded of skin over its proximal half, leaving an essentially complete forearm region as a normal autograft. This was implanted into the irradiated right upper arm stump, after ablation of the distal half of its humerus, with normal proximodistal polarity in all cases. The irradiated stump was reamputated through the distal portion of the implanted normal autograft two weeks after implantation, and was observed for four months. Periodic gross observations showed that over 90% of irradiated upper arms formed regenerates at a rate which paralleled that of nonirradiated controls. However, regenerates formed on irradiated upper arms exhibited a restriction of morphogenetic capacity, only 60% attaining 3- and 4-digit stages. Most of the morphologically more complex regenerates which developed on the irradiated upper arm stumps manifested left limb asymmetry despite their formation on right irradiated stumps, suggesting a relation between the asymmetry of the normal graft and that of the resulting regenerate. All regenerates which developed on irradiated upper arms showed marked deficiencies in the restoration of a complete proximodistal structural pattern appropriate to the level of amputation through the irradiated stump. However, the actual pattern produced was appropriate to the level of amputation through the implanted normal autograft. These findings support the hypothesis that normal grafts promote the formation of regenerates on irradiated limbs through the autonomous developmental activity of the transected graft. (BBB)« less

Exceptional high fatigue strength in Cu-15at.%Al alloy with moderate grain size

PubMed Central

Liu, Rui; Tian, Yanzhong; Zhang, Zhenjun; An, Xianghai; Zhang, Peng; Zhang, Zhefeng

2016-01-01

It is commonly proposed that the fatigue strength can be enhanced by increasing the tensile strength, but this conclusion needs to be reconsidered according to our study. Here a recrystallized α-Cu-15at.%Al alloy with moderate grain size of 0.62 μm was fabricated by cold rolling and annealing, and this alloy achieved exceptional high fatigue strength of 280 MPa at 107 cycles. This value is much higher than the fatigue strength of 200 MPa for the nano-crystalline counterpart (0.04 μm in grain size) despite its higher tensile strength. The remarkable improvement of fatigue strength should be mainly attributed to the microstructure optimization, which helps achieve the reduction of initial damage and the dispersion of accumulated damage. A new strategy of “damage reduction” was then proposed for fatigue strength improvement, to supplement the former strengthening principle. The methods and strategies summarized in this work offer a general pathway for further improvement of fatigue strength, in order to ensure the long-term safety of structural materials. PMID:27264347

Hydrogen-enabled microstructure and fatigue strength engineering of titanium alloys

NASA Astrophysics Data System (ADS)

Paramore, James D.; Fang, Zhigang Zak; Dunstan, Matthew; Sun, Pei; Butler, Brady G.

2017-02-01

Traditionally, titanium alloys with satisfactory mechanical properties can only be produced via energy-intensive and costly wrought processes, while titanium alloys produced using low-cost powder metallurgy methods consistently result in inferior mechanical properties, especially low fatigue strength. Herein, we demonstrate a new microstructural engineering approach for producing low-cost titanium alloys with exceptional fatigue strength via the hydrogen sintering and phase transformation (HSPT) process. The high fatigue strength presented in this work is achieved by creating wrought-like microstructures without resorting to wrought processing. This is accomplished by generating an ultrafine-grained as-sintered microstructure through hydrogen-enabled phase transformations, facilitating the subsequent creation of fatigue-resistant microstructures via simple heat treatments. The exceptional strength, ductility, and fatigue performance reported in this paper are a breakthrough in the field of low-cost titanium processing.

Hydrogen-enabled microstructure and fatigue strength engineering of titanium alloys

DOE PAGES

Paramore, James D.; Fang, Zhigang Zak; Dunstan, Matthew; ...

2017-02-01

Traditionally, titanium alloys with satisfactory mechanical properties can only be produced via energy-intensive and costly wrought processes, while titanium alloys produced using low-cost powder metallurgy methods consistently result in inferior mechanical properties, especially low fatigue strength. Herein, we demonstrate a new microstructural engineering approach for producing low-cost titanium alloys with exceptional fatigue strength via the hydrogen sintering and phase transformation (HSPT) process. The high fatigue strength presented in this work is achieved by creating wroughtlike microstructures without resorting to wrought processing. This is accomplished by generating an ultrafine-grained as-sintered microstructure through hydrogen-enabled phase transformations, facilitating the subsequent creation of fatigue-resistantmore » microstructures via simple heat treatments. Finally, the exceptional strength, ductility, and fatigue performance reported in this paper are a breakthrough in the field of low-cost titanium processing.« less

Hydrogen-enabled microstructure and fatigue strength engineering of titanium alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paramore, James D.; Fang, Zhigang Zak; Dunstan, Matthew

Traditionally, titanium alloys with satisfactory mechanical properties can only be produced via energy-intensive and costly wrought processes, while titanium alloys produced using low-cost powder metallurgy methods consistently result in inferior mechanical properties, especially low fatigue strength. Herein, we demonstrate a new microstructural engineering approach for producing low-cost titanium alloys with exceptional fatigue strength via the hydrogen sintering and phase transformation (HSPT) process. The high fatigue strength presented in this work is achieved by creating wroughtlike microstructures without resorting to wrought processing. This is accomplished by generating an ultrafine-grained as-sintered microstructure through hydrogen-enabled phase transformations, facilitating the subsequent creation of fatigue-resistantmore » microstructures via simple heat treatments. Finally, the exceptional strength, ductility, and fatigue performance reported in this paper are a breakthrough in the field of low-cost titanium processing.« less

Hydrogen-enabled microstructure and fatigue strength engineering of titanium alloys

PubMed Central

Paramore, James D.; Fang, Zhigang Zak; Dunstan, Matthew; Sun, Pei; Butler, Brady G.

2017-01-01

Traditionally, titanium alloys with satisfactory mechanical properties can only be produced via energy-intensive and costly wrought processes, while titanium alloys produced using low-cost powder metallurgy methods consistently result in inferior mechanical properties, especially low fatigue strength. Herein, we demonstrate a new microstructural engineering approach for producing low-cost titanium alloys with exceptional fatigue strength via the hydrogen sintering and phase transformation (HSPT) process. The high fatigue strength presented in this work is achieved by creating wrought-like microstructures without resorting to wrought processing. This is accomplished by generating an ultrafine-grained as-sintered microstructure through hydrogen-enabled phase transformations, facilitating the subsequent creation of fatigue-resistant microstructures via simple heat treatments. The exceptional strength, ductility, and fatigue performance reported in this paper are a breakthrough in the field of low-cost titanium processing. PMID:28145527

Strengths-Based Education: Probing Its Limits. The Cutting Edge

ERIC Educational Resources Information Center

Clabaugh, Gary K.

2005-01-01

Except for Timothy Hodges and James Harter's restrained research summary, the feature articles in this issue are evangelical in their praise of strengths-based education. It is, they assure us, a major innovation. English teacher Alexis Onishi writes that StrengthsQuest, a specific strengths-based approach, will have "a lifelong impact on how…

Association of physical performance and biochemical profile of mice with intrinsic endurance swimming.

PubMed

Huang, Wen-Ching; Hsu, Yi-Ju; Wei, Li; Chen, Ying-Ju; Huang, Chi-Chang

2016-01-01

We aimed to investigate the potential mediators and relationship affecting congenital exercise performance in an animal model with physical activity challenge from physiological and biochemical perspectives. A total of 75 male ICR mice (5 weeks old) were adapted for 1 week, then mice performed a non-loading and exhaustive swimming test and were assigned to 3 groups by exhaustive swimming time: low exercise capacity (LEC) (<3 hr), medium exercise capacity (MEC) (3-5 hr), and high exercise capacity (HEC) (>5 hr). After a 1-week rest, the 3 groups of mice performed an exhaustive swimming test with a 5% and 7.5% weight load and a forelimb grip-strength test, with a 1-week rest between tests. Blood samples were collected immediately after an acute exercise challenge and at the end of the experiment (resting status) to evaluate biochemical blood variables and their relation with physical performance. Physical activity, including exhaustive swimming and grip strength, was greater for HEC than other mice. The swimming performance and grip strength between groups were moderately correlated (r=0.443, p <0.05). Resting serum ammonium level was moderately correlated with endurance with a 7.5% weight load (r=-0.447, p <0.05) and with lactate level (r=0.598, p <0.05). The pulmonary morphology of the HEC group seemed to indicate benefits for aerobic exercise. Mice showed congenital exercise performance, which was significantly correlated with different physical challenges and biochemical variable values. This study may have implications for interference in intrinsic characteristics.

Slow Physical Growth, Delayed Reflex Ontogeny, and Permanent Behavioral as Well as Cognitive Impairments in Rats Following Intra-generational Protein Malnutrition

PubMed Central

Naik, Aijaz A.; Patro, Ishan K.; Patro, Nisha

2015-01-01

Environmental stressors including protein malnutrition (PMN) during pre-, neo- and post-natal age have been documented to affect cognitive development and cause increased susceptibility to neuropsychiatric disorders. Most studies have addressed either of the three windows and that does not emulate the clinical conditions of intra-uterine growth restriction (IUGR). Such data fail to provide a complete picture of the behavioral alterations in the F1 generation. The present study thus addresses the larger window from gestation to F1 generation, a new model of intra-generational PMN. Naive Sprague Dawley (SD) dams pre-gestationally switched to LP (8% protein) or HP (20% protein) diets for 45 days were bred and maintained throughout gestation on same diets. Pups born (HP/LP dams) were maintained on the respective diets post-weaningly. The present study aimed to show the sex specific differences in the neurobehavioral evolution and behavioral phenotype of the HP/LP F1 generation pups. A battery of neurodevelopmental reflex tests, behavioral (Open field and forelimb gripstrength test), and cognitive [Elevated plus maze (EPM) and Morris water maze (MWM)] assays were performed. A decelerated growth curve with significantly restricted body and brain weight, delays in apparition of neuro-reflexes and poor performance in the LP group rats was recorded. Intra-generational PMN induced poor habituation-with-time in novel environment exploration, low anxiety and hyperactive like profile in open field test in young and adult rats. The study revealed poor forelimb neuromuscular strength in LP F1 pups till adulthood. Group occupancy plots in MWM test revealed hyperactivity with poor learning, impaired memory retention and integration, thus modeling the signs of early onset Alzehemier phenotype. In addition, a gender specific effect of LP diet with severity in males and favoring female sex was also noticed. PMID:26696810

African American Therapists Working with African American Families: An Exploration of the Strengths Perspective in Treatment

ERIC Educational Resources Information Center

Bell-Tolliver, Laverne; Burgess, Ruby; Brock, Linda J.

2009-01-01

With the exception of Hill's (1971, 1999) work, historically much of the literature on African American families has focused more on pathology than strengths. This study used interviews with 30 African American psychotherapists, self-identified as employing a strengths perspective with African American families, to investigate which strengths they…

Progressive evolution of deformation band populations during Laramide fault-propagation folding: Navajo Sandstone, San Rafael monocline, Utah, U.S.A.

NASA Astrophysics Data System (ADS)

Zuluaga, Luisa F.; Fossen, Haakon; Rotevatn, Atle

2014-11-01

Monoclinal fault propagation folds are a common type of structure in orogenic foreland settings, particularly on the Colorado Plateau. We have studied a portion of the San Rafael monocline, Utah, assumed to have formed through pure thrust- or reverse-slip (blind) fault movement, and mapped a particular sequence of subseismic cataclastic deformation structures (deformation bands) that can be related in terms of geometry, density and orientation to the dip of the forelimb or fold interlimb angle. In simple terms, deformation bands parallel to bedding are the first structures to form, increasing exponentially in number as the forelimb gets steeper. At about 30° rotation of the forelimb, bands forming ladder structures start to cross-cut bedding, consolidating themselves into a well-defined and regularly spaced network of deformation band zones that rotate with the layering during further deformation. In summary, we demonstrate a close relationship between limb dip and deformation band density that can be used to predict the distribution and orientation of such subseismic structures in subsurface reservoirs of similar type. Furthermore, given the fact that these cataclastic deformation bands compartmentalize fluid flow, this relationship can be used to predict or model fluid flow across and along comparable fault-propagation folds.

Motor cortex stimulation does not lead to functional recovery after experimental cortical injury in rats.

PubMed

Schönfeld, Lisa-Maria; Jahanshahi, Ali; Lemmens, Evi; Bauwens, Matthias; Hescham, Sarah-Anna; Schipper, Sandra; Lagiere, Melanie; Hendrix, Sven; Temel, Yasin

2017-01-01

Motor impairments are among the major complications that develop after cortical damage caused by either stroke or traumatic brain injury. Motor cortex stimulation (MCS) can improve motor functions in animal models of stroke by inducing neuroplasticity. In the current study, the therapeutic effect of chronic MCS was assessed in a rat model of severe cortical damage. A controlled cortical impact (CCI) was applied to the forelimb area of the motor cortex followed by implantation of a flat electrode covering the lesioned area. Forelimb function was assessed using the Montoya staircase test and the cylinder test before and after a period of chronic MCS. Furthermore, the effect of MCS on tissue metabolism and lesion size was measured using [18F]-fluorodesoxyglucose (FDG) μPET scanning. CCI caused a considerable lesion at the level of the motor cortex and dorsal striatum together with a long-lasting behavioral phenotype of forelimb impairment. However, MCS applied to the CCI lesion did not lead to any improvement in limb functioning when compared to non-stimulated control rats. Also, MCS neither changed lesion size nor distribution of FDG. The use of MCS as a standalone treatment did not improve motor impairments in a rat model of severe cortical damage using our specific treatment modalities.

Cerebellar Modulation of Cortically Evoked Complex Movements in Rats.

PubMed

Viaro, Riccardo; Bonazzi, Laura; Maggiolini, Emma; Franchi, Gianfranco

2017-07-01

Intracortical microstimulation (ICMS) delivered to the motor cortex (M1) via long- or short-train duration (long- or short-duration ICMS) can evoke coordinated complex movements or muscle twitches, respectively. The role of subcortical cerebellar input in M1 output, in terms of long- and short-duration ICMS-evoked movement and motor skill performance, was evaluated in rats with bilateral lesion of the deep cerebellar nuclei. After the lesion, distal forelimb movements were seldom observed, and almost 30% of proximal forelimb movements failed to match criteria defining the movement class observed under control conditions. The classifiable movements could be evoked in different cortical regions with respect to control and many kinematic variables were strongly affected. Furthermore, movement endpoints within the rat's workspace shrunk closer to the body, while performance in the reaching/grasping task worsened. Surprisingly, neither the threshold current values for evoking movements nor the overall size of forelimb movement representation changed with respect to controls in either long- or short-duration ICMS. We therefore conclude that cerebellar input via the motor thalamus is crucial for expressing the basic functional features of the motor cortex. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Mesodermal and neuronal retinoids regulate the induction and maintenance of limb innervating spinal motor neurons.

PubMed

Ji, Sheng-Jian; Zhuang, BinQuan; Falco, Crystal; Schneider, André; Schuster-Gossler, Karin; Gossler, Achim; Sockanathan, Shanthini

2006-09-01

During embryonic development, the generation, diversification and maintenance of spinal motor neurons depend upon extrinsic signals that are tightly regulated. Retinoic acid (RA) is necessary for specifying the fates of forelimb-innervating motor neurons of the Lateral Motor Column (LMC), and the specification of LMC neurons into medial and lateral subtypes. Previous studies implicate motor neurons as the relevant source of RA for specifying lateral LMC fates at forelimb levels. However, at the time of LMC diversification, a significant amount of retinoids in the spinal cord originates from the adjacent paraxial mesoderm. Here we employ mouse genetics to show that RA derived from the paraxial mesoderm is required for lateral LMC induction at forelimb and hindlimb levels, demonstrating that mesodermally synthesized RA functions as a second source of signals to specify lateral LMC identity. Furthermore, reduced RA levels in postmitotic motor neurons result in a decrease of medial and lateral LMC neurons, and abnormal axonal projections in the limb; invoking additional roles for neuronally synthesized RA in motor neuron maintenance and survival. These findings suggest that during embryogenesis, mesodermal and neuronal retinoids act coordinately to establish and maintain appropriate cohorts of spinal motor neurons that innervate target muscles in the limb.

Effects of Electric Shock on Respiration in the Rabbit*

PubMed Central

Lee, W. R.; Zoledziowski, S.

1964-01-01

Death from electric shock has been investigated on and off for just over 200 years. By the turn of the present century the three main methods of immediate death had been described. They are tetanic contraction of the respiratory muscles, ventricular fibrillation, and respiratory arrest. Since then there has been controversy over the relative importance of the last two as modes of death. For over half a century the first-aid treatment advised has been artificial respiration, based on the assumption that respiratory arrest is common in the usual limb to limb shock. The evidence for this assumption is reviewed and found to be open to question. An experimental investigation of the effect of forelimb to forelimb electric shock on respiration in rabbits has shown that, with currents up to about 200 mA, respiratory arrest appears to be due solely to muscular contraction. Larger currents produce respiratory arrest, usually followed by a delay before spontaneous resumption of respiration. The experimental currents have been taken up to 1 ampere, and at this level they resulted in considerable heating of the tissues. This resulted in marked macroscopic and histological changes in the forelimbs, despite which the animal breathed again spontaneously if ventricular fibrillation had not occurred. Images PMID:14142518

Fetlock joint kinematics differ with age in Thoroughbred [was thoroughbred] racehorses.

PubMed

Butcher, Michael T; Ashley-Ross, M A

2002-05-01

Fetlock joint kinematics during galloping in 2-, 3-, 4-, and 5-year-old Thoroughbreds in race training were quantified to determine if differences due to age could account for the observation that 2-year old Thoroughbred racehorses incur a high number of injuries to the bones and soft tissues in the distal forelimbs during training and at the outset of racing. Twelve Thoroughbred racehorses were videotaped in the sagittal plane at 250 frames/s during their daily galloping workout on a 7/8 mile sand-surface training track. Four galloping strides were recorded for each horse and subsequently digitized to determine fetlock joint angles of the leading forelimb during the limb support period of a stride. Four kinematic variables were measured from each stride's angular profile: angle of fetlock joint dorsi-flexion at mid-stance, negative angular velocity, positive angular velocity and time from hoof impact to mid-stance phase of limb support. The 2-year old Thoroughbreds had significantly quicker rates of dorsi-flexion of their fetlock joints than 3- (p=0.01), 4- (p=0.01), and 5-year old (p<0.01) Thoroughbreds following impact of the leading forelimb during moderate galloping (avg. 14 m/s). Higher rates of dorsi-flexion in young Thoroughbreds may reflect immaturity (lack of stiffness) of the suspensory apparatus tissues.

The effect of caloric restriction on the forelimb skeletal muscle fibers of the hypertrophic myostatin null mice.

PubMed

Elashry, Mohamed I; Matsakas, Antonios; Wenisch, Sabine; Arnhold, Stefan; Patel, Ketan

2017-06-01

Skeletal muscle mass loss has a broad impact on body performance and physical activity. Muscle wasting occurs due to genetic mutation as in muscular dystrophy, age-related muscle loss (sarcopenia) as well as in chronic wasting disorders as in cancer cachexia. Food restriction reduces muscle mass underpinned by increased muscle protein break down. However the influence of dietary restriction on the morphometry and phenotype of forelimb muscles in a genetically modified myostatin null mice are not fully characterized. The effect of a five week dietary limitation on five anatomically and structurally different forelimb muscles was examined. C57/BL6 wild type (Mstn +/+ ) and myostatin null (Mstn -/- ) mice were either given a standard rodent normal daily diet ad libitum (ND) or 60% food restriction (FR) for a 5 week period. M. triceps brachii Caput laterale (T.lateral), M. triceps brachii Caput longum (T.long), M. triceps brachii Caput mediale (T.medial), M. extensor carpi ulnaris (ECU) and M. flexor carpi ulnaris (FCU) were dissected, weighted and processed for immunohistochemistry. Muscle mass, fibers cross sectional areas (CSA) and myosin heavy chain types IIB, IIX, IIA and type I were analyzed. We provide evidence that caloric restriction results in muscle specific weight reduction with the fast myofibers being more prone to atrophy. We show that slow fibers are less liable to dietary restriction induced muscle atrophy. The effect of dietary restriction was more pronounced in Mstn -/- muscles to implicate the oxidative fibers compared to Mstn +/+ . Furthermore, peripherally located myofibers are more susceptible to dietary induced reduction compared to deep fibers. We additionally report that dietary restriction alters the glycolytic phenotype of the Mstn -/- into the oxidative form in a muscle dependent manner. In summary our study shows that calorie restriction alters muscle fiber profile of forelimb muscles of Myostatin null mice. Copyright © 2017 Elsevier GmbH. All rights reserved.

Functional plasticity in the interposito-thalamo-cortical pathway during conditioning. Role of the interstimulus interval.

PubMed

Pananceau, M; Rispal-Padel, L

2000-06-01

In classic conditioning, the interstimulus interval (ISI) between the conditioned (CS) and unconditioned (US) stimulus is a critical parameter. The aim of the present experiment was to assess whether, during conditioning, modification of the CS-US interval could reliably produce changes in the functional properties of the interposito-thalamo-cortical pathways (INTCps). Five cats were prepared for chronic stimulation and recording from several brain regions along this pathway in awake animals. The CS was a weak electric shock applied on the interposed nucleus of the cerebellum in sites that initially elicited forelimb flexion (i.e., alpha motor responses) in three cats, and equal proportions of flexor and extensor responses in two cats. The US was an electric shock applied on the skin that elicited forelimb flexions. The motor and neurobiological effects of synchronous CS-US were compared with pairings in which the CS was applied 100 ms before US. Simultaneous and sequential application of CS and US produced different behavioral outcomes and resulted in different neural processes in the interposito-thalamo-cortical pathways (INTCps). The simultaneous presentation of stimuli only produced a small increase in excitability spreading to all the body representational zones of the primary motor cortex and a weak increase in the amplitude of the alpha motor response. In contrast, the sequential application led to a profound modification of the interposed output to neurons in the forelimb representation of the motor cortex. These robust neuronal correlates of conditioning were accompanied by a large facilitation of the alpha motor response (alpha-MR). There were also changes in the direction of misdirected alpha responses and an emergence of functionally appropriate, long-latency withdrawal forelimb flexion. These data revealed that, during conditioning, plastic changes within the thalamocortical connections are selectively induced by sequential information from central and peripheral afferents. This sequence significantly contributed to neural processes that are responsible for the acquisition, expression, and extinction of anticipatory flexion responses.

Combined SCI and TBI: Recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement

PubMed Central

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L.; Creasey, Graham H.; Manley, Geoffrey T.; Ferguson, Adam R.; Bresnahan, Jacqueline C.; Beattie, Michael S.

2015-01-01

A significant proportion (estimates range from 16–74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI + TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6 weeks, in the paw placement test, SCI + contralateral TBI produced a profound deficit that failed to recover, but SCI + ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI + contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI + contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. PMID:23770071

Combined SCI and TBI: recovery of forelimb function after unilateral cervical spinal cord injury (SCI) is retarded by contralateral traumatic brain injury (TBI), and ipsilateral TBI balances the effects of SCI on paw placement.

PubMed

Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L; Creasey, Graham H; Manley, Geoffrey T; Ferguson, Adam R; Bresnahan, Jacqueline C; Beattie, Michael S

2013-10-01

A significant proportion (estimates range from 16 to 74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI+TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6weeks, in the paw placement test, SCI+contralateral TBI produced a profound deficit that failed to recover, but SCI+ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI+contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI+contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. Copyright © 2013 Elsevier Inc. All rights reserved.

14 CFR 31.25 - Factor of safety.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: MANNED FREE BALLOONS Strength Requirements § 31.25 Factor of safety. (a) Except as specified in... of temperature, and other operating characteristics, or both, that may affect strength of the balloon...

A technique for magnetic resonance imaging of equine cadaver specimens.

PubMed

Widmer, W R; Buckwalter, K A; Hill, M A; Fessler, J F; Ivancevich, S

1999-01-01

We tested an adaptation of a technique for performing magnetic resonance (MR) imaging of human cadaver limbs in the horse. The forelimbs from a normal horse were collected, frozen, and sealed with a paraffin-polymer combination prior to imaging with either a high- or midfield magnetic resonance scanner. Each forelimb was defrosted, scanned, and refrozen on two separate occasions. A five-point scale was used to evaluate the quality of each set of sagittal and transverse, T1-weighted images of each digit. There was no difference in image quality between first and second scans of either specimen (p > 0.05). We conclude that this technique allows investigators to bank tissue specimens for future magnetic resonance imaging without significant loss of image quality.

Learned movements elicited by direct stimulation of cerebellar mossy fiber afferents.

PubMed

Hesslow, G; Svensson, P; Ivarsson, M

1999-09-01

Definitive evidence is presented that the conditioned stimulus (CS) in classical conditioning reaches the cerebellum via the mossy fiber system. Decerebrate ferrets received paired forelimb and periocular stimulation until they responded with blinks to the forelimb stimulus. When direct mossy fiber stimulation was then given, the animals responded with conditioned blinks immediately, that is, without ever having been trained to the mossy fiber stimulation. Antidromic activation was prevented by blocking mossy fibers with lignocaine ventral to the stimulation site. It could be excluded that cerebellar output functioned as the CS. Analysis of latencies suggests that conditioned responses (CRs) are not generated by mossy fiber collaterals to the deep nuclei. Hence, the memory trace is probably located in the cerebellar cortex.

46 CFR 129.410 - Lighting fixtures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... fixture must have a high-strength guard or be made of high-strength material, except in accommodations... Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the general marine requirements...

46 CFR 129.410 - Lighting fixtures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... fixture must have a high-strength guard or be made of high-strength material, except in accommodations... Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the general marine requirements...

46 CFR 129.410 - Lighting fixtures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... fixture must have a high-strength guard or be made of high-strength material, except in accommodations... Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the general marine requirements...

46 CFR 129.410 - Lighting fixtures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... fixture must have a high-strength guard or be made of high-strength material, except in accommodations... Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the general marine requirements...

Diagnosis and treatment of infraspinatus tendon-bursa ossification in a Eurasian Dog.

PubMed

Ungru, Julia; Hungerbühler, Stephan; Henninger, Wolfgang; Klupiec, Petra; Bödeker, Julia; Langer, Anna; Fehr, Michael; Harms, Oliver

2018-04-01

A 4-year-old male Eurasian Dog presented at our veterinary clinic with a history of perpetual forelimb lameness in both thoracic limbs. In the clinical exploration, direct pressure over the infraspinatus tendon of insertion caused pain in both thoracic forelimbs and a firm band-like structure was palpable. No improvement was observed after treatment with rest, non-steroidal anti-inflammatory drugs and an intralesional injection of a long-acting glucocorticoid. Radiographic examination, ultrasonographic exploration and computed tomography were performed, identifying ossified structures lateral to the proximal humerus and an irregular roughened periosteum at the insertion and tendon of the infraspinatus muscle on both sides. There were more distinct alterations on the right thoracic limb. The imaging results led to a diagnosis of an infraspinatus tendon-bursa ossification accompanied by a chronic tendinopathy/tendovaginitis, accentuated on the right side. The dog was subjected to physiotherapy and autologous conditioned plasma (ACP) was injected into the insertion of the infraspinatus muscle of both thoracic limbs. After 5 months of physiotherapy and two injections of ACP with an interval of one week in both forelimbs, the dog showed no signs of lameness. This case report describes the diagnosis and management of infraspinatus tendon-bursa ossification in a Eurasian Dog. To the authors' knowledge, this condition has previously not been described in this breed of dog. Schattauer GmbH.

Cholinergic systems are essential for late-stage maturation and refinement of motor cortical circuits

PubMed Central

Ramanathan, Dhakshin S.; Conner, James M.; Anilkumar, Arjun A.

2014-01-01

Previous studies reported that early postnatal cholinergic lesions severely perturb early cortical development, impairing neuronal cortical migration and the formation of cortical dendrites and synapses. These severe effects of early postnatal cholinergic lesions preclude our ability to understand the contribution of cholinergic systems to the later-stage maturation of topographic cortical representations. To study cholinergic mechanisms contributing to the later maturation of motor cortical circuits, we first characterized the temporal course of cortical motor map development and maturation in rats. In this study, we focused our attention on the maturation of cortical motor representations after postnatal day 25 (PND 25), a time after neuronal migration has been accomplished and cortical volume has reached adult size. We found significant maturation of cortical motor representations after this time, including both an expansion of forelimb representations in motor cortex and a shift from proximal to distal forelimb representations to an extent unexplainable by simple volume enlargement of the neocortex. Specific cholinergic lesions placed at PND 24 impaired enlargement of distal forelimb representations in particular and markedly reduced the ability to learn skilled motor tasks as adults. These results identify a novel and essential role for cholinergic systems in the late refinement and maturation of cortical circuits. Dysfunctions in this system may constitute a mechanism of late-onset neurodevelopmental disorders such as Rett syndrome and schizophrenia. PMID:25505106

Complete reorganization of the motor cortex of adult rats following long-term spinal cord injuries.

PubMed

Tandon, Shashank; Kambi, Niranjan; Mohammed, Hisham; Jain, Neeraj

2013-07-01

Understanding brain reorganization following long-term spinal cord injuries is important for optimizing recoveries based on residual function as well as developing brain-controlled assistive devices. Although it has been shown that the motor cortex undergoes partial reorganization within a few weeks after peripheral and spinal cord injuries, it is not known if the motor cortex of rats is capable of large-scale reorganization after longer recovery periods. Here we determined the organization of the rat (Rattus norvegicus) motor cortex at 5 or more months after chronic lesions of the spinal cord at cervical levels using intracortical microstimulation. The results show that, in the rats with the lesions, stimulation of neurons in the de-efferented forelimb motor cortex no longer evokes movements of the forelimb. Instead, movements of the body parts in the adjacent representations, namely the whiskers and neck were evoked. In addition, at many sites, movements of the ipsilateral forelimb were observed at threshold currents. The extent of representations of the eye, jaw and tongue movements was unaltered by the lesion. Thus, large-scale reorganization of the motor cortex leads to complete filling-in of the de-efferented cortex by neighboring representations following long-term partial spinal cord injuries at cervical levels in adult rats. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Functional anatomy of the cheetah (Acinonyx jubatus) forelimb

PubMed Central

Hudson, Penny E; Corr, Sandra A; Payne-Davis, Rachel C; Clancy, Sinead N; Lane, Emily; Wilson, Alan M

2011-01-01

Despite the cheetah being the fastest living land mammal, we know remarkably little about how it attains such high top speeds (29 m s−1). Here we aim to describe and quantify the musculoskeletal anatomy of the cheetah forelimb and compare it to the racing greyhound, an animal of similar mass, but which can only attain a top speed of 17 m s−1. Measurements were made of muscle mass, fascicle length and moment arms, enabling calculations of muscle volume, physiological cross-sectional area (PCSA), and estimates of joint torques and rotational velocities. Bone lengths, masses and mid-shaft cross-sectional areas were also measured. Several species differences were observed and have been discussed, such as the long fibred serratus ventralis muscle in the cheetah, which we theorise may translate the scapula along the rib cage (as has been observed in domestic cats), thereby increasing the cheetah's effective limb length. The cheetah's proximal limb contained many large PCSA muscles with long moment arms, suggesting that this limb is resisting large ground reaction force joint torques and therefore is not functioning as a simple strut. Its structure may also reflect a need for control and stabilisation during the high-speed manoeuvring in hunting. The large digital flexors and extensors observed in the cheetah forelimb may be used to dig the digits into the ground, aiding with traction when galloping and manoeuvring. PMID:21332715

Functional anatomy of the gibbon forelimb: adaptations to a brachiating lifestyle

PubMed Central

Michilsens, Fana; Vereecke, Evie E; D'Août, Kristiaan; Aerts, Peter

2009-01-01

It has been shown that gibbons are able to brachiate with very low mechanical costs. The conversion of muscle activity into smooth, purposeful movement of the limb depends on the morphometry of muscles and their mechanical action on the skeleton. Despite the gibbon's reputation for excellence in brachiation, little information is available regarding either its gross musculoskeletal anatomy or its more detailed muscle–tendon architecture. We provide quantitative anatomical data on the muscle–tendon architecture (muscle mass, physiological cross-sectional area, fascicle length and tendon length) of the forelimb of four gibbon species, collected by detailed dissections of unfixed cadavers. Data are compared between different gibbon species and with similar published data of non-brachiating primates such as macaques, chimpanzees and humans. No quantitative differences are found between the studied gibbon species. Both their forelimb anatomy and muscle dimensions are comparable when normalized to the same body mass. Gibbons have shoulder flexors, extensors, rotator muscles and elbow flexors with a high power or work-generating capacity and their wrist flexors have a high force-generating capacity. Compared with other primates, the elbow flexors of gibbons are particularly powerful, suggesting that these muscles are particularly important for a brachiating lifestyle. Based on this anatomical study, the shoulder flexors, extensors, rotator muscles, elbow flexors and wrist flexors are expected to contribute the most to brachiation. PMID:19519640

Neural and Hemodynamic Responses Elicited by Forelimb- and Photo-stimulation in Channelrhodopsin-2 Mice: Insights into the Hemodynamic Point Spread Function

PubMed Central

Vazquez, Alberto L.; Fukuda, Mitsuhiro; Crowley, Justin C.; Kim, Seong-Gi

2014-01-01

Hemodynamic responses are commonly used to map brain activity; however, their spatial limits have remained unclear because of the lack of a well-defined and malleable spatial stimulus. To examine the properties of neural activity and hemodynamic responses, multiunit activity, local field potential, cerebral blood volume (CBV)-sensitive optical imaging, and laser Doppler flowmetry were measured from the somatosensory cortex of transgenic mice expressing Channelrhodopsin-2 in cortex Layer 5 pyramidal neurons. The magnitude and extent of neural and hemodynamic responses were modulated using different photo-stimulation parameters and compared with those induced by somatosensory stimulation. Photo-stimulation-evoked spiking activity across cortical layers was similar to forelimb stimulation, although their activity originated in different layers. Hemodynamic responses induced by forelimb- and photo-stimulation were similar in magnitude and shape, although the former were slightly larger in amplitude and wider in extent. Altogether, the neurovascular relationship differed between these 2 stimulation pathways, but photo-stimulation-evoked changes in neural and hemodynamic activities were linearly correlated. Hemodynamic point spread functions were estimated from the photo-stimulation data and its full-width at half-maximum ranged between 103 and 175 µm. Therefore, submillimeter functional structures separated by a few hundred micrometers may be resolved using hemodynamic methods, such as optical imaging and functional magnetic resonance imaging. PMID:23761666

Motor Skills Training Improves Sensorimotor Dysfunction and Increases Microtubule-Associated Protein 2 mRNA Expression in Rats with Intracerebral Hemorrhage.

PubMed

Tamakoshi, Keigo; Kawanaka, Kentaro; Onishi, Hideaki; Takamatsu, Yasuyuki; Ishida, Kazuto

2016-08-01

In this study, we examined the effects of motor skills training on the sensorimotor function and the expression of genes associated with synaptic plasticity after intracerebral hemorrhage (ICH) in rats. Male Wistar rats were subjected to ICH or sham operation. ICH was caused by the injection of collagenase into the left striatum. Rats were randomly assigned to no training, acrobatic training, and sham groups. The acrobatic group performed 5 types of acrobatic tasks from 4 to 28 days after surgery. The forelimb sensorimotor function was evaluated over time using forepaw grasping, forelimb placing, and postural instability tests. At 14 and 29 days after the lesion, we analyzed the mRNA expression levels of microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor, and growth-associated protein 43 in the bilateral sensorimotor cortex (forelimb area) by real-time reverse transcription-polymerase chain reaction. Motor skills training in ICH rats improved the sensorimotor dysfunction significantly from the early phase. The mRNA expression level of MAP2 was upregulated in the ipsilesional sensorimotor cortex by motor skills training at 29 days after the lesion. Our results suggest that sensorimotor functional recovery following motor skills training after ICH is promoted by dendritic growth in the ipsilesional sensorimotor cortex. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Peripheral and central changes combine to induce motor behavioral deficits in a moderate repetition task

PubMed Central

Coq, Jacques-Olivier; Barr, Ann E; Strata, Fabrizio; Russier, Michael; Kietrys, David M; Merzenich, Michael M; Byl, Nancy N; Barbe, Mary F

2009-01-01

Repetitive motion disorders, such as carpal tunnel syndrome and focal hand dystonia, can be associated with tasks that require prolonged, repetitive behaviors. Previous studies using animal models of repetitive motion have correlated cortical neuroplastic changes or peripheral tissue inflammation with fine motor performance. However, the possibility that both peripheral and central mechanisms coexist with altered motor performance has not been studied. In this study, we investigated the relationship between motor behaviour changes associated with repetitive behaviors and both peripheral tissue inflammation and cortical neuroplasticity. A rat model of reaching and grasping involving moderate repetitive reaching with negligible force (MRNF) was used. Rats performed the MRNF task for 2 hrs/day, 3 days/wk for 8 weeks. Reach performance was monitored by measuring reach rate/success, daily exposure, reach movement reversals/patterns, reach/grasp phase times, grip strength and grooming function. With cumulative task exposure, reach performance, grip strength and agility declined while an inefficient food retrieval pattern increased. In S1 of MRNF rats, a dramatic disorganization of the topographic forepaw representation was observed, including the emergence of large receptive fields located on both the wrist/forearm and forepaw with alterations of neuronal properties. In M1, there was a drastic enlargement of the overall forepaw map area, and of the cortex devoted to digit, arm-digits and elbow-wrist responses. In addition, unusually low current amplitude evoked digit movements. IL-1β and TNF-α increased in forearm flexor muscles and tendons of MRNF animals. The increases in IL-1β and TNF-α negatively correlated with grip strength and amount of current needed to evoke forelimb movements. This study provides strong evidence that both peripheral inflammation and cortical neuroplasticity jointly contribute to the development of chronic repetitive motion disorders. PMID:19686738

Peripheral and central changes combine to induce motor behavioral deficits in a moderate repetition task.

PubMed

Coq, Jacques-Olivier; Barr, Ann E; Strata, Fabrizio; Russier, Michael; Kietrys, David M; Merzenich, Michael M; Byl, Nancy N; Barbe, Mary F

2009-12-01

Repetitive motion disorders, such as carpal tunnel syndrome and focal hand dystonia, can be associated with tasks that require prolonged, repetitive behaviors. Previous studies using animal models of repetitive motion have correlated cortical neuroplastic changes or peripheral tissue inflammation with fine motor performance. However, the possibility that both peripheral and central mechanisms coexist with altered motor performance has not been studied. In this study, we investigated the relationship between motor behavior changes associated with repetitive behaviors and both peripheral tissue inflammation and cortical neuroplasticity. A rat model of reaching and grasping involving moderate repetitive reaching with negligible force (MRNF) was used. Rats performed the MRNF task for 2 h/day, 3 days/week for 8 weeks. Reach performance was monitored by measuring reach rate/success, daily exposure, reach movement reversals/patterns, reach/grasp phase times, grip strength and grooming function. With cumulative task exposure, reach performance, grip strength and agility declined while an inefficient food retrieval pattern increased. In S1 of MRNF rats, a dramatic disorganization of the topographic forepaw representation was observed, including the emergence of large receptive fields located on both the wrist/forearm and forepaw with alterations of neuronal properties. In M1, there was a drastic enlargement of the overall forepaw map area, and of the cortex devoted to digit, arm-digits and elbow-wrist responses. In addition, unusually low current amplitude evoked digit movements. IL-1 beta and TNF-alpha increased in forearm flexor muscles and tendons of MRNF animals. The increases in IL-1 beta and TNF-alpha negatively correlated with grip strength and amount of current needed to evoke forelimb movements. This study provides strong evidence that both peripheral inflammation and cortical neuroplasticity jointly contribute to the development of chronic repetitive motion disorders.

Preliminary Validation and Reliability Testing of the Montreal Instrument for Cat Arthritis Testing, for Use by Veterinarians, in a Colony of Laboratory Cats

PubMed Central

Klinck, Mary P.; Rialland, Pascale; Guillot, Martin; Moreau, Maxim; Frank, Diane; Troncy, Eric

2015-01-01

Simple Summary Feline osteoarthritis (OA) is challenging to diagnose. A pain scale was developed for use by veterinarians, in association with their physical examination, and tested for reliability and validity. The scale items were: Interaction with the examiner, Exploration of the room, Body Posture, Gait, Body Condition, condition of Coat and Claws, and abnormal Findings or Cat Reaction upon joint Palpation. Expert review supported the scale content. Two studies using laboratory-housed cats found the most promising results for Gait and Body Posture, in terms of distinguishing between OA and non-OA cats, repeatability of results, and correlations with objectively measured kinetics (weight-bearing). Abstract Subtle signs and conflicting physical and radiographic findings make feline osteoarthritis (OA) challenging to diagnose. A physical examination-based assessment was developed, consisting of eight items: Interaction, Exploration, Posture, Gait, Body Condition, Coat and Claws, (joint) Palpation–Findings, and Palpation–Cat Reaction. Content (experts) and face (veterinary students) validity were excellent. Construct validity, internal consistency, and intra- and inter-rater reliability were assessed via a pilot and main study, using laboratory-housed cats with and without OA. Gait distinguished OA status in the pilot (p = 0.05) study. In the main study, no scale item achieved statistically significant OA detection. Forelimb peak vertical ground reaction force (PVF) correlated inversely with Gait (Rhos = −0.38 (p = 0.03) to −0.41 (p = 0.02)). Body Posture correlated with Gait, and inversely with forelimb PVF at two of three time points (Rhos = −0.38 (p = 0.03) to −0.43 (p = 0.01)). Palpation (Findings, Cat Reaction) did not distinguish OA from non-OA cats. Palpation—Cat Reaction (Forelimbs) correlated inversely with forelimb PVF at two time points (Rhos = −0.41 (p = 0.02) to −0.41 (p = 0.01)), but scores were highly variable, and poorly reliable. Gait and Posture require improved sensitivity, and Palpation should be interpreted cautiously, in diagnosing feline OA. PMID:26633524

Laminar-specific distribution of zinc: evidence for presence of layer IV in forelimb motor cortex in the rat.

PubMed

Alaverdashvili, Mariam; Hackett, Mark J; Pickering, Ingrid J; Paterson, Phyllis G

2014-12-01

The rat is the most widely studied pre-clinical model system of various neurological and neurodegenerative disorders affecting hand function. Although brain injury to the forelimb region of the motor cortex in rats mostly induces behavioral abnormalities in motor control of hand movements, behavioral deficits in the sensory-motor domain are also observed. This questions the prevailing view that cortical layer IV, a recipient of sensory information from the thalamus, is absent in rat motor cortex. Because zinc-containing neurons are generally not found in pathways that run from the thalamus, an absence of zinc (Zn) in a cortical layer would be suggestive of sensory input from the thalamus. To test this hypothesis, we used synchrotron micro X-ray fluorescence imaging to measure Zn distribution across cortical layers. Zn maps revealed a heterogeneous layered Zn distribution in primary and secondary motor cortices of the forelimb region in the adult rat. Two wider bands with elevated Zn content were separated by a narrow band having reduced Zn content, and this was evident in two rat strains. The Zn distribution pattern was comparable to that in sensorimotor cortex, which is known to contain a well demarcated layer IV. Juxtaposition of Zn maps and the images of brain stained for Nissl bodies revealed a "Zn valley" in primary motor cortex, apparently starting at the ventral border of pyramidal layer III and ending at the close vicinity of layer V. This finding indicates the presence of a conspicuous cortical layer between layers III and V, i.e. layer IV, the presence of which previously has been disputed. The results have implications for the use of rat models to investigate human brain function and neuropathology, such as after stroke. The presence of layer IV in the forelimb region of the motor cortex suggests that therapeutic interventions used in rat models of motor cortex injury should target functional abnormalities in both motor and sensory domains. The finding is also critical for future investigation of the biochemical mechanisms through which therapeutic interventions can enhance neural plasticity, particularly through Zn dependent pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

Laminar-specific distribution of zinc: Evidence for presence of layer IV in forelimb motor cortex in the rat

PubMed Central

Alaverdashvili, Mariam; Hackett, Mark J.; Pickering, Ingrid J.; Paterson, Phyllis G.

2015-01-01

The rat is the most widely studied pre-clinical model system of various neurological and neurodegenerative disorders affecting hand function. Although brain injury to the forelimb region of the motor cortex in rats mostly induces behavioral abnormalities in motor control of hand movements, behavioral deficits in the sensory-motor domain are also observed. This questions the prevailing view that cortical layer IV, a recipient of sensory information from the thalamus, is absent in rat motor cortex. Because zinc-containing neurons are generally not found in pathways that run from the thalamus, an absence of zinc (Zn) in a cortical layer would be suggestive of sensory input from the thalamus. To test this hypothesis, we used synchrotron micro X-ray fluorescence imaging to measure Zn distribution across cortical layers. Zn maps revealed a heterogeneous layered Zn distribution in primary and secondary motor cortices of the forelimb region in the adult rat. Two wider bands with elevated Zn content were separated by a narrow band having reduced Zn content, and this was evident in two rat strains. The Zn distribution pattern was comparable to that in sensorimotor cortex, which is known to contain a well demarcated layer IV. Juxtaposition of Zn maps and the images of brain stained for Nissl bodies revealed a “Zn valley” in primary motor cortex, apparently starting at the ventral border of pyramidal layer III and ending at the close vicinity of layer V. This finding indicates the presence of a conspicuous cortical layer between layers III and V, i.e. layer IV, the presence of which previously has been disputed. The results have implications for the use of rat models to investigate human brain function and neuropathology, such as after stroke. The presence of layer IV in the forelimb region of the motor cortex suggests that therapeutic interventions used in rat models of motor cortex injury should target functional abnormalities in both motor and sensory domains. The finding is also critical for future investigation of the biochemical mechanisms through which therapeutic interventions can enhance neural plasticity, particularly through Zn dependent pathways. PMID:25192655

Combined motor cortex and spinal cord neuromodulation promotes corticospinal system functional and structural plasticity and motor function after injury.

PubMed

Song, Weiguo; Amer, Alzahraa; Ryan, Daniel; Martin, John H

2016-03-01

An important strategy for promoting voluntary movements after motor system injury is to harness activity-dependent corticospinal tract (CST) plasticity. We combine forelimb motor cortex (M1) activation with co-activation of its cervical spinal targets in rats to promote CST sprouting and skilled limb movement after pyramidal tract lesion (PTX). We used a two-step experimental design in which we first established the optimal combined stimulation protocol in intact rats and then used the optimal protocol in injured animals to promote CST repair and motor recovery. M1 was activated epidurally using an electrical analog of intermittent theta burst stimulation (iTBS). The cervical spinal cord was co-activated by trans-spinal direct current stimulation (tsDCS) that was targeted to the cervical enlargement, simulated from finite element method. In intact rats, forelimb motor evoked potentials (MEPs) were strongly facilitated during iTBS and for 10 min after cessation of stimulation. Cathodal, not anodal, tsDCS alone facilitated MEPs and also produced a facilitatory aftereffect that peaked at 10 min. Combined iTBS and cathodal tsDCS (c-tsDCS) produced further MEP enhancement during stimulation, but without further aftereffect enhancement. Correlations between forelimb M1 local field potentials and forelimb electromyogram (EMG) during locomotion increased after electrical iTBS alone and further increased with combined stimulation (iTBS+c-tsDCS). This optimized combined stimulation was then used to promote function after PTX because it enhanced functional connections between M1 and spinal circuits and greater M1 engagement in muscle contraction than either stimulation alone. Daily application of combined M1 iTBS on the intact side and c-tsDCS after PTX (10 days, 27 min/day) significantly restored skilled movements during horizontal ladder walking. Stimulation produced a 5.4-fold increase in spared ipsilateral CST terminations. Combined neuromodulation achieves optimal motor recovery and substantial CST outgrowth with only 27 min of daily stimulation compared with 6h, as in our prior study, making it a potential therapy for humans with spinal cord injury. Copyright © 2015 Elsevier Inc. All rights reserved.

Use of brachial plexus blockade and medetomidine-ketamine-isoflurane anaesthesia for repair of radio-ulna fracture in an adult cheetah (Acinonyx jubatus).

PubMed

Kimeli, Peter; Mogoa, Eddy M; Mwangi, Willy E; Kipyegon, Ambrose N; Kirui, Gilbert; Muasya, Daniel W; Mande, John D; Kariuki, Edward; Mijele, Dominic

2014-10-10

Regional anaesthetic techniques have been used in combination with systemic analgesics during small animal surgery to provide multimodal analgesia. Brachial plexus nerves block using local anaesthetics provides analgesia of the thoracic limb through desensitization of the nerves that provide sensory and motor innervation. This has been shown to reduce intra-operative anesthetic requirements and provide postoperative pain relief. Decreasing the doses of general anaesthetics allows more stable cardiopulmonary function during anaesthesia and the development of less side effects. The present case reports a successful use of brachial plexus blockade to supplement medetomidine-ketamine-isoflurane anaesthesia for repair of radio-ulna fracture in an adult cheetah (acinonyx jubatus). An adult male Cheetah weighing about 65 kg was presented with a history of leg carrying lameness of the left forelimb sustained following a car accident a week earlier. Clinical examination under general anaesthesia revealed slight dehydration and a swelling with a wound on the caudo-medial aspect of the left radio-ulna region. Crepitation was present on manipulation and radiography confirmed a complete transverse radio-ulna fracture of the left forelimb, which required open reduction and internal fixation. Brachial plexus blockade using lignocaine hydrochloride was used to supplement medetomidine-ketamine-isoflurane anaesthesia for the surgical procedure. Isoflurane anaesthesia was maintained at 0.5 - 2.0% throughout the surgical procedure, which was uneventful. Temperature and cardio-pulmonary parameters remained stable intra-operatively. Limb paralysis extended for 5 hours post-operatively, suggesting prolonged anaesthesia. To the researchers' knowledge, this is the first reported case of the use of brachial plexus blockade to supplement general anaesthesia to facilitate forelimb surgery in an adult cheetah. The use of brachial plexus block with a light plane of general anaesthesia proved to be successful. Brachial plexus block had a sparing effect on isoflurane anaesthesia as evidenced by the concentration used for maintenance of anaesthesia and the stability of the cardiopulmonary function. Moreover, absence of autonomic cardiopulmonary reactions to the surgical manipulation may be attributed to the efficacy of brachial plexus block. This anaesthesia protocol is therefore recommended for surgeries of the forelimb in wild cats.

Individualized tracking of self-directed motor learning in group-housed mice performing a skilled lever positioning task in the home cage.

PubMed

Silasi, Gergely; Boyd, Jamie D; Bolanos, Federico; LeDue, Jeff M; Scott, Stephen H; Murphy, Timothy H

2018-01-01

Skilled forelimb function in mice is traditionally studied through behavioral paradigms that require extensive training by investigators and are limited by the number of trials individual animals are able to perform within a supervised session. We developed a skilled lever positioning task that mice can perform within their home cage. The task requires mice to use their forelimb to precisely hold a lever mounted on a rotary encoder within a rewarded position to dispense a water reward. A Raspberry Pi microcomputer is used to record lever position during trials and to control task parameters, thus making this low-footprint apparatus ideal for use within animal housing facilities. Custom Python software automatically increments task difficulty by requiring a longer hold duration, or a more accurate hold position, to dispense a reward. The performance of individual animals within group-housed mice is tracked through radio-frequency identification implants, and data stored on the microcomputer may be accessed remotely through an active internet connection. Mice continuously engage in the task for over 2.5 mo and perform ~500 trials/24 h. Mice required ~15,000 trials to learn to hold the lever within a 10° range for 1.5 s and were able to further refine movement accuracy by limiting their error to a 5° range within each trial. These results demonstrate the feasibility of autonomously training group-housed mice on a forelimb motor task. This paradigm may be used in the future to assess functional recovery after injury or cortical reorganization induced by self-directed motor learning. NEW & NOTEWORTHY We developed a low-cost system for fully autonomous training of group-housed mice on a forelimb motor task. We demonstrate the feasibility of tracking both end-point, as well as kinematic performance of individual mice, with each performing thousands of trials over 2.5 mo. The task is run and controlled by a Raspberry Pi microcomputer, which allows for cages to be monitored remotely through an active internet connection.

Kinetic and temporospatial parameters in male and female cats walking over a pressure sensing walkway.

PubMed

Verdugo, Mirela R; Rahal, Sheila C; Agostinho, Felipe S; Govoni, Verônica M; Mamprim, Maria J; Monteiro, Frederico O B

2013-06-27

Several factors may influence kinetic data measurements, including body conformation and body mass. In addition, gender differences in gait pattern have been observed in healthy humans. Therefore, the aim of this study was to compare the kinetic and temporospatial parameters in clinically healthy male and female cats using a pressure-sensitive walkway. Eighteen crossbreed adult cats were divided into two groups: G1 had ten male cats (nine neutered) aged from 1 to 4 years and body mass 3.1-6.8 kg; G2 had eight spayed female cats, aged from 1 to 6 years and body mass 3.3-4.75 kg. The data from the first five valid trials were collected for each cat. A trial was considered valid if the cat maintained a velocity between 0.54-0.74 m/s and acceleration from -0.20 to 0.20 m/s2. The peak vertical force (PVF), vertical impulse (VI), gait cycle time, stance time, swing time, stride length, and percentage body weight distribution among the four limbs were determined. In addition, the lengths of each forelimb and each hind limb were measured using a tape with the animal standing. No significant differences were observed in each group in either the forelimbs or the hind limbs or between the left and right sides for any of the variables. For both groups, the PVF (%BW), the VI, and the percentage body weight distribution were higher at the forelimbs than the hind limbs. The stride length was larger for males; however, the other kinetic and temporospatial variables did not show any statistically significant differences between the groups. The lengths of the forelimbs and hind limbs were larger in the male cats. There was a significant moderate positive correlation between the stride length and the length of the limbs. In conclusion, the only difference observed between male and female cats was the stride length, and this was due to the greater body size of male cats. This difference did not affect other temporospatial or kinetics variables.

Functional associations between support use and forelimb shape in strepsirrhines and their relevance to inferring locomotor behavior in early primates.

PubMed

Fabre, Anne-Claire; Marigó, Judit; Granatosky, Michael C; Schmitt, Daniel

2017-07-01

The evolution of primates is intimately linked to their initial invasion of an arboreal environment. However, moving and foraging in this milieu creates significant mechanical challenges related to the presence of substrates differing in their size and orientation. It is widely assumed that primates are behaviorally and anatomically adapted to movement on specific substrates, but few explicit tests of this relationship in an evolutionary context have been conducted. Without direct tests of form-function relationships in living primates it is impossible to reliably infer behavior in fossil taxa. In this study, we test a hypothesis of co-variation between forelimb morphology and the type of substrates used by strepsirrhines. If associations between anatomy and substrate use exist, these can then be applied to better understand limb anatomy of extinct primates. The co-variation between each forelimb long bone and the type of substrate used was studied in a phylogenetic context. Our results show that despite the presence of significant phylogenetic signal for each long bone of the forelimb, clear support use associations are present. A strong co-variation was found between the type of substrate used and the shape of the radius, with and without taking phylogeny into account, whereas co-variation was significant for the ulna only when taking phylogeny into account. Species that use a thin branch milieu show radii that are gracile and straight and have a distal articular shape that allows for a wide range of movements. In contrast, extant species that commonly use large supports show a relatively robust and curved radius with an increased surface area available for forearm and hand muscles in pronated posture. These results, especially for the radius, support the idea that strepsirrhine primates exhibit specific skeletal adaptations associated with the supports that they habitually move on. With these robust associations in hand it will be possible to explore the same variables in extinct early primates and primate relatives and thus improve the reliability of inferences concerning substrate use in early primates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined motor cortex and spinal cord neuromodulation promotes corticospinal system functional and structural plasticity and motor function after injury

PubMed Central

Song, Weiguo; Amer, Alzahraa; Ryan, Daniel; Martin, John H.

2016-01-01

An important strategy for promoting voluntary movements after motor system injury is to harness activity-dependent corticospinal tract (CST) plasticity. We combine forelimb motor cortex (M1) activation with co-activation of its cervical spinal targets in rats to promote CST sprouting and skilled limb movement after pyramidal tract lesion (PTX). We used a two-step experimental design in which we first established the optimal combined stimulation protocol in intact rats and then used the optimal protocol in injured animals to promote CST repair and motor recovery. M1 was activated epidurally using an electrical analog of intermittent theta burst stimulation (iTBS). The cervical spinal cord was co-activated by trans-spinal direct current stimulation (tsDCS) that was targeted to the cervical enlargement, simulated from finite element method. In intact rats, forelimb motor evoked potentials (MEPs) were strongly facilitated during iTBS and for 10 minutes after cessation of stimulation. Cathodal, not anodal, tsDCS alone facilitated MEPs and also produced a facilitatory aftereffect that peaked at 10 minutes. Combined iTBS and cathodal tsDCS (c-tsDCS) produced further MEP enhancement during stimulation, but without further aftereffect enhancement. Correlations between forelimb M1 local field potentials and forelimb electromyogram (EMG) during locomotion increased after electrical iTBS alone and further increased with combined stimulation (iTBS + c-tsDCS). This optimized combined stimulation was then used to promote function after PTX because it enhanced functional connections between M1 and spinal circuits and greater M1 engagement in muscle contraction than either stimulation alone. Daily application of combined M1 iTBS on the intact side and c-tsDCS after PTX (10 days, 27 minutes/day) significantly restored skilled movements during horizontal ladder walking. Stimulation produced a 5.4-fold increase in spared ipsilateral CST terminations. Combined neuromodulation achieves optimal motor recovery and substantial CST outgrowth with only 27 minutes of daily stimulation compared with 6 hours, as in our prior study, making it a potential therapy for humans with spinal cord injury. PMID:26708732

[Kinetics of heifers and cows walking on an instrumented treadmill].

PubMed

Nuss, K; Waldern, N M; Weishaupt, M A; Wiestner, T

2015-01-01

Kinetic data of stride characteristics and ground reaction forces of cattle become increasingly important as automated lameness detection may be installed in dairy cow housing systems in the future. Therefore, sound heifers and cows were measured on an instrumented treadmill to collect such basic data. Nine heifers and 10 cows were trained to walk on an instrumented treadmill. Vertical ground reaction forces as well as step and stride timing and length variables were measured for all limbs simultaneously. On average, 16 stride cycles in cows and 24 strides in heifers were analysed in each case. The cows walked on the treadmill at an average speed of 1.2 ± 0.05 m/s (mean ± standard deviation), with a stride rate of 43.0 ± 1.9/min and a stride length of 1.68 ± 0.1 m. The heifers had average values of 1.3 ± 0.04 m/s, 53.7 ± 2.2/min and 1.49 ± 0.05 m, respectively. The stance duration relative to stride duration (the duty factor) was for the cows significantly longer in the forelimbs (67%) than in the hind limbs (64%). Force-time-curves of all limbs showed two peaks, one after landing (FP1) and another during push off (FP2). Vertical ground reaction force was highest for FP1 in the hind limbs, but for FP2 in the forelimbs. At all limbs, force minimum between the peaks occurred shortly before midstance. The vertical impulse carried by both forelimbs amounted to 53.7% of the total stride impulse in cows and to 55.0% in heifers. The location of the centre of body mass varied during the stride cycle but was always located more towards the front limbs. Cows and heifers showed a symmetrical walk with minimal intra-individual variations. Relative stride impulse of the front limbs was higher than that of the hind limbs. Peak vertical force in the hind limbs was highest at landing and in the forelimbs at push off. The present study offers kinetic data of sound cows and heifers which might be helpful as guidelines for automated systems for lameness detection in cattle.

EFFECTS OF PRENATAL EXPOSURE TO SODIUM ARSENITE ON MOTOR AND FOOD-MOTIVATED BEHAVIORS FROM BIRTH TO ADULTHOOD IN C57BL6/J MICE

PubMed Central

Markowski, Vincent P.; Reeve, Elizabeth A.; Onos, Kristen; Assadollahzadeh, Mina; McKay, Naomi

2012-01-01

Consumption of arsenic-contaminated drinking water is associated with numerous cancers and dermal and vascular diseases. Arsenic is also a potent nervous system toxicant and epidemiological studies indicate that intellectual functions in children are compromised following early developmental exposure. This study was designed to examine the effects of arsenic on a broad range of age-specific behaviors including basic sensory-motor responses in neonates, locomotor activity and grip strength in juveniles, and operant measures of learning and attention in adults. Pregnant C57BL6/J mice consumed drinking water containing 0, 8, 25, or 80 ppm sodium arsenite from the fourth day of gestation until birth. Arsenic produced a range of behavioral impairments in male and female offspring at each of the test ages. The most striking effects of arsenic were on the development of gait and other motor responses including acoustic startle, righting reflexes, and forelimb grip. These results suggest that developmental arsenic exposure can produce other behavioral impairments in children in addition to cognitive impairment. PMID:22266078

Strong transverse fields in delta-spots

NASA Technical Reports Server (NTRS)

Zirin, Harold; Wang, Haimin

1993-01-01

Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

Dislocation mechanisms and 3D twin architectures generate exceptional strength-ductility-toughness combination in CrCoNi medium-entropy alloy

DOE PAGES

Zhang, Zijiao; Sheng, Hongwei; Wang, Zhangjie; ...

2017-02-20

Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highest combinations of strength, ductility and toughness on record. Ab initio modelling suggests that it has negative stacking-fault energy at 0K and high propensity for twinning. With deformation we find that a three-dimensional (3D) hierarchical twin network forms from the activation of three twinning systems. This serves a dualmore » function: conventional twin-boundary (TB) strengthening from blockage of dislocations impinging on TBs, coupled with the 3D twin network which offers pathways for dislocation glide along, and cross-slip between, intersecting TB-matrix interfaces. The stable twin architecture is not disrupted by interfacial dislocation glide, serving as a continuous source of strength, ductility and toughness.« less

Dislocation mechanisms and 3D twin architectures generate exceptional strength-ductility-toughness combination in CrCoNi medium-entropy alloy

PubMed Central

Zhang, Zijiao; Sheng, Hongwei; Wang, Zhangjie; Gludovatz, Bernd; Zhang, Ze; George, Easo P.; Yu, Qian; Mao, Scott X.; Ritchie, Robert O.

2017-01-01

Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highest combinations of strength, ductility and toughness on record. Ab initio modelling suggests that it has negative stacking-fault energy at 0K and high propensity for twinning. With deformation we find that a three-dimensional (3D) hierarchical twin network forms from the activation of three twinning systems. This serves a dual function: conventional twin-boundary (TB) strengthening from blockage of dislocations impinging on TBs, coupled with the 3D twin network which offers pathways for dislocation glide along, and cross-slip between, intersecting TB-matrix interfaces. The stable twin architecture is not disrupted by interfacial dislocation glide, serving as a continuous source of strength, ductility and toughness. PMID:28218267

Dislocation mechanisms and 3D twin architectures generate exceptional strength-ductility-toughness combination in CrCoNi medium-entropy alloy.

PubMed

Zhang, Zijiao; Sheng, Hongwei; Wang, Zhangjie; Gludovatz, Bernd; Zhang, Ze; George, Easo P; Yu, Qian; Mao, Scott X; Ritchie, Robert O

2017-02-20

Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highest combinations of strength, ductility and toughness on record. Ab initio modelling suggests that it has negative stacking-fault energy at 0K and high propensity for twinning. With deformation we find that a three-dimensional (3D) hierarchical twin network forms from the activation of three twinning systems. This serves a dual function: conventional twin-boundary (TB) strengthening from blockage of dislocations impinging on TBs, coupled with the 3D twin network which offers pathways for dislocation glide along, and cross-slip between, intersecting TB-matrix interfaces. The stable twin architecture is not disrupted by interfacial dislocation glide, serving as a continuous source of strength, ductility and toughness.

Growth of Fault-Cored Anticlines by Flexural Slip Folding: Analysis by Boundary Element Modeling

NASA Astrophysics Data System (ADS)

Johnson, Kaj M.

2018-03-01

Fault-related folds develop due to a combination of slip on the associated fault and distributed deformation off the fault. Under conditions that are sufficient for sedimentary layering to act as a stack of mechanical layers with contact slip, buckling can dramatically amplify the folding process. We develop boundary element models of fault-related folding of viscoelastic layers embedded with a reverse fault to examine the influence of such layering on fold growth. The strength of bedding contacts, the thickness and stiffness of layering, and fault geometry all contribute significantly to the resulting fold form. Frictional contact strength between layers controls the degree of localization of slip within fold limbs; high contact friction in relatively thin bedding tends to localize bedding slip within narrow kink bands on fold limbs, and low contact friction tends to produce widespread bedding slip and concentric fold form. Straight ramp faults tend to produce symmetric folds, whereas listric faults tend to produce asymmetric folds with short forelimbs and longer backlimbs. Fault-related buckle folds grow exponentially with time under steady loading rates. At early stages of folding, fold growth is largely attributed to slip on the fault, but as the fold increases amplitude, a larger portion of the fold growth is attributed to distributed slip across bedding contacts on the limbs of the fold. An important implication for geologic and earthquake studies is that not all surface deformation associated with blind reverse faults may be attributed to slip on the fault during earthquakes.

Heme Oxygenase-2 Modulates Early Pathogenesis after Traumatic Injury to the Immature Brain

PubMed Central

Yoneyama-Sarnecky, Tomoko; Olivas, Andrea D.; Azari, Soraya; Ferriero, Donna M.; Manvelyan, Hovhannes M.; Noble-Haeusslein, Linda J.

2010-01-01

We determined if heme oxygenase-2 (HO-2), an enzyme that degrades the pro-oxidant heme, confers neuroprotection in the developing brain after traumatic brain injury (TBI). Male HO-2 wild-type (WT) and homozygous knockout (KO) mice at postnatal day 21 were subjected to TBI and euthanized 1, 7, and 14 days later. Relative cerebral blood flow, measured by laser Doppler, cortical and hippocampal pathogenesis, and motor recovery were evaluated at all time points. Cerebral blood flow was found to be similar between experimental groups. Blood flow significantly decreased immediately after injury, returned to baseline by 1 day, and was significantly elevated by 7 days, post-injury. Nonheme iron preferentially accumulated in the ipsilateral cortex, hippocampus, and external capsule in both WT and KO brain-injured genotypes. There were, however, a significantly greater number of TUNEL-positive cells in the hippocampal dentate gyrus and a significantly greater cortical lesion volume in KOs relative to WTs within the first week post-injury. By 14 days post-injury, however, cortical lesion volume and cell density in the hippocampal CA3 region and dorsal thalamus were similar between the two groups. Assays of fine motor function (grip strength) over the first 2 weeks post-injury revealed a general pattern of decreased strength in the contralateral forelimbs of KOs as compared to WTs. Together, these findings demonstrate that deficiency in HO-2 alters both the kinetics of secondary damage and fine motor recovery after TBI. PMID:20389079

Role of dopamine D3 and serotonin 5-HT 1A receptors in L: -DOPA-induced dyskinesias and effects of sarizotan in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease.

PubMed

Gerlach, Manfred; Bartoszyk, Gerd D; Riederer, Peter; Dean, Olivia; van den Buuse, Maarten

2011-12-01

Sarizotan, a 5-HT(1A) agonist with additional affinity for D(3) and D(4) receptors, has been demonstrated to have anti-dyskinetic effects. The mechanism by which these effects occur is not clear. Using unilateral 6-hydroxydopamine-lesioned rats that received chronic intraperitoneal (ip) administration of L: -3,4-dihydroxyphenylalanine (L: -DOPA) we investigated the involvement of D(3) and 5-HT(1A) receptors in the effects of sarizotan on contraversive circling and abnormal involuntary movements (AIMs). Before sensitization by chronic L: -DOPA treatment (12.5 with 3.25 mg/kg benserazide ip, twice daily for 21 days), no effect of the selective D(3) agonist, PD128907 (1 or 3 mg/kg ip), or the selective D(3) antagonist, GR103691 (0.5 or 1.5 mg/kg ip), was observed. Treatment with sarizotan (1 or 5 mg/kg ip) dose-dependently inhibited the L: -DOPA-induced contraversive turning and AIMs. In co-treatment with the 5-HT(1A) antagonist, WAY100635 (1 mg/kg ip), sarizotan failed to affect this behaviour, confirming the prominent 5-HT(1A) receptor-mediated mechanism of action. In the presence of PD128907 (3 mg/kg ip), the effects of sarizotan on contraversive turning, locomotive dyskinesia and axial dystonia, but not on orolingual and forelimb dyskinesia, were blocked. On its own, PD128907 had no effect on the behavioural effects of L: -DOPA except that it tended to reduce orolingual and forelimb dyskinesia. GR103691 had no effect on its own or in combination with sarizotan. These data identify an involvement of D(3) receptors in the action of sarizotan on some, but not all L: -DOPA-induced motor side effects. This selective involvement is in contrast to the more general involvement of 5-HT(1A) receptors in the anti-dyskinetic effects of sarizotan.

Long-Term Post-Stroke Changes Include Myelin Loss, Specific Deficits in Sensory and Motor Behaviors and Complex Cognitive Impairment Detected Using Active Place Avoidance

PubMed Central

Li, Jie; Ooi, Evelyn; Bloom, Jonathan; Poon, Carrie; Lax, Daniel; Rosenbaum, Daniel M.; Barone, Frank C.

2013-01-01

Persistent neurobehavioral deficits and brain changes need validation for brain restoration. Two hours middle cerebral artery occlusion (tMCAO) or sham surgery was performed in male Sprague-Dawley rats. Neurobehavioral and cognitive deficits were measured over 10 weeks included: (1) sensory, motor, beam balance, reflex/abnormal responses, hindlimb placement, forepaw foot fault and cylinder placement tests, and (2) complex active place avoidance learning (APA) and simple passive avoidance retention (PA). Electroretinogram (ERG), hemispheric loss (infarction), hippocampus CA1 neuronal loss and myelin (Luxol Fast Blue) staining in several fiber tracts were also measured. In comparison to Sham surgery, tMCAO surgery produced significant deficits in all behavioral tests except reflex/abnormal responses. Acute, short lived deficits following tMCAO were observed for forelimb foot fault and forelimb cylinder placement. Persistent, sustained deficits for the whole 10 weeks were exhibited for motor (p<0.001), sensory (p<0.001), beam balance performance (p<0.01) and hindlimb placement behavior (p<0.01). tMCAO produced much greater and prolonged cognitive deficits in APA learning (maximum on last trial of 604±83% change, p<0.05) but only a small, comparative effect on PA retention. Hemispheric loss/atrophy was measured 10 weeks after tMCAO and cross-validated by two methods (e.g., almost identical % ischemic hemispheric loss of 33.4±3.5% for H&E and of 34.2±3.5% for TTC staining). No visual dysfunction by ERG and no hippocampus neuronal loss were detected after tMCAO. Fiber tract damage measured by Luxol Fast Blue myelin staining intensity was significant (p<0.01) in the external capsule and striatum but not in corpus callosum and anterior commissure. In summary, persistent neurobehavioral deficits were validated as important endpoints for stroke restorative research in the future. Fiber myelin loss appears to contribute to these long term behavioral dysfunctions and can be important for cognitive behavioral control necessary for complex APA learning. PMID:23505432

Assessing Forelimb Function after Unilateral Cervical SCI using Novel Tasks: Limb Step-alternation, Postural Instability and Pasta Handling

PubMed Central

Schallert, Timothy; Schmidt, Christine E.

2013-01-01

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority of the spinal cord injuries in humans occur at the cervical levels. Therefore, developing cervical injury models and developing relevant and sensitive behavioral tests is of great importance. Here we describe the use of a newly developed forelimb step-alternation test after cervical spinal cord injury in rats. In addition, we describe two behavioral tests that have not been used after spinal cord injury: a postural instability test (PIT), and a pasta-handling test. All three behavioral tests are highly sensitive to injury and are easy to use. Therefore, we feel that these behavioral tests can be instrumental in investigating therapeutic strategies after cSCI. PMID:24084700

Assessing forelimb function after unilateral cervical SCI using novel tasks: limb step-alternation, postural instability and pasta handling.

PubMed

Khaing, Zin Z; Geissler, Sydney A; Schallert, Timothy; Schmidt, Christine E

2013-09-16

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority of the spinal cord injuries in humans occur at the cervical levels. Therefore, developing cervical injury models and developing relevant and sensitive behavioral tests is of great importance. Here we describe the use of a newly developed forelimb step-alternation test after cervical spinal cord injury in rats. In addition, we describe two behavioral tests that have not been used after spinal cord injury: a postural instability test (PIT), and a pasta-handling test. All three behavioral tests are highly sensitive to injury and are easy to use. Therefore, we feel that these behavioral tests can be instrumental in investigating therapeutic strategies after cSCI.

Output Properties of the Cortical Hindlimb Motor Area in Spinal Cord-Injured Rats.

PubMed

Frost, Shawn B; Dunham, Caleb L; Barbay, Scott; Krizsan-Agbas, Dora; Winter, Michelle K; Guggenmos, David J; Nudo, Randolph J

2015-11-01

The purpose of this study was to examine neuronal activity levels in the hindlimb area of motor cortex following spinal cord injury (SCI) in rats and compare the results with measurements in normal rats. Fifteen male Fischer-344 rats received a 200 Kdyn contusion injury in the thoracic cord at level T9-T10. After a minimum of 4 weeks following SCI, intracortical microstimulation (ICMS) and single-unit recording techniques were used in both the forelimb and hindlimb motor areas (FLA, HLA) under ketamine anesthesia. Although movements could be evoked using ICMS in the forelimb area with relatively low current levels, no movements or electromyographical responses could be evoked from ICMS in the HLA in any of the injured rats. During the same procedure, electrophysiological recordings were obtained with a single-shank, 16-channel Michigan probe (Neuronexus) to monitor activity. Neural spikes were discriminated using principle component analysis. Neural activity (action potentials) was collected and digitized for a duration of 5 min. Despite the inability to evoke movement from stimulation of cortex, robust single-unit activity could be recorded reliably from hindlimb motor cortex in SCI rats. Activity in the motor cortex of SCI rats was significantly higher compared with uninjured rats, and increased in hindlimb and forelimb motor cortex by similar amounts. These results demonstrate that in a rat model of thoracic SCI, an increase in single-unit cortical activity can be reliably recorded for several weeks post-injury.

Task-specific compensation and recovery following focal motor cortex lesion in stressed rats.

PubMed

Kirkland, Scott W; Smith, Lori K; Metz, Gerlinde A

2012-03-01

One reason for the difficulty to develop effective therapies for stroke is that intrinsic factors, such as stress, may critically influence pathological mechanisms and recovery. In cognitive tasks, stress can both exaggerate and alleviate functional loss after focal ischemia in rodents. Using a comprehensive motor assessment in rats, this study examined if chronic stress and corticosterone treatment affect skill recovery and compensation in a task-specific manner. Groups of rats received daily restraint stress or oral corticosterone supplementation for two weeks prior to a focal motor cortex lesion. After lesion, stress and corticosterone treatments continued for three weeks. Motor performance was assessed in two skilled reaching tasks, skilled walking, forelimb inhibition, forelimb asymmetry and open field behavior. The results revealed that persistent stress and elevated corticosterone levels mainly limit motor recovery. Treated animals dropped larger amounts of food in successful reaches and showed exaggerated loss of forelimb inhibition early after lesion. Stress also caused a moderate, but non-significant increase in infarct size. By contrast, stress and corticosterone treatments promoted reaching success and other quantitative measures in the tray reaching task. Comparative analysis revealed that improvements are due to task-specific development of compensatory strategies. These findings suggest that stress and stress hormones may partially facilitate task-specific and adaptive compensatory movement strategies. The observations support the notion that hypothalamic-pituitary-adrenal axis activation may be a key determinant of recovery and motor system plasticity after ischemic stroke.

Functional anatomy of the cheetah (Acinonyx jubatus) forelimb.

PubMed

Hudson, Penny E; Corr, Sandra A; Payne-Davis, Rachel C; Clancy, Sinead N; Lane, Emily; Wilson, Alan M

2011-04-01

Despite the cheetah being the fastest living land mammal, we know remarkably little about how it attains such high top speeds (29 m s(-1)). Here we aim to describe and quantify the musculoskeletal anatomy of the cheetah forelimb and compare it to the racing greyhound, an animal of similar mass, but which can only attain a top speed of 17 m s(-1). Measurements were made of muscle mass, fascicle length and moment arms, enabling calculations of muscle volume, physiological cross-sectional area (PCSA), and estimates of joint torques and rotational velocities. Bone lengths, masses and mid-shaft cross-sectional areas were also measured. Several species differences were observed and have been discussed, such as the long fibred serratus ventralis muscle in the cheetah, which we theorise may translate the scapula along the rib cage (as has been observed in domestic cats), thereby increasing the cheetah's effective limb length. The cheetah's proximal limb contained many large PCSA muscles with long moment arms, suggesting that this limb is resisting large ground reaction force joint torques and therefore is not functioning as a simple strut. Its structure may also reflect a need for control and stabilisation during the high-speed manoeuvring in hunting. The large digital flexors and extensors observed in the cheetah forelimb may be used to dig the digits into the ground, aiding with traction when galloping and manoeuvring. © 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.

An Automated Test of Rat Forelimb Supination Quantifies Motor Function Loss and Recovery After Corticospinal Injury.

PubMed

Sindhurakar, Anil; Butensky, Samuel D; Meyers, Eric; Santos, Joshua; Bethea, Thelma; Khalili, Ashley; Sloan, Andrew P; Rennaker, Robert L; Carmel, Jason B

2017-02-01

Rodents are the primary animal model of corticospinal injury and repair, yet current behavioral tests do not show the large deficits after injury observed in humans. Forearm supination is critical for hand function and is highly impaired by corticospinal injury in both humans and rats. Current tests of rodent forelimb function do not measure this movement. To determine if quantification of forelimb supination in rats reveals large-scale functional loss and partial recovery after corticospinal injury. We developed a knob supination device that quantifies supination using automated and objective methods. Rats in a reaching box have to grasp and turn a knob in supination in order to receive a food reward. Performance on this task and the single pellet reaching task were measured before and after 2 manipulations of the pyramidal tract: a cut lesion of 1 pyramid and inactivation of motor cortex using 2 different drug doses. A cut lesion of the corticospinal tract produced a large deficit in supination. In contrast, there was no change in pellet retrieval success. Supination function recovered partially over 6 weeks after injury, and a large deficit remained. Motor cortex inactivation produced a dose-dependent loss of knob supination; the effect on pellet reaching was more subtle. The knob supination task reveals in rodents 3 signature hand function changes observed in humans with corticospinal injury: (1) large-scale loss with injury, (2) partial recovery in the weeks after injury, and (3) loss proportional to degree of dysfunction.

Movement asymmetry in working polo horses.

PubMed

Pfau, T; Parkes, R S; Burden, E R; Bell, N; Fairhurst, H; Witte, T H

2016-07-01

The high, repetitive demands imposed on polo horses in training and competition may predispose them to musculoskeletal injuries and lameness. To quantify movement symmetry and lameness in a population of polo horses, and to investigate the existence of a relationship with age. Convenience sampled cross-sectional study. Sixty polo horses were equipped with inertial measurement units (IMUs) attached to the poll, and between the tubera sacrale. Six movement symmetry measures were calculated for vertical head and pelvic displacement during in-hand trot and compared with values for perfect symmetry, compared between left and right limb lame horses, and compared with published thresholds for lameness. Regression lines were calculated as a function of age of horse. Based on 2 different sets of published asymmetry thresholds 52-53% of the horses were quantified with head movement asymmetry and 27-50% with pelvic movement asymmetry resulting in 60-67% of horses being classified with movement asymmetry outside published guideline values for either the forelimbs, hindlimbs or both. Neither forelimb nor hindlimb asymmetries were preferentially left or right sided, with directional asymmetry values across all horses not different from perfect symmetry and absolute values not different between left and right lame horses (P values >0.6 for all forelimb symmetry measures and >0.2 for all hindlimb symmetry measures). None of the symmetry parameters increased or decreased significantly with age. A large proportion of polo horses show gait asymmetries consistent with previously defined thresholds for lameness. These do not appear to be lateralised or associated with age. © 2015 EVJ Ltd.

Output Properties of the Cortical Hindlimb Motor Area in Spinal Cord-Injured Rats

PubMed Central

Dunham, Caleb L.; Barbay, Scott; Krizsan-Agbas, Dora; Winter, Michelle K.; Guggenmos, David J.; Nudo, Randolph J.

2015-01-01

Abstract The purpose of this study was to examine neuronal activity levels in the hindlimb area of motor cortex following spinal cord injury (SCI) in rats and compare the results with measurements in normal rats. Fifteen male Fischer-344 rats received a 200 Kdyn contusion injury in the thoracic cord at level T9–T10. After a minimum of 4 weeks following SCI, intracortical microstimulation (ICMS) and single-unit recording techniques were used in both the forelimb and hindlimb motor areas (FLA, HLA) under ketamine anesthesia. Although movements could be evoked using ICMS in the forelimb area with relatively low current levels, no movements or electromyographical responses could be evoked from ICMS in the HLA in any of the injured rats. During the same procedure, electrophysiological recordings were obtained with a single-shank, 16-channel Michigan probe (Neuronexus) to monitor activity. Neural spikes were discriminated using principle component analysis. Neural activity (action potentials) was collected and digitized for a duration of 5 min. Despite the inability to evoke movement from stimulation of cortex, robust single-unit activity could be recorded reliably from hindlimb motor cortex in SCI rats. Activity in the motor cortex of SCI rats was significantly higher compared with uninjured rats, and increased in hindlimb and forelimb motor cortex by similar amounts. These results demonstrate that in a rat model of thoracic SCI, an increase in single-unit cortical activity can be reliably recorded for several weeks post-injury. PMID:26406381

Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys.

PubMed

Collins, Simon N; Dyson, Sue J; Murray, Rachel C; Newton, J Richard; Burden, Faith; Trawford, Andrew F

2012-08-01

To establish and validate an objective method of radiographic diagnosis of anatomic changes in laminitic forefeet of donkeys on the basis of data from a comprehensive series of radiographic measurements. 85 donkeys with and 85 without forelimb laminitis for baseline data determination; a cohort of 44 donkeys with and 18 without forelimb laminitis was used for validation analyses. For each donkey, lateromedial radiographic views of 1 weight-bearing forelimb were obtained; images from 11 laminitic and 2 nonlaminitic donkeys were excluded (motion artifact) from baseline data determination. Data from an a priori selection of 19 measurements of anatomic features of laminitic and nonlaminitic donkey feet were analyzed by use of a novel application of multivariate statistical techniques. The resultant diagnostic models were validated in a blinded manner with data from the separate cohort of laminitic and nonlaminitic donkeys. Data were modeled, and robust statistical rules were established for the diagnosis of anatomic changes within laminitic donkey forefeet. Component 1 scores ≤ -3.5 were indicative of extreme anatomic change, and scores from -2.0 to 0.0 denoted modest change. Nonlaminitic donkeys with a score from 0.5 to 1.0 should be considered as at risk for laminitis. Results indicated that the radiographic procedures evaluated can be used for the identification, assessment, and monitoring of anatomic changes associated with laminitis. Screening assessments by use of this method may enable early detection of mild anatomic change and identification of at-risk donkeys.

Bat Accelerated Regions Identify a Bat Forelimb Specific Enhancer in the HoxD Locus

PubMed Central

Mason, Mandy K.; VanderMeer, Julia E.; Zhao, Jingjing; Eckalbar, Walter L.; Logan, Malcolm; Illing, Nicola; Pollard, Katherine S.; Ahituv, Nadav

2016-01-01

The molecular events leading to the development of the bat wing remain largely unknown, and are thought to be caused, in part, by changes in gene expression during limb development. These expression changes could be instigated by variations in gene regulatory enhancers. Here, we used a comparative genomics approach to identify regions that evolved rapidly in the bat ancestor, but are highly conserved in other vertebrates. We discovered 166 bat accelerated regions (BARs) that overlap H3K27ac and p300 ChIP-seq peaks in developing mouse limbs. Using a mouse enhancer assay, we show that five Myotis lucifugus BARs drive gene expression in the developing mouse limb, with the majority showing differential enhancer activity compared to the mouse orthologous BAR sequences. These include BAR116, which is located telomeric to the HoxD cluster and had robust forelimb expression for the M. lucifugus sequence and no activity for the mouse sequence at embryonic day 12.5. Developing limb expression analysis of Hoxd10-Hoxd13 in Miniopterus natalensis bats showed a high-forelimb weak-hindlimb expression for Hoxd10-Hoxd11, similar to the expression trend observed for M. lucifugus BAR116 in mice, suggesting that it could be involved in the regulation of the bat HoxD complex. Combined, our results highlight novel regulatory regions that could be instrumental for the morphological differences leading to the development of the bat wing. PMID:27019019

Manipulated Changes in Limb Mass and Rotational Inertia in Trotting Dogs (Canis lupus familiaris) and Their Effect on Limb Kinematics.

PubMed

Kilbourne, Brandon M; Carrier, David R

2016-12-01

While the mass distribution of limbs is known to influence the metabolic energy consumed during locomotion, it remains unknown how the mass distribution of limbs may influence overall limb kinematics and whether the influence of limb mass distribution on limb kinematics differs between fore- and hindlimbs. To examine limb mass distribution's influence upon fore- and hindlimb kinematics, temporal stride parameters and swing phase joint kinematics were recorded from four dogs trotting on a treadmill with 0.5% and 1.0% body mass added to each limb, forelimbs alone, and hindlimbs alone, as well as with no added mass. Under all loading conditions, stride period did not differ between fore- and hindlimbs; however, forelimbs exhibited greater duty factors and stance durations, whereas hindlimbs exhibited greater swing durations, which may be related to the hindlimb's greater mass. Changes in forelimb joint and hip range of motion (RoM), flexion, and extension were subject to a high amount of kinematic plasticity among dogs. In contrast, for the knee and ankle, distally loading all four limbs or hindlimbs alone substantially increased joint RoM and flexion. Increased flexion of the knee and ankle has the potential to reduce the hindlimb's rotational inertia during swing phase. The differing response of fore- and hindlimbs with regard to joint kinematics is likely due to differences in their mass and mass distribution and differences in the physiological traits of fore- and hindlimb protractors and joint flexors. © 2017 Wiley Periodicals, Inc.

Effect of solutes in binary columbium /Nb/ alloys on creep strength

NASA Technical Reports Server (NTRS)

Klein, M. J.; Metcalfe, A. G.

1973-01-01

The effect of seven different solutes in binary columbium (Nb) alloys on creep strength was determined from 1400 to 3400 F for solute concentrations to 20 at.%, using a new method of creep-strength measurement. The technique permits rapid determination of approximate creep strength over a large temperature span. All of the elements were found to increase the creep strength of columbium except tantalum. This element did not strengthen columbium until the concentration exceeded 10 at.%. Hafnium, zirconium, and vanadium strengthed columbium most at low temperatures and concentrations, whereas tungsten, molybdenum, and rhenium contributed more to creep strength at high temperatures and concentrations.

Hydrogen-Resistant Fe/Ni/Cr-Base Superalloy

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Chen, Po-Shou; Panda, Binayak

1994-01-01

Strong Fe/Ni/Cr-base hydrogen- and corrosion-resistant alloy developed. Superalloy exhibits high strength and exceptional resistance to embrittlement by hydrogen. Contains two-phase microstructure consisting of conductivity precipitated phase in conductivity matrix phase. Produced in wrought, weldable form and as castings, alloy maintains high ductility and strength in air and hydrogen. Strength exceeds previously known Fe/Cr/Ni hydrogen-, oxidation-, and corrosion-resistant alloys. Provides higher strength-to-weight ratios for lower weight in applications as storage vessels and pipes that must contain hydrogen.

Adaptation to suspensory locomotion in Australopithecus sediba.

PubMed

Rein, Thomas R; Harrison, Terry; Carlson, Kristian J; Harvati, Katerina

2017-03-01

Australopithecus sediba is represented by well-preserved fossilized remains from the locality of Malapa, South Africa. Recent work has shown that the combination of features in the limb skeleton of A. sediba was distinct from that of earlier species of Australopithecus, perhaps indicating that this species moved differently. The bones of the arm and forearm indicate that A. sediba was adapted to suspensory and climbing behaviors. We used a geometric morphometric approach to examine ulnar shape, potentially identifying adaptations to forelimb suspensory locomotion in A. sediba. Results indicated suspensory capabilities in this species and a stronger forelimb suspensory signal than has been documented in Australopithecus afarensis. Our study confirms the adaptive significance of functional morphological traits for arboreal movements in the locomotor repertoire of A. sediba and provides important insight into the diversity and mosaic nature of locomotor adaptations among early hominins. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shifting Paradigms to Better Serve Twice-Exceptional African-American Learners

ERIC Educational Resources Information Center

Owens, Charissa M.; Ford, Donna Y.; Lisbon, April J.; Owens, Michael T.

2016-01-01

Existing research on students with twice-exceptional abilities concentrates on strategies to improve the educational experiences of individuals who demonstrate the comorbid presence of a talent for high academic achievement (often considered a strength) and a disability (often considered a weakness). However, this body of work typically excludes…

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2012 CFR

2012-07-01

... protection requirements for employees performing steel erection work (except for towers and tanks) are... protection systems, except in relation to steel erection activities and the use of equipment covered by... refusal, breakage, or separation of component parts. Load refusal is the point where the ultimate strength...

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2011 CFR

2011-07-01

... protection requirements for employees performing steel erection work (except for towers and tanks) are... protection systems, except in relation to steel erection activities and the use of equipment covered by... refusal, breakage, or separation of component parts. Load refusal is the point where the ultimate strength...

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Fall protection requirements for employees performing steel erection work (except for towers and tanks... protection systems, except in relation to steel erection activities. (b) Definitions. Anchorage means a... component parts. Load refusal is the point where the ultimate strength is exceeded. Free fall means the act...

29 CFR 1926.500 - Scope, application, and definitions applicable to this subpart.

Code of Federal Regulations, 2013 CFR

2013-07-01

... protection requirements for employees performing steel erection work (except for towers and tanks) are... protection systems, except in relation to steel erection activities and the use of equipment covered by... refusal, breakage, or separation of component parts. Load refusal is the point where the ultimate strength...

49 CFR 238.203 - Static end strength.

Code of Federal Regulations, 2014 CFR

2014-10-01

... inches by 24 inches. The alternative specified in this paragraph is not applicable to a cab car or an MU... use of the equipment; and (v) A quantitative risk assessment, incorporating the design information... Equipment § 238.203 Static end strength. (a)(1) Except as further specified in this paragraph or in...

49 CFR 238.203 - Static end strength.

Code of Federal Regulations, 2013 CFR

2013-10-01

... inches by 24 inches. The alternative specified in this paragraph is not applicable to a cab car or an MU... use of the equipment; and (v) A quantitative risk assessment, incorporating the design information... Equipment § 238.203 Static end strength. (a)(1) Except as further specified in this paragraph or in...

49 CFR 238.203 - Static end strength.

Code of Federal Regulations, 2012 CFR

2012-10-01

... inches by 24 inches. The alternative specified in this paragraph is not applicable to a cab car or an MU... use of the equipment; and (v) A quantitative risk assessment, incorporating the design information... Equipment § 238.203 Static end strength. (a)(1) Except as further specified in this paragraph or in...

Motor Skills Training Enhances α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor Subunit mRNA Expression in the Ipsilateral Sensorimotor Cortex and Striatum of Rats Following Intracerebral Hemorrhage.

PubMed

Tamakoshi, Keigo; Ishida, Kazuto; Kawanaka, Kentaro; Takamatsu, Yasuyuki; Tamaki, Hiroyuki

2017-10-01

We investigated the effects of acrobatic training (AT) on expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunits in the sensorimotor cortex and striatum after intracerebral hemorrhage (ICH). Male Wistar rats were divided into 4 groups: ICH without AT (ICH), ICH with AT (ICH + AT), sham operation without AT (SHAM), and sham operation with AT (SHAM + AT). ICH was induced by collagenase injection into the left striatum. The ICH + AT group performed 5 acrobatic tasks daily on days 4-28 post ICH. Forelimb sensorimotor function was evaluated using the forelimb placing test. On days 14 and 29, mRNA expression levels of AMPAR subunits GluR1-4 were measured by real-time reverse transcription-polymerase chain reaction. Forelimb placing test scores were significantly higher in the ICH + AT group than in the ICH group. Expression levels of all AMPAR subunit mRNAs were significantly higher in the ipsilateral sensorimotor cortex of rats in the ICH + AT group than in that of rats in the ICH group on day 29. GluR3 and GluR4 expression levels were reduced in the ipsilateral striatum of rats in the ICH group compared with that of rats in the SHAM group on day 14. These changes may play a critical role in motor skills training-induced recovery after ICH. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Morphological integration in the forelimb of musteloid carnivorans

PubMed Central

Fabre, Anne-Claire; Goswami, Anjali; Peigné, Stéphane; Cornette, Raphaël

2014-01-01

The forelimb forms a functional unit that allows a variety of behaviours and needs to be mobile, yet at the same time stable. Both mobility and stability are controlled, amongst others, at the level of the elbow joint. This joint is composed of the humero-ulnar articulation, mainly involved during parasagittal movements; and the radio-ulnar articulation, mainly allowing rotation. In contrast, the humero-radial articulation allows both movements of flexion–extension and rotation. Here, we study the morphological integration between each bone of the forelimb at the level of the entire arm, as well as at the elbow joint, in musteloid carnivorans. To do so, we quantitatively test shape co-variation using surface 3D geometric morphometric data. Our results show that morphological integration is stronger for bones that form functional units. Different results are obtained depending on the level of investigation: for the entire arm, results show a greater degree of shape co-variation between long bones of the lower arm than between the humerus and either bone of the lower arm. Thus, at this level the functional unit of the lower arm is comprised of the radius and ulna, permitting rotational movements of the lower arm. At the level of the elbow, results display a stronger shape co-variation between bones allowing flexion and stability (humerus and ulna) than between bones allowing mobility (ulna and radius and humerus and radius). Thus, the critical functional unit appears to be the articulation between the humerus and ulna providing the stability of the joint. PMID:24836555

Fore-Aft Ground Force Adaptations to Induced Forelimb Lameness in Walking and Trotting Dogs

PubMed Central

Abdelhadi, Jalal; Wefstaedt, Patrick; Nolte, Ingo; Schilling, Nadja

2012-01-01

Animals alter their locomotor mechanics to adapt to a loss of limb function. To better understand their compensatory mechanisms, this study evaluated the changes in the fore-aft ground forces to forelimb lameness and tested the hypothesis that dogs unload the affected limb by producing a nose-up pitching moment via the exertion of a net-propulsive force when the lame limb is on the ground. Seven healthy Beagles walked and trotted at steady speed on an instrumented treadmill while horizontal force data were collected before and after a moderate lameness was induced. Peak, mean and summed braking and propulsive forces as well as the duration each force was exerted and the time to reach maximum force were evaluated for both the sound and the lame condition. Compared with the sound condition, a net-propulsive force was produced by the lame diagonal limbs due to a reduced braking force in the affected forelimb and an increased propulsive force in the contralateral hindlimb when the dogs walked and trotted. To regain pitch stability and ensure steady speed for a given locomotor cycle, the dogs produced a net-braking force when the sound diagonal limbs were on the ground by exerting greater braking forces in both limbs during walking and additionally reducing the propulsive force in the hindlimb during trotting. Consistent with the proposed mechanism, dogs maximize their double support phases when walking. Likely associated with the fore-aft force adaptations to lameness are changes in muscle recruitment that potentially result in short- and long-term effects on the limb and trunk muscles. PMID:23300614

Hindlimb motion during steady flight of the lesser dog-faced fruit bat, Cynopterus brachyotis.

PubMed

Cheney, Jorn A; Ton, Daniel; Konow, Nicolai; Riskin, Daniel K; Breuer, Kenneth S; Swartz, Sharon M

2014-01-01

In bats, the wing membrane is anchored not only to the body and forelimb, but also to the hindlimb. This attachment configuration gives bats the potential to modulate wing shape by moving the hindlimb, such as by joint movement at the hip or knee. Such movements could modulate lift, drag, or the pitching moment. In this study we address: 1) how the ankle translates through space during the wingbeat cycle; 2) whether amplitude of ankle motion is dependent upon flight speed; 3) how tension in the wing membrane pulls the ankle; and 4) whether wing membrane tension is responsible for driving ankle motion. We flew five individuals of the lesser dog-faced fruit bat, Cynopterus brachyotis (Family: Pteropodidae), in a wind tunnel and documented kinematics of the forelimb, hip, ankle, and trailing edge of the wing membrane. Based on kinematic analysis of hindlimb and forelimb movements, we found that: 1) during downstroke, the ankle moved ventrally and during upstroke the ankle moved dorsally; 2) there was considerable variation in amplitude of ankle motion, but amplitude did not correlate significantly with flight speed; 3) during downstroke, tension generated by the wing membrane acted to pull the ankle dorsally, and during upstroke, the wing membrane pulled laterally when taut and dorsally when relatively slack; and 4) wing membrane tension generally opposed dorsoventral ankle motion. We conclude that during forward flight in C. brachyotis, wing membrane tension does not power hindlimb motion; instead, we propose that hindlimb movements arise from muscle activity and/or inertial effects.

Population Coding of Forelimb Joint Kinematics by Peripheral Afferents in Monkeys

PubMed Central

Umeda, Tatsuya; Seki, Kazuhiko; Sato, Masa-aki; Nishimura, Yukio; Kawato, Mitsuo; Isa, Tadashi

2012-01-01

Various peripheral receptors provide information concerning position and movement to the central nervous system to achieve complex and dexterous movements of forelimbs in primates. The response properties of single afferent receptors to movements at a single joint have been examined in detail, but the population coding of peripheral afferents remains poorly defined. In this study, we obtained multichannel recordings from dorsal root ganglion (DRG) neurons in cervical segments of monkeys. We applied the sparse linear regression (SLiR) algorithm to the recordings, which selects useful input signals to reconstruct movement kinematics. Multichannel recordings of peripheral afferents were performed by inserting multi-electrode arrays into the DRGs of lower cervical segments in two anesthetized monkeys. A total of 112 and 92 units were responsive to the passive joint movements or the skin stimulation with a painting brush in Monkey 1 and Monkey 2, respectively. Using the SLiR algorithm, we reconstructed the temporal changes of joint angle, angular velocity, and acceleration at the elbow, wrist, and finger joints from temporal firing patterns of the DRG neurons. By automatically selecting a subset of recorded units, the SLiR achieved superior generalization performance compared with a regularized linear regression algorithm. The SLiR selected not only putative muscle units that were responsive to only the passive movements, but also a number of putative cutaneous units responsive to the skin stimulation. These results suggested that an ensemble of peripheral primary afferents that contains both putative muscle and cutaneous units encode forelimb joint kinematics of non-human primates. PMID:23112841

The Role of Endogenous Neurogenesis in Functional Recovery and Motor Map Reorganization Induced by Rehabilitative Therapy after Stroke in Rats.

PubMed

Shiromoto, Takashi; Okabe, Naohiko; Lu, Feng; Maruyama-Nakamura, Emi; Himi, Naoyuki; Narita, Kazuhiko; Yagita, Yoshiki; Kimura, Kazumi; Miyamoto, Osamu

2017-02-01

Endogenous neurogenesis is associated with functional recovery after stroke, but the roles it plays in such recovery processes are unknown. This study aims to clarify the roles of endogenous neurogenesis in functional recovery and motor map reorganization induced by rehabilitative therapy after stroke by using a rat model of cerebral ischemia (CI). Ischemia was induced via photothrombosis in the caudal forelimb area of the rat cortex. First, we examined the effect of rehabilitative therapy on functional recovery and motor map reorganization, using the skilled forelimb reaching test and intracortical microstimulation. Next, using the same approaches, we examined how motor map reorganization changed when endogenous neurogenesis after stroke was inhibited by cytosine-β-d-arabinofuranoside (Ara-C). Rehabilitative therapy for 4 weeks after the induction of stroke significantly improved functional recovery and expanded the rostral forelimb area (RFA). Intraventricular Ara-C administration for 4-10 days after stroke significantly suppressed endogenous neurogenesis compared to vehicle, but did not appear to influence non-neural cells (e.g., microglia, astrocytes, and vascular endothelial cells). Suppressing endogenous neurogenesis via Ara-C administration significantly inhibited (~50% less than vehicle) functional recovery and RFA expansion (~33% of vehicle) induced by rehabilitative therapy after CI. After CI, inhibition of endogenous neurogenesis suppressed both the functional and anatomical markers of rehabilitative therapy. These results suggest that endogenous neurogenesis contributes to functional recovery after CI related to rehabilitative therapy, possibly through its promotion of motor map reorganization, although other additional roles cannot be ruled out. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

A pressure plate study on fore and hindlimb loading and the association with hoof contact area in sound ponies at the walk and trot.

PubMed

Oosterlinck, M; Pille, F; Back, W; Dewulf, J; Gasthuys, F

2011-10-01

The aim of this study was to evaluate the association between fore- and hind-hoof contact area and limb loading. Data from a previous study on forelimb loading and symmetry were compared with data on hindlimb kinetics, and the fore- and hind-hoof contact area at the walk and trot was evaluated. Five sound ponies, selected for symmetrical feet, were walked and trotted over a pressure plate embedded in a custom-made runway. The hindlimb peak vertical force (PVF) and vertical impulse (VI) were found to be significantly lower than in the forelimb, whereas their high symmetry ratios (>95%) did not show a significant difference from forelimb data. Hindlimb PVF in ponies was found to be slightly higher when compared to data reported for horses even though the ponies moved at a similar or lower relative velocity. The contact area had low intra-individual variability and was significantly smaller in the hind- than in the fore-hooves. A larger contact area was significantly associated with lower peak vertical pressure (PVP) but higher PVF and VI. No significant differences between left and right sides were found for contact area or loading variables. Pressure plate measurements demonstrated a significant association between hoof contact area and limb loading, in addition to intrinsic differences between fore and hindlimb locomotor function. The pressure plate provides the clinician with a tool to quantify simultaneously contralateral differences in hoof contact area and limb loading. Copyright © 2010 Elsevier Ltd. All rights reserved.

Dexterity: A MATLAB-based analysis software suite for processing and visualizing data from tasks that measure arm or forelimb function.

PubMed

Butensky, Samuel D; Sloan, Andrew P; Meyers, Eric; Carmel, Jason B

2017-07-15

Hand function is critical for independence, and neurological injury often impairs dexterity. To measure hand function in people or forelimb function in animals, sensors are employed to quantify manipulation. These sensors make assessment easier and more quantitative and allow automation of these tasks. While automated tasks improve objectivity and throughput, they also produce large amounts of data that can be burdensome to analyze. We created software called Dexterity that simplifies data analysis of automated reaching tasks. Dexterity is MATLAB software that enables quick analysis of data from forelimb tasks. Through a graphical user interface, files are loaded and data are identified and analyzed. These data can be annotated or graphed directly. Analysis is saved, and the graph and corresponding data can be exported. For additional analysis, Dexterity provides access to custom scripts created by other users. To determine the utility of Dexterity, we performed a study to evaluate the effects of task difficulty on the degree of impairment after injury. Dexterity analyzed two months of data and allowed new users to annotate the experiment, visualize results, and save and export data easily. Previous analysis of tasks was performed with custom data analysis, requiring expertise with analysis software. Dexterity made the tools required to analyze, visualize and annotate data easy to use by investigators without data science experience. Dexterity increases accessibility to automated tasks that measure dexterity by making analysis of large data intuitive, robust, and efficient. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative anatomy, homologies and evolution of the pectoral and forelimb musculature of tetrapods with special attention to extant limbed amphibians and reptiles

PubMed Central

Abdala, Virginia; Diogo, Rui

2010-01-01

The main aim of the present work is to synthesize the information obtained from our dissections of the pectoral and forelimb muscles of representative members of the major extant taxa of limbed amphibians and reptiles and from our review of the literature, in order to provide an account of the comparative anatomy, homologies and evolution of these muscles in the Tetrapoda. The pectoral and forelimb musculature of all these major taxa conform to a general pattern that seems to have been acquired very early in the evolutionary history of tetrapods. Although some muscles are missing in certain taxa, and a clear departure from this general pattern is obviously present in derived groups such as birds, the same overall configuration is easily distinguishable in these taxa. Among the most notable anatomical differences between the groups, one that seems to have relevant evolutionary and functional implications, concerns the distal insertion points of the forearm musculature. In tetrapods, the muscles of the radial and ulnar complexes of the forearm are pleisomorphically mainly inserted onto the radius/ulna or onto the more proximal carpal bones, but in mammals some of these muscles insert more distally onto bones such as the metacarpals. Interestingly, a similar trend towards a more distal insertion of these muscles is also found in some non-mammalian tetrapod taxa, such as some anurans (e.g. Phyllomedusa). This may be correlated with the acquisition of more subtle digital movement abilities in these latter taxa. PMID:20807270

Targeted mini-strokes produce changes in interhemispheric sensory signal processing that are indicative of disinhibition within minutes.

PubMed

Mohajerani, Majid H; Aminoltejari, Khatereh; Murphy, Timothy H

2011-05-31

Most processing of sensation involves the cortical hemisphere opposite (contralateral) to the stimulated limb. Stroke patients can exhibit changes in the interhemispheric balance of sensory signal processing. It is unclear whether these changes are the result of poststroke rewiring and experience, or whether they could result from the immediate effect of circuit loss. We evaluated the effect of mini-strokes over short timescales (<2 h) where cortical rewiring is unlikely by monitoring sensory-evoked activity throughout much of both cortical hemispheres using voltage-sensitive dye imaging. Blockade of a single pial arteriole within the C57BL6J mouse forelimb somatosensory cortex reduced the response evoked by stimulation of the limb contralateral to the stroke. However, after stroke, the ipsilateral (uncrossed) forelimb response within the unaffected hemisphere was spared and became independent of the contralateral forelimb cortex. Within the unaffected hemisphere, mini-strokes in the opposite hemisphere significantly enhanced sensory responses produced by stimulation of either contralateral or ipsilateral pathways within 30-50 min of stroke onset. Stroke-induced enhancement of responses within the spared hemisphere was not reproduced by inhibition of either cortex or thalamus using pharmacological agents in nonischemic animals. I/LnJ acallosal mice showed similar rapid interhemispheric redistribution of sensory processing after stroke, suggesting that subcortical connections and not transcallosal projections were mediating the novel activation patterns. Thalamic inactivation before stroke prevented the bilateral rearrangement of sensory responses. These findings suggest that acute stroke, and not merely loss of activity, activates unique pathways that can rapidly redistribute function within the spared cortical hemisphere.

Prevalence of Prostate Cancer Metastases after Intravenous Inoculation Provides Clues into the Molecular Basis of Dormancy in the Bone Marrow Microenvironment1

PubMed Central

Jung, Younghun; Shiozawa, Yusuke; Wang, Jingcheng; McGregor, Natalie; Dai, Jinlu; Park, Serk In; Berry, Janice E; Havens, Aaron M; Joseph, Jeena; Kim, Jin Koo; Patel, Lalit; Carmeliet, Peter; Daignault, Stephanie; Keller, Evan T; McCauley, Laurie K; Pienta, Kenneth J; Taichman, Russell S

2012-01-01

Bone is the preferred metastasis site of advanced prostate cancer (PCa). Using an in vivo murine model of human PCa cell metastasis to bone, we noted that the majority of animals that develop skeletal metastasis have either spinal lesions or lesions in the bones of the hindlimb. Much less frequently, lesions develop in the bones of the forelimb. We therefore speculated whether the environment of the forelimb bones is not permissive for the growth of PCa. Consequently, data on tumor prevalence were normalized to account for the number of PCa cells arriving after intravascular injection, marrow cellularity, and number of hematopoietic stem cell niches. None of these factors were able to account for the observed differences in tumor prevalence. An analysis of differential gene and protein levels identified that growth arrest specific-6 (GAS6) levels were significantly greater in the forelimb versus hindlimb bone marrow. When murine RM1 cells were implanted into subcutaneous spaces in immune competent animals, tumor growth in the GAS6-/- animals was greater than in GAS6+/+ wild-type animals. In an osseous environment, the human PC3 cell line grew significantly better in vertebral body transplants (vossicles) derived from GAS6-/- animals than in vossicles derived from GAS6+/+ animals. Together, these data suggest that the differences in tumor prevalence after intravascular inoculation are a useful model to study the molecular basis of tumor dormancy. Importantly, these data suggest that therapeutic manipulation of GAS6 levels may prove useful as a therapy for metastatic disease. PMID:22745589

[Biomechanical study on effects of bone mineral density on fixation strength of expansive pedicle screw].

PubMed

Gao, Mingxuan; Li, Xusheng; Zhen, Ping; Wu, Zhigang; Zhou, Shenghu; Tian, Qi; Lei, Wei

2013-08-01

To evaluate the fixation strength of expansive pedicle screw (EPS) at different bone mineral density (BMD) levels, further to provide theoretical evidence for the clinical application of the EPS in patients with osteoporosis. Fresh human cadaver spines (T12-L5 spines) were divided into 4 levels: normal BMD, osteopenia, osteoporosis, and severe osteoporosis according to the value of BMD, 12 vertebra in each level. Conventional pedicle screw (CPS) or EPS was implanted into the bilateral vertebra in CPS group and EPS group, respectively, 12 screws in each group per BMD level. Screw pullout tests were conducted. The maximum pullout strength, stiffness, and energy absorption were determined by an AG-IS material testing machine with constant rate of loading in a speed of 5 mm/min. With the decline of BMD from normal to severe osteoporosis level, the maximum pullout strength and the stiffness correspondingly declined (P < 0.05). In CPS group, the energy absorption gradually decreased (P < 0.05); in EPS group, significant difference was found between other different BMD levels (P < 0.05) except between normal BMD and osteopenia and between osteoporosis and severe osteoporosis (P > 0.05). At the same BMD level, the maximum pullout strength of EPS group was significantly larger than that of CPS group (P < 0.05); the stiffness of EPS group was significantly higher than that of CPS group (P < 0.05) except one at normal BMD level; and no significant difference was found in the energy absorption between 2 groups (P > 0.05) except one at osteopenia level. No significant difference was found in maximum pullout strength, stiffness, and energy absorption between EPS group at osteoporosis level and CPS group at osteopenia level (P > 0.05); however, the maximum pullout strength, stiffness, and energy absorption of EPS group at severe osteoporosis level were significantly lower than those of CPS group at osteopenia level (P < 0.05). Compared with CPS, the EPS can significantly improve the fixation strength, especially in patients with osteopenia or osteoporosis.

Stabilization of cat paw trajectory during locomotion

PubMed Central

Klishko, Alexander N.; Farrell, Bradley J.; Beloozerova, Irina N.; Latash, Mark L.

2014-01-01

We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it (“bad variance,” variance orthogonal to the UCM, VORT) while the other one did not (“good variance,” variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. PMID:24899676

Intralimb and Interlimb Cutaneous Reflexes during Locomotion in the Intact Cat.

PubMed

Hurteau, Marie-France; Thibaudier, Yann; Dambreville, Charline; Danner, Simon M; Rybak, Ilya A; Frigon, Alain

2018-04-25

When the foot contacts an obstacle during locomotion, cutaneous inputs activate spinal circuits to ensure dynamic balance and forward progression. In quadrupeds, this requires coordinated reflex responses between the four limbs. Here, we investigated the patterns and phasic modulation of cutaneous reflexes in forelimb and hindlimb muscles evoked by inputs from all four limbs. Five female cats were implanted to record muscle activity and to stimulate the superficial peroneal and superficial radial nerves during locomotion. Stimulating these nerves evoked short-, mid-, and longer-latency excitatory and/or inhibitory responses in all four limbs that were phase-dependent. The largest responses were generally observed during the peak activity of the muscle. Cutaneous reflexes during mid-swing were consistent with flexion of the homonymous limb and accompanied by modification of the stance phases of the other three limbs, by coactivating flexors and extensors and/or by delaying push-off. Cutaneous reflexes during mid-stance were consistent with stabilizing the homonymous limb by delaying and then facilitating its push-off and modifying the support phases of the homolateral and diagonal limbs, characterized by coactivating flexors and extensors, reinforcing extensor activity and/or delaying push-off. The shortest latencies of homolateral and diagonal responses were consistent with fast-conducting disynaptic or trisynaptic pathways. Descending homolateral and diagonal pathways from the forelimbs to the hindlimbs had a higher probability of eliciting responses compared with ascending pathways from the hindlimbs to the forelimbs. Thus, in quadrupeds, intralimb and interlimb reflexes activated by cutaneous inputs ensure dynamic coordination of the four limbs, producing a whole-body response. SIGNIFICANCE STATEMENT The skin contains receptors that, when activated, send inputs to spinal circuits, signaling a perturbation. Rapid responses, or reflexes, in muscles of the contacted limb and opposite homologous limb help maintain balance and forward progression. Here, we investigated reflexes during quadrupedal locomotion in the cat by electrically stimulating cutaneous nerves in each of the four limbs. Functionally, responses appear to modify the trajectory or stabilize the movement of the stimulated limb while modifying the support phase of the other limbs. Reflexes between limbs are mediated by fast-conducting pathways that involve excitatory and inhibitory circuits controlling each limb. The comparatively stronger descending pathways from cervical to lumbar circuits controlling the forelimbs and hindlimbs, respectively, could serve a protective function. Copyright © 2018 the authors 0270-6474/18/384104-19$15.00/0.

Muscle synergies obtained from comprehensive mapping of the primary motor cortex forelimb representation using high-frequency, long-duration ICMS.

PubMed

Amundsen Huffmaster, Sommer L; Van Acker, Gustaf M; Luchies, Carl W; Cheney, Paul D

2017-07-01

Simplifying neuromuscular control for movement has previously been explored by extracting muscle synergies from voluntary movement electromyography (EMG) patterns. The purpose of this study was to investigate muscle synergies represented in EMG recordings associated with direct electrical stimulation of single sites in primary motor cortex (M1). We applied single-electrode high-frequency, long-duration intracortical microstimulation (HFLD-ICMS) to the forelimb region of M1 in two rhesus macaques using parameters previously found to produce forelimb movements to stable spatial end points (90-150 Hz, 90-150 μA, 1,000-ms stimulus train lengths). To develop a comprehensive representation of cortical output, stimulation was applied systematically across the full extent of M1. We recorded EMG activity from 24 forelimb muscles together with movement kinematics. Nonnegative matrix factorization (NMF) was applied to the mean stimulus-evoked EMG, and the weighting coefficients associated with each synergy were mapped to the cortical location of the stimulating electrode. Synergies were found for three data sets including 1 ) all stimulated sites in the cortex, 2 ) a subset of sites that produced stable movement end points, and 3 ) EMG activity associated with voluntary reaching. Two or three synergies accounted for 90% of the overall variation in voluntary movement EMG whereas four or five synergies were needed for HFLD-ICMS-evoked EMG data sets. Maps of the weighting coefficients from the full HFLD-ICMS data set show limited regional areas of higher activation for particular synergies. Our results demonstrate fundamental NMF-based muscle synergies in the collective M1 output, but whether and how the central nervous system might coordinate movements using these synergies remains unclear. NEW & NOTEWORTHY While muscle synergies have been investigated in various muscle activity sets, it is unclear whether and how synergies may be organized in the cortex. We have investigated muscle synergies resulting from high-frequency, long-duration intracortical microstimulation (HFLD-ICMS) applied throughout M1. We compared HFLD-ICMS synergies to synergies from voluntary movement. While synergies can be identified from M1 stimulation, they are not clearly related to voluntary movement synergies and do not show an orderly topographic organization across M1. Copyright © 2017 the American Physiological Society.

Vertical head and pelvic movement symmetry at the trot in dogs with induced supporting limb lameness.

PubMed

Gómez Álvarez, C B; Gustås, P; Bergh, A; Rhodin, M

2017-11-01

Compensatory limb loading has been studied in lame dogs; however, little is known about how these compensations relate to motion of the head and pelvis, assessment of which is an important component of lameness examinations. The aim of this study was to describe the patterns of vertical head and pelvic motion symmetry at the trot in dogs with induced supporting limb lameness in the forelimbs or hind limbs. Ten sound dogs were trotted on a treadmill before and after temporary induction of moderate lameness (grade 2/5) in each limb. Reflective markers were located on the head, pelvis and right forelimb, and kinematic data were captured with a motion capture system. Upper body symmetry parameters were calculated, including differences in the highest (HDmax) and in the lowest (HDmin) positions of the head, and in the highest (PDmax) and in the lowest (PDmin) positions of the mid-pelvis, with a value of zero indicating symmetry. The head was lowered more during the sound limb stance phase and lowered less during the lame limb stance phase in supporting forelimb lameness (HDmin: 4.6mm in dogs when sound, -18.3mm when left limb lameness was induced and 20.5mm when right limb lameness was induced). The mid-pelvis was lowered more during the sound limb stance phase and lowered and lifted less during the lame limb stance phase in supporting hind limb lameness (PDmin: 1mm in dogs when sound, -10.1mm in left limb lameness and 8.4mm in right limb lameness). The hip of the lame side, measured at the level of the greater trochanter, had an increased downwards displacement during the lame limb swing phase (-21mm in left hind limb lameness, P=0.005; 23.4mm in right hind limb lameness, P=0.007). Asymmetry in the lowering of the head or mid-pelvis is a more sensitive indicator of supporting forelimb and hind limb lameness, respectively, than asymmetry in the raising of the head. Increased displacement of the hip ('hip drop' of the lame side during its swing phase) is a good indicator of hind limb lameness in dogs. Copyright © 2017. Published by Elsevier Ltd.

Relations between premise similarity and inductive strength.

PubMed

Heit, Evan; Feeney, Aidan

2005-04-01

According to the diversity principle, diverse evidence is strong evidence. There has been considerable evidence that people respect this principle in inductive reasoning. However, exceptions may be particularly informative. Medin, Coley, Storms, and Hayes (2003) introduced a relevance theory of inductive reasoning and used this theory to predict exceptions, including the nondiversity-by-property-reinforcement effect. A new experiment in which this phenomenon was investigated is reported here. Subjects made inductive strength judgments and similarity judgments for stimuli from Medin et al. (2003). The inductive strength judgments showed the same pattern as that in Medin et al. (2003); however, the similarity judgments suggested that the pattern should be interpreted as a diversity effect, rather than as a nondiversity effect. It is concluded that the evidence regarding the predicted nondiversity-by-property-reinforcement effect does not give distinctive support for relevance theory, although this theory does address other results.

African American therapists working with African American families: an exploration of the strengths perspective in treatment.

PubMed

Bell-Tolliver, LaVerne; Burgess, Ruby; Brock, Linda J

2009-07-01

With the exception of Hill's (1971, 1999) work, historically much of the literature on African American families has focused more on pathology than strengths. This study used interviews with 30 African American psychotherapists, self-identified as employing a strengths perspective with African American families, to investigate which strengths they identified in the families and how they use those strengths in therapy. Themes emerging from data analysis confirmed the continued importance of the five strengths Hill noted. In addition, two new strengths were identified by the participants: a willingness of a greater number of families to seek therapy, and the importance of family structure. Strategies used in engaging the families in therapy and practice implications for family therapists are discussed.

Periconceptional Folic Acid Supplementation Benefit to Development of Early Sensory-Motor Function through Increase DNA Methylation in Rat Offspring

PubMed Central

Li, Wen; Li, Zhenshu; Li, Shou; Wang, Xinyan; Wilson, John X.; Huang, Guowei

2018-01-01

Periconceptional maternal folate levels may alter DNA methylation patterns and health outcomes in offspring. We hypothesized that maternal folic acid supplementation alters fetal neural development through DNA methylation in the fetal brain. Twenty-eight rats were randomly assigned to four groups: three groups of the female rats were fed folate-normal, folate-deficient or folate-supplemented diets from seven days before mating to delivery. In another group, folic acid supplementation diet short-period group was fed a folate-normal diet, except for 10 days (begin mating) when this group was fed a folate-supplemented diet. After delivery, the diets were changed to folate-normal diet for all four groups. The cliff avoidance and forelimb grip tests were used to assess sensory motor function of rat offspring. The results indicate that maternal folic acid supplementation improved the early development of sensory-motor function in offspring. Maternal folic acid supplementation increased the methylation potential, global DNA methylation (5-mC) and DNA methyltransferase expression and activity in the brains of the offspring. In conclusion, maternal folic acid supplementation increases DNA methylation pattern in offspring brain and improves the early development of sensory-motor function. PMID:29494536

Inhibition of Activin Receptor Type IIB Increases Strength and Lifespan in Myotubularin-Deficient Mice

PubMed Central

Lawlor, Michael W.; Read, Benjamin P.; Edelstein, Rachel; Yang, Nicole; Pierson, Christopher R.; Stein, Matthew J.; Wermer-Colan, Ariana; Buj-Bello, Anna; Lachey, Jennifer L.; Seehra, Jasbir S.; Beggs, Alan H.

2011-01-01

X-linked myotubular myopathy (XLMTM) is a congenital disorder caused by deficiency of the lipid phosphatase, myotubularin. Patients with XLMTM often have severe perinatal weakness that requires mechanical ventilation to prevent death from respiratory failure. Muscle biopsy specimens from patients with XLMTM exhibit small myofibers with central nuclei and central aggregations of organelles in many cells. It was postulated that therapeutically increasing muscle fiber size would cause symptomatic improvement in myotubularin deficiency. Recent studies have elucidated an important role for the activin-receptor type IIB (ActRIIB) in regulation of muscle growth and have demonstrated that ActRIIB inhibition results in significant muscle hypertrophy. To evaluate whether promoting muscle hypertrophy can attenuate symptoms resulting from myotubularin deficiency, the effect of ActRIIB-mFC treatment was determined in myotubularin-deficient (Mtm1δ4) mice. Compared with wild-type mice, untreated Mtm1δ4 mice have decreased body weight, skeletal muscle hypotrophy, and reduced survival. Treatment of Mtm1δ4 mice with ActRIIB-mFC produced a 17% extension of lifespan, with transient increases in weight, forelimb grip strength, and myofiber size. Pathologic analysis of Mtm1δ4 mice during treatment revealed that ActRIIB-mFC produced marked hypertrophy restricted to type 2b myofibers, which suggests that oxidative fibers in Mtm1δ4 animals are incapable of a hypertrophic response in this setting. These results support ActRIIB-mFC as an effective treatment for the weakness observed in myotubularin deficiency. PMID:21281811

Effect of a novel load-bearing trabecular Nitinol scaffold on rabbit radius bone regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gotman, Irena, E-mail: gotman@technion.ac.il; Gutmanas, Elazar Y., E-mail: gutmanas@technion.ac.il; National Research Tomsk Polytechnic University, Tomsk, 634050

The research aim was to evaluate the bone regeneration capability of novel load-bearing NiTi alloy (Nitinol) scaffolds in a critical-size defect (CSD) model. High strength “trabecular Nitinol” scaffolds were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) annealing of the highly porous Ni foam in Ti powder at 900°C. This was followed by PIRAC nitriding to mitigate the release of potentially toxic Ni ions. Scaffolds phase composition and microstructure were characterized by X-ray diffraction and scanning electron microscopy (SEM/EDS), and their mechanical properties were tested in compression. New Zealand white rabbits received bone defect in right radius and were dividedmore » in four groups randomly. In the control group, nothing was placed in the defect. In other groups, NiTi scaffolds were implanted in the defect: (i) as produced, (ii) loaded with bone marrow aspirate (BMA), and (iii) biomimetically CaP-coated. The animals were sacrificed after 12 weeks. The forelimbs with scaffolds were resected, fixed, sectioned and examined in SEM. New bone formation inside the scaffold was studied by EDS analysis and by the processing of backscattered electron images. Bone ingrowth into the scaffold was observed in all implant groups, mostly next to the ulna. New bone formation was strongly enhanced by BMA loading and biomimeatic CaP coating, the bone penetrating as much as 1–1.5 mm into the scaffold. The results of this preliminary study demonstrate that the newly developed high strength trabecular Nitinol scaffolds can be successfully used for bone regeneration in critical size defects.« less

Development of Ferrium S53 High-Strength, Corrosion-Resistant Steel

DTIC Science & Technology

2009-01-01

strength steel used in landing gear, and equivalent in corrosion resistance to the lower strength 15-5PH stainless steel used in actuators. It also...5PH stainless steel used in modern aerospace actuators. These objectives were met, with two minor exceptions: (1) the tensile yield of S53 is... stainless steel used in modern aerospace actuators. The work was initially funded as a 1-year SERDP proof-of-principle project. In this first

Type 1 Diabetes in Young Rats Leads to Progressive Trabecular Bone Loss, Cessation of Cortical Bone Growth, and Diminished Whole Bone Strength and Fatigue Life

PubMed Central

Silva, Matthew J.; Brodt, Michael D.; Lynch, Michelle A.; McKenzie, Jennifer A.; Tanouye, Kristi M.; Nyman, Jeffry S.; Wang, Xiaodu

2009-01-01

People with diabetes have increased risk of fracture disproportionate to BMD, suggesting reduced material strength (quality). We quantified the skeletal effects of type 1 diabetes in the rat. Fischer 344 and Sprague-Dawley rats (12 wk of age) were injected with either vehicle (Control) or streptozotocin (Diabetic). Forelimbs were scanned at 0, 4, 8, and 12 wk using pQCT. Rats were killed after 12 wk. We observed progressive osteopenia in diabetic rats. Trabecular osteopenia was caused by bone loss: volumetric BMD decreased progressively with time in diabetic rats but was constant in controls. Cortical osteopenia was caused by premature arrest of cortical expansion: cortical area did not increase after 4–8 wk in diabetic rats but continued to increase in controls. Postmortem μCT showed a 60% reduction in proximal tibial trabecular BV/TV in diabetic versus control rats, whereas moments of inertia of the ulnar and femoral diaphysis were reduced ∼30%. Monotonic bending tests indicated that ulna and femora from diabetic animals were ∼25% less stiff and strong versus controls. Estimates of material properties indicated no changes in elastic modulus or ultimate stress but modest (∼10%) declines in yield stress for diabetic bone. These changes were associated with a ∼50% increase in the nonenzymatic collagen cross-link pentosidine. Last, cyclic testing showed diminished fatigue life in diabetic bones at the structural (force) level but not at the material (stress) level. In summary, type 1 diabetes, left untreated, causes trabecular bone loss and a reduction in diaphyseal growth. Diabetic bone has greatly increased nonenzymatic collagen cross-links but only modestly reduced material properties. The loss of whole bone strength under both monotonic and fatigue loading is attributed mainly to reduced bone size. PMID:19338453

Motor Performance is Impaired Following Vestibular Stimulation in Ageing Mice

PubMed Central

Tung, Victoria W. K.; Burton, Thomas J.; Quail, Stephanie L.; Mathews, Miranda A.; Camp, Aaron J.

2016-01-01

Balance and maintaining postural equilibrium are important during stationary and dynamic movements to prevent falls, particularly in older adults. While our sense of balance is influenced by vestibular, proprioceptive, and visual information, this study focuses primarily on the vestibular component and its age-related effects on balance. C57Bl/6J mice of ages 1, 5–6, 8–9 and 27–28 months were tested using a combination of standard (such as grip strength and rotarod) and newly-developed behavioral tests (including balance beam and walking trajectory tests with a vestibular stimulus). In the current study, we confirm a decline in fore-limb grip strength and gross motor coordination as age increases. We also show that a vestibular stimulus of low frequency (2–3 Hz) and duration can lead to age-dependent changes in balance beam performance, which was evident by increases in latency to begin walking on the beam as well as the number of times hind-feet slip (FS) from the beam. Furthermore, aged mice (27–28 months) that received continuous access to a running wheel for 4 weeks did not improve when retested. Mice of ages 1, 10, 13 and 27–28 months were also tested for changes in walking trajectory as a result of the vestibular stimulus. While no linear relationship was observed between the changes in trajectory and age, 1-month-old mice were considerably less affected than mice of ages 10, 13 and 27–28 months. Conclusion: this study confirms there are age-related declines in grip strength and gross motor coordination. We also demonstrate age-dependent changes to finer motor abilities as a result of a low frequency and duration vestibular stimulus. These changes showed that while the ability to perform the balance beam task remained intact across all ages tested, behavioral changes in task performance were observed. PMID:26869921

Motor Performance is Impaired Following Vestibular Stimulation in Ageing Mice.

PubMed

Tung, Victoria W K; Burton, Thomas J; Quail, Stephanie L; Mathews, Miranda A; Camp, Aaron J

2016-01-01

Balance and maintaining postural equilibrium are important during stationary and dynamic movements to prevent falls, particularly in older adults. While our sense of balance is influenced by vestibular, proprioceptive, and visual information, this study focuses primarily on the vestibular component and its age-related effects on balance. C57Bl/6J mice of ages 1, 5-6, 8-9 and 27-28 months were tested using a combination of standard (such as grip strength and rotarod) and newly-developed behavioral tests (including balance beam and walking trajectory tests with a vestibular stimulus). In the current study, we confirm a decline in fore-limb grip strength and gross motor coordination as age increases. We also show that a vestibular stimulus of low frequency (2-3 Hz) and duration can lead to age-dependent changes in balance beam performance, which was evident by increases in latency to begin walking on the beam as well as the number of times hind-feet slip (FS) from the beam. Furthermore, aged mice (27-28 months) that received continuous access to a running wheel for 4 weeks did not improve when retested. Mice of ages 1, 10, 13 and 27-28 months were also tested for changes in walking trajectory as a result of the vestibular stimulus. While no linear relationship was observed between the changes in trajectory and age, 1-month-old mice were considerably less affected than mice of ages 10, 13 and 27-28 months. this study confirms there are age-related declines in grip strength and gross motor coordination. We also demonstrate age-dependent changes to finer motor abilities as a result of a low frequency and duration vestibular stimulus. These changes showed that while the ability to perform the balance beam task remained intact across all ages tested, behavioral changes in task performance were observed.

[Primary cutaneous and metastasing haemangiosarcoma in an addax (Addax nasomaculatus)].

PubMed

Wohlsein, P; Schöpper, H; Kämmerling, J; Wünsch, U; Schulze, C

2008-01-01

Neoplastic diseases were described very rarely in addax (Addax nasomaculatus). In this communication clinical signs, morphological and immunohistological findings in a 15-year-old, female addax with a primary cutaneous, re-occurring and metastasing haemangiosarcoma of a forelimb are reported.

Some strength and related properties of yagrumo hembra (Cecropia peltata) from Puerto Rico

Treesearch

B. A. Bendtsen

1964-01-01

Evaluations of several mechanical and physical properties were conducted on specimens from five yagrumo hembra (Cecropia peltata) trees from Puerto Rico. With the exception of toughness and modulus of elasticity in both bending and compression parallel to grain, these specimens were lower in specific gravity and in strength properties than material reported previously...

Design and validation of a computer-aided learning program to enhance students' ability to recognize lameness in the horse.

PubMed

Barstow, Amy; Pfau, Thilo; Bolt, David M; Smith, Roger K; Weller, Renate

2014-01-01

The ability to recognize lameness in the horse is an important skill for veterinary graduates; however, opportunities to develop this skill at the undergraduate level are limited. Computer-aided learning programs (CALs) have been successful in supplementing practical skills teaching. The aim of this study was to design and validate a CAL for the teaching of equine lameness recognition (CAL1). A control CAL was designed to simulate learning by experience (CAL2). Student volunteers were randomly assigned to either CAL and tested to establish their current ability to recognize lameness. Retesting occurred both immediately following exposure and 1 week later. At each test point, the number of correct responses for forelimb and hind limb cases was determined. Student confidence was assessed before and after CAL exposure, with previous opportunities to recognize lameness taken into account. Immediately following exposure, the number of correct responses was significantly higher for CAL1 than for CAL2, both overall and for forelimb cases but not for hind limb cases. After 1 week, the CAL1 group performed significantly better overall compared to the CAL2 group, with no significant difference between forelimb and hind limb cases. Student confidence and ability to recognize lameness were significantly improved following exposure to CAL1. When considered as one category, students in years 4 and 5 performed significantly better than year 3 students. Gender did not significantly affect performance. CAL1 could be used to supplement current lameness recognition opportunities. CAL1 is, however, limited in its ability to improve lameness recognition, especially in relation to hind limb lameness where it was unable to attain a significant difference from CAL2.

Factors regulating collagen synthesis and degradation during second-intention healing of wounds in the thoracic region and the distal aspect of the forelimb of horses.

PubMed

Schwartz, Anne J; Wilson, David A; Keegan, Kevin G; Ganjam, Venkataseshu K; Sun, Yao; Weber, Karl T; Zhang, Jiakun

2002-11-01

To determine significant molecular and cellular factors responsible for differences in second-intention healing in thoracic and metacarpal wounds of horses. 6 adult mixed-breed horses. A full-thickness skin wound on the metacarpus and another such wound on the pectoral region were created, photographed, and measured, and tissue was harvested from these sites weekly for 4 weeks. Gene expression of type-I collagen, transforming growth factor (TGF)-beta1, matrix metalloproteinase (MMP)-1, and tissue inhibitor of metalloproteinase (TIMP)-1 were determined by quantitative in situ hybridization. Myofibroblasts were detected by immunohistochemical labeling with alpha-smooth muscle actin (alpha-SMA). Collagen accumulation was detected by use of picrosirius red staining. Tissue morphology was examined by use of H&E staining. Unlike thoracic wounds, forelimb wounds enlarged during the first 2 weeks. Myofibroblasts, detected by week 1, remained abundant with superior organization in thoracic wounds. Type-I collagen mRNA accumulated progressively in both wounds. More type-I collagen and TGF-beta1 mRNA were seen in forelimb wounds. Volume of MMP-1 mRNA decreased from day 0 in both wounds. By week 3, TIMP-1 mRNA concentration was greater in thoracic wounds. Greater collagen synthesis in metacarpal than thoracic wounds was documented by increased concentrations of myofibroblasts, type-I collagen mRNA,TGF-beta1 mRNA, and decreased collagen degradation (ie, MMP-1). Imbalanced collagen synthesis and degradation likely correlate with development of exuberant granulation tissue, delaying healing in wounds of the distal portions of the limbs. Factors that inhibit collagen synthesis or stimulate collagenase may provide treatment options for horses with exuberant granulation tissue.

The role of sexual selection and conflict in mediating among-population variation in mating strategies and sexually dimorphic traits in Sepsis punctum.

PubMed

Dmitriew, Caitlin; Blanckenhorn, Wolf U

2012-01-01

The black scavenger fly Sepsis punctum exhibits striking among-population variation in the direction and magnitude of sexual size dimorphism, modification to the male forelimb and pre-copulatory behaviour. In some populations, male-biased sexual size dimorphism is observed; in other, less dimorphic, populations males court prior to mating. Such variation in reproductive traits is of interest to evolutionary biologists because it has the potential to limit gene flow among populations, contributing to speciation. Here, we investigate whether large male body size and modified forefemur are associated with higher male mating success within populations, whether these traits are associated with higher mating success among populations, and if these traits carry viability costs that could constrain their response to sexual selection. Flies from five distinct populations were reared at high or low food, generating high and low quality males. The expression of body size, forelimb morphology and courtship rate were each greater at high food, but high food males experienced higher mating success or reduced latency to first copulation in only one of the populations. Among populations, overall mating success increased with the degree of male-bias in overall body size and forelimb modification, suggesting that these traits have evolved as a means of increasing male mating rate. The increased mating success observed in large-male populations raises the question of why variation in magnitude of dimorphism persists among populations. One reason may be that costs of producing a large size constrain the evolution of ever-larger males. We found no evidence that juvenile mortality under food stress was greater for large-male populations, but development time was considerably longer and may represent an important constraint in an ephemeral and competitive growth environment.

A novel model to assess lamellar signaling relevant to preferential weight bearing in the horse.

PubMed

Gardner, A K; van Eps, A W; Watts, M R; Burns, T A; Belknap, J K

2017-03-01

Supporting limb laminitis (SLL) is a devastating sequela to severe unilateral lameness in equine patients. The manifestation of SLL, which usually only affects one limb, is unpredictable and the etiology is unknown. A novel, non-painful preferential weight bearing model designed to mimic the effects of severe unilateral forelimb lameness was developed to assess lamellar signaling events in the supporting limb (SL). A custom v-shaped insert was attached to the shoe of one forelimb to prevent normal weight bearing and redistribute weight onto the SL. Testing of the insert using a custom scale platform built into the floor of stocks confirmed increased distribution of weight on the SL compared with the unloaded forelimb (UL) and the contralateral (CH) and ipsilateral (IH) hind limbs in six Standardbred horses. In a second part of the study, eight healthy Standardbred horses were fitted with the insert and tied with consistent monitoring and free access to hay and water for 48 h, after which the lamellae were harvested. Real-time qPCR was performed to assess lamellar mRNA concentrations of inflammatory genes and immunoblotting and immunofluorescence were performed to assess lamellar protein concentration and cellular localization of hypoxia-related proteins, respectively. Lamellar mRNA concentrations of inflammatory signaling proteins did not differ between SL and either CH or IH samples. HIF-1α concentrations were greater (P < 0.05) in the SL compared to the CH. This work establishes an experimental model to study preferential weight bearing and initial results suggest that lamellar hypoxia may occur in the SL. Copyright © 2017. Published by Elsevier Ltd.

Pharmacokinetics of buprenorphine after single-dose subcutaneous administration in red-eared sliders (Trachemys scripta elegans).

PubMed

Kummrow, Maya S; Tseng, Florina; Hesse, Leah; Court, Michael

2008-12-01

Buprenorphine, a mu opioid receptor agonist, is expected to be a suitable analgesic drug for use in reptiles. However, to date, dosage recommendations have been based on anecdotal observations. The aim of this study was to provide baseline pharmacokinetic data in red-eared sliders (Trachemys scripta elegans) targeting a plasma level of 1 ng/ml reported effective for analgesia in humans. Serial blood samples were taken after subcutaneous injection of buprenorphine, and plasma buprenorphine levels were measured by radioimmunoassay. Pharmacokinetic parameters of a lower dose (0.02 mg/kg) injected into the forelimb were compared with a higher dose (0.05 mg/kg) given in the same forelimb as well as a lower dose (0.02 mg/kg) given in the hind limb of the same animals with 2 wk between studies. After administration of 0.05 mg/kg in the front limb, 85% of animals maintained the minimum effective plasma level for 24 hr, while only 43% of animals maintained this level after 0.02 mg/kg. After hind limb injection at 0.02 mg/kg, maximum plasma concentrations and areas under the buprenorphine concentration-time curve were less than 20% and 70%, respectively, of values after forelimb injection, consistent with substantial first pass extraction by the liver. Furthermore, a secondary rise in the buprenorphine level was found after having only a hind limb injection, probably from enterohepatic recirculation of glucuronidated drug. In conclusion, buprenorphine dosages of at least 0.075 mg/kg s.i.d. should be appropriate for evaluation of analgesia efficacy, and front limb administration may be preferable to hind limb administration for optimal drug exposure.

Surface response of blind thrust shown from high resolution topographic data and updated geochronology at Wheeler Ridge, CA

NASA Astrophysics Data System (ADS)

Kleber, E.; Arrowsmith, R.; DeVecchio, D. E.; Johnstone, S. A.; Rittenour, T. M.

2015-12-01

Wheeler Ridge is an asymmetric east-propagating anticline (10km axis, 330m relief) above a north-vergent blind thrust deforming Quaternary alluvial fan and shallow marine rocks at the northern front of the Transverse Ranges, San Joaquin Valley, CA. This area was a research foci in the 1990's when the soils, u-series soil carbonate dating, and subsurface structure of deformed strata identified from oil wells were used to create a kinematic model of deformation, and estimates of fault slip, uplift, and lateral propagation rates. A recent collection of light detection and ranging (lidar) topographic data and optically stimulated luminescence (OSL) data allow us to complete meter scale topographic analyses of the fluvial networks and hillslopes and correlate geomorphic response to tectonics. We interpret these results using a detailed morphological map and observe drainage network and hillslope process transitions both along and across the fold axis. With lidar topography, we extract common morphometrics (e.g., channel steepness-- ksn, eroded volume, hillslope relief) to illustrate how the landscape is responding to variations in uplift rate along the fold axis and show asymmetry of surface response on the forelimb and backlimb. The forelimb is dominated by large drainages with landslides initiating in the marine units at the core of the fold. Our topographic analysis shows that the stream channel indices values on the forelimb increase along the fold axis, away from the propagation tip. The backlimb drainages are dominantly long and linear with broad ridgelines. Using lidar and fieldwork, we see that uplifted backlimb surfaces preserve the deformed fan surface. The preliminary OSL results from alluvial fan units improve age control of previously defined surfaces, refining our understanding of the deposition and uplift of alluvial fan units on preserved on backlimb.

Improved single pellet grasping using automated ad libitum full-time training robot.

PubMed

Fenrich, Keith K; May, Zacnicte; Hurd, Caitlin; Boychuk, Carolyn E; Kowalczewski, Jan; Bennett, David J; Whishaw, Ian Q; Fouad, Karim

2015-03-15

The single pellet grasping (SPG) task is a skilled forelimb motor task commonly used to evaluate reaching and grasp kinematics and recovery of forelimb function in rodent models of CNS injuries and diseases. To train rats in the SPG task, the animals are usually food restricted then placed in an SPG task enclosure and presented food pellets on a platform located beyond a slit located at the front of the task enclosure for 10-30 min, normally every weekday for several weeks. When the SPG task is applied in studies involving various experimental groups, training quickly becomes labor intensive, and can yield results with significant day-to-day variability. Furthermore, training is frequently done during the animals' light-cycle, which for nocturnal rodents such as mice and rats could affect performance. Here we describe an automated pellet presentation (APP) robotic system to train and test rats in the SPG task that reduces some of the procedural weaknesses of manual training. We found that APP trained rats performed significantly more trials per 24 h period, and had higher success rates with less daily and weekly variability than manually trained rats. Moreover, the results show that success rates are positively correlated with the number of dark-cycle trials, suggesting that dark-cycle training has a positive effect on success rates. These results demonstrate that automated training is an effective method for evaluating and training skilled reaching performance of rats, opening up the possibility for new approaches to investigating the role of motor systems in enabling skilled forelimb use and new approaches to investigating rehabilitation following CNS injury. Copyright © 2014 Elsevier B.V. All rights reserved.

Discharge of primate magnocellular red nucleus neurons during reaching to grasp in different spatial locations.

PubMed

van Kan, Peter L E; McCurdy, Martha L

2002-01-01

Reaching to grasp is of fundamental importance to primate motor behavior. One descending motor pathway that contributes to the control of this behavior is the rubrospinal tract. An important source of origin of the rubrospinal tract is the magnocellular red nucleus (RNm). Forelimb RNm neurons discharge vigorously during reach-to-grasp movements. RNm discharge is important for hand use, as coordinated whole-limb movements without hand use are not associated with strong discharge. Because RNm is functionally linked to muscles of the entire forelimb, RNm discharge may also contribute to use of the proximal limb that accompanies hand use. If RNm contributes to proximal limb use, we predict discharge to differ for reaches that differ in proximal limb involvement but require the same grasp. We tested this prediction by measuring discharge of individual RNm neurons while monkeys reached to grasp objects in four spatial locations in front of them. The animals reached from the waist to locations to the left, right, above, and below the shoulder of the "reaching" limb. RNm neurons of our sample were activated strongly during reach-to-grasp, and discharge of a third of the neurons tested depended on the spatial location of the object grasped. Discharge of RNm neurons and EMG activity of many of the distal and proximal forelimb muscles we tested were larger for reaching to grasp in the upper and/or right than lower and left target locations. Based on comparisons of each individual neuron's discharge patterns during reaches with and without preshaping the hand, we conclude that target location-dependent modulations in discharge rate of the majority of RNm neurons whose discharge differed for reaching to grasp in the four target locations contributed to aspects of hand preshaping that covaried with reach direction.

Fine-tuning the onset of myogenesis by homeobox proteins that interact with the Myf5 limb enhancer

PubMed Central

Daubas, Philippe; Duval, Nathalie; Bajard, Lola; Langa Vives, Francina; Robert, Benoît; Mankoo, Baljinder S.; Buckingham, Margaret

2015-01-01

ABSTRACT Skeletal myogenesis in vertebrates is initiated at different sites of skeletal muscle formation during development, by activation of specific control elements of the myogenic regulatory genes. In the mouse embryo, Myf5 is the first myogenic determination gene to be expressed and its spatiotemporal regulation requires multiple enhancer sequences, extending over 120 kb upstream of the Mrf4-Myf5 locus. An enhancer, located at −57/−58 kb from Myf5, is responsible for its activation in myogenic cells derived from the hypaxial domain of the somite, that will form limb muscles. Pax3 and Six1/4 transcription factors are essential activators of this enhancer, acting on a 145-bp core element. Myogenic progenitor cells that will form the future muscle masses of the limbs express the factors necessary for Myf5 activation when they delaminate from the hypaxial dermomyotome and migrate into the forelimb bud, however they do not activate Myf5 and the myogenic programme until they have populated the prospective muscle masses. We show that Msx1 and Meox2 homeodomain-containing transcription factors bind in vitro and in vivo to specific sites in the 145-bp element, and are implicated in fine-tuning activation of Myf5 in the forelimb. Msx1, when bound between Pax and Six sites, prevents the binding of these key activators, thus inhibiting transcription of Myf5 and consequent premature myogenic differentiation. Meox2 is required for Myf5 activation at the onset of myogenesis via direct binding to other homeodomain sites in this sequence. Thus, these homeodomain factors, acting in addition to Pax3 and Six1/4, fine-tune the entry of progenitor cells into myogenesis at early stages of forelimb development. PMID:26538636

Effect of lungeing on head and pelvic movement asymmetry in horses with induced lameness.

PubMed

Rhodin, M; Pfau, T; Roepstorff, L; Egenvall, A

2013-12-01

Lungeing is an important part of lameness examinations, since the circular path enforced during lungeing is thought to accentuate low grade lameness. However, during lungeing the movement of sound horses becomes naturally asymmetric, which may mimic lameness. Also, compensatory movements in the opposite half of the body may mimic lameness. The aim of this study was to objectively study the presence of circle-dependent and compensatory movement asymmetries in horses with induced lameness. Ten horses were trotted in a straight line and lunged in both directions on a hard surface. Lameness was induced (reversible hoof pressure) in each limb, one at a time, in random order. Vertical head and pelvic movements were measured with body-mounted, uni-axial accelerometers. Differences between maximum and minimum height observed during/after left and right stance phases for the head (HDmax, HDmin) and pelvis (PDmax, PDmin) were measured. Mixed models were constructed to study the effect of lungeing direction and induction, and to quantify secondary compensatory asymmetry mechanisms in the forelimbs and hind limbs. Head and pelvic movement symmetries were affected by lungeing. Minimum pelvic height difference (PDmin) changed markedly, increasing significantly during lungeing, giving the impression of inner hind limb lameness. Primary hind limb lameness induced compensatory head movement, which mimicked an ipsilateral forelimb lameness of almost equal magnitude to the primary hind limb lameness. This could contribute to difficulty in correctly detecting hind limb lameness. Induced forelimb lameness caused both a compensatory contralateral (change in PDmax) and an ipsilateral (change in PDmin) hind limb asymmetry, potentially mimicking hind limb lameness, but of smaller magnitude. Both circle-dependent and compensatory movement mechanisms must be taken into account when evaluating lameness. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparative anatomy, homologies and evolution of the pectoral and forelimb musculature of tetrapods with special attention to extant limbed amphibians and reptiles.

PubMed

Abdala, Virginia; Diogo, Rui

2010-11-01

The main aim of the present work is to synthesize the information obtained from our dissections of the pectoral and forelimb muscles of representative members of the major extant taxa of limbed amphibians and reptiles and from our review of the literature, in order to provide an account of the comparative anatomy, homologies and evolution of these muscles in the Tetrapoda. The pectoral and forelimb musculature of all these major taxa conform to a general pattern that seems to have been acquired very early in the evolutionary history of tetrapods. Although some muscles are missing in certain taxa, and a clear departure from this general pattern is obviously present in derived groups such as birds, the same overall configuration is easily distinguishable in these taxa. Among the most notable anatomical differences between the groups, one that seems to have relevant evolutionary and functional implications, concerns the distal insertion points of the forearm musculature. In tetrapods, the muscles of the radial and ulnar complexes of the forearm are pleisomorphically mainly inserted onto the radius/ulna or onto the more proximal carpal bones, but in mammals some of these muscles insert more distally onto bones such as the metacarpals. Interestingly, a similar trend towards a more distal insertion of these muscles is also found in some non-mammalian tetrapod taxa, such as some anurans (e.g. Phyllomedusa). This may be correlated with the acquisition of more subtle digital movement abilities in these latter taxa. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements.

PubMed

Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

2015-04-21

Limb skeletal elements originate from the limb progenitor cells, which undergo expansion and patterning to develop each skeletal element. Posterior-distal skeletal elements, such as the ulna/fibula and posterior digits develop in a Sonic hedgehog (Shh)-dependent manner. However, it is poorly understood how anterior-proximal elements, such as the humerus/femur, the radius/tibia and the anterior digits, are developed. Here we show that the zinc finger factors Sall4 and Gli3 cooperate for proper development of the anterior-proximal skeletal elements and also function upstream of Shh-dependent posterior skeletal element development. Conditional inactivation of Sall4 in the mesoderm before limb outgrowth caused severe defects in the anterior-proximal skeletal elements in the hindlimb. We found that Gli3 expression is reduced in Sall4 mutant hindlimbs, but not in forelimbs. This reduction caused posteriorization of nascent hindlimb buds, which is correlated with a loss of anterior digits. In proximal development, Sall4 integrates Gli3 and the Plzf-Hox system, in addition to proliferative expansion of cells in the mesenchymal core of nascent hindlimb buds. Whereas forelimbs developed normally in Sall4 mutants, further genetic analysis identified that the Sall4-Gli3 system is a common regulator of the early limb progenitor cells in both forelimbs and hindlimbs. The Sall4-Gli3 system also functions upstream of the Shh-expressing ZPA and the Fgf8-expressing AER in fore- and hindlimbs. Therefore, our study identified a critical role of the Sall4-Gli3 system at the early steps of limb development for proper development of the appendicular skeletal elements.

Repeatability of quantitative sensory testing in healthy cats in a clinical setting with comparison to cats with osteoarthritis.

PubMed

Addison, Elena S; Clements, Dylan N

2017-12-01

Objectives The aim of this study was to evaluate the repeatability of quantitative sensory tests (QSTs) in a group of healthy untrained cats (n = 14) and to compare the results with those from cats with osteoarthritis (n = 7). Methods Peak vertical force (PVF) and vertical impulse were measured on a pressure plate system. Thermal sensitivity was assessed using a temperature-controlled plate at 7°C and 40°C. Individual paw lifts and overall duration of paw lifts were counted and measured for each limb. Paw withdrawal thresholds were measured using manual and electronic von Frey monofilaments (MVF and EVF, respectively) applied to the metacarpal or metatarsal pads. All measurements were repeated twice to assess repeatability of the tests. Results In healthy cats all tests were moderately repeatable. When compared with cats with osteoarthritis the PVF was significantly higher in healthy hindlimbs in repeat 1 but not in repeat 2. Cats with osteoarthritis of the forelimbs showed a decrease in the frequency of paw lifts on the 7°C plate compared with cats with healthy forelimbs, and the duration of paw lifts was significantly less than healthy forelimbs in the first repeat but not in the second repeat. Osteoarthritic limbs had significantly lower paw withdrawal thresholds with both MVF and EVF than healthy limbs. Conclusions and relevance QSTs are moderately repeatable in untrained cats. Kinetic gait analysis did not permit differentiation between healthy limbs and those with osteoarthritis, but thermal sensitivity testing (cold) does. Sensory threshold testing can differentiate osteoarthritic and healthy limbs, and may be useful in the diagnosis and monitoring of this condition in cats in the clinical setting.

A single hydrotherapy session increases range of motion and stride length in Labrador retrievers diagnosed with elbow dysplasia.

PubMed

Preston, T; Wills, A P

2018-04-01

Canine elbow dysplasia is a debilitating condition of unknown aetiology and is a common cause of forelimb lameness in dogs. Canine hydrotherapy is a therapeutic approach rapidly increasing in popularity for the treatment of a range of musculoskeletal pathologies. In this study, kinematic analysis was used to assess the effect of a customised hydrotherapy session on the range of motion, stride length and stride frequency of healthy Labrador retrievers (n=6) and Labrador retrievers diagnosed with bilateral elbow dysplasia (n=6). Reflective kinematic markers were attached to bony anatomical landmarks and dogs were recorded walking at their preferred speed on a treadmill before and 10min after a single hydrotherapy session. Range of motion, stride length and stride frequency were calculated for both forelimbs. Data were analysed via a robust mixed ANOVA to assess the effect of hydrotherapy on the kinematic parameters of both groups. Range of motion was greater in the healthy dogs at baseline (P<0.05). Hydrotherapy increased the range of motion of the forelimbs of both groups (P<0.05); dogs with elbow dysplasia demonstrated a greater improvement in range of motion than healthy dogs (P<0.05). Hydrotherapy stride length (P<0.01) of all dogs, but differences were not seen between the two groups. Stride frequency increased after hydrotherapy only in the left limb (P<0.05) in all dogs. These results support the potential of canine hydrotherapy as a therapeutic tool for the rehabilitation and treatment of Labradors with elbow dysplasia. Furthermore, results indicate that hydrotherapy might improve the gait and movement of healthy dogs. However, whether these results are transient or sustained remains undetermined. Copyright © 2018 Elsevier Ltd. All rights reserved.

Exceptional points enhance sensing in an optical microcavity

NASA Astrophysics Data System (ADS)

Chen, Weijian; Kaya Özdemir, Şahin; Zhao, Guangming; Wiersig, Jan; Yang, Lan

2017-08-01

Sensors play an important part in many aspects of daily life such as infrared sensors in home security systems, particle sensors for environmental monitoring and motion sensors in mobile phones. High-quality optical microcavities are prime candidates for sensing applications because of their ability to enhance light-matter interactions in a very confined volume. Examples of such devices include mechanical transducers, magnetometers, single-particle absorption spectrometers, and microcavity sensors for sizing single particles and detecting nanometre-scale objects such as single nanoparticles and atomic ions. Traditionally, a very small perturbation near an optical microcavity introduces either a change in the linewidth or a frequency shift or splitting of a resonance that is proportional to the strength of the perturbation. Here we demonstrate an alternative sensing scheme, by which the sensitivity of microcavities can be enhanced when operated at non-Hermitian spectral degeneracies known as exceptional points. In our experiments, we use two nanoscale scatterers to tune a whispering-gallery-mode micro-toroid cavity, in which light propagates along a concave surface by continuous total internal reflection, in a precise and controlled manner to exceptional points. A target nanoscale object that subsequently enters the evanescent field of the cavity perturbs the system from its exceptional point, leading to frequency splitting. Owing to the complex-square-root topology near an exceptional point, this frequency splitting scales as the square root of the perturbation strength and is therefore larger (for sufficiently small perturbations) than the splitting observed in traditional non-exceptional-point sensing schemes. Our demonstration of exceptional-point-enhanced sensitivity paves the way for sensors with unprecedented sensitivity.

Antifungal activity in thrips soldiers suggests a dual role for this caste.

PubMed

Turnbull, Christine; Caravan, Holly; Chapman, Thomas; Nipperess, David; Dennison, Siobhan; Schwarz, Michael; Beattie, Andrew

2012-08-23

The social insect soldier is perhaps the most widely known caste, because it often exhibits spectacular weapons, such as highly enlarged jaws or reinforced appendages, which are used to defend the colony against enemies ranging in size from wasps to anteaters. We examined the function of the enlarged forelimbs of soldiers (both male and female) of the eusocial, gall-inhabiting insect Kladothrips intermedius, and discovered that they have little impact on their ability to repel the specialized invading thrips Koptothrips species. While the efficacy of the enlarged forelimb appears equivocal, we show that soldiers secrete strong antifungal compounds capable of controlling the specialized insect fungal pathogen, Cordyceps bassiana. Our data suggest that these thrips soldiers have evolved in response to selection by both macro- and micro-organisms. While it is unknown whether specialized fungal pathogens have been major selective agents in the evolution of the soldier caste in general, they were probably present when sociality first evolved and may have been the primordial enemies of social insects.

Impaired limb reaction to displacement of center of gravity in rats with unilateral striatal ischemic injury.

PubMed

Nobile, Cameron W; Palmateer, Julie M; Kane, Jackie; Hurn, Patricia D; Schallert, Timothy; Adkins, DeAnna L

2014-10-01

Clinical stroke often results in impaired balance and increased vulnerability to severe injuries due to falling. To evaluate potential preclinical treatments that might target these deficits, it will be important to include tests capable of assessing these impairments chronically in animal models. Previously, we developed a postural instability test (PIT) that revealed chronic, unilateral impairments in postural stability in rat models of hemi-Parkinson's disease (PD) and of unilateral cervical spinal cord injury. Here, we investigated whether this test was also capable of revealing long-term stroke-induced impairments in postural support in rats. Additionally, we examined the ability of more common tests of sensorimotor function to detect chronic impairments. We found that the PIT detected chronic deficits in postural stability/balance enduring for up to 6 weeks post-stroke, outlasting impairments detected in other tests of forelimb sensorimotor function, including asymmetries in upright postural support (cylinder test) and vibrissae-evoked forelimb placing.

Hypervitaminosis A in the cat: a case report and review of the literature.

PubMed

Polizopoulou, Zoe S; Kazakos, George; Patsikas, Michael N; Roubies, Nikolaos

2005-12-01

A case of hypervitaminosis A with secondary entrapment and compression of the left brachial plexus nerve roots is described. A 9-year-old male castrated domestic shorthair, fed a home-made diet based on raw pork liver, was submitted for examination for a left forelimb lameness that evolved to paralysis over a 2-month period. Clinical examination revealed a flaccid paralysis and atrophy of all left forelimb muscles. An ipsilateral Horner's syndrome was also noted. Radiological examination of the cervical and thoracic spine showed massive new bone formation at the ventral aspect of the second cervical to sixth thoracic vertebra. The diagnosis of hypervitaminosis A was made, based on the clinical and radiographic findings, as well as the determination of serum vitamin A concentration, which was 630 microg/dl, three times above the upper normal limit for this species. Despite the unfavourable initial prognosis, the cat progressively regained function of the affected limb approximately 6 months after the diet was changed to a commercial canned food.

Reward-timing-dependent bidirectional modulation of cortical microcircuits during optical single-neuron operant conditioning.

PubMed

Hira, Riichiro; Ohkubo, Fuki; Masamizu, Yoshito; Ohkura, Masamichi; Nakai, Junichi; Okada, Takashi; Matsuzaki, Masanori

2014-11-24

Animals rapidly adapt to environmental change. To reveal how cortical microcircuits are rapidly reorganized when an animal recognizes novel reward contingency, we conduct two-photon calcium imaging of layer 2/3 motor cortex neurons in mice and simultaneously reinforce the activity of a single cortical neuron with water delivery. Here we show that when the target neuron is not relevant to a pre-trained forelimb movement, the mouse increases the target neuron activity and the number of rewards delivered during 15-min operant conditioning without changing forelimb movement behaviour. The reinforcement bidirectionally modulates the activity of subsets of non-target neurons, independent of distance from the target neuron. The bidirectional modulation depends on the relative timing between the reward delivery and the neuronal activity, and is recreated by pairing reward delivery and photoactivation of a subset of neurons. Reward-timing-dependent bidirectional modulation may be one of the fundamental processes in microcircuit reorganization for rapid adaptation.

Measurements of normal joint angles by goniometry in calves.

PubMed

Sengöz Şirin, O; Timuçin Celik, M; Ozmen, A; Avki, S

2014-01-01

The aim of this study was to establish normal reference values of the forelimb and hindlimb joint angles in normal Holstein calves. Thirty clinically normal Holstein calves that were free of any detectable musculoskeletal abnormalities were included in the study. A standard transparent plastic goniometer was used to measure maximum flexion, maximum extension, and range-of-motion of the shoulder, elbow, carpal, hip, stifle, and tarsal joints. The goniometric measurements were done on awake calves that were positioned in lateral recumbency. The goniometric values were measured and recorded by two independent investigators. As a result of the study it was concluded that goniometric values obtained from awake calves in lateral recumbency were found to be highly consistent and accurate between investigators (p <0.05). The data of this study acquired objective and useful information on the normal forelimb and hindlimb joint angles in normal Holstein calves. Further studies can be done to predict detailed goniometric values from different diseases and compare them.

Extracorporeal shockwave therapy in a dog with chronic bicipital tenosynovitis.

PubMed

Venzin, C; Ohlerth, S; Koch, D; Spreng, D

2004-03-01

A 15-month-old, spayed female, Bernese mountain dog was presented to the Institute of Small Animal Surgery at the University of Zurich because of chronic left forelimb lameness. The referring veterinarian diagnosed pain in the left shoulder region and had treated the dog with systemic non-steroidal anti-inflammatory drugs and restricted exercise for a two-week period. The follow-up examination revealed only minimal improvement and therefore, the dog was referred for further diagnostic evaluation. Chronic bicipital tenosynovitis and tendinitis of the infraspinatus muscle was diagnosed based on survey radiographs, arthrography, ultrasound, computed tomography (CT), and synovial fluid cytology. The dog underwent three sessions of extracorporeal shockwave therapy and substantial clinical improvement was observed. On follow-up examinations, only mild left forelimb lameness was evident following exercise, and changes in the intertubercular groove and at the supraglenoid tuberosity appeared less active on radiographs and CT. However, six months following treatment, mild degenerative joint disease was apparent.

Molecular shifts in limb identity underlie development of feathered feet in two domestic avian species

PubMed Central

Domyan, Eric T; Kronenberg, Zev; Infante, Carlos R; Vickrey, Anna I; Stringham, Sydney A; Bruders, Rebecca; Guernsey, Michael W; Park, Sungdae; Payne, Jason; Beckstead, Robert B; Kardon, Gabrielle; Menke, Douglas B; Yandell, Mark; Shapiro, Michael D

2016-01-01

Birds display remarkable diversity in the distribution and morphology of scales and feathers on their feet, yet the genetic and developmental mechanisms governing this diversity remain unknown. Domestic pigeons have striking variation in foot feathering within a single species, providing a tractable model to investigate the molecular basis of skin appendage differences. We found that feathered feet in pigeons result from a partial transformation from hindlimb to forelimb identity mediated by cis-regulatory changes in the genes encoding the hindlimb-specific transcription factor Pitx1 and forelimb-specific transcription factor Tbx5. We also found that ectopic expression of Tbx5 is associated with foot feathers in chickens, suggesting similar molecular pathways underlie phenotypic convergence between these two species. These results show how changes in expression of regional patterning genes can generate localized changes in organ fate and morphology, and provide viable molecular mechanisms for diversity in hindlimb scale and feather distribution. DOI: http://dx.doi.org/10.7554/eLife.12115.001 PMID:26977633

Precision of Discrete and Rhythmic Forelimb Movements Requires a Distinct Neuronal Subpopulation in the Interposed Anterior Nucleus.

PubMed

Low, Aloysius Y T; Thanawalla, Ayesha R; Yip, Alaric K K; Kim, Jinsook; Wong, Kelly L L; Tantra, Martesa; Augustine, George J; Chen, Albert I

2018-02-27

The deep cerebellar nuclei (DCN) represent output channels of the cerebellum, and they transmit integrated sensorimotor signals to modulate limb movements. But the functional relevance of identifiable neuronal subpopulations within the DCN remains unclear. Here, we examine a genetically tractable population of neurons in the mouse interposed anterior nucleus (IntA). We show that these neurons represent a subset of glutamatergic neurons in the IntA and constitute a specific element of an internal feedback circuit within the cerebellar cortex and cerebello-thalamo-cortical pathway associated with limb control. Ablation and optogenetic stimulation of these neurons disrupt efficacy of skilled reach and locomotor movement and reveal that they control positioning and timing of the forelimb and hindlimb. Together, our findings uncover the function of a distinct neuronal subpopulation in the deep cerebellum and delineate the anatomical substrates and kinematic parameters through which it modulates precision of discrete and rhythmic limb movements. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Dielectric breakdown of additively manufactured polymeric materials

DOE PAGES

Monzel, W. Jacob; Hoff, Brad W.; Maestas, Sabrina S.; ...

2016-01-11

Dielectric strength testing of selected Polyjet-printed polymer plastics was performed in accordance with ASTM D149. This dielectric strength data is compared to manufacturer-provided dielectric strength data for selected plastics printed using the stereolithography (SLA), fused deposition modeling (FDM), and selective laser sintering (SLS) methods. Tested Polyjet samples demonstrated dielectric strengths as high as 47.5 kV/mm for a 0.5 mm thick sample and 32.1 kV/mm for a 1.0 mm sample. As a result, the dielectric strength of the additively manufactured plastics evaluated as part of this study was lower than the majority of non-printed plastics by at least 15% (with themore » exception of polycarbonate).« less

Dielectric breakdown of additively manufactured polymeric materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monzel, W. Jacob; Hoff, Brad W.; Maestas, Sabrina S.

Dielectric strength testing of selected Polyjet-printed polymer plastics was performed in accordance with ASTM D149. This dielectric strength data is compared to manufacturer-provided dielectric strength data for selected plastics printed using the stereolithography (SLA), fused deposition modeling (FDM), and selective laser sintering (SLS) methods. Tested Polyjet samples demonstrated dielectric strengths as high as 47.5 kV/mm for a 0.5 mm thick sample and 32.1 kV/mm for a 1.0 mm sample. As a result, the dielectric strength of the additively manufactured plastics evaluated as part of this study was lower than the majority of non-printed plastics by at least 15% (with themore » exception of polycarbonate).« less

Bond strength of primer/cement systems to zirconia subjected to artificial aging.

PubMed

Zhao, Li; Jian, Yu-Tao; Wang, Xiao-Dong; Zhao, Ke

2016-11-01

Creating reliable and durable adhesion to the nonactive zirconia surface is difficult and has limited zirconia use. The introduction of functional monomers such as 10-methacryloyloxydecyl dihydrogen phosphate (MDP) appears to have enhanced bond strength to zirconia. The purpose of this in vitro study was to evaluate the long-term bond strength of several MDP-containing primer/cement systems to zirconia. Zirconia blocks were divided into 6 groups (n=24) according to the 3 primers/cements to be bonded, as follows: Scotchbond Universal/RelyX Ultimate (SU/RU; consisting of MDP-containing primer/MDP-free cement); Clearfil ceramic primer/Panavia F (CCP/PAN; consisting ofMDP-containing/MDP-containing); and Z-Prime Plus/Duo-Link (ZP/DUO; consisting ofMDP-containing/MDP-free), which were compared with 3 nonprimed groups, RU, PAN, and DUO. After bonding, each group was further divided into 3 subgroups (n=8) according to the level of aging: 24-hour storage in water at 37°C (24H); 30-day storage at 37°C (30D); and 30-day storage at 37°C followed by 3000 thermal cycles (30D/TC). After aging, a shear bond strength test and failure mode analysis were performed. The data were analyzed using 2-way ANOVA (α=.05). After aging, nearly all primer/cement groups presented significantly higher bond strength than the related nonprimed groups for each level of aging (P<.05), except for CCP/PAN versus PAN with 24H (P=.741). SU/RU had the highest bond strength among the groups for all treatments (P<.05), except for CCP/PAN versus SU/RU with 30D/TC (P=.171). Among the nonprimed groups, only RU went through 30D/TC without premature debonding. With 24H and 30D, the failure modes in SU/RU and CCP/PAN were purely mixed, whereas those in the other groups were mainly adhesive, except for RU. The superiority of the initial bond strength in SU/RU may result from some functional components other than MDP. The presence of MDP in the cement did not appear to have a positive effect on long-term bond strength to zirconia. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Tooth surface treatment strategies for adhesive cementation

PubMed Central

2017-01-01

PURPOSE The aim of this study was to evaluate the effect of tooth surface pre-treatment steps on shear bond strength, which is essential for understanding the adhesive cementation process. MATERIALS AND METHODS Shear bond strengths of different cements with various tooth surface treatments (none, etching, priming, or etching and priming) on enamel and dentin of human teeth were measured using the Swiss shear test design. Three adhesives (Permaflo DC, Panavia F 2.0, and Panavia V5) and one self-adhesive cement (Panavia SA plus) were included in this study. The interface of the cement and the tooth surface with the different pre-treatments was analyzed using SEM. pH values of the cements and primers were measured. RESULTS The highest bond strength values for all cements were achieved with etching and primer on enamel (25.6 ± 5.3 - 32.3 ± 10.4 MPa). On dentin, etching and priming produced the highest bond strength values for all cements (8.6 ± 2.9 - 11.7 ± 3.5 MPa) except for Panavia V5, which achieved significantly higher bond strengths when pre-treated with primer only (15.3 ± 4.1 MPa). Shear bond strength values were correlated with the micro-retentive surface topography of enamel and the tag length on dentin except for Panavia V5, which revealed the highest bond strength with primer application only without etching, resulting in short but sturdy tags. CONCLUSION The highest bond strength can be achieved for Panavia F 2.0, Permaflo DC, and Panavia SA plus when the tooth substrate is previously etched and the respective primer is applied. The new cement Panavia V5 displayed low technique-sensitivity and attained significantly higher adhesion of all tested cements to dentin when only primer was applied. PMID:28435616

Continuous transition between weak and ultrastrong coupling through exceptional points in carbon nanotube microcavity exciton-polaritons

NASA Astrophysics Data System (ADS)

Gao, Weilu; Li, Xinwei; Bamba, Motoaki; Kono, Junichiro

2018-06-01

Non-perturbative coupling of photons and excitons produces hybrid particles, exciton-polaritons, which have exhibited a variety of many-body phenomena in various microcavity systems. However, the vacuum Rabi splitting (VRS), which defines the strength of photon-exciton coupling, is usually a single constant for a given system. Here, we have developed a unique architecture in which excitons in an aligned single-chirality carbon nanotube film interact with cavity photons in polarization-dependent manners. The system reveals ultrastrong coupling (VRS up to 329 meV or a coupling-strength-to-transition-energy ratio of 13.3%) for polarization parallel to the nanotube axis, whereas VRS is absent for perpendicular polarization. Between these two extremes, VRS is continuously tunable through polarization rotation with exceptional points separating crossing and anticrossing. The points between exceptional points form equienergy arcs onto which the upper and lower polaritons coalesce. The demonstrated on-demand ultrastrong coupling provides ways to explore topological properties of polaritons and quantum technology applications.

Bioinspired, Graphene/Al2O3 Doubly Reinforced Aluminum Composites with High Strength and Toughness.

PubMed

Zhang, Yunya; Li, Xiaodong

2017-11-08

Nacre, commonly referred to as nature's armor, has served as a blueprint for engineering stronger and tougher bioinspired materials. Nature organizes a brick-and-mortar-like architecture in nacre, with hard bricks of aragonite sandwiched with soft biopolymer layers. However, cloning nacre's entire reinforcing mechanisms in engineered materials remains a challenge. In this study, we employed hybrid graphene/Al 2 O 3 platelets with surface nanointerlocks as hard bricks for primary load bearer and mechanical interlocking, along with aluminum laminates as soft mortar for load distribution and energy dissipation, to replicate nacre's architecture and reinforcing effects in aluminum composites. Compared with aluminum, the bioinspired, graphene/Al 2 O 3 doubly reinforced aluminum composite demonstrated an exceptional, joint improvement in hardness (210%), strength (223%), stiffness (78%), and toughness (30%), which are even superior over nacre. This design strategy and model material system should guide the synthesis of bioinspired materials to achieve exceptionally high strength and toughness.

Motor Performance of Women as a Function of Age and Physical Activity Level.

ERIC Educational Resources Information Center

Rikli, Roberta; Busch, Sharman

Two studies compared motor skills of women in terms of the influence of age and activity level. In the first study, simple and choice reaction time, balance, flexibility, and grip strength of older active women were compared with that of older inactive women, and active and inactive younger women. Except for grip strength, scores of older active…

Effective Use of Weld Metal Yield Strength for HY-Steels

DTIC Science & Technology

1983-01-01

Boiler and Pressure Vessel Code The ASME Boiler and Pressure Vessel Code (B&PV Code) is divided...As noted earlier, the ASME Boiler and Pressure Vessel Code makes only one exception to its overall philosophy of matching weld-metal strength and...material where toughness is of primary importance. REFERENCES American Society of Mechanical Engineers, Boiler and Pressure Vessel

Effects of hypothyroidism on vascular /sup 125/I-albumin permeation and blood flow in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tilton, R.G.; Pugliese, G.; Chang, K.

1989-05-01

Effects of hypothyroidism on vascular 125I-albumin permeation and on blood flow were assessed in multiple tissues of male Sprague-Dawley rats rendered hypothyroid by dietary supplementation with 0.5% (wt/wt) 2-thiouracil or by thyroidectomy. In both thiouracil-treated and thyroidectomized rats, body weights, kidney weight, arterial blood pressure, and pulse rate were decreased significantly v age-matched controls. After 10 to 12 weeks of thiouracil treatment, 125I-albumin permeation was increased significantly in the kidney, aorta, eye (anterior uvea, choroid, retina), skin, and new granulation tissue, remained unchanged in brain, sciatic nerve, and heart, and was decreased in forelimb skeletal muscle. A similar pattern wasmore » observed in thyroidectomized rats, except that increases in 125I-albumin permeation for all tissues were smaller than those observed in thiouracil-treated rats, and 125I-albumin permeation in retina did not differ from controls. In both thiouracil-treated and thyroidectomized rats, changes in blood flow (assessed with 15-microns, 85Sr-labeled microspheres) relative to the decrease in arterial blood pressure were indicative of a decrease in regional vascular resistance except in the choroid and in the kidney, in which vascular resistance was increased significantly. Glomerular filtration rate was decreased, but filtration fraction and urinary excretion of albumin remained unchanged by thiouracil treatment and thyroidectomy. These results indicate that vascular hemodynamics and endothelial cell barrier functional integrity are modulated in many different tissues by the thyroid. In view of the correspondence of hypothyroid- and diabetes-induced vascular permeability changes, these results raise the possibility that altered thyroid function in diabetes may play a role in the pathogenesis of diabetic vascular disease.« less

Exceptional damage-tolerance of a medium-entropy alloy CrCoNi at cryogenic temperatures

DOE PAGES

Gludovatz, Bernd; Hohenwarter, Anton; Thurston, Keli V. S.; ...

2016-02-02

The high-entropy alloys are an intriguing new class of metallic materials that derive their properties not from a single dominant constituent, such as iron in steels, nor from the presence of a second phase, such as in nickel-base superalloys, but rather comprise multi-element systems that crystallize as a single phase, despite containing high concentrations (~20 at.%) of five or more elements with different crystal structures. Indeed, we have recently reported on one such single-phase high-entropy alloy, NiCoCrFeMn, which displays exceptional strength and toughness at cryogenic temperatures. Here which displays unprecedented strength-toughness properties that exceed those of all high-entropy alloys andmore » most multi-phase alloys. With roomtemperature tensile strengths of almost 1 GPa and KJIc fracture-toughness values above 200 MPa.m 1/2 (with crack-growth toughnesses exceeding 300 MPa.m 1/2), the strength, ductility and toughness of the NiCoCr alloy actually improve at cryogenic temperatures to unprecedented levels of strengths above 1.3 GPa, failure strains up to 90% and K JIc values of 275 MPa.m 1/2 (with crackgrowth toughnesses above 400 MPa.m 1/2). These properties appear to result from continuous steady strain hardening, which acts to suppress plastic instability, resulting from pronounced dislocation activity and deformation-induced nano-twinning.« less

Capsaicin Supplementation Reduces Physical Fatigue and Improves Exercise Performance in Mice

PubMed Central

Hsu, Yi-Ju; Huang, Wen-Ching; Chiu, Chien-Chao; Liu, Yan-Lin; Chiu, Wan-Chun; Chiu, Chun-Hui; Chiu, Yen-Shuo; Huang, Chi-Chang

2016-01-01

Chili pepper is used as a food, seasoning and has been revered for its medicinal and health claims. It is very popular and is the most common spice worldwide. Capsaicin (CAP) is a major pungent and bioactive phytochemical in chili peppers. CAP has been shown to improve mitochondrial biogenesis and adenosine triphosphate (ATP) production. However, there is limited evidence around the effects of CAP on physical fatigue and exercise performance. The purpose of this study was to evaluate the potential beneficial effects of CAP on anti-fatigue and ergogenic functions following physiological challenge. Female Institute of Cancer Research (ICR) mice from four groups (n = 8 per group) were orally administered CAP for 4 weeks at 0, 205, 410, and 1025 mg/kg/day, which were respectively designated the vehicle, CAP-1X, CAP-2X, and CAP-5X groups. The anti-fatigue activity and exercise performance was evaluated using forelimb grip strength, exhaustive swimming time, and levels of serum lactate, ammonia, glucose, BUN (blood urea nitrogen) and creatine kinase (CK) after a 15-min swimming exercise. The grip strength and exhaustive swimming time of the CAP-5X group were significantly higher than other groups. CAP supplementation dose-dependently reduced serum lactate, ammonia, BUN and CK levels, and increased glucose concentration after the 15-min swimming test. In addition, CAP also increased hepatic glycogen content, an important energy source for exercise. The possible mechanism was relevant to energy homeostasis and the physiological modulations by CAP supplementation. Therefore, our results suggest that CAP supplementation may have a wide spectrum of bioactivities for promoting health, performance improvement and fatigue amelioration. PMID:27775591

Soluble Milk Protein Supplementation with Moderate Physical Activity Improves Locomotion Function in Aging Rats.

PubMed

Lafoux, Aude; Baudry, Charlotte; Bonhomme, Cécile; Le Ruyet, Pascale; Huchet, Corinne

2016-01-01

Aging is associated with a loss of muscle mass and functional capacity. Present study was designed to compare the impact of specific dairy proteins on muscular function with or without a low-intensity physical activity program on a treadmill in an aged rat model. We investigated the effects of nutritional supplementation, five days a week over a 2-month period with a slow digestible protein, casein or fast digestible proteins, whey or soluble milk protein, on strength and locomotor parameters in sedentary or active aged Wistar RjHan rats (17-19 months of age). An extensive gait analysis was performed before and after protein supplementation. After two months of protein administration and activity program, muscle force was evaluated using a grip test, spontaneous activity using an open-field and muscular mass by specific muscle sampling. When aged rats were supplemented with proteins without exercise, only minor effects of different diets on muscle mass and locomotion were observed: higher muscle mass in the casein group and improvement of stride frequencies with soluble milk protein. By contrast, supplementation with soluble milk protein just after physical activity was more effective at improving overall skeletal muscle function in old rats compared to casein. For active old rats supplemented with soluble milk protein, an increase in locomotor activity in the open field and an enhancement of static and dynamic gait parameters compared to active groups supplemented with casein or whey were observed without any differences in muscle mass and forelimb strength. These results suggest that consumption of soluble milk protein as a bolus immediately after a low intensity physical activity may be a suitable nutritional intervention to prevent decline in locomotion in aged rats and strengthen the interest to analyze the longitudinal aspect of locomotion in aged rodents.

The mitochondrial metabolic reprogramming agent trimetazidine as an ‘exercise mimetic’ in cachectic C26‐bearing mice

PubMed Central

Molinari, Francesca; Pin, Fabrizio; Gorini, Stefania; Chiandotto, Sergio; Pontecorvo, Laura; Penna, Fabio; Rizzuto, Emanuele; Pisu, Simona; Musarò, Antonio; Costelli, Paola

2017-01-01

Abstract Background Cancer cachexia is characterized by muscle depletion and exercise intolerance caused by an imbalance between protein synthesis and degradation and by impaired myogenesis. Myofibre metabolic efficiency is crucial so as to assure optimal muscle function. Some drugs are able to reprogram cell metabolism and, in some cases, to enhance metabolic efficiency. Based on these premises, we chose to investigate the ability of the metabolic modulator trimetazidine (TMZ) to counteract skeletal muscle dysfunctions and wasting occurring in cancer cachexia. Methods For this purpose, we used mice bearing the C26 colon carcinoma as a model of cancer cachexia. Mice received 5 mg/kg TMZ (i.p.) once a day for 12 consecutive days. A forelimb grip strength test was performed and tibialis anterior, and gastrocnemius muscles were excised for analysis. Ex vivo measurement of skeletal muscle contractile properties was also performed. Results Our data showed that TMZ induces some effects typically achieved through exercise, among which is grip strength increase, an enhanced fast‐to slow myofibre phenotype shift, reduced glycaemia, PGC1α up‐regulation, oxidative metabolism, and mitochondrial biogenesis. TMZ also partially restores the myofibre cross‐sectional area in C26‐bearing mice, while modulation of autophagy and apoptosis were excluded as mediators of TMZ effects. Conclusions In conclusion, our data show that TMZ acts like an ‘exercise mimetic’ and is able to enhance some mechanisms of adaptation to stress in cancer cachexia. This makes the modulation of the metabolism, and in particular TMZ, a suitable candidate for a therapeutic rehabilitative protocol design, particularly considering that TMZ has already been approved for clinical use. PMID:29130633

Capsaicin Supplementation Reduces Physical Fatigue and Improves Exercise Performance in Mice.

PubMed

Hsu, Yi-Ju; Huang, Wen-Ching; Chiu, Chien-Chao; Liu, Yan-Lin; Chiu, Wan-Chun; Chiu, Chun-Hui; Chiu, Yen-Shuo; Huang, Chi-Chang

2016-10-20

Chili pepper is used as a food, seasoning and has been revered for its medicinal and health claims. It is very popular and is the most common spice worldwide. Capsaicin (CAP) is a major pungent and bioactive phytochemical in chili peppers. CAP has been shown to improve mitochondrial biogenesis and adenosine triphosphate (ATP) production. However, there is limited evidence around the effects of CAP on physical fatigue and exercise performance. The purpose of this study was to evaluate the potential beneficial effects of CAP on anti-fatigue and ergogenic functions following physiological challenge. Female Institute of Cancer Research (ICR) mice from four groups ( n = 8 per group) were orally administered CAP for 4 weeks at 0, 205, 410, and 1025 mg/kg/day, which were respectively designated the vehicle, CAP-1X, CAP-2X, and CAP-5X groups. The anti-fatigue activity and exercise performance was evaluated using forelimb grip strength, exhaustive swimming time, and levels of serum lactate, ammonia, glucose, BUN (blood urea nitrogen) and creatine kinase (CK) after a 15-min swimming exercise. The grip strength and exhaustive swimming time of the CAP-5X group were significantly higher than other groups. CAP supplementation dose-dependently reduced serum lactate, ammonia, BUN and CK levels, and increased glucose concentration after the 15-min swimming test. In addition, CAP also increased hepatic glycogen content, an important energy source for exercise. The possible mechanism was relevant to energy homeostasis and the physiological modulations by CAP supplementation. Therefore, our results suggest that CAP supplementation may have a wide spectrum of bioactivities for promoting health, performance improvement and fatigue amelioration.

Soluble Milk Protein Supplementation with Moderate Physical Activity Improves Locomotion Function in Aging Rats

PubMed Central

Lafoux, Aude; Baudry, Charlotte; Bonhomme, Cécile; Le Ruyet, Pascale; Huchet, Corinne

2016-01-01

Aging is associated with a loss of muscle mass and functional capacity. Present study was designed to compare the impact of specific dairy proteins on muscular function with or without a low-intensity physical activity program on a treadmill in an aged rat model. We investigated the effects of nutritional supplementation, five days a week over a 2-month period with a slow digestible protein, casein or fast digestible proteins, whey or soluble milk protein, on strength and locomotor parameters in sedentary or active aged Wistar RjHan rats (17–19 months of age). An extensive gait analysis was performed before and after protein supplementation. After two months of protein administration and activity program, muscle force was evaluated using a grip test, spontaneous activity using an open-field and muscular mass by specific muscle sampling. When aged rats were supplemented with proteins without exercise, only minor effects of different diets on muscle mass and locomotion were observed: higher muscle mass in the casein group and improvement of stride frequencies with soluble milk protein. By contrast, supplementation with soluble milk protein just after physical activity was more effective at improving overall skeletal muscle function in old rats compared to casein. For active old rats supplemented with soluble milk protein, an increase in locomotor activity in the open field and an enhancement of static and dynamic gait parameters compared to active groups supplemented with casein or whey were observed without any differences in muscle mass and forelimb strength. These results suggest that consumption of soluble milk protein as a bolus immediately after a low intensity physical activity may be a suitable nutritional intervention to prevent decline in locomotion in aged rats and strengthen the interest to analyze the longitudinal aspect of locomotion in aged rodents. PMID:27973615

Effect of ultraviolet light irradiation and sandblasting treatment on bond strengths between polyamide and chemical-cured resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

2014-01-01

The aim of this study was to evaluate the effects of ultraviolet light (UV) irradiation and sandblasting treatment on the shear bond strength between polyamide and chemical-cured resin. Three types of commercial polyamides were treated using UV irradiation, sandblasting treatment, and a combining sandblasting and UV irradiation. The shear bond strength was measured and analyzed using the Kruskal-Wallis test (α=0.05). Comparing shear bond strengths without surface treatment, from 4.1 to 5.7 MPa, the UV irradiation significantly increased the shear bond strengths except for Valplast, whose shear bond strengths ranged from 5.2 to 9.3 MPa. The sandblasting treatment also significantly increased the shear bond strengths (8.0 to 11.4 MPa). The combining sandblasting and UV irradiation significantly increased the shear bond strengths (15.2 to 18.3 MPa) comparing without surface treatment. This combined treatment was considered the most effective at improving the shear bond strength between polyamide and chemical-cured resin.

Thermoplastic composites for veneering posterior teeth-a feasibility study.

PubMed

Gegauff, Anthony G; Garcia, Jose L; Koelling, Kurt W; Seghi, Robert R

2002-09-01

This pilot study was conducted to explore selected commercially-available thermoplastic composites that potentially had physical properties superior to currently available dental systems for restoring esthetic posterior crowns. Polyurethane, polycarbonate, and poly(ethylene/tetrafluoroethylene) (ETFE) composites and unfilled polyurethane specimens were injection molded to produce shapes adaptive to five standardized mechanical tests. The mechanical testing included abrasive wear rate, yield strength, apparent fracture toughness (strength ratio), flexural strength, and compressive strength. Compared to commercially available dental composites, abrasion wear rates were lower for all materials tested, yield strength was greater for the filled polycarbonates and filled polyurethane resins, fracture toughness testing was invalid (strength ratios were calculated for comparison of the pilot test materials), flexural strength was roughly similar except for the filled ETFE which was significantly greater, and compressive strength was lower. Commercially available thermoplastic resin composites, such as polyurethane, demonstrate the potential for development of an artificial crown material which exceeds the mechanical properties of currently available esthetic systems, if compressive strength can be improved.

Isokinetic Strength and Endurance Tests used Pre- and Post-Spaceflight: Test-Retest Reliability

NASA Technical Reports Server (NTRS)

Laughlin, Mitzi S.; Lee, Stuart M. C.; Loehr, James A.; Amonette, William E.

2009-01-01

To assess changes in muscular strength and endurance after microgravity exposure, NASA measures isokinetic strength and endurance across multiple sessions before and after long-duration space flight. Accurate interpretation of pre- and post-flight measures depends upon the reliability of each measure. The purpose of this study was to evaluate the test-retest reliability of the NASA International Space Station (ISS) isokinetic protocol. Twenty-four healthy subjects (12 M/12 F, 32.0 +/- 5.6 years) volunteered to participate. Isokinetic knee, ankle, and trunk flexion and extension strength as well as endurance of the knee flexors and extensors were measured using a Cybex NORM isokinetic dynamometer. The first weekly session was considered a familiarization session. Data were collected and analyzed for weeks 2-4. Repeated measures analysis of variance (alpha=0.05) was used to identify weekly differences in isokinetic measures. Test-retest reliability was evaluated by intraclass correlation coefficients (ICC) (3,1). No significant differences were found between weeks in any of the strength measures and the reliability of the strength measures were all considered excellent (ICC greater than 0.9), except for concentric ankle dorsi-flexion (ICC=0.67). Although a significant difference was noted in weekly endurance measures of knee extension (p less than 0.01), the reliability of endurance measure by week were considered excellent for knee flexion (ICC=0.97) and knee extension (ICC=0.96). Except for concentric ankle dorsi-flexion, the isokinetic strength and endurance measures are highly reliable when following the NASA ISS protocol. This protocol should allow accurate interpretation isokinetic data even with a small number of crew members.

The Impact of Plasma Treatment of Cercon® Zirconia Ceramics on Adhesion to Resin Composite Cements and Surface Properties.

PubMed

Tabari, Kasra; Hosseinpour, Sepanta; Mohammad-Rahimi, Hossein

2017-01-01

Introduction: In recent years, the use of ceramic base zirconia is considered in dentistry for all ceramic restorations because of its chemical stability, biocompatibility, and good compressive as well as flexural strength. However, due to its chemical stability, there is a challenge with dental bonding. Several studies have been done to improve zirconia bonding but they are not reliable. The purpose of this research is to study the effect of plasma treatment on bonding strength of zirconia. Methods: In this in vitro study, 180 zirconia discs' (thickness was 0.85-0.9 mm) surfaces were processed with plasma of oxygen, argon, air and oxygen-argon combination with 90-10 and 80-20 ratio (n=30 for each group) after being polished by sandblast. Surface modifications were assessed by measuring the contact angle, surface roughness, and topographical evaluations. Cylindrical Panavia f2 resin-cement and Diafill were used for microshear strength bond measurements. The data analysis was performed by SPSS 20.0 software and one-way analysis of variance (ANOVA) and Tukey test as the post hoc. Results: Plasma treatment in all groups significantly reduces contact angle compare with control ( P =0.001). Topographic evaluations revealed coarseness promotion occurred in all plasma treated groups which was significant when compared to control ( P <0.05), except argon plasma treated group that significantly decreased surface roughness ( P <0.05). In all treated groups, microshear bond strength increased, except oxygen treated plasma group which decreased this strength. Air and argon-oxygen combination (both groups) significantly increased microshear bond strength ( P <0.05). Conclusion: According to this research, plasmatic processing with dielectric barrier method in atmospheric pressure can increase zirconia bonding strength.

Correlation between subacute sensorimotor deficits and brain edema in two mouse models of intracerebral hemorrhage.

PubMed

Krafft, Paul R; McBride, Devin W; Lekic, Tim; Rolland, William B; Mansell, Charles E; Ma, Qingyi; Tang, Jiping; Zhang, John H

2014-05-01

Formation of brain edema after intracerebral hemorrhage (ICH) is highly associated with its poor outcome. However, the relationship between cerebral edema and behavioral deficits has not been thoroughly examined in the preclinical setting. Hence, this study aimed to evaluate the ability of common sensorimotor tests to predict the extent of brain edema in two mouse models of ICH. One hundred male CD-1 mice were subjected to sham surgery or ICH induction via intrastriatal injection of either autologous blood (30 μL) or bacterial collagenase (0.0375U or 0.075U). At 24 and 72 h after surgery, animals underwent a battery of behavioral tests, including the modified Garcia neuroscore (Neuroscore), corner turn test (CTT), forelimb placing test (FPT), wire hang task (WHT) and beam walking (BW). Brain edema was evaluated via the wet weight/dry weight method. Intrastriatal injection of autologous blood or bacterial collagenase resulted in a significant increase in brain water content and associated sensorimotor deficits (p<0.05). A significant correlation between brain edema and sensorimotor deficits was observed for all behavioral tests except for WHT and BW. Based on these findings, we recommend implementing the Neuroscore, CTT and/or FPT in preclinical studies of unilateral ICH in mice. Copyright © 2014 Elsevier B.V. All rights reserved.

Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs

PubMed Central

Sereno, Paul C.

2012-01-01

Abstract Heterodontosaurids comprise an important early radiation of small-bodied herbivores that persisted for approximately 100 My from Late Triassic to Early Cretaceous time. Review of available fossils unequivocally establishes Echinodon as a very small-bodied, late-surviving northern heterodontosaurid similar to the other northern genera Fruitadens and Tianyulong. Tianyulong from northern China has unusual skeletal proportions, including a relatively large skull, short forelimb, and long manual digit II. The southern African heterodontosaurid genus Lycorhinus is established as valid, and a new taxon from the same formation is named Pegomastax africanus gen. n., sp. n. Tooth replacement and tooth-to-tooth wear is more common than previously thought among heterodontosaurids, and in Heterodontosaurus the angle of tooth-to-tooth shear is shown to increase markedly during maturation. Long-axis rotation of the lower jaw during occlusion is identified here as the most likely functional mechanism underlying marked tooth wear in mature specimens of Heterodontosaurus. Extensive tooth wear and other evidence suggests that all heterodontosaurids were predominantly or exclusively herbivores. Basal genera such as Echinodon, Fruitadens and Tianyulong with primitive, subtriangular crowns currently are known only from northern landmasses. All other genera except the enigmatic Pisanosaurus have deeper crown proportions and currently are known only from southern landmasses. PMID:23166462

Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia

PubMed Central

Fowler, Denver W.; Woodward, Holly N.; Freedman, Elizabeth A.; Larson, Peter L.; Horner, John R.

2011-01-01

The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size. PMID:21738646

Zooplankton Aggregation Near Sills

DTIC Science & Technology

2004-04-01

Other species of pteropods , chaetognaths, 2 DRDC Atlantic ECR 2004-086 ctenophores, and cnidaria are sometimes present, and known to migrate...strength (these are soft-bodied animals). The exception to this is the hard-shelled planktonic pteropod Limacina helicina, which for typical...animal size near 2 mm have a target strength at 200 kHz near -76 dB (Stanton et al. 1998), more similar to that of adult euphausiids. A few pteropods

Soy Flour Adhesive Strength Compared with That of Purified Soy Proteins*

Treesearch

Linda Lorenz; Michael Birkeland; Chera Daurio; Charles R. Frihart

2015-01-01

Except for the substitution of soy flour in phenolic resins (Frihart et al. 2013) and the use of soy flour at high pHs (Lambuth 2003), the literature on soy protein properties for adhesives has mainly focused on soy protein isolate and specific protein fractions (Sun 2005b). The assumption is that proteins are the main portion of soy flour giving bond strength and the...

Glenoid dysplasia and osteochondritis dissecans in a cat

PubMed Central

Schwarze, Rebecca A.; Tano, Cheryl A.; Carroll, Vincent W.

2015-01-01

A 2-year-old Maine coon cat was presented for a right forelimb lameness. Computed tomography of the shoulder revealed a shallow glenoid, osteophyte deposition at the caudal humeral head and medial glenoid, and an intra-articular osseous body. This cat had glenoid dysplasia and osteochondritis dissecans of the glenoid. PMID:26130839

Carpal intra-articular blastomycosis in a Labrador retriever.

PubMed

Woods, Katharine S; Barry, Maureen; Richardson, Danielle

2013-02-01

A 6-month-old male castrated Labrador retriever was presented for coughing and forelimb lameness. Blastomyces dermatitidis was identified in cytology of sputum and synovial fluid. Repeat arthrocentesis 7 months later revealed resolution of septic arthritis. Fungal septic arthritis should be considered for cases of monoarthritis and may respond to oral itraconazole treatment.

The Occurrence and Prevalence of Giraffe Skin Disease in Protected Areas of Northern Tanzania.

PubMed

Lee, Derek E; Bond, Monica L

2016-07-01

Giraffe skin disease (GSD) is a disorder of undetermined etiology that causes lesions on the forelimbs of Masai giraffe ( Giraffa camelopardalis tippelskirchi). We estimated occurrence and prevalence of GSD in six wildlife conservation areas of Tanzania. The disjunct spatial pattern of occurrence implies that environmental factors may influence GSD.

Florida's Manatee. An Educator's Guide. Third Edition Revised.

ERIC Educational Resources Information Center

Fritz-Quincy, Debbie

This revised and updated guide provides resources for teaching about the Florida manatee, a nearly hairless, thick-skinned marine mammal without hindlimbs and with paddle-like forelimbs. The manatee (an endangered species) is sometimes called a sea cow. The guide includes: (1) a vocabulary list; (2) a list of suggested readings; (3) an annotated…

Cellular mechanisms underlying behavioral state-dependent bidirectional modulation of motor cortex output.

PubMed

Schiemann, Julia; Puggioni, Paolo; Dacre, Joshua; Pelko, Miha; Domanski, Aleksander; van Rossum, Mark C W; Duguid, Ian

2015-05-26

Neuronal activity in primary motor cortex (M1) correlates with behavioral state, but the cellular mechanisms underpinning behavioral state-dependent modulation of M1 output remain largely unresolved. Here, we performed in vivo patch-clamp recordings from layer 5B (L5B) pyramidal neurons in awake mice during quiet wakefulness and self-paced, voluntary movement. We show that L5B output neurons display bidirectional (i.e., enhanced or suppressed) firing rate changes during movement, mediated via two opposing subthreshold mechanisms: (1) a global decrease in membrane potential variability that reduced L5B firing rates (L5Bsuppressed neurons), and (2) a coincident noradrenaline-mediated increase in excitatory drive to a subpopulation of L5B neurons (L5Benhanced neurons) that elevated firing rates. Blocking noradrenergic receptors in forelimb M1 abolished the bidirectional modulation of M1 output during movement and selectively impaired contralateral forelimb motor coordination. Together, our results provide a mechanism for how noradrenergic neuromodulation and network-driven input changes bidirectionally modulate M1 output during motor behavior. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Speed and stamina trade-off in lacertid lizards.

PubMed

Vanhooydonck, B; Van Damme, R; Aerts, P

2001-05-01

Morphological and physiological considerations suggest that sprinting ability and endurance capacity put conflicting demands on the design of an animal's locomotor apparatus and therefore cannot be maximized simultaneously. To test this hypothesis, we correlated size-corrected maximal sprint speed and stamina of 12 species of lacertid lizards. Phylogenetically independent contrasts of sprint speed and stamina showed a significant negative relationship, giving support to the idea of an evolutionary trade-off between the two performance measures. To test the hypothesis that the trade-off is mediated by a conflict in morphological requirements, we correlated both performance traits with snout-vent length, size-corrected estimates of body mass and limb length, and relative hindlimb length (the residuals of the relationship between hind- and forelimb length). Fast-running species had hindlimbs that were long compared to their forelimbs. None of the other size or shape variables showed a significant relationship with speed or endurance. We conclude that the evolution of sprint capacity may be constrained by the need for endurance capacity and vice versa, but the design conflict underlying this trade-off has yet to be identified.

Quantitative inferences on the locomotor behaviour of extinct species applied to Simocyon batalleri (Ailuridae, Late Miocene, Spain)

NASA Astrophysics Data System (ADS)

Fabre, Anne-Claire; Salesa, Manuel J.; Cornette, Raphael; Antón, Mauricio; Morales, Jorge; Peigné, Stéphane

2015-06-01

Inferences of function and ecology in extinct taxa have long been a subject of interest because it is fundamental to understand the evolutionary history of species. In this study, we use a quantitative approach to investigate the locomotor behaviour of Simocyon batalleri, a key taxon related to the ailurid family. To do so, we use 3D surface geometric morphometric approaches on the three long bones of the forelimb of an extant reference sample. Next, we test the locomotor strategy of S. batalleri using a leave-one-out cross-validated linear discriminant analysis. Our results show that S. batalleri is included in the morphospace of the living species of musteloids. However, each bone of the forelimb appears to show a different functional signal suggesting that inferring the lifestyle or locomotor behaviour of fossils can be difficult and dependent on the bone investigated. This highlights the importance of studying, where possible, a maximum of skeletal elements to be able to make robust inferences on the lifestyle of extinct species. Finally, our results suggest that S. batalleri may be more arboreal than previously suggested.

Parallel changes in cortical neuron biochemistry and motor function in protein-energy malnourished adult rats.

PubMed

Alaverdashvili, Mariam; Hackett, Mark J; Caine, Sally; Paterson, Phyllis G

2017-04-01

While protein-energy malnutrition in the adult has been reported to induce motor abnormalities and exaggerate motor deficits caused by stroke, it is not known if alterations in mature cortical neurons contribute to the functional deficits. Therefore, we explored if PEM in adult rats provoked changes in the biochemical profile of neurons in the forelimb and hindlimb regions of the motor cortex. Fourier transform infrared spectroscopic imaging using a synchrotron generated light source revealed for the first time altered lipid composition in neurons and subcellular domains (cytosol and nuclei) in a cortical layer and region-specific manner. This change measured by the area under the curve of the δ(CH 2 ) band may indicate modifications in membrane fluidity. These PEM-induced biochemical changes were associated with the development of abnormalities in forelimb use and posture. The findings of this study provide a mechanism by which PEM, if not treated, could exacerbate the course of various neurological disorders and diminish treatment efficacy. Copyright © 2017 Elsevier Inc. All rights reserved.

The role of early development in mammalian limb diversification: a descriptive comparison of early limb development between the Natal long-fingered bat (Miniopterus natalensis) and the mouse (Mus musculus).

PubMed

Hockman, Dorit; Mason, Mandy K; Jacobs, David S; Illing, Nicola

2009-04-01

Comparative embryology expands our understanding of unique limb structures, such as that found in bats. Bat forelimb digits 2 to 5 are differentially elongated and joined by webbing, while the hindlimb digits are of similar length in many species. We compare limb development between the mouse and the Natal long-fingered bat, Miniopterus natalensis, to pinpoint the stage at which their limbs begin to differ. The bat forelimb differs from the mouse at Carollia stage (CS) 14 with the appearance of the wing membrane primordia. This difference is enhanced at CS 15 with the posterior expansion of the hand plate. The bat hindlimb begins to differ from the mouse between CS 15 and 16 when the foot plate undergoes a proximal expansion resulting in digit primordia of very similar length. Our findings support recent gene expression studies, which reveal a role for early patterning in the development of the bat limb. Copyright 2009 Wiley-Liss, Inc.

Extraction of motor activity from the cervical spinal cord of behaving rats

NASA Astrophysics Data System (ADS)

Prasad, Abhishek; Sahin, Mesut

2006-12-01

Injury at the cervical region of the spinal cord results in the loss of the skeletal muscle control from below the shoulders and hence causes quadriplegia. The brain-computer interface technique is one way of generating a substitute for the lost command signals in these severely paralyzed individuals using the neural signals from the brain. In this study, we are investigating the feasibility of an alternative method where the volitional signals are extracted from the cervical spinal cord above the point of injury. A microelectrode array assembly was implanted chronically at the C5-C6 level of the spinal cord in rats. Neural recordings were made during the face cleaning behavior with forelimbs as this task involves cyclic forelimb movements and does not require any training. The correlation between the volitional motor signals and the elbow movements was studied. Linear regression technique was used to reconstruct the arm movement from the rectified-integrated version of the principal neural components. The results of this study demonstrate the feasibility of extracting the motor signals from the cervical spinal cord and using them for reconstruction of the elbow movements.

Dicephalic Parapagus Conjoined Twins in a Large Fruit-eating Bat, Genus Artibeus (Chiroptera, Phyllostomidae).

PubMed

Nogueira, M R; Ventura, A; da Veiga, C C P; Monteiro, L R; Pinheiro, N L; Peracchi, A L

2017-08-01

Conjoined twinning is an embryological anomaly rarely reported in wild mammals and with only two previous records in Chiroptera. Here, we report a case of dicephalic parapagus conjoined twins in the Neotropical phyllostomid genus Artibeus. These twins are males and present separated heads and necks, but a conjoined trunk with an expanded upper thoracic region. They developed two complete forelimbs and two complete hindlimbs, all laterally to the trunk. There is a volume in the upper midback and between the heads that resembles a third rudimentary medial forelimb, but X-ray images only suggest the presence of medial skeletal elements of the pectoral girdle (clavicle and scapulae) in this region. The X-ray images also show that vertebral columns run separated from head until the base of lumbar region, where they form a single structure. Using ultrasound images, we detected the presence of two similarly sized and apparently separated hearts. The accumulation of study cases like this will help in the understanding of patterns and process behind this phenomena, and collection material plays a key role in this context. © 2017 Blackwell Verlag GmbH.

One foot out the door: limb function during swimming in terrestrial versus aquatic turtles.

PubMed

Young, Vanessa K Hilliard; Vest, Kaitlyn G; Rivera, Angela R V; Espinoza, Nora R; Blob, Richard W

2017-01-01

Specialization for a new habitat often entails a cost to performance in the ancestral habitat. Although aquatic lifestyles are ancestral among extant cryptodiran turtles, multiple lineages, including tortoises (Testudinidae) and emydid box turtles (genus Terrapene), independently specialized for terrestrial habitats. To what extent is swimming function retained in such lineages despite terrestrial specialization? Because tortoises diverged from other turtles over 50 Ma, but box turtles did so only 5 Ma, we hypothesized that swimming kinematics for box turtles would more closely resemble those of aquatic relatives than those of tortoises. To test this prediction, we compared high-speed video of swimming Russian tortoises (Testudo horsfieldii), box turtles (Terrapene carolina) and two semi-aquatic emydid species: sliders (Trachemys scripta) and painted turtles (Chrysemys picta). We identified different kinematic patterns between limbs. In the forelimb, box turtle strokes most resemble those of tortoises; for the hindlimb, box turtles are more similar to semi-aquatic species. Such patterns indicate functional convergence of the forelimb of terrestrial species, whereas the box turtle hindlimb exhibits greater retention of ancestral swimming motions. © 2017 The Author(s).

The temporal response of bone to unloading

NASA Technical Reports Server (NTRS)

Globus, R. K.; Bikle, D. D.; Morey-Holton, E.

1984-01-01

Rats were suspended by their tails with the forelimbs bearing the weight load to simulate the weightlessness of space flight. Growth in bone mass ceased by 1 week in the hindlimbs and lumbar vertebrae in growing rats, while growth in the forelimbs and cervical vertebrae remained unaffected. The effects of selective skeletal unloading on bone formation during 2 weeks of suspension was investigated using radio iostope incorporation (with Ca-45 and H-3 proline) and histomorphometry (with tetracycline labeling). The results of these studies were confirmed by histomorphometric measurements of bone formation using triple tetracycline labeling. This model of simulated weightlessness results in an initial inhibition of bone formation in the unloaded bones. This temporary cessation of bone formation is followed in the accretion of bone mass, which then resumes at a normal rate by 14 days, despite continued skeletal unloading. This cycle of inhibition and resumption of bone formation has profound implication for understanding bone dynamics durng space flight, immobilization, or bed rest and offers an opportunity to study the hormonal and mechanical factors that regulate bone formation.

Energetics of swimming by the ferret: consequences of forelimb paddling.

PubMed

Fish, Frank E; Baudinette, Russell V

2008-06-01

The domestic ferret (Mustela putorius furo) swims by alternate strokes of the forelimbs. This pectoral paddling is rare among semi-aquatic mammals. The energetic implications of swimming by pectoral paddling were examined by kinematic analysis and measurement of oxygen consumption. Ferrets maintained a constant stroke frequency, but increased swimming speed by increasing stroke amplitude. The ratio of swimming velocity to foot stroke velocity was low, indicating a low propulsive efficiency. Metabolic rate increased linearly with increasing speed. The cost of transport decreased with increasing swimming speed to a minimum of 3.59+/-0.28 J N(-1) m(-1) at U=0.44 m s(-1). The minimum cost of transport for the ferret was greater than values for semi-aquatic mammals using hind limb paddling, but lower than the minimum cost of transport for the closely related quadrupedally paddling mink. Differences in energetic performance may be due to the amount of muscle recruited for propulsion and the interrelationship hydrodynamic drag and interference between flow over the body surface and flow induced by propulsive appendages.

One foot out the door: limb function during swimming in terrestrial versus aquatic turtles

PubMed Central

Vest, Kaitlyn G.; Rivera, Angela R. V.; Espinoza, Nora R.; Blob, Richard W.

2017-01-01

Specialization for a new habitat often entails a cost to performance in the ancestral habitat. Although aquatic lifestyles are ancestral among extant cryptodiran turtles, multiple lineages, including tortoises (Testudinidae) and emydid box turtles (genus Terrapene), independently specialized for terrestrial habitats. To what extent is swimming function retained in such lineages despite terrestrial specialization? Because tortoises diverged from other turtles over 50 Ma, but box turtles did so only 5 Ma, we hypothesized that swimming kinematics for box turtles would more closely resemble those of aquatic relatives than those of tortoises. To test this prediction, we compared high-speed video of swimming Russian tortoises (Testudo horsfieldii), box turtles (Terrapene carolina) and two semi-aquatic emydid species: sliders (Trachemys scripta) and painted turtles (Chrysemys picta). We identified different kinematic patterns between limbs. In the forelimb, box turtle strokes most resemble those of tortoises; for the hindlimb, box turtles are more similar to semi-aquatic species. Such patterns indicate functional convergence of the forelimb of terrestrial species, whereas the box turtle hindlimb exhibits greater retention of ancestral swimming motions. PMID:28123109

Trefoil Factor 3 as an Endocrine Neuroprotective Factor from the Liver in Experimental Cerebral Ischemia/Reperfusion Injury

PubMed Central

Liu, Shu Q.; Roberts, Derek; Zhang, Brian; Ren, Yupeng; Zhang, Li-Qun; Wu, Yu H.

2013-01-01

Cerebral ischemia, while causing neuronal injury, can activate innate neuroprotective mechanisms, minimizing neuronal death. In this report, we demonstrate that experimental cerebral ischemia/reperfusion injury in the mouse causes upregulation of the secretory protein trefoil factor 3 (TFF3) in the hepatocyte in association with an increase in serum TFF3. Partial hepatectomy (~60% liver resection) immediately following cerebral injury significantly lowered the serum level of TFF3, suggesting a contribution of the liver to the elevation of serum TFF3. Compared to wild-type mice, TFF3-/- mice exhibited a significantly higher activity of caspase 3 and level of cell death in the ischemic cerebral lesion, a larger fraction of cerebral infarcts, and a smaller fraction of the injured cerebral hemisphere, accompanied by severer forelimb motor deficits. Intravenous administration of recombinant TFF3 reversed changes in cerebral injury and forelimb motor function due to TFF3 deficiency. These observations suggest an endocrine neuroprotective mechanism involving TFF3 from the liver in experimental cerebral ischemia/reperfusion injury. PMID:24204940

A method to determine shear adhesive strength of fibrin sealants.

PubMed

Sierra, D H; Feldman, D S; Saltz, R; Huang, S

1992-01-01

The adhesive strength of fibrin sealants has not been rigorously evaluated to date. The adhesive strength of six different concentrations of cryoprecipitated fibrinogen as well as the commercially available fibrin tissue adhesive Tissucol was tested under controlled conditions utilizing split-thickness skin grafts as the test adherand. This test configuration permitted the modeling of bonding strength for attachment of skin grafts as well as incorporate established engineering test standards for adhesives. An increase in fibrin concentration corresponded with an increase in shear adhesive strength. No significant increases in adhesive strength were attained after 5 min of bonding for all tested concentrations, except for the commercial adhesive, which attained the adhesive strength of an equivalent concentration of cryoprecipitated adhesive after 90 min. The adhesive strength, however, was an order of magnitude less than reported values of the tensile strength of fibrin material for similar concentrations. Therefore, it is important that the surgeon use a sufficiently high fibrinogen concentration for the specific clinical indication. The method of fibrin sealant preparation and/or the compounding adjuncts appear to have an effect on the development of adhesive strength.

Fitting unanchored puzzle pieces in the skeleton: appropriate 3D scapular positions for the quadrupedal support in tetrapods.

PubMed

Fujiwara, Shin-Ichi

2018-05-01

Deducing the scapular positions of extinct tetrapod skeletons remains difficult, because the scapulae and rib cage are connected with each other not directly by skeletal joint, but by thoracic muscles. In extant non-testudine quadrupedal tetrapods, the top positions of the scapulae/suprascapulae occur at the anterior portion of the rib cage, above the vertebral column and near the median plane. The adequacy of this position was tested using three-dimensional mechanical models of Felis, Rattus and Chamaeleo that assumed stances on a forelimb on a single side and the hindlimbs. The net moment about the acetabulum generated by the gravity force and the contractive forces of the anti-gravity thoracic muscles, and the resistance of the rib to vertical compression between the downward gravity and upward lifting force from the anti-gravity thoracic muscle depend on the scapular position. The scapular position common among quadrupeds corresponds to the place at which the roll and yaw moments of the uplifted portion of the body are negligible, where the pitch moment is large enough to lift the body, and above the ribs having high strength against vertical compression. These relationships between scapular position and rib cage morphology should allow reliable reconstruction of limb postures of extinct taxa. © 2018 Anatomical Society.

Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology.

PubMed

Rabey, Karyne N; Green, David J; Taylor, Andrea B; Begun, David R; Richmond, Brian G; McFarlin, Shannon C

2015-01-01

The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Decreases in bone blood flow and bone material properties in aging Fischer-344 rats

NASA Technical Reports Server (NTRS)

Bloomfield, Susan A.; Hogan, Harry A.; Delp, Michael D.

2002-01-01

The purpose of this study was to quantify precisely aging-induced changes in skeletal perfusion and bone mechanical properties in a small rodent model. Blood flow was measured in conscious juvenile (2 months old), adult (6 months old), and aged (24 months old) male Fischer-344 rats using radiolabeled microspheres. There were no significant differences in bone perfusion rate or vascular resistance between juvenile and adult rats. However, blood flow was lower in aged versus adult rats in the forelimb bones, scapulas, and femurs. To test for functional effects of this decline in blood flow, bone mineral density and mechanical properties were measured in rats from these two age groups. Bone mineral density and cross-sectional moment of inertia in femoral and tibial shafts and the femoral neck were significantly larger in the aged versus adult rats, resulting in increased (+14%-53%) breaking strength and stiffness. However, intrinsic material properties at midshaft of the long bones were 12% to 25% lower in the aged rats. Although these data are consistent with a potential link between decreased perfusion and focal alterations in bone remodeling activity related to clinically relevant bone loss, additional studies are required to establish the mechanisms for this putative relationship.

Motor coordination defects in mice deficient for the Sam68 RNA-binding protein.

PubMed

Lukong, Kiven E; Richard, Stéphane

2008-06-03

The role of RNA-binding proteins in the central nervous system and more specifically their role in motor coordination and learning are poorly understood. We previously reported that ablation of RNA-binding protein Sam68 in mice results in male sterility and delayed mammary gland development and protection against osteoporosis in females. Sam68 however is highly expressed in most regions of the brain especially the cerebellum and thus we investigated the cerebellar-related manifestations in Sam68-null mice. We analyzed the mice for motor function, sensory function, and learning and memory abilities. Herein, we report that Sam68-null mice have motor coordination defects as assessed by beam walking and rotorod performance. Forty-week-old Sam68-null mice (n=12) were compared to their wild-type littermates (n=12). The Sam68-null mice exhibited more hindpaw faults in beam walking tests and fell from the rotating drum at lower speeds and prematurely compared to the wild-type controls. The Sam68-null mice were, however, normal for forelimb strength, tail-hang reflex, balance test, grid walking, the Morris water task, recognition memory, visual discrimination, auditory stimulation and conditional taste aversion. Our findings support a role for Sam68 in the central nervous system in the regulation of motor coordination.

Cell therapy for spinal cord injuries: what is really going on?

PubMed

Granger, Nicolas; Franklin, Robin J M; Jeffery, Nick D

2014-12-01

During the last two decades, many experiments have examined the ability of cell transplants to ameliorate the loss of function after spinal cord injuries, with the hope of developing interventions to benefit patients. Although many reports suggest positive effects, there is growing concern over the quality of the available preclinical data. It is therefore important to ask whether this worldwide investigative process is close to defining a cell transplant protocol that could be translated into human patients with a realistic chance of success. This review systematically examines the strength of the preclinical evidence and outlines mechanisms by which transplanted cells may mediate their effects in spinal cord injuries. First, we examined changes in voluntary movements in the forelimb associated with cell transplants after partial cervical lesions. Second, we examined the efficacy of transplanted cells to restore electrophysiological conduction across a complete thoracic lesion. We postulated that cell therapies found to be successful in both models could reasonably have potential to treat human patients. We conclude that although there are data to support a beneficial effect of cell transplantation, most reports provide only weak evidence because of deficits in experimental design. The mechanisms by which transplanted cells mediate their functional effects remain unclear. © The Author(s) 2014.

Effects of pre- and postnatal exposure to chromium picolinate or picolinic acid on neurological development in CD-1 mice.

PubMed

Bailey, Melissa M; Boohaker, Jonathan G; Jernigan, Peter L; Townsend, Megan B; Sturdivant, John; Rasco, Jane F; Vincent, John B; Hood, Ronald D

2008-07-01

Chromium picolinate, Cr(pic)3, a popular dietary supplement marketed as an aid in fat loss and lean muscle gain, has also been suggested as a therapy for women with gestational diabetes. The current study investigated the effects of maternal exposure to Cr(pic)3 and picolinic acid during gestation and lactation on neurological development of the offspring. Mated female CD-1 mice were fed diets from implantation through weaning that were either untreated or that contained Cr(pic)3 (200 mg kg(-1) day(-1)) or picolinic acid (174 mg kg(-1) day(-1)). A comprehensive battery of postnatal tests was administered, including a modified Fox battery, straight-channel swim, open-field activity, and odor-discrimination tests. Pups exposed to picolinic acid tended to weigh less than either control or Cr(pic)3-exposed pups, although the differences were not significant. Offspring of picolinic acid-treated dams also appeared to display impaired learning ability, diminished olfactory orientation ability, and decreased forelimb grip strength, although the differences among the treatment groups were not significant. The results indicate that there were no significant effects on the offspring with regard to neurological development from supplementation of the dams with either Cr(pic)3 or picolinic acid.

Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology

PubMed Central

Rabey, Karyne N.; Green, David J.; Taylor, Andrea B.; Begun, David R.; Richmond, Brian G.; McFarlin, Shannon C.

2014-01-01

The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual’s past behaviour. PMID:25467113

Temperature dependence of elastic and strength properties of T300/5208 graphite-epoxy

NASA Technical Reports Server (NTRS)

Milkovich, S. M.; Herakovich, C. T.

1984-01-01

Experimental results are presented for the elastic and strength properties of T300/5208 graphite-epoxy at room temperature, 116K (-250 F), and 394K (+250 F). Results are presented for unidirectional 0, 90, and 45 degree laminates, and + or - 30, + or - 45, and + or - 60 degree angle-ply laminates. The stress-strain behavior of the 0 and 90 degree laminates is essentially linear for all three temperatures and that the stress-strain behavior of all other laminates is linear at 116K. A second-order curve provides the best fit for the temperature is linear at 116K. A second-order curve provides the best fit for the temperature dependence of the elastic modulus of all laminates and for the principal shear modulus. Poisson's ratio appears to vary linearly with temperature. all moduli decrease with increasing temperature except for E (sub 1) which exhibits a small increase. The strength temperature dependence is also quadratic for all laminates except the 0 degree - laminate which exhibits linear temperature dependence. In many cases the temperature dependence of properties is nearly linear.

New Specimens of the Rare Taeniodont Wortmania (Mammalia: Eutheria) from the San Juan Basin of New Mexico and Comments on the Phylogeny and Functional Morphology of “Archaic” Mammals

PubMed Central

Williamson, Thomas E.; Brusatte, Stephen L.

2013-01-01

Background Taeniodonta is a clade of Late Cretaceous – Paleogene mammals remarkable for their relatively extreme cranial, dental, and postcranial adaptations and notable for being among the first mammals to achieve relatively large size following the Cretaceous-Paleogene mass extinction. Previous workers have hypothesized that taeniodonts can be divided into two clades: Conoryctidae, a group of small-bodied taeniodonts with supposedly “generalized” postcranial skeletons, and Stylinodontidae, a group of large-bodied, robust animals with massive forelimbs and claws adapted for scratch-digging. However, many taeniodont taxa are poorly known and few are represented by postcranial material, leaving many details about their anatomy, biology, and evolution ambiguous. Methodology/Principal Findings In this paper, we describe three new specimens of the rare taxon Wortmaniaotariidens from the early Paleocene (Puercan) of New Mexico. Among these specimens is one that includes remarkably complete cranial and dental material, including associated upper and lower teeth, and another that consists of partial forelimbs. These specimens allow for an updated anatomical description of this unusual taxon, supply new data for phylogenetic analyses, and enable a more constrained discussion of taeniodont biology and functional morphology. Conclusions/Significance The new specimen of Wortmania that includes associated upper and lower teeth indicates that previous interpretations of the upper dentition of this taxon were not accurate and the taxon Robertschochiasullivani is a junior synonym of W . otariidens . New specimens that include partial forelimbs indicate that Wortmania is very similar to later, large-bodied taeniodonts, with marked and distinctive adaptations for scratch-digging. Comparisons with other taeniodont taxa that include postcranial material suggest that all taeniodonts may have had scratch-digging adaptations. A phylogenetic analysis shows that Schowalteria and Onychodectes are basal taeniodonts, Stylinodontidae (including Wortmania) is monophyletic, and a monophyletic Conoryctidae (but not including Onychodectes) is only recovered when certain characters are ordered. PMID:24098738

The Advantage of Standing Up to Fight and the Evolution of Habitual Bipedalism in Hominins

PubMed Central

Carrier, David R.

2011-01-01

Background Many quadrupedal species stand bipedally on their hindlimbs to fight. This posture may provide a performance advantage by allowing the forelimbs to strike an opponent with the range of motion that is intrinsic to high-speed running, jumping, rapid braking and turning; the range of motion over which peak force and power can be produced. Methodology/Principal Findings To test the hypothesis that bipedal (i.e., orthograde) posture provides a performance advantage when striking with the forelimbs, I measured the force and energy produced when human subjects struck from “quadrupedal” (i.e., pronograde) and bipedal postures. Downward and upward directed striking energy was measured with a custom designed pendulum transducer. Side and forward strikes were measured with a punching bag instrumented with an accelerometer. When subjects struck downward from a bipedal posture the work was 43.70±12.59% (mean ± S.E.) greater than when they struck from a quadrupedal posture. Similarly, 47.49±17.95% more work was produced when subjects struck upward from a bipedal stance compared to a quadrupedal stance. Importantly, subjects did 229.69±44.19% more work in downward than upward directed strikes. During side and forward strikes the force impulses were 30.12±3.68 and 43.04±9.00% greater from a bipedal posture than a quadrupedal posture, respectively. Conclusions/Significance These results indicate that bipedal posture does provide a performance advantage for striking with the forelimbs. The mating systems of great apes are characterized by intense male-male competition in which conflict is resolved through force or the threat of force. Great apes often fight from bipedal posture, striking with both the fore- and hindlimbs. These observations, plus the findings of this study, suggest that sexual selection contributed to the evolution of habitual bipedalism in hominins. PMID:21611167

Head, withers and pelvic movement asymmetry and their relative timing in trot in racing Thoroughbreds in training.

PubMed

Pfau, T; Noordwijk, K; Sepulveda Caviedes, M F; Persson-Sjodin, E; Barstow, A; Forbes, B; Rhodin, M

2018-01-01

Horses show compensatory head movement in hindlimb lameness and compensatory pelvis movement in forelimb lameness but little is known about the relationship of withers movement symmetry with head and pelvic asymmetry in horses with naturally occurring gait asymmetries. To document head, withers and pelvic movement asymmetry and timing differences in horses with naturally occurring gait asymmetries. Retrospective analysis of gait data. Head, withers and pelvic movement asymmetry and timing of displacement minima and maxima were quantified from inertial sensors in 163 Thoroughbreds during trot-ups on hard ground. Horses were divided into 4 subgroups using the direction of head and withers movement asymmetry. Scatter plots of head vs. pelvic movement asymmetry illustrated how the head-withers relationship distinguishes between contralateral and ipsilateral head-pelvic movement asymmetry. Independent t test or Mann-Whitney U test (P<0.05) compared pelvic movement asymmetry and timing differences between groups. The relationship between head and withers asymmetry (i.e. same sided or opposite sided asymmetry) predicts the relationship between head and pelvic asymmetry in 69-77% of horses. Pelvic movement symmetry was significantly different between horses with same sign vs. opposite sign of head-withers asymmetry (P<0.0001). Timing of the maximum head height reached after contralateral ('sound') stance was delayed compared to withers (P = 0.02) and pelvis (P = 0.04) in horses with contralateral head-withers asymmetry. The clinical lameness status of the horses was not investigated. In the Thoroughbreds with natural gait asymmetries investigated here, the direction of head vs. withers movement asymmetry identifies the majority of horses with ipsilateral and contralateral head and pelvic movement asymmetries. Withers movement should be further investigated for differentiating between forelimb and hindlimb lame horses. Horses with opposite sided head and withers asymmetry significantly delay the upward movement of the head after 'sound' forelimb stance. © 2017 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

New specimens of the rare taeniodont Wortmania (Mammalia: Eutheria) from the San Juan Basin of New Mexico and comments on the phylogeny and functional morphology of "archaic" mammals.

PubMed

Williamson, Thomas E; Brusatte, Stephen L

2013-01-01

Taeniodonta is a clade of Late Cretaceous-Paleogene mammals remarkable for their relatively extreme cranial, dental, and postcranial adaptations and notable for being among the first mammals to achieve relatively large size following the Cretaceous-Paleogene mass extinction. Previous workers have hypothesized that taeniodonts can be divided into two clades: Conoryctidae, a group of small-bodied taeniodonts with supposedly "generalized" postcranial skeletons, and Stylinodontidae, a group of large-bodied, robust animals with massive forelimbs and claws adapted for scratch-digging. However, many taeniodont taxa are poorly known and few are represented by postcranial material, leaving many details about their anatomy, biology, and evolution ambiguous. In this paper, we describe three new specimens of the rare taxon Wortmania otariidens from the early Paleocene (Puercan) of New Mexico. Among these specimens is one that includes remarkably complete cranial and dental material, including associated upper and lower teeth, and another that consists of partial forelimbs. These specimens allow for an updated anatomical description of this unusual taxon, supply new data for phylogenetic analyses, and enable a more constrained discussion of taeniodont biology and functional morphology. The new specimen of Wortmania that includes associated upper and lower teeth indicates that previous interpretations of the upper dentition of this taxon were not accurate and the taxon Robertschochia sullivani is a junior synonym of W. otariidens. New specimens that include partial forelimbs indicate that Wortmania is very similar to later, large-bodied taeniodonts, with marked and distinctive adaptations for scratch-digging. Comparisons with other taeniodont taxa that include postcranial material suggest that all taeniodonts may have had scratch-digging adaptations. A phylogenetic analysis shows that Schowalteria and Onychodectes are basal taeniodonts, Stylinodontidae (including Wortmania) is monophyletic, and a monophyletic Conoryctidae (but not including Onychodectes) is only recovered when certain characters are ordered.

40 CFR 265.1101 - Design and operating standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... wastes to which they are exposed; climatic conditions; and the stresses of daily operation, including the... the waste management operation to take place in the unit, an exception to the structural strength...

40 CFR 264.1101 - Design and operating standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... they are exposed; climatic conditions; and the stresses of daily operation, including the movement of... management operation to take place in the unit, an exception to the structural strength requirement may be...

40 CFR 265.1101 - Design and operating standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... wastes to which they are exposed; climatic conditions; and the stresses of daily operation, including the... the waste management operation to take place in the unit, an exception to the structural strength...

40 CFR 264.1101 - Design and operating standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... they are exposed; climatic conditions; and the stresses of daily operation, including the movement of... management operation to take place in the unit, an exception to the structural strength requirement may be...

Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant.

PubMed

Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

2015-01-01

To evaluate and compare the tensile strength values and influence of taper on the tensile strength of Gutta-percha (GP) cones after disinfection with sodium hypochlorite (SH) and Aloe vera gel (AV). Sixty GP cones of size 110, 2% taper, 60 GP cones F3 ProTaper, and 60 GP of size 30, 6% taper were obtained from sealed packs as three different groups. Experimental groups were disinfected with 5.25% SH and 90% AV gel except the control group. Tensile strengths of GP were measured using the universal testing machine. The mean tensile strength values for Group IA, IIA and IIIA are 11.8 MPa, 8.69 MPa, and 9.24 MPa, respectively. Results were subjected to statistical analysis one-way analysis of variance test and Tukey post-hoc test. 5.25% SH solutions decreased the tensile strength of GP cones whereas with 90% AV gel it was not significantly altered. Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones.

Mechanical properties of woven glass fiber-reinforced composites.

PubMed

Kanie, Takahito; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

2006-06-01

The aim of this investigation was to measure the flexural and compressive strengths and the corresponding moduli of cylindrical composite specimens reinforced with woven glass fiber. Test specimens were made by light-curing urethane dimethacrylate oligomer with woven glass fiber of 0.18-mm standard thickness. Tests were conducted using four reinforcement methods and two specimen diameters. Flexural strength and modulus of woven glass fiber-reinforced specimens were significantly greater than those without woven glass fiber (p < 0.01). Likewise, compressive strength of reinforced specimens was significantly greater than those without woven glass fiber (p < 0.01), except for specimens reinforced with woven glass fiber oriented at a tilt direction in the texture (p > 0.05). In terms of comparison between the two specimen diameters, no statistically significant differences in flexural strength and compressive strength (p > 0.05) were observed.

Capricornus

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

(the Sea Goat; abbrev. Cap, gen. Capricorni; area 414 sq. deg.) A southern zodiacal constellation which lies between Sagittarius and Aquarius, and culminates at midnight in early August. The origin of the unusual constellation figure, which comprises the head and forelimbs of a goat and tail of a fish, dates back to Babylonian times and has also been associated in Greek mythology with Pan, who ha...

Motivational State, Reward Value, and Pavlovian Cues Differentially Affect Skilled Forelimb Grasping in Rats

ERIC Educational Resources Information Center

Mosberger, Alice C.; de Clauser, Larissa; Kasper, Hansjörg; Schwab, Martin E.

2016-01-01

Motor skills represent high-precision movements performed at optimal speed and accuracy. Such motor skills are learned with practice over time. Besides practice, effects of motivation have also been shown to influence speed and accuracy of movements, suggesting that fast movements are performed to maximize gained reward over time as noted in…

A MICROARRAY ANALYSIS OF GENE EXPRESSION IN THE EMBRYONIC FORELIMB OF THE C57BL/6J MOUSE REVEALS SIGNIFICANT ALTERATIONS METABOLIC AND DEVELOPMENTAL REGULATION FOLLOWING ETHANOL EXPOSURE.

EPA Science Inventory

The observation of transcriptional changes following embryonic ethanol exposure may provide significant insights into the biological response to ethanol exposure. In this study, we used microarray analysis to examine the transcriptional response of the developing limb to a dose ...

21 CFR 886.1650 - Ophthalmic bar prism.

Code of Federal Regulations, 2014 CFR

2014-04-01

... strengths intended to measure latent and manifest strabismus (eye muscle deviation) or the power of fusion... quality system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

21 CFR 886.1650 - Ophthalmic bar prism.

Code of Federal Regulations, 2010 CFR

2010-04-01

... strengths intended to measure latent and manifest strabismus (eye muscle deviation) or the power of fusion... quality system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

21 CFR 886.1650 - Ophthalmic bar prism.

Code of Federal Regulations, 2012 CFR

2012-04-01

... strengths intended to measure latent and manifest strabismus (eye muscle deviation) or the power of fusion... quality system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

21 CFR 886.1650 - Ophthalmic bar prism.

Code of Federal Regulations, 2013 CFR

2013-04-01

... strengths intended to measure latent and manifest strabismus (eye muscle deviation) or the power of fusion... quality system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

21 CFR 886.1650 - Ophthalmic bar prism.

Code of Federal Regulations, 2011 CFR

2011-04-01

... strengths intended to measure latent and manifest strabismus (eye muscle deviation) or the power of fusion... quality system regulation in part 820 of this chapter, with the exception of § 820.180, with respect to...

Sex differences and growth-related adaptations in bone microarchitecture, geometry, density and strength from childhood to early adulthood: a mixed longitudinal HR-pQCT study

PubMed Central

Gabel, Leigh; Macdonald, Heather M.; McKay, Heather A.

2016-01-01

Sex differences in bone strength and fracture risk are well-documented. However, we know little about bone strength accrual during growth and adaptations in bone microstructure, density and geometry that accompany gains in bone strength. Thus, our objectives are to 1) describe growth related adaptations in bone microarchitecture, geometry, density and strength at the distal tibia and radius in boys and girls; 2) compare differences in adaptations in bone microarchitecture, geometry, density and strength between boys and girls. We used HR-pQCT at the distal tibia (8% site) and radius (7% site) in 184 boys and 209 girls (9–20y at baseline). We aligned boys and girls on a common maturational landmark (age at peak height velocity; APHV) and fit a mixed effects model to these longitudinal data. Importantly, boys demonstrated 28–63% greater estimated bone strength across 12 years of longitudinal growth. Boys demonstrated 28–80% more porous cortices compared with girls at both sites across all biological ages, except at the radius at 9 years post-APHV. However, cortical density was similar between boys and girls at all ages at both sites, except at 9 years post-APHV at the tibia when girls’ values were 2% greater than boys’. Boys demonstrated 13–48% greater cortical and total bone area across growth. Load-to-strength ratio was 26–27% lower in boys at all ages, indicating lower risk of distal forearm fracture compared with girls. Contrary to previous HR-pQCT studies that did not align boys and girls at the same biological age, we did not observe sex differences in Ct.BMD. Boys’ superior bone size and strength compared with girls may confer them a protective advantage. However, boys’ consistently more porous cortices may contribute to boys’ higher fracture incidence during adolescence. Large prospective studies using HR-pQCT that target boys and girls who have sustained a fracture are needed to verify this. PMID:27556581

Alloy NASA-HR-1

NASA Technical Reports Server (NTRS)

Chen, Po-Shou; Mitchell, Michael

2005-01-01

NASA-HR-1 is a high-strength Fe-Ni-base superalloy that resists high-pressure hydrogen environment embrittlement (HEE), oxidation, and corrosion. Originally derived from JBK-75, NASA-HR-1 has exceptional HEE resistance that can be attributed to its gamma-matrix and eta-free (Ni3Ti) grain boundaries. The chemistry was formulated using a design approach capable of accounting for the simultaneous effects of several alloy additions. This approach included: (1) Systematically modifying gamma-matrix compositions based on JBK-75; (2) Increasing gamma (Ni3(Al,Ti)) volume fraction and adding gamma-matrix strengthening elements to obtain higher strength; and (3) Obtaining precipitate-free grain boundaries. The most outstanding attribute of NASA-HR-1 is its ability to resist HEE while showing much improved strength. NASA-HR-1 has approximately 25% higher yield strength than JXK-75 and exhibits tensile elongation of more than 20% with no ductility loss in a hydrogen environment at 5 ksi, an achievement unparalleled by any other commercially available alloy. Its Cr and Ni contents provide exceptional resistance to environments that promote oxidation and corrosion. Microstructural stability was maintained by improved solid solubility of the gamma-matrix, along with the addition of alloying elements to retard eta (Ni3Ti) precipitation. NASA-HR-1 represents a new system that greatly extends the compositional ranges of existing HEE-resistant Fe-Ni-base superalloys.

The effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes.

PubMed

Fallahi, Ali Asghar; Jadidian, Ali Akbar

2011-09-01

It has been suggested that athletes with longer fingers and larger hand surfaces enjoy stronger grip power. Therefore, some researchers have examined a number of factors and anthropometric variables that explain this issue. To our knowledge, the data is scarce. Thus, the aim of this study was to investigate the effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes. 80 subjects aged between 19 and 29 participated in this study in two groups including: national and collegian grip athletes (n=40), and non-athletes (n=40). Body height and mass were measured to calculate body mass index. The shape of the dominant hand was drawn on a piece of paper with a thin marker so that finger spans, finger lengths, and perimeters of the hand could be measured. The hand shape was estimated as the ratio of the hand width to hand length. Handgrip strength was measured in the dominant and non-dominant hand using a standard dynamometer. Descriptive statistics were used for each variable and independent t test was used to analyze the differences between the two groups. The Pearson correlation coefficient test was used to evaluate the correlation between studied variables. Also, to predict important variables in handgrip strength, the linear trend was assessed using a linear regression analysis. There was a significant difference between the two groups in absolute handgrip strength (p<0.001) and handgrip/height ratio (p<0.001). The indices of body height, body mass, lean body mass and body fat content (p<0.001) were significantly greater in grip athletes. All hand variables except FS1-4 (p>0.05) were significantly different between the groups (p<0.001). After controlling body mass all hand anthropometric characteristics except thumb length (r=0.240, p= 0.135), hand shape (r=-0.029, p=0.858), middle finger length (r=0.305, p=0.056) and forearm circumference (r=0.162, p=0.319) significantly correlated with handgrip strength in grip athletes, but not in non-athletes, except for forearm circumference (r=0.406, p=0.010). The results showed that handgrip strength and some of the hand dimensions may be different in athletes who have handgrip movements with an object or opponent in comparison to non-athletes. Also, there was a significant positive correlation between handgrip strength and most of the hand dimensions in grip athletes. Therefore, these can be used in talent identification in handgrip-related sports and in clinical settings as well.

The Effect of Hand Dimensions, Hand Shape and Some Anthropometric Characteristics on Handgrip Strength in Male Grip Athletes and Non-Athletes

PubMed Central

Fallahi, Ali Asghar; Jadidian, Ali Akbar

2011-01-01

It has been suggested that athletes with longer fingers and larger hand surfaces enjoy stronger grip power. Therefore, some researchers have examined a number of factors and anthropometric variables that explain this issue. To our knowledge, the data is scarce. Thus, the aim of this study was to investigate the effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes. 80 subjects aged between 19 and 29 participated in this study in two groups including: national and collegian grip athletes (n=40), and non-athletes (n=40). Body height and mass were measured to calculate body mass index. The shape of the dominant hand was drawn on a piece of paper with a thin marker so that finger spans, finger lengths, and perimeters of the hand could be measured. The hand shape was estimated as the ratio of the hand width to hand length. Handgrip strength was measured in the dominant and non-dominant hand using a standard dynamometer. Descriptive statistics were used for each variable and independent t test was used to analyze the differences between the two groups. The Pearson correlation coefficient test was used to evaluate the correlation between studied variables. Also, to predict important variables in handgrip strength, the linear trend was assessed using a linear regression analysis. There was a significant difference between the two groups in absolute handgrip strength (p<0.001) and handgrip/height ratio (p<0.001). The indices of body height, body mass, lean body mass and body fat content (p<0.001) were significantly greater in grip athletes. All hand variables except FS1-4 (p>0.05) were significantly different between the groups (p<0.001). After controlling body mass all hand anthropometric characteristics except thumb length (r=0.240, p= 0.135), hand shape (r=−0.029, p=0.858), middle finger length (r=0.305, p=0.056) and forearm circumference (r=0.162, p=0.319) significantly correlated with handgrip strength in grip athletes, but not in non-athletes, except for forearm circumference (r=0.406, p=0.010). The results showed that handgrip strength and some of the hand dimensions may be different in athletes who have handgrip movements with an object or opponent in comparison to non-athletes. Also, there was a significant positive correlation between handgrip strength and most of the hand dimensions in grip athletes. Therefore, these can be used in talent identification in handgrip-related sports and in clinical settings as well. PMID:23486361

Physical profile of elite young motorcyclists.

PubMed

Sánchez-Muñoz, C; Rodríguez, M A; Casimiro-Andújar, A J; Ortega, F B; Mateo-March, M; Zabala, M

2011-10-01

The aim of the study was to describe anthropometric and physical characteristics of elite young road-race motorcyclists (MC). 27 riders (15.6±1.1 years, 54.6±6.9 kg, 166.9±6.7 cm) competing at international elite level participated in this study. Anthropometric variables, hand grip and lumbar isometric strength, and lower-body muscular strength were measured. Comparisons of the MC and a reference group of Spanish physically active adolescents (16.0±0.6 years) showed that the riders were significantly lighter (-12.5 kg), and smaller (-4.7 cm). Riders also had significantly lower values for almost all skinfolds, and for all the measured girths (except forearm) than the reference group. Motorcyclists showed significantly less percent body fat (%BF) and higher muscle mass, and differences were observed for somatotype components compared to the reference group, except for the ectomorphy. Somatotype could be defined as mesomorphic-ectomorph (2.5-4.4-3.7). Mean (±SD) values of all riders were 34.8±5.0 cm for vertical jump height, 402.1±74.5 N for the right hand and 370.7±77.5 N for the left hand strengths, and 120.6±19.3 kg for lumbar isometric strength, respectively. Results demonstrate that MC are small and light, with lower body mass index, skinfolds, girth and breadth dimensions, and %BF than a reference group and other athletes, with high values of hand grip and lumbar isometric strength. © Georg Thieme Verlag KG Stuttgart · New York.

46 CFR 120.410 - Lighting fixtures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or be made of high strength material, except in an accommodation space, radio room, galley, or...,” UL 1573, “Stage and Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the...

46 CFR 120.410 - Lighting fixtures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or be made of high strength material, except in an accommodation space, radio room, galley, or...,” UL 1573, “Stage and Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the...

46 CFR 120.410 - Lighting fixtures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or be made of high strength material, except in an accommodation space, radio room, galley, or...,” UL 1573, “Stage and Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the...

46 CFR 120.410 - Lighting fixtures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or be made of high strength material, except in an accommodation space, radio room, galley, or...,” UL 1573, “Stage and Studio Lighting Units,” or UL 1574, “Track Lighting Systems,” as long as the...

Threshold values of physical performance tests for locomotive syndrome.

PubMed

Muramoto, Akio; Imagama, Shiro; Ito, Zenya; Hirano, Kenichi; Tauchi, Ryoji; Ishiguro, Naoki; Hasegawa, Yukiharu

2013-07-01

Our previous study determined which physical performance tests were the most useful for evaluating locomotive syndrome. Our current study establishes reference values for these major physical performance tests with regards to diagnosing and assessing risk of locomotive syndrome (LS). We measured timed-up-and-go test, one-leg standing time, back muscle strength, grip strength, 10-m gait time and maximum stride in 406 individuals (167 men, 239 women) between the ages of 60-88 years (mean 68.8 ± 6.7 years) during Yakumo Study 2011-12. The LS was defined as having a score of >16 points on the 25-Question Geriatric Locomotive Function Scale (GLFS-25). The reference value of each physical test was determined using receiver operating characteristics analysis. Women had a significantly higher prevalence of LS than men did and also scored significantly higher on the GLFS-25: women, 9.2 ± 10.3 pts; men, 6.7 ± 8.0 pts. Both genders in the non-LS group performed significantly better in all physical performance test gender except for back muscle strength in men and grip strength in both genders than those in the LS group, even after adjusting for age. The results of all the physical performance tests correlated significantly with the GLFS-25 scores of both genders even after adjusting for age except for grip strength. Reference values for TUG, one-leg standing time, back muscle strength, 10-m gait time, maximum stride and grip strength in men were 6.7 s, 21 s, 78 kg, 5.5 s and, 119 cm and 34 kg, respectively, and those for women were 7.5 s, 15 s, 40 kg, 6.2 s, 104 cm, and 22 kg, respectively. We established reference values for major physical performance tests used when assessing locomotive syndrome as defined by the GLFS-25. Our results can be used to characterize physical function and to help tailor an anti-LS training program for each individual.

In-vitro study of resin-modified glass ionomer cements for cementation of orthodontic bands. Isolation, surplus removal and humidity as factors influencing the bond strength between enamel, cement and metal.

PubMed

Liebmann, S M; Jost-Brinkmann, P G

1999-01-01

The aim of this in vitro study was to investigate different light-cured and chemically cured resin-modified glass ionomer cements used for the cementation of orthodontic bands and to analyze various factors influencing the adhesive strength between enamel, cement and stainless steel. Four resin-modified glass ionomers (Fuji Ortho LC/GC, Fuji Duet/GC, Unitek Multi-Cure Glass Ionomer Orthodontic Band Cement/3M Unitek, Vitremer/3M) and 1 compomer (Band-Lok/Reliance) were examined. Flattened and polished bovine teeth embedded in polyurethane resin were used as enamel specimens. Before cementation, 50% of the specimens were moistened with the aerosol of an inhalation device, while the rest were dried with compressed air. Stainless steel cylinders (CrNi 18 10) were perpendicularly bonded onto the polished enamel using a custom-made cementation device and immediately topped with a pressure of 0.25 MPa. The cement was isolated with either Ketac Glaze/ESPE, Fuji Coat/GC, Cacao Butter/GC, Dryfoil/Jalenko or Final Varnish/VOCO, or was left uncoated. Eight minutes after the beginning of mixing, either the surplus cement was removed with a scalpel or surplus removal was simulated with ultrasound. After 24 hours storage in a water bath at 37 degrees C and 1,000 thermocycles the shear bond strength was determined. Significant differences with respect to the shear bond strength were found among the following cements, ranking from highest to lowest: Fuji Duet, Unitek cement > Fuji Ortho LC > Vitremer > Band-Lok. The application of a barrier coating significantly increased the shear bond strength of all cements except Fuji Ortho LC. The light-cured resin Ketac Glaze proved to be the most effective barrier coating. A dry enamel surface increased the bond strength of all investigated cements except Unitek cement. The use of ultrasound led to no significant reduction in shear bond strength in comparison with surplus removal with a scalpel.

Mechanical properties of direct core build-up materials.

PubMed

Combe, E C; Shaglouf, A M; Watts, D C; Wilson, N H

1999-05-01

This work was undertaken to measure mechanical properties of a diverse group of materials used for direct core build-ups, including a high copper amalgam, a silver cermet cement, a VLC resin composite and two composites specifically developed for this application. Compressive strength, elastic modulus, diametral tensile strength and flexural strength and modulus were measured for each material as a function of time up to 3 months, using standard specification tests designed for the materials. All the materials were found to meet the minimum specification requirements except in terms of flexural strength for the amalgam after 1 h and the silver cermet at all time intervals. There proved to be no obvious superior material in all respects for core build-ups, and the need exists for a specification to be established specifically for this application.

Voicing the strengths of Pacific Island parent caregivers of children who are medically fragile.

PubMed

Haley, Janice; Harrigan, Rosanne C

2004-07-01

Research is deficient regarding the strengths of Pacific Island parents of children who are medically fragile. The purpose of this qualitative ethnographic study was to explore the strengths of Pacific Island parents of these children. Audiotaped interviews were analyzed using Text Smart and peer review. The core theme reflecting strength was positive energy. Participants believed that parents needed to have the ability to handle emotional feelings, solve problems, connect with their spirituality, find meaning, take care of themselves, use family support, use community support, use a positive attitude, be resourceful, meet a challenge, interact with nature, and focus on the present. Themes were affirmed by the literature with the exception of interacting with nature, which may be indigenous to the population's cultural orientation.

Exercise-Dependent Modulation of Neurourological Health Following Spinal Cord Injury

DTIC Science & Technology

2014-11-01

Neurobiology, 2Kentucky Spinal Cord Injury Research Center, 3Department of Neurological Surgery, 4Frazier Rehab Institute, University of Louisville...an infusion pump and pressure transducer.24 Behavioral procedures Training paradigm. Training interventions initiated acutely post-SCI may be...proper plantar placement—e.g. complete toe extension, no ankle rotation, and incorporation of forelimb-hindlimb coordination with minimal assistance

A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs.

PubMed

Pol, Diego; Rauhut, Oliver W M

2012-08-22

Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates.

Digital dissection and three-dimensional interactive models of limb musculature in the Australian estuarine crocodile (Crocodylus porosus)

PubMed Central

Wilhite, D. Ray; White, Matt A.; Wroe, Stephen

2017-01-01

Digital dissection is a relatively new technique that has enabled scientists to gain a better understanding of vertebrate anatomy. It can be used to rapidly disseminate detailed, three-dimensional information in an easily accessible manner that reduces the need for destructive, traditional dissections. Here we present the results of a digital dissection on the appendicular musculature of the Australian estuarine crocodile (Crocodylus porosus). A better understanding of this until now poorly known system in C. porosus is important, not only because it will expand research into crocodilian locomotion, but because of its potential to inform muscle reconstructions in dinosaur taxa. Muscles of the forelimb and hindlimb are described and three-dimensional interactive models are included based on CT and MRI scans as well as fresh-tissue dissections. Differences in the arrangement of musculature between C. porosus and other groups within the Crocodylia were found. In the forelimb, differences are restricted to a single tendon of origin for triceps longus medialis. For the hindlimb, a reduction in the number of heads of ambiens was noted as well as changes to the location of origin and insertion for iliofibularis and gastrocnemius externus. PMID:28384201

Loss of ATRX Does Not Confer Susceptibility to Osteoarthritis

PubMed Central

Solomon, Lauren A.; Russell, Bailey A.; Makar, David; Bérubé, Nathalie G.; Beier, Frank

2013-01-01

The chromatin remodelling protein ATRX is associated with the rare genetic disorder ATR-X syndrome. This syndrome includes developmental delay, cognitive impairment, and a variety of skeletal deformities. ATRX plays a role in several basic chromatin-mediated cellular events including DNA replication, telomere stability, gene transcription, and chromosome congression and cohesion during cell division. We have used a loss-of-function approach to directly investigate the role of Atrx in the adult skeleton in three different models of selective Atrx loss. We specifically targeted deletion of Atrx to the forelimb mesenchyme, to cartilage and to bone-forming osteoblasts. We previously demonstrated that loss of ATRX in forelimb mesenchyme causes brachydactyly while deletion in chondrocytes had minimal effects during development. We now show that targeted deletion of Atrx in osteoblasts causes minor dwarfism but does not recapitulate most of the skeletal phenotypes seen in ATR-X syndrome patients. In adult mice from all three models, we find that joints lacking Atrx are not more susceptible to osteoarthritis, as determined by OARSI scoring and immunohistochemistry. These results indicate that while ATRX plays limited roles during early stages of skeletal development, deficiency of the protein in adult tissues does not confer susceptibility to osteoarthritis. PMID:24386478

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice

PubMed Central

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal. PMID:26962395

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice.

PubMed

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal.

Establishment of a Method to Measure Length of the Ulnar Nerve and Standardize F-wave Values in Clinically Normal Beagles

PubMed Central

HIRASAWA, Shun; SHIMIZU, Miki; MARUI, Yuumi; KISHIMOTO, Miori; OKUNO, Seiichi

2014-01-01

We designed a new method of measuring the length of the ulnar nerve and determining standard values for F-wave parameters of the ulnar nerve in clinically normal beagles. Nerve length must be precisely measured to determine F-wave latency and conduction velocity. The length of the forelimb has served as the length of the ulnar nerve for F-wave assessments, but report indicates that F-wave latency is proportional to the length of the pathway traveled by nerve impulses. Therefore, we measured the surface distance from a stimulus point to the spinous process of the first thoracic vertebra (nerve length 1) and the anterior horn of the scapula (nerve length 2) as landmarks through the olecranon and the shoulder blade acromion. The correlation coefficients between the shortest F-wave latency and the length of nerves 1, 2 or the forelimb were 0.61, 0.7 and 0.58. Nerve length 2 generated the highest value. Furthermore, the anterior horn of the scapula was easily palpated in any dog regardless of well-fed body. We concluded that nerve length 2 was optimal for measuring the length of the ulnar nerve. PMID:25649942

Two new species of shrews (Soricidae) from the western highlands of Guatemala

USGS Publications Warehouse

Woodman, Neal

2010-01-01

The broad-clawed shrews (Soricomorpha: Soricidae: Cryptotis) encompass a clade of 5 species—Cryptotis alticolus (Merriam), C. goldmani (Merriam), C. goodwini Jackson, C. griseoventris Jackson, and C. peregrinus (Merriam)—that is known collectively as the Cryptotis goldmani group and is characterized by broadened forefeet, elongated and broadened fore claws, and broadened humeri. These shrews are distributed in highland regions from central Mexico to Honduras. Two broad-clawed shrews, C. goodwini and C. griseoventris, occur in southern Mexico and Guatemala and are presumed sister species whose primary distinguishing feature is the larger size of C. goodwini. In an investigation of variation within and between these 2 species, I studied characteristics of the postcranial skeleton. Statistical analyses of a variety of character suites indicate that the forelimb morphology in this group exhibits less intraspecific variation and greater interspecific variation than cranio-mandibular morphology, although most skull characters support groupings based on forelimb characters. Together, these characters define 4 distinct groups among the specimens examined. C. griseoventris is restricted to the northern highlands of Chiapas, Mexico, and C. goodwini occurs in the southern highlands of Chiapas and Guatemala. Herein, I describe 2 new species of broad-clawed shrews from the Sierra de los Cuchumatanes, Guatemala.

Ultrasonography of the equine shoulder: technique and normal appearance.

PubMed

Tnibar, M A; Auer, J A; Bakkali, S

1999-01-01

This study was intended to document normal ultrasonographic appearance of the equine shoulder and anatomic landmarks useful in clinical imaging. Both forelimbs of five equine cadavers and both forelimbs of six live adult horses were used. To facilitate understanding of the images, a zoning system assigned to the biceps brachii and to the infraspinatus tendon was developed. Ultrasonography was performed with a real-time B-mode semiportable sector scanner using 7.5- and 5-MHz transducers. On one cadaver limb, magnetic resonance imaging (MRI) was performed using a system at 1.5 Tesla, T1-weighted spin-echo sequence. Ultrasonography images were compared to frozen specimens and MRI images to correlate the ultrasonographic findings to the gross anatomy of the shoulder. Ultrasonography allowed easy evaluation of the biceps brachii and the infraspinatus tendon and their bursae, the supraspinatus muscle and tendons, the superficial muscles of the shoulder, and the underlying humerus and scapula. Only the lateral and, partially, the caudal aspects of the humeral head could be visualized with ultrasound. Ultrasonographic appearance, orientation, and anatomic relationships of these structures are described. Ultrasonographic findings correlated well with MRI images and with gross anatomy in the cadavers' limbs.

Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

PubMed

Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

2016-07-01

Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A strategy for enhancing shear strength and bending strength of FRP laminate using MWCNTs

NASA Astrophysics Data System (ADS)

Rawat, Prashant; Singh, K. K.

2016-09-01

Multi-wall carbon nanotubes (MWCNTs) promises to enhance mechanical properties exceptionally when it is doped with fiber reinforced polymer (FRP) composite. Glass fiber symmetrical laminate with eight layers of 4.0 mm thickness was fabricated by hand lay-up technique assisted by vacuum bagging method. Ply orientations for symmetrical laminate used [(0,90)/(+45,-45)/(+45,-45)/(0,90)//(90,0)/(+45,-45)/(+45,-45)/(90,0)]. MWCNTs reinforced three different samples (0 wt.%, 0.5 wt.% and 0.75 wt.% by weight) were tested on universal testing machine (UTM). Short beam strength test and inter laminar shear strength (ILSS) calculation have been done according to ASTM D2344 and ASTM D7264. UTM having maximum load capacity of 50 KN with loading rate of 0.1 mm/min to 50 mm/min was used for mechanical testing. Testing results justified that by adding 0.50 wt.% MWCNTs in symmetrical GFRP laminate can enhance inter laminar shear strength by 13.66% and bending strength by 44.22%.

Morphology and the Strength of Intermolecular Contact in Protein Crystals

NASA Technical Reports Server (NTRS)

Matsuura, Yoshiki; Chernov, Alexander A.

2002-01-01

The strengths of intermolecular contacts (macrobonds) in four lysozyme crystals were estimated based on the strengths of individual intermolecular interatomic interaction pairs. The periodic bond chain of these macrobonds accounts for the morphology of protein crystals as shown previously. Further in this paper, the surface area of contact, polar coordinate representation of contact site, Coulombic contribution on the macrobond strength, and the surface energy of the crystal have been evaluated. Comparing location of intermolecular contacts in different polymorphic crystal modifications, we show that these contacts can form a wide variety of patches on the molecular surface. The patches are located practically everywhere on this surface except for the concave active site. The contacts frequently include water molecules, with specific intermolecular hydrogen-bonds on the background of non-specific attractive interactions. The strengths of macrobonds are also compared to those of other protein complex systems. Making use of the contact strengths and taking into account bond hydration we also estimated crystal-water interfacial energies for different crystal faces.

Thin and thick layers of resin-based sealer cement bonded to root dentine compared: Adhesive behaviour.

PubMed

Pane, Epita S; Palamara, Joseph E A; Messer, Harold H

2015-12-01

This study aims to evaluate tensile and shear bond strengths of one epoxy (AH) and two methacrylate resin-based sealers (EZ and RS) in thin and thick layers bonded to root dentine. An alignment device was prepared for accurate positioning of 20 root dentine cylinders in a predefined gap of 0.1 or 1 mm. Sealer was placed in the interface. Bond strength tests were conducted. Mode of failures and representative surfaces were evaluated. Data were analysed using anova and post-hoc tests, with P < 0.05. The thick layer of sealer produced higher bond strength, except for the shear bond strength of EZ. Significant differences between thin and thick layers were found only in tensile bond strengths of AH and RS. Mixed type of failure was constantly found with all sealers. Bond strengths of thick layers of resin-based sealers to root dentine tended to be higher than with thin layers. © 2015 Australian Society of Endodontology.

Comparative study of mechanical properties of direct core build-up materials

PubMed Central

Kumar, Girish; Shivrayan, Amit

2015-01-01

Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipulated according to the manufacturer's recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Results: Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Conclusions: Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success. PMID:25684905

Development of a Family of Ultra-High Performance Concrete Pi-Girders

DOT National Transportation Integrated Search

2014-01-01

Ultra-high performance concrete (UHPC) is an advanced cementitious composite material, which tends to exhibit superior properties such as exceptional durability, increased strength, and long-term stability. (See references 1-4.) The use of existing s...

Correlation between subacute sensorimotor deficits and brain edema in two mouse models of intracerebral hemorrhage

PubMed Central

Krafft, Paul R.; McBride, Devin W.; Lekic, Tim; Rolland, William B.; Mansell, Charles E.; Ma, Qingyi; Tang, Jiping; Zhang, John H.

2014-01-01

Formation of brain edema after intracerebral hemorrhage (ICH) is highly associated with its poor outcome, thus it is clinically important to understand the effect brain edema has on outcome. However, the relationship between cerebral edema and behavioral deficits has not been thoroughly examined in the preclinical setting. Hence, this study aimed to evaluate the ability of common sensorimotor tests to predict the extent of brain edema in two mouse models of ICH. One hundred male CD-1 mice were subjected to sham surgery or ICH induction via intrastriatal injection of either autologous blood (30 μL) or bacterial collagenase (0.0375 U or 0.075 U). At 24 and 72 hours after surgery, animals underwent a battery of behavioral tests, including the modified Garcia neuroscore (Neuroscore), corner turn test (CTT), forelimb placing test (FPT), wire hang task (WHT) and beam walking (BW). Brain edema was evaluated via the wet weight/dry weight method. Intrastriatal injection of autologous blood or bacterial collagenase resulted in a significant increase in brain water content and associated sensorimotor deficits (p<0.05). A significant correlation between brain edema and sensorimotor deficits was observed for all behavioral tests except for WHT and BW. Based on these findings, we recommend implementing the Neuroscore, CTT and/or FPT in preclinical studies of unilateral ICH in mice. PMID:24518201

Development of Specifications for Engineered Cementitious Composites for Use in Bridge Deck Overlays

DOT National Transportation Integrated Search

2016-02-01

Engineered cementitious composite (ECC) material is a high strength, fiber-reinforced, ductile mortar mixture that can exhibit tensile strains of up to 5%. ECC has a dense matrix, giving the material exceptional durability characteristics. The durabi...

Talampanel improves the functional deficit after transient focal cerebral ischemia in rats. A 30-day follow up study.

PubMed

Erdo, Franciska; Berzsenyi, Pál; Német, László; Andrási, Ferenc

2006-01-15

The neuroprotective effect of talampanel, a negative allosteric modulator of alpha-amino-3-hydroxy-methyl-4-isoxazolyl-propionic acid (AMPA) receptors has been described previously. However, in these studies the histological changes and not the functional consequences of the brain damage were evaluated. The aim of present investigation was to analyze the sensorimotor function after stroke and to test the influence of talampanel (GYKI-53773, LY-300164) by 30-day monitoring in rats. After 1h middle cerebral artery occlusion (MCAO) general 'well-being', neurological status, spontaneous motor activity, rotation, motor coordination, balancing, muscle strength and reaction time were followed for 1 month. Talampanel (6 x 10 mg/kg i.p. given on the day of stroke) improved the motor coordination in rotarod (p < 0.01) and beam walking (p < 0.01) tests, reduced the number of stroke-induced rotations (p < 0.05), shortened the reflex time on the forelimb contralateral to brain ischemia and improved the survival rate comparing with vehicle treated control. After stroke, serious sensorimotor deficits appeared in rats but they showed partial spontaneous recovery after 30 days. Talampanel treatment enhanced the rate of functional improvement without changing the morphology at the end of the experiment. Our results indicate that modulation of AMPA receptors by talampanel can be a promising therapeutic approach to the treatment of stroke.

Progression of motor deficits in glioma-bearing mice: impact of CNF1 therapy at symptomatic stages

PubMed Central

Fabbri, Alessia; Costa, Mario; Caleo, Matteo; Baroncelli, Laura

2017-01-01

Glioblastoma (GBM) is the most aggressive type of brain tumor. In this context, animal models represent excellent tools for the early detection and longitudinal mapping of neuronal dysfunction, that are critical in the preclinical validation of new therapeutic strategies. In a mouse glioma model, we developed sensitive behavioral readouts that allow early recognizing and following neurological symptoms. We injected GL261 cells into the primary motor cortex of syngenic mice and we used a battery of behavioral tests to longitudinally monitor the dysfunction induced by tumor growth. Grip strength test revealed an early onset of functional deficit associated to the glioma growth, with a significant forelimb weakness appearing 9 days after tumor inoculation. A later deficit was observed in the rotarod and in the grid walk tasks. Using this model, we found reduced tumor growth and maintenance of behavioral functions following treatment with Cytotoxic Necrotizing Factor 1 (CNF1) at a symptomatic stage. Our data provide a detailed and precise examination of how tumor growth reverberates on the behavioral functions of glioma-bearing mice, providing normative data for the study of therapeutic strategies for glioma treatment. The reduced tumor volume and robust functional sparing observed in CNF1-treated, glioma-bearing mice strengthen the notion that CNF1 delivery is a promising strategy for glioma therapy. PMID:28212563

Neuroprotective effect of Feronia limonia on ischemia reperfusion induced brain injury in rats

PubMed Central

Rakhunde, Purushottam B.; Saher, Sana; Ali, Syed Ayaz

2014-01-01

Objectives: Brain stroke is a leading cause of death without effective treatment. Feronia limonia have potent antioxidant activity and can be proved as neuroprotective against ischemia-reperfusion induced brain injury. Materials and Methods: We studied the effect of methanolic extract of F. limonia fruit (250 mg/kg, 500 mg/kg body weight, p.o.) and Vitamin E as reference standard drug on 30 min induced ischemia, followed by reperfusion by testing the neurobehavioral tests such as neurodeficit score, rota rod test, hanging wire test, beam walk test and elevated plus maze. The biochemical parameters, which were measured in animals brain were catalase, superoxide dismutase (SOD), malondialdehyde and nitric oxide in control and treated rats. Results: The methanolic extract of F. limonia fruit (250 mg/kg, 500 mg/kg body weight, p.o.) treated groups showed a statistically significant improvement in the neurobehavioral parameters such as motor performance (neurological status, significant increase in grasping ability, forelimb strength improvement in balance and co-ordination). The biochemical parameters in the brains of rats showed a significant reduction in the total nitrite (P < 0.01) and lipid peroxidation (P < 0.01), also a significant enhanced activity of enzymatic antioxidants such as catalase (P < 0.01) and SOD (P < 0.05). Conclusion: These observations suggest the neuroprotective and antioxidant activity of F. limonia and Vitamin E on ischemia reperfusion induced brain injury and may require further evaluation. PMID:25538333

Neuroprotective effect of Feronia limonia on ischemia reperfusion induced brain injury in rats.

PubMed

Rakhunde, Purushottam B; Saher, Sana; Ali, Syed Ayaz

2014-01-01

Brain stroke is a leading cause of death without effective treatment. Feronia limonia have potent antioxidant activity and can be proved as neuroprotective against ischemia-reperfusion induced brain injury. We studied the effect of methanolic extract of F. limonia fruit (250 mg/kg, 500 mg/kg body weight, p.o.) and Vitamin E as reference standard drug on 30 min induced ischemia, followed by reperfusion by testing the neurobehavioral tests such as neurodeficit score, rota rod test, hanging wire test, beam walk test and elevated plus maze. The biochemical parameters, which were measured in animals brain were catalase, superoxide dismutase (SOD), malondialdehyde and nitric oxide in control and treated rats. The methanolic extract of F. limonia fruit (250 mg/kg, 500 mg/kg body weight, p.o.) treated groups showed a statistically significant improvement in the neurobehavioral parameters such as motor performance (neurological status, significant increase in grasping ability, forelimb strength improvement in balance and co-ordination). The biochemical parameters in the brains of rats showed a significant reduction in the total nitrite (P < 0.01) and lipid peroxidation (P < 0.01), also a significant enhanced activity of enzymatic antioxidants such as catalase (P < 0.01) and SOD (P < 0.05). These observations suggest the neuroprotective and antioxidant activity of F. limonia and Vitamin E on ischemia reperfusion induced brain injury and may require further evaluation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samoylenko, Vitaliy V., E-mail: samoylenko.vitaliy@mail.ru; Lenivtseva, Olga G., E-mail: lenivtseva-olga@mail.ru; Polyakov, Igor A., E-mail: status9@mail.ru

In this paper structural investigations and mechanical tests of Ti-Ta-Zr coatings obtained on surfaces of cp-titanium workpieces were carried out. It was found that the coatings had a dendrite structure; investigations at high-power magnifications revealed a platelet structure. An increase of tantalum concentration led to refinement of structural components. The microhardness level of all coatings, excepting a specimen with the maximum tantalum content, was 370 HV. The microhardness of this coating reached 400 HV. The ultimate tensile strength of cladded layers varied from 697 to 947 MPa. Adhesion tests showed that bimetallic composites were characterized by high bond strength of claddedmore » layers to the substrate, which exceeded cp-titanium strength characteristics.« less

Linking the evolution of body shape and locomotor biomechanics in bird-line archosaurs.

PubMed

Allen, Vivian; Bates, Karl T; Li, Zhiheng; Hutchinson, John R

2013-05-02

Locomotion in living birds (Neornithes) has two remarkable features: feather-assisted flight, and the use of unusually crouched hindlimbs for bipedal support and movement. When and how these defining functional traits evolved remains controversial. However, the advent of computer modelling approaches and the discoveries of exceptionally preserved key specimens now make it possible to use quantitative data on whole-body morphology to address the biomechanics underlying this issue. Here we use digital body reconstructions to quantify evolutionary trends in locomotor biomechanics (whole-body proportions and centre-of-mass position) across the clade Archosauria. We use three-dimensional digital reconstruction to estimate body shape from skeletal dimensions for 17 archosaurs along the ancestral bird line, including the exceptionally preserved, feathered taxa Microraptor, Archaeopteryx, Pengornis and Yixianornis, which represent key stages in the evolution of the avian body plan. Rather than a discrete transition from more-upright postures in the basal-most birds (Avialae) and their immediate outgroup deinonychosauria, our results support hypotheses of a gradual, stepwise acquisition of more-crouched limb postures across much of theropod evolution, although we find evidence of an accelerated change within the clade Maniraptora (birds and their closest relatives, such as deinonychosaurs). In addition, whereas reduction of the tail is widely accepted to be the primary morphological factor correlated with centre-of-mass position and, hence, evolution of hindlimb posture, we instead find that enlargement of the pectoral limb and several associated trends have a much stronger influence. Intriguingly, our support for the onset of accelerated morpho-functional trends within Maniraptora is closely correlated with the evolution of flight. Because we find that the evolution of enlarged forelimbs is strongly linked, via whole-body centre of mass, to hindlimb function during terrestrial locomotion, we suggest that the evolution of avian flight is linked to anatomical novelties in the pelvic limb as well as the pectoral.

Characterization of the differences in strength and power between different levels of competition in rugby union athletes.

PubMed

Argus, Christos K; Gill, Nicholas D; Keogh, Justin W L

2012-10-01

Levels of strength and power have been used to effectively discriminate between different levels of competition; however, there is limited literature in rugby union athletes. To assess the difference in strength and power between levels of competition, 112 rugby union players, including 43 professionals, 19 semiprofessionals, 32 academy level, and 18 high school level athletes, were assessed for bench press and box squat strength, and bench throw, and jump squat power. High school athletes were not assessed for jump squat power. Raw data along with data normalized to body mass with a derived power exponent were log transformed and analyzed. With the exception of box squat and bench press strength between professional and semiprofessional athletes, higher level athletes produced greater absolute and relative strength and power outputs than did lower level athletes (4-51%; small to very large effect sizes). Lower level athletes should strive to attain greater levels of strength and power in an attempt to reach or to be physically prepared for the next level of competition. Furthermore, the ability to produce high levels of power, rather than strength, may be a better determinate of playing ability between professional and semiprofessional athletes.

Effect of Fly-Ash Cenospheres on Properties of Clay-Ceramic Syntactic Foams

PubMed Central

Rugele, Kristine; Lehmhus, Dirk; Hussainova, Irina; Peculevica, Julite; Lisnanskis, Marks; Shishkin, Andrei

2017-01-01

A low-density clay ceramic syntactic foam (CSF) composite material was successfully synthesized from illitic clay added by fly ash cenospheres (CS) using the semi-dry formation method. The content of CS varied in the range of 10, 30, 50 and 60 vol %. Furthermore, reference samples without cenospheres were produced for property comparison. The materials comprising different amount of the additives were fired at temperatures of 600, 950, 1000, 1050, 1100, 1150 and 1200 °C. Firing times were kept constant at 30 min. Processing characteristics of the materials were evaluated in terms of density achieved and shrinkage observed as functions of both the CS content and the sintering temperature. The compressive strength and water uptake were determined as application-oriented properties. Except for the reference and the low CS level samples, the materials show an increase in strength with the increase in firing temperature, and a decrease of mechanical reliability with a decrease in density, which is typical for porous materials. Exceptions are the samples with no or low (10 vol %) content of cenospheres. In this case, the maximum strength is obtained at an intermediate sintering temperature of 1100 °C. At a low density (1.10 and 1.25 g/cm3), the highest levels of strength are obtained after sintering at 1200 °C. For nominal porosity levels of 50 and 60 vol %, 41 and 26 MPa peak stresses, respectively, are recorded under compressive load. PMID:28773190

Improving Urogenital Function with Step Training after Spinal Cord Injury

DTIC Science & Technology

2016-10-01

pump and pressure transducer. Normal saline was infused into the bladder at a rate of 0.25mL/min to evoke voiding contractions [34]. Uro - dynamic data...3 4 5 6 7 8 BB B op en fi el d lo co m ot or sc or e Weeks post-SCI Nontrain Forelimb Train Spontaneous recovery Training began ∗ ∗∗ ∗ Figure

Changes in Somatosensory Responsiveness in Behaving Primates

DTIC Science & Technology

1988-08-01

visually vs. vibratory-triggered movements; 2) to record from the cerebral cortex of awake , behaving monkeys during the performance of these sensory...vibratory-triggered movements; 2) to record from the cerebral cortex of awake , behaving monkeys during the performance of these sensory-triggered...recording chamber was implanted over the forelimb * region of the left sensorimotor cortices following a craniotomy and secured with smaller bolts and the

Fibrosarcoma in the distal radius and carpus of a four-year-old Persian.

PubMed

Cook, J L; Turk, J R; Tomlinson, J L; Corwin, L A; Shaw, D C

1998-01-01

A four-year-old Persian was presented for evaluation of a nonweight-bearing, left forelimb lameness. Radioulnar and pancarpal osteolysis with minimal periosteal reaction were seen on radiographs of the antebrachium. Cytological examinations of fine-needle aspirates and impression smears were suggestive of sarcoma. After forequarter amputation, histopathological examination provided a diagnosis of fibrosarcoma with axillary lymph-node metastasis.

Handbook on Gopher Tortoise (Gopherus polyphemus): Health Evaluation Procedures for Use by Land Managers and Researchers

DTIC Science & Technology

2009-01-01

H12 Swollen forelimb (a) and hind limb (b)....................................................................................58 H13 Predator...tortoises have been impacted by incidental take permits issued to developers in the past 14 years (J. Berish, pers. comm.). The inherent impacts of...respect to the potential infectious diseases present within wild populations, the impact of disease status on relocation or reproduction of species

Geometry and Kinematics of Fault-Propagation Folds with Variable Interlimb Angles

NASA Astrophysics Data System (ADS)

Dhont, D.; Jabbour, M.; Hervouet, Y.; Deroin, J.

2009-12-01

Fault-propagation folds are common features in foreland basins and fold-and-thrust belts. Several conceptual models have been proposed to account for their geometry and kinematics. It is generally accepted that the shape of fault-propagation folds depends directly from both the amount of displacement along the basal decollement level and the dip angle of the ramp. Among these, the variable interlimb angle model proposed by Mitra (1990) is based on a folding kinematics that is able to explain open and close natural folds. However, the application of this model is limited because the geometric evolution and thickness variation of the fold directly depend on imposed parameters such as the maximal value of the ramp height. Here, we use the ramp and the interlimb angles as input data to develop a forward fold modelling accounting for thickness variations in the forelimb. The relationship between the fold amplitude and fold wavelength are subsequently applied to build balanced geologic cross-sections from surface parameters only, and to propose a kinematic restoration of the folding through time. We considered three natural examples to validate the variable interlimb angle model. Observed thickness variations in the forelimb of the Turner Valley anticline in the Alberta foothills of Canada precisely correspond to the theoretical values proposed by our model. Deep reconstruction of the Alima anticline in the southern Tunisian Atlas implies that the decollement level is localized in the Triassic-Liassic series, as highlighted by seismic imaging. Our kinematic reconstruction of the Ucero anticline in the Spanish Castilian mountains is also in agreement with the anticline geometry derived from two cross-sections. The variable interlimb angle model implies that the fault-propagation fold can be symmetric, normal asymmetric (with a greater dip value in the forelimb than in the backlimb), or reversely asymmetric (with greater dip in the backlimb) depending on the shortening amount. This model allows also: (i) to easily explain folds with wide variety of geometries; (ii) to understand the deep architecture of anticlines; and (iii) to deduce the kinematic evolution of folding with time. Mitra, S., 1990, Fault-propagation folds: geometry, kinematic evolution, and hydrocarbon traps. AAPG Bulletin, v. 74, no. 6, p. 921-945.

Trabecular architecture in the forelimb epiphyses of extant xenarthrans (Mammalia).

PubMed

Amson, Eli; Arnold, Patrick; van Heteren, Anneke H; Canoville, Aurore; Nyakatura, John A

2017-01-01

Bone structure has a crucial role in the functional adaptations that allow vertebrates to conduct their diverse lifestyles. Much has been documented regarding the diaphyseal structure of long bones of tetrapods. However, the architecture of trabecular bone, which is for instance found within the epiphyses of long bones, and which has been shown experimentally to be extremely plastic, has received little attention in the context of lifestyle adaptations (virtually only in primates). We therefore investigated the forelimb epiphyses of extant xenarthrans, the placental mammals including the sloths, anteaters, and armadillos. They are characterised by several lifestyles and degrees of fossoriality involving distinct uses of their forelimb. We used micro computed tomography data to acquire 3D trabecular parameters at regions of interest (ROIs) for all extant genera of xenarthrans (with replicates). Traditional, spherical, and phylogenetically informed statistics (including the consideration of size effects) were used to characterise the functional signal of these parameters. Several trabecular parameters yielded functional distinctions. The main direction of the trabeculae distinguished lifestyle categories for one ROI (the radial trochlea). Among the other trabecular parameters, it is the degree of anisotropy (i.e., a preferential alignment of the trabeculae) that yielded the clearest functional signal. For all ROIs, the armadillos, which represent the fully terrestrial and fossorial category, were found as characterised by a greater degree of anisotropy (i.e., more aligned trabeculae). Furthermore, the trabeculae of the humeral head of the most fossorial armadillos were also found to be more anisotropic than in the less fossorial species. Most parameters were marked by an important intraspecific variability and by a size effect, which could, at least partly, be masking the functional signal. But for some parameters, the degree of anisotropy in particular, a clear functional distinction was recovered. Along with data on primates, our findings suggest that a trabecular architecture characterised by a greater degree of anisotropy is to be expected in species in which the relevant epiphyses withstand a restricted range of load directions. Trabecular architecture therefore is a promising research avenue for the reconstruction of lifestyles in extinct or cryptic species.

Tectonic geomorphology of the Safeen Anticline (Northern Iraq)

NASA Astrophysics Data System (ADS)

Bartl, N.; Grasemann, B.; Faber, R.; Lockhart, D.

2009-04-01

The Zagros Fold- and Thrust Belt extends over 1800 km from Kurdistan in N-Iraq to the Strait of Hormuz in Iran and is one of the world most promising regions for the future hydrocarbon exploration. The Zagros Mountains are the result of the collision of the Eurasian and the Arabian Plates starting in the Late Cretaceous. Recent GPS measurements in have shown that the shortening between these two plates is about 2.5 cm/a most of which is distributed within the Zagros collision orogen. Whereas the tectonic structure and the geomorphological response to active deformation is thoroughly studied in the SE part of the Zagros in Iran, there are almost no modern field based studies of the NW part of the Zagros in Iraq. Here we present the first structural field studies, the mechanical stratigraphy and geomorphological investigations of the Safeen anticline in the NE of the city of Erbil in the Kurdistan region, which is a province of Northern Iraq. The sub-cylindrical part of the anticline strikes for about 65 km NW-SE and has a dominant wavelength of about 6 km. Perpendicular to the strike of the anticline Cretaceous to Tertiary sediments are exposed consisting mainly of bedded to massif limestones and sandstones (competent lithologies), intercalated with marl and claystones (incompetent lithologies). Whereas deformation in the competent lithologies is accommodated by diffusive mass transfer processes and mainly fracturing, the incompetent lithologies record distributed plastic deformation. Along the investigated section, the limbs of the anticline dip with 55° towards NE (backlimb) and 60° towards SW (forelimb). Interestingly the drainage pattern of the forelimb differs significantly to the erosional signature along the backlimb. Both limbs are dominated by transverse river segments. The backlimb records straight almost perpendicular to the fold axis with a spacing of the segments of about 200 m. The forelimb, however, is dominated by a more irregular pattern with a wider spacing of the main segments of about 600m. We use an ASTER digital elevation model in combination with the geological map in order to quantify the differences in geomorphological signal along the different limbs of the Safeen anticline.

Motor Experience Reprograms Development of a Genetically-Altered Bilateral Corticospinal Motor Circuit

PubMed Central

Serradj, Najet

2016-01-01

Evidence suggests that motor experience plays a role in shaping development of the corticospinal system and voluntary motor control, which is a key motor function of the system. Here we used a mouse model with conditional forebrain deletion of the gene for EphA4 (Emx1-Cre:EphA4tm2Kldr), which regulates development of the laterality of corticospinal tract (CST). We combined study of Emx1-Cre:EphA4tm2Kldr with unilateral forelimb constraint during development to expand our understanding of experience-dependent CST development from both basic and translational perspectives. This mouse develops dense ipsilateral CST projections, a bilateral motor cortex motor representation, and bilateral motor phenotypes. Together these phenotypes can be used as readouts of corticospinal system organization and function and the changes brought about by experience. The Emx1-Cre:EphA4tm2Kldr mouse shares features with the common developmental disorder cerebral palsy: bilateral voluntary motor impairments and bilateral CST miswiring. Emx1-Cre:EphA4tm2Kldr mice with typical motor experiences during development display the bilateral phenotype of “mirror” reaching, because of a strongly bilateral motor cortex motor representation and a bilateral CST. By contrast, Emx1-Cre:EphA4tm2Kldr mice that experienced unilateral forelimb constraint from P1 to P30 and tested at maturity had a more contralateral motor cortex motor representation in each hemisphere; more lateralized CST projections; and substantially more lateralized/independent reaching movements. Changes in CST organization and function in this model can be explained by reduced synaptic competition of the CST from the side without developmental forelimb motor experiences. Using this model we show that unilateral constraint largely abrogated the effects of the genetic mutation on CST projections and thus demonstrates how robust and persistent experience-dependent development can be for the establishment of corticospinal system connections and voluntary control. Further, our findings inform the mechanisms of and strategies for developing behavioral therapies to treat bilateral movement impairments and CST miswiring in cerebral palsy. PMID:27673329

Head and pelvic movement asymmetries at trot in riding horses in training and perceived as free from lameness by the owner

PubMed Central

Egenvall, Agneta; Haubro Andersen, Pia; Pfau, Thilo

2017-01-01

Recent studies evaluating horses in training and considered free from lameness by their owners have identified a large proportion of horses with motion asymmetries. However the prevalence, type and magnitude of asymmetries when trotting in a straight line or on the lunge have not been investigated. The aim of this study was to objectively investigate the presence of motion asymmetries in riding horses in training by identifying the side and quantifying the degree and type (impact, pushoff) of forelimb and hind limb asymmetries found during straight line trot and on the lunge. In a cross-sectional study, vertical head and pelvic movement symmetry was measured in 222 Warmblood type riding horses, all without perceived performance issues and considered free from lameness by their owners. Body-mounted uni-axial accelerometers were used and differences between maximum and minimum head (HDmax, HDmin) and pelvic (PDmax, PDmin) vertical displacement between left and right forelimb and hind limb stances were calculated during straight line trot and on the lunge. Previously reported symmetry thresholds were used. The thresholds for symmetry were exceeded in 161 horses for at least one variable while trotting in a straight line, HDmin (n = 58, mean 14.3 mm, SD 7.1), HDmax (n = 41, mean 12.7 mm, SD 5.5), PDmax (n = 87, mean 6.5 mm, SD 3.10), PDmin (n = 79, mean 5.7 mm, SD 2.1). Contralateral and ipsilateral concurrent forelimb and hind limb asymmetries were detected in 41 and 49 horses, respectively. There was a linear association between the straight line PDmin values and the values on the lunge with the lame limb to the inside of the circle. A large proportion (72.5%) of horses in training which were perceived as free from lameness by their owner showed movement asymmetries above previously reported asymmetry thresholds during straight line trot. It is not known to what extent these asymmetries are related to pain or to mechanical abnormalities. Therefore, one of the most important questions that must be addressed is how objective asymmetry scores can be translated into pain, orthopedic abnormality, or any type of unsoundness. PMID:28441406

Head and pelvic movement asymmetries at trot in riding horses in training and perceived as free from lameness by the owner.

PubMed

Rhodin, Marie; Egenvall, Agneta; Haubro Andersen, Pia; Pfau, Thilo

2017-01-01

Recent studies evaluating horses in training and considered free from lameness by their owners have identified a large proportion of horses with motion asymmetries. However the prevalence, type and magnitude of asymmetries when trotting in a straight line or on the lunge have not been investigated. The aim of this study was to objectively investigate the presence of motion asymmetries in riding horses in training by identifying the side and quantifying the degree and type (impact, pushoff) of forelimb and hind limb asymmetries found during straight line trot and on the lunge. In a cross-sectional study, vertical head and pelvic movement symmetry was measured in 222 Warmblood type riding horses, all without perceived performance issues and considered free from lameness by their owners. Body-mounted uni-axial accelerometers were used and differences between maximum and minimum head (HDmax, HDmin) and pelvic (PDmax, PDmin) vertical displacement between left and right forelimb and hind limb stances were calculated during straight line trot and on the lunge. Previously reported symmetry thresholds were used. The thresholds for symmetry were exceeded in 161 horses for at least one variable while trotting in a straight line, HDmin (n = 58, mean 14.3 mm, SD 7.1), HDmax (n = 41, mean 12.7 mm, SD 5.5), PDmax (n = 87, mean 6.5 mm, SD 3.10), PDmin (n = 79, mean 5.7 mm, SD 2.1). Contralateral and ipsilateral concurrent forelimb and hind limb asymmetries were detected in 41 and 49 horses, respectively. There was a linear association between the straight line PDmin values and the values on the lunge with the lame limb to the inside of the circle. A large proportion (72.5%) of horses in training which were perceived as free from lameness by their owner showed movement asymmetries above previously reported asymmetry thresholds during straight line trot. It is not known to what extent these asymmetries are related to pain or to mechanical abnormalities. Therefore, one of the most important questions that must be addressed is how objective asymmetry scores can be translated into pain, orthopedic abnormality, or any type of unsoundness.

Motor Experience Reprograms Development of a Genetically-Altered Bilateral Corticospinal Motor Circuit.

PubMed

Serradj, Najet; Martin, John H

Evidence suggests that motor experience plays a role in shaping development of the corticospinal system and voluntary motor control, which is a key motor function of the system. Here we used a mouse model with conditional forebrain deletion of the gene for EphA4 (Emx1-Cre:EphA4tm2Kldr), which regulates development of the laterality of corticospinal tract (CST). We combined study of Emx1-Cre:EphA4tm2Kldr with unilateral forelimb constraint during development to expand our understanding of experience-dependent CST development from both basic and translational perspectives. This mouse develops dense ipsilateral CST projections, a bilateral motor cortex motor representation, and bilateral motor phenotypes. Together these phenotypes can be used as readouts of corticospinal system organization and function and the changes brought about by experience. The Emx1-Cre:EphA4tm2Kldr mouse shares features with the common developmental disorder cerebral palsy: bilateral voluntary motor impairments and bilateral CST miswiring. Emx1-Cre:EphA4tm2Kldr mice with typical motor experiences during development display the bilateral phenotype of "mirror" reaching, because of a strongly bilateral motor cortex motor representation and a bilateral CST. By contrast, Emx1-Cre:EphA4tm2Kldr mice that experienced unilateral forelimb constraint from P1 to P30 and tested at maturity had a more contralateral motor cortex motor representation in each hemisphere; more lateralized CST projections; and substantially more lateralized/independent reaching movements. Changes in CST organization and function in this model can be explained by reduced synaptic competition of the CST from the side without developmental forelimb motor experiences. Using this model we show that unilateral constraint largely abrogated the effects of the genetic mutation on CST projections and thus demonstrates how robust and persistent experience-dependent development can be for the establishment of corticospinal system connections and voluntary control. Further, our findings inform the mechanisms of and strategies for developing behavioral therapies to treat bilateral movement impairments and CST miswiring in cerebral palsy.

An in vitro biomechanical comparison of equine proximal interphalangeal joint arthrodesis techniques: an axial positioned dynamic compression plate and two abaxial transarticular cortical screws inserted in lag fashion versus three parallel transarticular cortical screws inserted in lag fashion.

PubMed

Sod, Gary A; Riggs, Laura M; Mitchell, Colin F; Hubert, Jeremy D; Martin, George S

2010-01-01

To compare in vitro monotonic biomechanical properties of an axial 3-hole, 4.5 mm narrow dynamic compression plate (DCP) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion (DCP-TLS) with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion (3-TLS) for the equine proximal interphalangeal (PIP) joint arthrodesis. Paired in vitro biomechanical testing of 2 methods of stabilizing cadaveric adult equine forelimb PIP joints. Cadaveric adult equine forelimbs (n=15 pairs). For each forelimb pair, 1 PIP joint was stabilized with an axial 3-hole narrow DCP (4.5 mm) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion and 1 with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion. Five matching pairs of constructs were tested in single cycle to failure under axial compression, 5 construct pairs were tested for cyclic fatigue under axial compression, and 5 construct pairs were tested in single cycle to failure under torsional loading. Mean values for each fixation method were compared using a paired t-test within each group with statistical significance set at P<.05. Mean yield load, yield stiffness, and failure load under axial compression and torsion, single cycle to failure, of the DCP-TLS fixation were significantly greater than those of the 3-TLS fixation. Mean cycles to failure in axial compression of the DCP-TLS fixation was significantly greater than that of the 3-TLS fixation. The DCP-TLS was superior to the 3-TLS in resisting the static overload forces and in resisting cyclic fatigue. The results of this in vitro study may provide information to aid in the selection of a treatment modality for arthrodesis of the equine PIP joint.

Eight Weeks of Strength and Power Training Improves Club Head Speed in Collegiate Golfers.

PubMed

Oranchuk, Dustin J; Mannerberg, Jason M; Robinson, Tracey L; Nelson, Megan C

2018-02-14

Club head speed (CHS) is a major determinant of drive distance, a key component of golf performance. The purpose of this study was to determine the indirect effects of an eight-week strength and power program on CHS. Twelve (6 male, 6 female) NCAA Division II golfers (20.3±1.5 years) randomly assigned to an intervention or control group, underwent either a periodized strength and power program consisting of high-load barbell movements or a bodyweight and rotational movement focused resistance training program. Outcomes were CHS, countermovement jump (CMJ) height, and 1RM back squat (BS), power clean (PC), and deadlift (DL). Dependent t-tests were utilized to assess differences in outcome variables pre-to-post for each group, independent t-tests were utilized to assess differences between groups, and Pearson correlations were utilized to assess associations between CHS and outcome variables. On average, the intervention group experienced improvements in all outcome variables except peak CHS (p=0.60); the control group displayed no changes in any outcome variable except a decrease in average CHS (p=0.028). Compared to the control group, the intervention group experienced greater improvements in average CHS, BS, PC, and average and peak CMJ height (p<0.05). Additionally, CHS had large associations with PC (r=0.70, p=0.012), BS (r=0.64, p=0.025), DL (r=0.54, p=0.068) and CMJ (r=0.73, p=0.007). These results suggest improving muscular strength and power by increasing PC, BS, and CMJ is associated with increased CHS in collegiate golfers. Integrating a high-load, barbell-focused strength and power program may be beneficial for improving CHS and indirectly, golf performance.

Computed tomographic analysis of the internal structure of the metacarpals and its implications for hand use, pathology, and surgical intervention.

PubMed

Wong, Alison L; Meals, Clifton G; Ruff, Christopher B

2018-03-01

The variation of bone structure and biomechanics between the metacarpals is not well characterized. It was hypothesized that their structure would reflect their common patterns of use (i.e., patterns of hand grip), specifically that trabecular bone density would be greater on the volar aspect of all metacarpal bases, that this would be most pronounced in the thumb, and that the thumb diaphysis would have the greatest bending strength. Cross-sections at basal and mid-diaphyseal locations of 50 metacarpals from 10 human hands were obtained by peripheral quantitative computed tomography. The volar and dorsal trabecular densities of each base were measured and characterized using the volar/dorsal density ratio. The polar stress-strain index (SSIp), a surrogate measure of torsional/bending strength, was measured for each diaphysis and standardized for bone length and mass. Comparisons were made using mixed-model analyses of variance (ANOVAs) and post hoc tests. Volar/dorsal trabecular density ratios showed even distribution in all metacarpal bases except for the thumb, which showed greater values on the volar aspect. The thumb, second, and third metacarpals all had high bending strength (SSIp), but the thumb's SSIp relative to its length and trabecular mass was much higher than those of the other metacarpals. Trabecular density of the metacarpal bases was evenly distributed except in the thumb, which also showed higher bending strength relative to its length and mass. Understanding of how these indicators of strength differ across metacarpals may improve both fracture diagnosis and treatment and lays the groundwork for investigating changes with age, hand dominance, and occupation.

Nitrate uptake and utilization is modulated by exogenous gamma-aminobutyric acid in Arabidopsis thaliana seedlings.

PubMed

Barbosa, Jose M; Singh, Narendra K; Cherry, Joe H; Locy, Robert D

2010-06-01

Exogenously applied GABA modulates root growth by inhibition of root elongation when seedlings were grown in vitro on full-strength Murashige and Skoog (MS) salts, but root elongation was stimulated when seedlings were grown on 1/8 strength MS salts. When the concentration of single ions in MS salts was individually varied, the control of growth between inhibition and stimulation was found to be related to the level of nitrate (NO(3)(-)) in the growth medium. At NO(3)(-) concentrations below 40 mM (full-strength MS salts level), root growth was stimulated by the addition of GABA to the growth medium; whereas at concentrations above 40 mM NO(3)(-), the addition of GABA to the growth medium inhibited root elongation. GABA promoted NO(3)(-) uptake at low NO(3)(-), while GABA inhibited NO(3)(-) uptake at high NO(3)(-). Activities of several enzymes involved in nitrogen and carbon metabolism including nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (NADH-GOGAT), NADP-dependent isocitrate dehydrogenase (NADP-ICDH), and phosphoenol pyruvate carboxylase (PEPCase) were regulated by GABA in the growth medium. Supplementing 1/8 strength MS medium with 50 mM GABA enhanced the activities of all of the above enzymes except ICDH activities in root tissues. However, at full-strength MS, GABA showed no inhibitory effect on the activities of these enzymes, except on GS in both root and shoot tissues, and PEPCase activity in shoot tissues. Exogenous GABA increased the amount of NR protein rather than its activation status in the tissues. This study shows that GABA affects the growth of Arabidopsis, possibly by acting as a signaling molecule, modulating the activity of enzymes involved in primary nitrogen metabolism and nitrate uptake.

Cryogenic mechanical properties of low density superplastically formable Al-Li alloys

NASA Technical Reports Server (NTRS)

Verzasconi, S. L.; Morris, J. W., Jr.

1989-01-01

The aerospace industry is considering the use of low density, superplastically formable (SPF) materials, such as Al-Li alloys in cryogenic tankage. SPF modifications of alloys 8090, 2090, and 2090+In were tested for strength and Kahn tear toughness. The results were compared to those of similar tests of 2219-T87, an alloy currently used in cryogenic tankage, and 2090-T81, a recently studied Al-Li alloy with exceptional cryogenic properties (1-9). With decreasing temperature, all materials showed an increase in strength, while most materials showed an increase in elongation and decrease in Kahn toughness. The indium addition to 2090 increased alloy strength, but did not improve the strength-toughness combination. The fracture mode was predominantly intergranular along small, recrystallized grains, with some transgranular fracture, some ductile rupture, and some delamination on large, unrecrystallized grains.

One day of motor training with amphetamine impairs motor recovery following spinal cord injury.

PubMed

Wong, Jamie K; Steward, Oswald

2012-02-01

It has previously been reported that a single dose of amphetamine paired with training on a beam walking task can enhance locomotor recovery following brain injury (Feeney et al., 1982). Here, we investigated whether this same drug/training regimen could enhance functional recovery following either thoracic (T9) or cervical (C5) spinal cord injury. Different groups of female Sprague-Dawley rats were trained on a beam walking task, and in a straight alley for assessment of hindlimb locomotor recovery using the BBB locomotor scale. For rats that received C5 hemisections, forelimb grip strength was assessed using a grip strength meter. Three separate experiments assessed the consequences of training rats on the beam walking task 24 h following a thoracic lateral hemisection with administration of either amphetamine or saline. Beginning 1 h following drug administration, rats either received additional testing/retraining on the beam hourly for 6 h, or they were returned to their home cages without further testing/retraining. Rats with thoracic spinal cord injuries that received amphetamine in conjunction with testing/retraining on the beam at 1 day post injury (DPI) exhibited significantly impaired recovery on the beam walking task and BBB. Rats with cervical spinal cord injuries that received training with amphetamine also exhibited significant impairments in beam walking and locomotion, as well as impairments in gripping and reaching abilities. Even when administered at 14 DPI, the drug/training regimen significantly impaired reaching ability in cervical spinal cord injured rats. Impairments were not seen in rats that received amphetamine without training. Histological analyses revealed that rats that received training with amphetamine had significantly larger lesions than saline controls. These data indicate that an amphetamine/training regimen that improves recovery after cortical injury has the opposite effect of impairing recovery following spinal cord injury because early training with amphetamine increases lesion severity. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of Tadalafil on Seizure Threshold and Activity of Antiepileptic Drugs in Three Acute Seizure Tests in Mice.

PubMed

Socała, Katarzyna; Nieoczym, Dorota; Pieróg, Mateusz; Wyska, Elżbieta; Szafarz, Małgorzata; Doboszewska, Urszula; Wlaź, Piotr

2018-02-09

Tadalafil, a selective phosphodiesterase type 5 inhibitor, is a long-acting oral agent for the treatment of erectile dysfunction of multiple etiologies. Although generalized tonic-clonic seizures were reported in a healthy man after taking tadalafil, the influence of tadalafil on seizure susceptibility has not been studied so far. Therefore, the aim of the present study was to investigate the effect of tadalafil on seizure threshold as well as on the activity of some first- and second-generation antiepileptic drugs in three acute seizure tests in mice. The obtained results showed that tadalafil, at the highest dose tested (20 mg/kg), significantly decreased the threshold for the first myoclonic twitch in the intravenous pentylenetetrazole (i.v. PTZ) seizure test. It did not affect the threshold for generalized clonic seizure and forelimb tonus in the i.v. PTZ, for tonic hindlimb extension in the maximal electroshock seizure threshold test, and for psychomotor seizure in the 6-Hz-induced seizure threshold test. Tadalafil did not alter the anticonvulsant activity of any of the studied antiepileptic drugs in electrically induced seizure tests. Interestingly, tadalafil potentiated the anticonvulsant activity of clonazepam and decreased the anticonvulsant activity of oxcarbazepine in the i.v. PTZ test. These interactions were pharmacodynamic in nature, as tadalafil did not alter clonazepam and oxcarbazepine concentrations both in serum and brain tissue. Furthermore, neither tadalafil alone nor its combinations with the studied antiepileptic drugs produced any significant impairment of motor coordination (assessed in the chimney test), muscular strength (investigated in the grip-strength test), and long-term memory (assessed in the passive avoidance task). In conclusion, tadalafil may increase the risk of myoclonic seizure and decrease the anticonvulsant efficacy of oxcarbazepine. Further studies are warranted to evaluate the safety of tadalafil usage in patients with epilepsy.

Comparison of Three Methods of Assessing Muscle Strength and Imbalance Ratios of the Knee

PubMed Central

Moss, Crayton L.; Wright, P. Thomas

1993-01-01

Three strength measurement methods for determining muscle strength and imbalance ratios of the knee were compared in 41 (23 female, 18 male) NCAA Division I track and field athletes. Peak quadriceps extensions and hamstring flexions were measured isotonically, isometrically, and isokinetically. Isokinetic measurements were performed on a Cybex II at 60°/s. Isometric extension and flexion measurements were performed using the Nicholas Manual Muscle Tester (Lafayette Instruments; Lafayette, Ind). Isotonic measurements were done on both Universal and Nautilus apparatuses. Testing order was randomized to avoid a treatment order effect. A repeated measures ANOVA and a post hoc Tukey test were used to compare the three methods of assessing strength and imbalance ratios of the knee. Absolute strength values were significantly different according to gender and mode of testing. Bilateral strength imbalance ratios for knee flexion were significantly lower for the Nautilus leg curl machine. Ipsilateral strength imbalance ratios were significantly greater for the Cybex II. Our results indicated that absolute strength values cannot be interchanged between testing modes. Except for Cybex II (ipsilateral) and Nautilus (bilateral knee flexion), strength imbalance ratios could be interchanged. ImagesFig 1.Fig 2.Fig 3.Fig 4.Fig 5.Fig 6.Fig 7.INGING PMID:16558207

Effects of strain rate and temperature on the mechanical behavior of carbon black reinforced elastomers based on butyl rubber and high molecular weight polyethylene

NASA Astrophysics Data System (ADS)

Hussein, M.

2018-06-01

The influence of the mechanical property and morphology of different blend ratio of Butyl rubber (IIR)/high molecular weight polyethylene (PE) by temperature and strain rate are performed. Special attention has been considered to a ductile-brittle transition that is known to occur at around 60 °C. The idea is to explain the unexpected phenomenon of brittleness which directly related to all tensile mechanical properties such as the strength of blends, modulus of elasticity of filled and unfilled IIR-polyethylene blends. In particular, the initial Young's modulus, tensile strength and strain at failure exhibit similar dependency on strain rate and temperature. These quantities lowered and increased with an increment of temperature, whereas the increased with increasing of strain rate. Furthermore, the tensile strength and strain at failure decreases for all temperatures range with the increase of PE content in the blend, except Young's modulus in reverse. The strain rate sensitivity index parameter of the examined polymeric materials is consistent with the micro-mechanisms of deformation and the behavior was well described by an Eyring relationship leading to an activation volume of ∼1 nm3, except for the highest value of unfilled IIR ∼8.45 nm3.

Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.

PubMed

Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke

2008-02-22

Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).

Effects of cationic xylan from annual plants on the mechanical properties of paper.

PubMed

Deutschle, Alexander L; Römhild, Katrin; Meister, Frank; Janzon, Ron; Riegert, Christiane; Saake, Bodo

2014-02-15

Xylan from oat spelt and wheat was used as an additive to enhance the dry strength of paper. The absorption of xylan by the cellulose fibers was increased by cationization to different degrees of substitution. Paper hand sheets with different doses of xylan and industrial cationic starch were produced, and the mechanical properties were determined. Absorption measurements of cationic oat spelt xylan on pulp fibers explained the differing influences of low and high cationized xylan addition on paper strength. The addition of cationic oat spelt xylan with a degree of substitution of 0.1 at a 4% dose provided the largest improvement in the tensile-index (67%), burst-index (105%) and tear-index (77%). Compared to cationic starch, cationic oat spelt xylan additives led to similar paper strength values, excepting the tear strength. The structural differences and protein impurities made the wheat xylan unsuitable as a strength additive for paper pulp. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparative study of the physical properties of core materials.

PubMed

Saygili, Gülbin; Mahmali, Sevil M

2002-08-01

This study was undertaken to measure physical properties of materials used for direct core buildups, including high-copper amalgam, visible light-cured resin composite, autocured titanium-containing composite, polyacid-modified composite, resin-modified glass-ionomer, and silver cermet cement. Compressive strength, diametral tensile strength, and flexural strength of six core materials of various material classes were measured for each material as a function of time up to 3 months at different storage conditions, using a standard specification test designed for the materials. Three different storage conditions (dry, humid, wet) at 37 degrees C were chosen. Materials were manipulated according to manufacturers' instructions for use as cores. Mean compressive, diametral tensile, and flexural strengths with associated standard deviations were calculated for each material. Multiple comparison and Newman-Keuls tests discerned many differences among materials. All materials were found to meet the minimum specification requirements, except in terms of flexural strength for amalgam after 1 hour and the silver cermet at all time intervals.

A dislocation-based, strain–gradient–plasticity strengthening model for deformation processed metal–metal composites

DOE PAGES

Tian, Liang; Russell, Alan; Anderson, Iver

2014-01-03

Deformation processed metal–metal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. A dislocation-density-based, strain–gradient–plasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with our experimental findings of Cu–Nb, Cu–Ta, and Al–Ti DMMC systems to verify the applicability of the new model. The results show that this model predicts themore » strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.« less

Effects of mechanical and thermal cycling on composite and hybrid laminates with residual stresses

NASA Technical Reports Server (NTRS)

Daniel, I. M.; Liber, T.

1977-01-01

The effects of tensile load cycling and thermal cycling on residual stiffness and strength properties of the following composite and hybrid angle-ply laminates were studied: boron/epoxy, boron/polyimide, graphite/low-modulus epoxy, graphite/high-modulus epoxy, graphite/polyimide, S-glass/epoxy, graphite/Kevlar 49/epoxy, and graphite/S-glass/epoxy. Specimens of the first six types were mechanically cycled up to 90% of static strength. Those that survived 10 million cycles were tested statically to failure, and no significant changes in residual strength and modulus were noted. Specimens of all types were subjected to thermal cycling between room temperature and 411 K for the epoxy-matrix composites and 533 K for the polyimide-matrix composites. The residual strength and stiffness remained largely unchanged, except for the graphite/low-modulus epoxy, which showed reductions in both of approximately 35%. When low-temperature thermal cycling under tensile load was applied, there was a noticeable reduction in modulus and strength in the graphite/low-modulus epoxy and some strength reduction in the S-glass/epoxy.

Effect of contamination and etching on enamel bond strength of new light-cured glass ionomer cements.

PubMed

Itoh, T; Matsuo, N; Fukushima, T; Inoue, Y; Oniki, Y; Matsumoto, M; Caputo, A A

1999-10-01

The effect of water and saliva contamination on the bond strength of metal orthodontic brackets cemented to etched (10% polyacrylic acid) and unetched human premolar enamel was investigated. Two bonding agents were used: one commercially available product (LC) and one experimental (EX) light-cured glass ionomer. Shear bond strength was measured after aging for 5 minutes, 15 minutes, and 24 hours. The results were compared by ANOVA and Scheffe's tests at p = 0.05. For LC, the bond strength of brackets bonded to etched enamel, with and without contamination, was statistically higher than that of brackets bonded to unetched enamel for all aging times. An exception was the bond strength to unetched enamel with saliva contamination after 24 hours; for EX, this value was statistically higher than that measured on unetched enamel with water contamination. Contamination by saliva did not reduce bond strength to unetched enamel. For both etched and unetched enamel, there was no significant difference between LC and EX after 24 hours for all contamination conditions.

Standard methods for filled hole tension testing of textile composites

NASA Technical Reports Server (NTRS)

Portanova, M. A.; Masters, J. E.

1995-01-01

The effects of two test specimen geometry parameters, the specimen width and W/D ratio, on filled-hole tensile strength were determined for textile composite materials. Test data generated by Boeing and Lockheed on 2-D and 3-D braids, and 3-D weaves were used to make these evaluations. The investigation indicated that filled-hole tensile-strength showed little sensitivity to either parameter. Test specimen configurations used in open-hole tension tests, such as those suggested by ASTM D5766 - Standard Test Method for Open Hole Tensile Strength of Polymer Matrix Composite Laminates or those proposed by MIL-HDBK-17-lD should provide adequate results for material comparisons studies. Comparisons of the materials' open-hole and filled-hole tensile strengths indicated that the latter were generally lower than the former. The 3-D braids were the exception; their filled-hole strengths were unexpected larger than their open-hole strengths. However, these increases were small compared to the scatter in the data. Thus, filled hole tension may be a critical design consideration for textile composite materials.

Coupled ion redistribution and electronic breakdown in low-alkali boroaluminosilicate glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Doo Hyun, E-mail: cooldoo@add.re.kr; Randall, Clive, E-mail: car4@psu.edu; Furman, Eugene, E-mail: euf1@psu.edu

2015-08-28

Dielectrics with high electrostatic energy storage must have exceptionally high dielectric breakdown strength at elevated temperatures. Another important consideration in designing a high performance dielectric is understanding the thickness and temperature dependence of breakdown strengths. Here, we develop a numerical model which assumes a coupled ionic redistribution and electronic breakdown is applied to predict the breakdown strength of low-alkali glass. The ionic charge transport of three likely charge carriers (Na{sup +}, H{sup +}/H{sub 3}O{sup +}, Ba{sup 2+}) was used to calculate the ionic depletion width in low-alkali boroaluminosilicate which can further be used for the breakdown modeling. This model predictsmore » the breakdown strengths in the 10{sup 8}–10{sup 9 }V/m range and also accounts for the experimentally observed two distinct thickness dependent regions for breakdown. Moreover, the model successfully predicts the temperature dependent breakdown strength for low-alkali glass from room temperature up to 150 °C. This model showed that breakdown strengths were governed by minority charge carriers in the form of ionic transport (mostly sodium) in these glasses.« less

Isometric shoulder strength in young swimmers.

PubMed

McLaine, Sally J; Ginn, Karen A; Fell, James W; Bird, Marie-Louise

2018-01-01

The prevalence of shoulder pain in young swimmers is high. Shoulder rotation strength and the ratio of internal to external rotation strength have been reported as potential modifiable risk factors associated with shoulder pain. However, relative strength measures in elevated positions, which include flexion and extension, have not been established for the young swimmer. The aim of this study was to establish clinically useful, normative shoulder strength measures and ratios for swimmers (14-20 years) without shoulder pain. Cross-sectional, observational study. Swimmers (N=85) without a recent history of shoulder pain underwent strength testing of shoulder flexion and extension (in 140° abduction); and internal and external rotation (in 90° abduction). Strength tests were performed in supine using a hand-held dynamometer and values normalised to body weight. Descriptive statistics were calculated for strength and strength ratios (flexion:extension and internal:external rotation). Differences between groups (based on gender, history of pain, test and arm dominance) were explored using independent and paired t tests. Normative shoulder strength values and ratios were established for young swimmers. There was a significant difference (p<0.002) in relative strength between males and females for all tests with no differences in strength ratios. Relative strength of the dominant and non-dominant shoulders (except for extension); and for swimmers with and without a history of shoulder pain was not significantly different. A normal shoulder strength profile for the young swimmer has been established which provides a valuable reference for the clinician assessing shoulder strength in this population. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

14 CFR 23.253 - High speed characteristics.

Code of Federal Regulations, 2013 CFR

2013-01-01

... and characteristics include gust upsets, inadvertent control movements, low stick force gradients in relation to control friction, passenger movement, leveling off from climb, and descent from Mach to... normal attitude and its speed reduced to VMO/MMO, without— (1) Exceptional piloting strength or skill; (2...

14 CFR 23.253 - High speed characteristics.

Code of Federal Regulations, 2014 CFR

2014-01-01

... and characteristics include gust upsets, inadvertent control movements, low stick force gradients in relation to control friction, passenger movement, leveling off from climb, and descent from Mach to... normal attitude and its speed reduced to VMO/MMO, without— (1) Exceptional piloting strength or skill; (2...

Coupled spin and electron-phonon interaction at the Tl/Si(111) surface from relativistic first-principles calculations

NASA Astrophysics Data System (ADS)

Garcia-Goiricelaya, Peio; Gurtubay, Idoia G.; Eiguren, Asier

2018-05-01

We investigate the role played by the electron spin and the spin-orbit interaction in the exceptional electron-phonon coupling at the Tl/Si(111) surface. Our first-principles calculations demonstrate that the particular spin pattern of this system dominates the whole low-energy electron-phonon physics, which is remarkably explained by forbidden spin-spin scattering channels. In particular, we show that the strength of the electron-phonon coupling appears drastically weakened for surface states close to the K ¯ and K'¯ valleys, which is unambiguously attributed to the spin polarization through the associated modulation due to the spinor overlaps. However, close to the Γ ¯ point, the particular spin pattern in this area is less effective in damping the electron-phonon matrix elements, and the result is an exceptional strength of the electron-phonon coupling parameter λ ˜1.4 . These results are rationalized by a simple model for the electron-phonon matrix elements including the spinor terms.

Functional fitness norms for community-dwelling older adults in Hong Kong.

PubMed

Chung, Pak-Kwong; Zhao, Yanan; Liu, Jing-Dong; Quach, Binh

2016-01-01

This study aimed to establish normative data for older adults in Hong Kong and explore age and sex differences in functional fitness. A sample of 944 independent community-dwellers, aged 65-74 years, was evaluated using the Senior Fitness Test battery in addition to hand grip and single leg stance tests. Normative data were reported for the 10th, 25th, 50th, 75th, and 90th percentiles in 5-year age groups. Except for upper extremity muscle strength in women and body mass index (BMI) in both sexes, ageing-associated degradation was observed in all testing parameters especially in flexibility, balance, and agility. Significant sex differences were found in all testing parameters with the exception of BMI and static balance with eyes open. Moreover, men demonstrated higher capacities for muscle strength, agility, balance, and aerobic endurance, whereas women showed superior flexibility. The normative values enable the evaluation of individual performance regarding the fitness status of older adults in Hong Kong. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ushizima, Daniela; Perciano, Talita; Krishnan, Harinarayan

Fibers provide exceptional strength-to-weight ratio capabilities when woven into ceramic composites, transforming them into materials with exceptional resistance to high temperature, and high strength combined with improved fracture toughness. Microcracks are inevitable when the material is under strain, which can be imaged using synchrotron X-ray computed micro-tomography (mu-CT) for assessment of material mechanical toughness variation. An important part of this analysis is to recognize fibrillar features. This paper presents algorithms for detecting and quantifying composite cracks and fiber breaks from high-resolution image stacks. First, we propose recognition algorithms to identify the different structures of the composite, including matrix cracks andmore » fibers breaks. Second, we introduce our package F3D for fast filtering of large 3D imagery, implemented in OpenCL to take advantage of graphic cards. Results show that our algorithms automatically identify micro-damage and that the GPU-based implementation introduced here takes minutes, being 17x faster than similar tools on a typical image file.« less

The importance of fracture toughness in ultrafine and nanocrystalline bulk materials

PubMed Central

Pippan, R.; Hohenwarter, A.

2016-01-01

ABSTRACT The suitability of high-strength ultrafine and nanocrystalline materials processed by severe plastic deformation methods and aimed to be used for structural applications will strongly depend on their resistance against crack growth. In this contribution some general available findings on the damage tolerance of this material class will be summarized. Particularly, the occurrence of a pronounced fracture anisotropy will be in the center of discussion. In addition, the great potential of this generated anisotropy to obtain high-strength materials with exceptionally high fracture toughness in specific loading and crack growth directions will be enlightened. IMPACT STATEMENT Severely plastically deformed materials are reviewed in light of their damage tolerance. The frequently observed toughness anisotropy allows unprecedented fracture toughness – strength combinations. PMID:27570712

Structure and mechanical properties of coatings fabricated by nonvacuum electron beam cladding of Ti-Ta-Zr powder mixtures

NASA Astrophysics Data System (ADS)

Samoylenko, Vitaliy V.; Lenivtseva, Olga G.; Polyakov, Igor A.; Laptev, Ilya S.

2015-10-01

In this paper structural investigations and mechanical tests of Ti-Ta-Zr coatings obtained on surfaces of cp-titanium workpieces were carried out. It was found that the coatings had a dendrite structure; investigations at high-power magnifications revealed a platelet structure. An increase of tantalum concentration led to refinement of structural components. The microhardness level of all coatings, excepting a specimen with the maximum tantalum content, was 370 HV. The microhardness of this coating reached 400 HV. The ultimate tensile strength of cladded layers varied from 697 to 947 MPa. Adhesion tests showed that bimetallic composites were characterized by high bond strength of cladded layers to the substrate, which exceeded cp-titanium strength characteristics.

The Center for Regenerative Biology and Medicine at Mount Desert Island Biological Laboratory

DTIC Science & Technology

2014-06-01

Positional Memory Code Axolotl 15. SUBJECT TERMS microRNAs Zebrafish Polypterus 16...miR-7a, let-7j, miR-130c, miR-338, miR-204 and miR- 2184 that are shared between regenerating axolotl forelimbs, zebrafish caudal fins and...regeneration was defective in both zebrafish and Polypterus fin appendages and axolotl limbs (Fig. 1, 2). Polypterus caudal and pectoral fins

Haemangiosarcoma of the interventricular septum in a dog.

PubMed

Thompson, D J; Cave, N J; Scrimgeour, A B; Thompson, K G

2011-11-01

Abstract A 5-year-old male neutered Labrador Retriever Afghan crossbred dog was examined after collapsing. The dog was recumbent, dyspnoeic and mildly tachypnoeic. There was a tachyarrhythmia (300 beats per minute) and subcutaneous oedema of the ventral neck and right forelimb. The dog had a sustained ventricular tachycardia originating in the right ventricle and on echocardiography a mass was identified in the interventricular septum. Due to the poor prognosis the owners agreed to euthanasia of the dog. A reddish-grey mass was found in the interventricular septum and smaller red foci found scattered throughout the myocardium. There was a single, raised, splenic nodule with several smaller red foci within the splenic parenchyma. Hepatic congestion, pancreatic oedema, ascites and subcutaneous oedema of the right forelimb and neck were present. Sections of the splenic nodule, interventricular septal mass and both ventricular-free walls showed neoplastic mesenchymal cells. Haemangiosarcoma of the myocardium and spleen with right-sided congestive heart failure. This case report describes an atypical location for haemangiosarcoma. The investigation supports the use of echocardiography as a component of the protocol for staging haemangiosarcoma even in the absence of apericardial effusion. It also provides further evidence for the inclusion of intracardiac neoplasia as a differential diagnosis for dogs with unexplained cardiac arrhythmias.

Analyzing structural variations along strike in a deep-water thrust belt

NASA Astrophysics Data System (ADS)

Totake, Yukitsugu; Butler, Robert W. H.; Bond, Clare E.; Aziz, Aznan

2018-03-01

We characterize a deep-water fold-thrust arrays imaged by a high-resolution 3D seismic dataset in the offshore NW Borneo, Malaysia, to understand the kinematics behind spatial arrangement of structural variations throughout the fold-thrust system. The seismic volume used covers two sub-parallel fold trains associated with a series of fore-thrusts and back-thrusts. We measured fault heave, shortening value, fold geometries (forelimb dip, interlimb angle and crest depth) along strike in individual fold trains. Heave plot on strike projection allows to identify individual thrust segments showing semi-elliptical to triangular to bimodal patterns, and linkages of these segments. The linkage sites are marked by local minima in cumulative heave. These local heave minima are compensated by additional structures, such as small imbricate thrusts and tight folds indicated by large forelimb dip and small interlimb angle. Complementary profiles of the shortening amount for the two fold trains result in smoother gradient of total shortening across the structures. We interpret this reflects kinematic interaction between two fold-thrust trains. This type of along-strike variation analysis provides comprehensive understanding of a fold-thrust system and may provide an interpretative strategy for inferring the presence of complex multiple faults in less well-imaged parts of seismic volumes.

Functional-adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus.

PubMed

Argot, C

2001-01-01

An attempt to determine the locomotor activities of Mayulestes ferox (Borhyaenoidea) and Pucadelphys andinus (Didelphoidea) from the early Paleocene site of Tiupampa (Bolivia) is presented. The functional anatomy of the forelimbs of these South American marsupials is compared to that of some living didelphids: Caluromys philander, Micoureus demerarae, Marmosa murina, Didelphis marsupialis, Monodelphis brevicaudata and Metachirus nudicaudatus. Deductions from bone morphology to myology and locomotor behavior in the fossils are inferred from the comparisons with living forms. Some features of the postcranial skeleton, indicative of arboreal adaptations, are found in the extinct marsupials: anteriorly projected acromion, hemispherical head of the humerus, extended humeral lateral epicondylar ridge, medially protruding humeral entepicondyle, proximal ulnar posterior convexity, and deep flexor fossa on the medial side of the ulna. But other features are related to a more terrestrial pattern: the well-developed tubercles of the humeral head, the elongated olecranon process of the ulna, and the oval shape of the radial head. Mayulestes had clear arboreal abilities, but, as a predaceous mammal, probably hunted on the ground. Pucadelphys was less specialized, close to the living Monodelphis, a terrestrial insectivorous form with some skeletal features related to arboreal locomotion that are probably plesiomorphic for marsupials. Copyright 2001 Wiley-Liss, Inc.

The role of the extrinsic thoracic limb muscles in equine locomotion.

PubMed

Payne, R C; Veenman, P; Wilson, A M

2005-02-01

Muscles have two major roles in locomotion: to generate force and to absorb/generate power (do work). Economical force generation is achieved by short-fibred pennate muscle while the maximum power output of a muscle is architecture independent. In this study we tested the hypothesis that there is an anatomical and structural separation between the force-generating anti-gravity muscles and the propulsive (limb/trunk moving) muscles of the equine forelimb. Muscle mass and fascicle length measurements were made on the thoracic limb extrinsic muscles of six fresh horse cadavers. Physiological cross-sectional area and maximum isometric force were then estimated. Maximum power was estimated from muscle volume and published contraction velocity data. The majority of extrinsic forelimb muscles were large with long fascicles arranged in parallel to the long axis of the muscle. Muscles arranged in this way are optimised for doing work. The architecture of serratus ventralis thoracis (SVT) was unique. It had short (48 +/- 17 mm) fascicles, arranged at about 45 degrees to the long axis of the muscle, which would suggest a force-generating, anti-gravity role. The muscle belly of SVT was sandwiched between two broad, thick sheets of aponeurosis. Hence, SVT could make a significant contribution to the overall elastic properties of the thoracic limb.

The role of the extrinsic thoracic limb muscles in equine locomotion.

PubMed

Payne, R C; Veenman, P; Wilson, A M

2004-12-01

Muscles have two major roles in locomotion: to generate force and to absorb/generate power (do work). Economical force generation is achieved by short-fibred pennate muscle while the maximum power output of a muscle is architecture independent. In this study we tested the hypothesis that there is an anatomical and structural separation between the force-generating anti-gravity muscles and the propulsive (limb/trunk moving) muscles of the equine forelimb. Muscle mass and fascicle length measurements were made on the thoracic limb extrinsic muscles of six fresh horse cadavers. Physiological cross-sectional area and maximum isometric force were then estimated. Maximum power was estimated from muscle volume and published contraction velocity data. The majority of extrinsic forelimb muscles were large with long fascicles arranged in parallel to the long axis of the muscle. Muscles arranged in this way are optimised for doing work. The architecture of serratus ventralis thoracis (SVT) was unique. It had short (48 +/- 17 mm) fascicles, arranged at about 45 degrees to the long axis of the muscle, which would suggest a force-generating, anti-gravity role. The muscle belly of SVT was sandwiched between two broad, thick sheets of aponeurosis. Hence, SVT could make a significant contribution to the overall elastic properties of the thoracic limb.

Can they dig it? Functional morphology and semifossoriality among small-eared shrews, genus Cryptotis (Mammalia, Soricidae)

USGS Publications Warehouse

Woodman, Neal; Gaffney, Sarah A.

2014-01-01

Small-eared shrews (Mammalia: Soricidae: Cryptotis), exhibit modifications of the forelimb skeleton that have been interpreted as adaptations for semifossoriality. Most species inhabit remote regions, however, and their locomotory and foraging behaviors remain mostly speculative. To better understand the morphological modifications in the absence of direct observations, we quantified variation in these species by measuring 151 individuals representing 18 species and populations of Cryptotis and two species of moles (Talpidae) for comparison. From our measurements, we calculated 22 indices, most of which have been used previously to characterize substrate use among rodents and other taxa. We analyzed the indices using 1) average percentile ranks, 2) principal components analysis, and 3) cluster analysis. From these analyses, we determined that three basic modes of substrate adaptation are present within Cryptotis: 1) a primarily terrestrial mode, with species that are capable of burrowing, but lack adaptations to increase digging efficiency, 2) a semifossorial mode, with species whose forelimbs bones show strong muscle attachment areas and increased mechanical advantage, and 3) an intermediate mode. In addition to identifying new morphological characters and contributing to our understanding of the functional morphology of soricids, these analyses provide additional insight into the ecology of the species of interest.

In search of the pitching momentum that enables some lizards to sustain bipedal running at constant speeds

PubMed Central

Van Wassenbergh, Sam; Aerts, Peter

2013-01-01

The forelimbs of lizards are often lifted from the ground when they start sprinting. Previous research pointed out that this is a consequence of the propulsive forces from the hindlimbs. However, despite forward acceleration being hypothesized as necessary to lift the head, trunk and forelimbs, some species of agamids, teiids and basilisks sustain running in a bipedal posture at a constant speed for a relatively long time. Biomechanical modelling of steady bipedal running in the agamid Ctenophorus cristatus now shows that a combination of three mechanisms must be present to generate the angular impulse needed to cancel or oppose the effect of gravity. First, the trunk must be lifted significantly to displace the centre of mass more towards the hip joint. Second, the nose-up pitching moment resulting from aerodynamic forces exerted at the lizard's surface must be taken into account. Third, the vertical ground-reaction forces at the hindlimb must show a certain degree of temporal asymmetry with higher forces closer to the instant of initial foot contact. Such asymmetrical vertical ground-reaction force profiles, which differ from the classical spring-mass model of bipedal running, seem inherent to the windmilling, splayed-legged running style of lizards. PMID:23658116

A cadaveric study to determine the minimum volume of methylene blue to completely color the nerves of brachial plexus in cats. An update in forelimb and shoulder surgeries.

PubMed

Mencalha, Rodrigo; Fernandes, Neide; Sousa, Carlos Augusto dos Santos; Abidu-Figueiredo, Marcelo

2014-06-01

To determine the minimum volume of methylene blue (MB) to completely color the brachial plexus (BP) nerves, simulating an effective anesthetic block in cats. Fifteen adult male cat cadavers were injected through subscapular approach with volumes of 2, 3, 4, 5 and 6 ml in both forelimbs, for a total of 30 brachial plexus blocks (BPB). After infusions, the specimens were carefully dissected preserving each nervous branch. The measurement of the effective area was indicated by the impregnation of MB. Nerves were divided into four segments from the origin at the spinal level until the insertion into the thoracic limb muscles. The blocks were considered effective only when all the nerves were strongly or totally colored. Volumes of 2, 3 and 4 ml were considered insufficient suggesting a failed block, however, volumes of 5 and 6 ml were associated with a successful block. The injection of methylene blue, in a volume of 6 ml, completely colored the brachial plexus. At volumes of 5 and 6 ml the brachial plexus blocks were considered a successful regional block, however, volumes of 2, 3 and 4 ml were considered a failed regional block.

Inspiration for wing design: how forelimb specialization enables active flight in modern vertebrates

PubMed Central

2017-01-01

Harnessing flight strategies refined by millions of years of evolution can help expedite the design of more efficient, manoeuvrable and robust flying robots. This review synthesizes recent advances and highlights remaining gaps in our understanding of how bird and bat wing adaptations enable effective flight. Included in this discussion is an evaluation of how current robotic analogues measure up to their biological sources of inspiration. Studies of vertebrate wings have revealed skeletal systems well suited for enduring the loads required during flight, but the mechanisms that drive coordinated motions between bones and connected integuments remain ill-described. Similarly, vertebrate flight muscles have adapted to sustain increased wing loading, but a lack of in vivo studies limits our understanding of specific muscular functions. Forelimb adaptations diverge at the integument level, but both bird feathers and bat membranes yield aerodynamic surfaces with a level of robustness unparalleled by engineered wings. These morphological adaptations enable a diverse range of kinematics tuned for different flight speeds and manoeuvres. By integrating vertebrate flight specializations—particularly those that enable greater robustness and adaptability—into the design and control of robotic wings, engineers can begin narrowing the wide margin that currently exists between flying robots and vertebrates. In turn, these robotic wings can help biologists create experiments that would be impossible in vivo. PMID:28592663

The functional origin of dinosaur bipedalism: Cumulative evidence from bipedally inclined reptiles and disinclined mammals.

PubMed

Persons, W Scott; Currie, Philip J

2017-05-07

Bipedalism is a trait basal to, and widespread among, dinosaurs. It has been previously argued that bipedalism arose in the ancestors of dinosaurs for the function of freeing the forelimbs to serve as predatory weapons. However, this argument does not explain why bipedalism was retained among numerous herbivorous groups of dinosaurs. We argue that bipedalism arose in the dinosaur line for the purpose of enhanced cursoriality. Modern facultatively bipedal lizards offer an analog for the first stages in the evolution of dinosaurian bipedalism. Many extant lizards assume a bipedal stance while attempting to flee predators at maximum speed. Bipedalism, when combined with a caudofemoralis musculature, has cursorial advantages because the caudofemoralis provides a greater source of propulsion to the hindlimbs than is generally available to the forelimbs. That cursorial advantage explains the relative abundance of cursorial facultative bipeds and obligate bipeds among fossil diapsids and the relative scarcity of either among mammals. Having lost their caudofemoralis in the Permian, perhaps in the context of adapting to a fossorial lifestyle, the mammalian line has been disinclined towards bipedalism, but, having never lost the caudofemoralis of their ancestors, cursorial avemetatarsalians (bird-line archosaurs) were naturally inclined towards bipedalism. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs

PubMed Central

Pol, Diego; Rauhut, Oliver W. M.

2012-01-01

Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates. PMID:22628475

Ergonomic task reduction prevents bone osteopenia in a rat model of upper extremity overuse

PubMed Central

BARBE, Mary F.; JAIN, Nisha X.; MASSICOTTE, Vicky S.; POPOFF, Steven N.; BARR-GILLESPIE, Ann E.

2015-01-01

We evaluated the effectiveness of ergonomic workload reduction of switching rats from a high repetition high force (HRHF) lever pulling task to a reduced force and reach rate task for preventing task-induced osteopenic changes in distal forelimb bones. Distal radius and ulna trabecular structure was examined in young adult rats performing one of three handle-pulling tasks for 12 wk: 1) HRHF, 2) low repetition low force (LRLF); or 3) HRHF for 4 wk and than LRLF thereafter (HRHF-to-LRLF). Results were compared to age-matched controls rats. Distal forelimb bones of 12-wk HRHF rats showed increased trabecular resorption and decreased volume, as control rats. HRHF-to-LRLF rats had similar trabecular bone quality as control rats; and decreased bone resorption (decreased trabecular bone volume and serum CTX1), increased bone formation (increased mineral apposition, bone formation rate, and serum osteocalcin), and decreased osteoclasts and inflammatory cytokines, than HRHF rats. Thus, an ergonomic intervention of HRHF-to-LRLF prevented loss of trabecular bone volume occurring with prolonged performance of a repetitive upper extremity task. These findings support the idea of reduced workload as an effective approach to management of work-related musculoskeletal disorders, and begin to define reach rate and load level boundaries for such interventions. PMID:25739896

The role of the extrinsic thoracic limb muscles in equine locomotion

PubMed Central

Payne, RC; Veenman, P; Wilson, AM

2005-01-01

Muscles have two major roles in locomotion: to generate force and to absorb/generate power (do work). Economical force generation is achieved by short-fibred pennate muscle while the maximum power output of a muscle is architecture independent. In this study we tested the hypothesis that there is an anatomical and structural separation between the force-generating anti-gravity muscles and the propulsive (limb/trunk moving) muscles of the equine forelimb. Muscle mass and fascicle length measurements were made on the thoracic limb extrinsic muscles of six fresh horse cadavers. Physiological cross-sectional area and maximum isometric force were then estimated. Maximum power was estimated from muscle volume and published contraction velocity data. The majority of extrinsic forelimb muscles were large with long fascicles arranged in parallel to the long axis of the muscle. Muscles arranged in this way are optimised for doing work. The architecture of serratus ventralis thoracis (SVT) was unique. It had short (48 ± 17 mm) fascicles, arranged at about 45° to the long axis of the muscle, which would suggest a force-generating, anti-gravity role. The muscle belly of SVT was sandwiched between two broad, thick sheets of aponeurosis. Hence, SVT could make a significant contribution to the overall elastic properties of the thoracic limb. PMID:15730484

The role of the extrinsic thoracic limb muscles in equine locomotion

PubMed Central

Payne, R C; Veenman, P; Wilson, A M

2004-01-01

Muscles have two major roles in locomotion: to generate force and to absorb/generate power (do work). Economical force generation is achieved by short-fibred pennate muscle while the maximum power output of a muscle is architecture independent. In this study we tested the hypothesis that there is an anatomical and structural separation between the force-generating anti-gravity muscles and the propulsive (limb/trunk moving) muscles of the equine forelimb. Muscle mass and fascicle length measurements were made on the thoracic limb extrinsic muscles of six fresh horse cadavers. Physiological cross-sectional area and maximum isometric force were then estimated. Maximum power was estimated from muscle volume and published contraction velocity data. The majority of extrinsic forelimb muscles were large with long fascicles arranged in parallel to the long axis of the muscle. Muscles arranged in this way are optimised for doing work. The architecture of serratus ventralis thoracis (SVT) was unique. It had short (48 ± 17 mm) fascicles, arranged at about 45° to the long axis of the muscle, which would suggest a force-generating, anti-gravity role. The muscle belly of SVT was sandwiched between two broad, thick sheets of aponeurosis. Hence, SVT could make a significant contribution to the overall elastic properties of the thoracic limb. PMID:15610395

Isolated Avulsion of the Tendon of Insertion of the Infraspinatus and Supraspinatus Muscles in Five Juvenile Labrador Retrievers.

PubMed

Mikola, Karoliina; Piras, Alessandro; Hakala, Laura

2018-06-02

 Five juvenile Labrador Retrievers between the ages of 6 and 8 months were presented to our referral centres with a history of intermittent forelimb lameness.  The clinical examination revealed the presence of bilateral orthopaedic problems in four out of five cases.  Radiographic and computed tomography examinations showed the presence of a radiolucent defect corresponding to the area of insertion of the infraspinatus or supraspinatus tendons on the proximal humerus. Three dogs were concurrently affected by elbow disease on the contralateral forelimb and one dog with bilateral infraspinatus avulsion also had osteochondritis dissecans affecting both shoulder joints.  Avulsion of the insertion of the infraspinatus tendon in four dogs and of the supraspinatus tendon in one dog.  According to the current literature, the incidence of infraspinatus and supraspinatus tendinopathies in adult Labrador Retrievers is higher than in other breeds. In our five cases, the patients were juvenile and the nature of the injury was an avulsion of the tendinous insertion. Avulsion of the tendon of insertion of the infraspinatus or supraspinatus has been poorly described in the veterinary literature, and this would represent the first series of cases affecting juvenile Labrador Retrievers. Schattauer GmbH Stuttgart.